1 00:00:00,420 --> 00:00:17,390 I think it's sort of. The topic is machine perfusion, the new dawn or optimistic hyperbole? 2 00:00:17,390 --> 00:00:23,180 The idea of a fusing isolated organs is not new. 3 00:00:23,180 --> 00:00:29,270 There was lots of lots of interest in this long before the era of clinical transplantation. 4 00:00:29,270 --> 00:00:35,000 This This image on the left comes from the Journal of Experimental Medicine in 1935, 5 00:00:35,000 --> 00:00:41,450 describing a series of experiments carried out by Lindbergh and Carol, very famous in their own right. 6 00:00:41,450 --> 00:00:49,580 Both his aviator and and researcher found themselves on the front cover of Time magazine four years later, 7 00:00:49,580 --> 00:00:54,290 which doesn't happen to many surgeons or, for that matter, scientists. 8 00:00:54,290 --> 00:01:01,370 And in fact, it was not for another 30 years that another transplant surgeon found their face on the front cover of Time magazine. 9 00:01:01,370 --> 00:01:13,910 But what's this all about? Why are we replacing good old fashioned technology, i.e. an ice box with something which is so complicated, so expensive? 10 00:01:13,910 --> 00:01:21,020 What is it that these two young surgeons are staring at with such interest in this box? 11 00:01:21,020 --> 00:01:26,150 The answer is it's a liver which is functioning. It's fully fused. 12 00:01:26,150 --> 00:01:30,290 It's fully functioning. It's running at 37 degrees centigrade. It's having oxygen. 13 00:01:30,290 --> 00:01:37,010 Is having nutrition. It's been given all sorts of additives to make it function completely normally. 14 00:01:37,010 --> 00:01:42,830 The objective, of course, is to allow it to be preserved without injury and indeed to recover, 15 00:01:42,830 --> 00:01:49,670 to repair itself and potentially to be available for therapeutic interventions. 16 00:01:49,670 --> 00:01:53,900 Well, if we look at liver transplantation on the face of it, it is simply a success story. 17 00:01:53,900 --> 00:02:00,890 Look at what's happened in the UK over the last 10 years, the number of organ donors has increased, which is good. 18 00:02:00,890 --> 00:02:07,640 The number of transplants has increased. We topped over a thousand liver transplants last year on the waiting list has come down. 19 00:02:07,640 --> 00:02:16,580 It's 359 at the beginning of the financial year, but actually it's not as successful, not as straightforward as that. 20 00:02:16,580 --> 00:02:20,720 The demand is going up actually significantly faster than the supply, 21 00:02:20,720 --> 00:02:27,200 and that's because liver failure is increasing and cancer involving the liver is increasing. 22 00:02:27,200 --> 00:02:32,450 Meanwhile, the suitability of the organ donors, rather than the number is decreasing. 23 00:02:32,450 --> 00:02:39,800 Organ donors are on average now older and have more medical problems diabetes, cardiovascular disease, et cetera. 24 00:02:39,800 --> 00:02:44,840 There are more donors who are being declared dead by cardiovascular criteria, 25 00:02:44,840 --> 00:02:52,160 i.e. cardiac arrest rather than brain death, and that brings with it an inevitable injury, a hypoxic injury. 26 00:02:52,160 --> 00:02:57,710 And as a result, these organ donors are actually not as well used as well utilised as we would like. 27 00:02:57,710 --> 00:03:05,210 And in fact, in the UK, slightly less than two thirds of deceased organ donors result in a liver transplant. 28 00:03:05,210 --> 00:03:09,050 And this is associated with a substantial waiting list mortality. 29 00:03:09,050 --> 00:03:14,210 There are about 60 patients died on the transplant waiting list last year, 30 00:03:14,210 --> 00:03:21,500 and even and even then, we are very restrictive as to which patients get onto the waiting list. 31 00:03:21,500 --> 00:03:25,980 So last year, there were almost 6500 organ donors. 32 00:03:25,980 --> 00:03:32,660 Eleven hundred and forty nine livers retrieved. 85 percent of those were transplanted. 33 00:03:32,660 --> 00:03:38,930 And if we look at the split between the brain dead, that's what it called DVD and the circulatory arrest. 34 00:03:38,930 --> 00:03:47,150 That's the CD. That's where the figure of 62 percent comes from, and it's the high risk livers which are very, very poorly used. 35 00:03:47,150 --> 00:03:52,370 So that's really what we're going after. It's these poorly utilised donor organs. 36 00:03:52,370 --> 00:03:57,110 So what's that got to do with organ preservation? We're ready for things. 37 00:03:57,110 --> 00:04:00,770 The icebox has got problems insofar as, first of all, 38 00:04:00,770 --> 00:04:07,430 cooling down biological tissue is not very good for it, and the damage is not entirely reversible. 39 00:04:07,430 --> 00:04:13,940 The second, there is no oxygen delivery in the icebox, and we now know that even at ice temperature, 40 00:04:13,940 --> 00:04:21,590 delivering oxygen is important in terms of the the switch to aerobic metabolism. 41 00:04:21,590 --> 00:04:22,340 As a result, 42 00:04:22,340 --> 00:04:32,240 anaerobic metabolism leads to the accumulation of metabolites and these metabolites from the substrates for what we call ischaemia reperfusion. 43 00:04:32,240 --> 00:04:35,960 And finally, because the organ is not functioning normally in the icebox, 44 00:04:35,960 --> 00:04:40,370 we can't measure its function and work out whether it's a viable liver or not. 45 00:04:40,370 --> 00:04:44,300 That's absolutely fine if the liver is a perfect liver from an ideal donor, 46 00:04:44,300 --> 00:04:49,380 a 25 year old head injury, for example, it's not fine with a high risk donor organ. 47 00:04:49,380 --> 00:04:58,250 These limitations become more severe, so there's lots of interest in machine perfusion trying to do something better than the ice box. 48 00:04:58,250 --> 00:05:10,710 And these four devices shown here are all different devices designed and in clinical trials or on sale for the perfusion of human livers and. 49 00:05:10,710 --> 00:05:17,370 Really, three issues, one of which is whether fusion makes a difference, the second is whether it's important to deliver oxygen. 50 00:05:17,370 --> 00:05:25,500 And third is which temperature to do is that there has been quite good evidence for a long time now that cold fusion 51 00:05:25,500 --> 00:05:33,930 simply simply pumping a solution through through an organ during preservation is better than static cold storage. 52 00:05:33,930 --> 00:05:37,140 And this device shown here is a kidney fusion device. 53 00:05:37,140 --> 00:05:43,230 It's been around for quite a long time, and variants along these this line have been around for several decades, 54 00:05:43,230 --> 00:05:48,810 and there is evidence that it's beneficial in higher risk donor organs. 55 00:05:48,810 --> 00:05:53,760 But developing this in the context of the liver is a much more recent phenomenon. 56 00:05:53,760 --> 00:05:56,160 This was the first paper to describe just that, 57 00:05:56,160 --> 00:06:04,530 which is a very simple machine perfusion system of a human liver, and it was shown to be feasible and safe. 58 00:06:04,530 --> 00:06:12,930 And we are really awaiting more substantial evidence as to whether it adds value rather than just being possible. 59 00:06:12,930 --> 00:06:20,100 But we do know, and this is this is a much more recent phenomenon that delivering oxygen even when organs are in the refrigerator, 60 00:06:20,100 --> 00:06:27,420 even ice temperature is important. And it's all about mitochondrial metabolism. 61 00:06:27,420 --> 00:06:37,050 Accumulation of succinate in the mitochondria is a universal feature of ischaemia, and it accumulates and at the time of fusion. 62 00:06:37,050 --> 00:06:40,020 In other words, the time that oxygen is provided, 63 00:06:40,020 --> 00:06:49,680 there is a reversal of an enzyme at mitochondrial complex to which results in the generation of reactive oxygen species. 64 00:06:49,680 --> 00:06:54,270 A complex one and reactive oxygen species are the essence of what happens when 65 00:06:54,270 --> 00:06:59,490 organs are transplanted and experiences so-called ischaemia reperfusion. 66 00:06:59,490 --> 00:07:04,680 And the reason why the oxygen thing is important is that given giving oxygen 67 00:07:04,680 --> 00:07:09,570 prevents such an accumulation and that works independently of temperature. 68 00:07:09,570 --> 00:07:14,100 And that's the that's the recent finding, which probably matters a lot. 69 00:07:14,100 --> 00:07:22,590 And this concept has been translated into a hypothermic, oxygenated perfusion here in the context of the liver, 70 00:07:22,590 --> 00:07:27,720 whereby livers which have been retrieved with oxygen depletion so so circulatory death, 71 00:07:27,720 --> 00:07:35,280 livers stored on ice for a few hours and then given a brief period of machine perfusion with oxygen. 72 00:07:35,280 --> 00:07:43,590 And the preliminary results of these studies looked very encouraging randomised clinical trial to certain not yet available. 73 00:07:43,590 --> 00:07:49,800 But what we're discussing today is non-Islamic machine perfusion that's recreating the physiological 74 00:07:49,800 --> 00:07:57,510 environment that's pumping the organ with blood at 37 degrees centigrade with option with nutrients. 75 00:07:57,510 --> 00:08:02,910 And this allows normal metabolic activity. It allows prolonged preservation. 76 00:08:02,910 --> 00:08:09,210 It allows viability assessment as you can measure the function of the organ, and it should allow organ repair. 77 00:08:09,210 --> 00:08:12,420 So that's the hypothesis that we are discussing this morning. 78 00:08:12,420 --> 00:08:23,690 I'm not going to hand over to my colleague David Nasrullah, who spent three of the best years of his life working on this. 79 00:08:23,690 --> 00:08:26,990 They were three great years. Thank you very much, Prof. 80 00:08:26,990 --> 00:08:34,290 So as Professor Friend said, I'm going to talk about the clinical application to date of normal thermic liver perfusion. 81 00:08:34,290 --> 00:08:42,260 So the first clinical studies in man were done again here by our group in Oxford. 82 00:08:42,260 --> 00:08:46,130 They were published a couple of years ago in the American Journal of Transplantation, 83 00:08:46,130 --> 00:08:50,930 and their 20 human livers there were preserved using normal thermic liver perfusion 84 00:08:50,930 --> 00:08:54,470 were transplanted at King's College Hospital London and the Queen Elizabeth Hospital, 85 00:08:54,470 --> 00:09:01,040 Birmingham. And that study essentially showed that normal terminal liver perfusion was feasible and it was safe. 86 00:09:01,040 --> 00:09:07,430 And on the basis of those findings, we then moved on to perform a much larger, randomised controlled trial. 87 00:09:07,430 --> 00:09:11,750 So this was one of several clinical trials being run by the COPE consortium. 88 00:09:11,750 --> 00:09:18,140 So the Consortium for Organ Preservation in Europe, it was funded by the European Commission and sponsored by the University of Oxford. 89 00:09:18,140 --> 00:09:28,640 It took place in seven European liver transplant centres so far in England, one in Belgium, one in Germany and one in Barcelona, in Spain. 90 00:09:28,640 --> 00:09:33,620 And we needed to randomise 220 livers into the trial. 91 00:09:33,620 --> 00:09:41,990 And they were randomised in a one to one ratio to either conventional static cold storage or normal perfusion on the machine. 92 00:09:41,990 --> 00:09:47,480 Now, in an ideal world, the primary outcome for such a study would be one year graft survival. 93 00:09:47,480 --> 00:09:51,350 But the problem is graft survival in the UK is very high end. 94 00:09:51,350 --> 00:09:58,280 To power such a trial, you need very large numbers. So we chose a surrogate, and that surrogate we chose was the peak trans Amina's levels. 95 00:09:58,280 --> 00:10:02,450 And we know from a large number of studies that the peak trans manet's levels in the 96 00:10:02,450 --> 00:10:08,090 first week after transplantation correlate well with the likely the patient will die, 97 00:10:08,090 --> 00:10:15,380 the likelihood the graft will be lost, but the patient will survive, or the likelihood that the graft in the patient will survive. 98 00:10:15,380 --> 00:10:24,680 And so we this study had a 90 percent power to detect what we felt would be a clinically relevant 33 percent drop in the peak AST. 99 00:10:24,680 --> 00:10:28,640 We also looked at a large number of secondary outcomes, including organ utilisation, 100 00:10:28,640 --> 00:10:36,320 which is perhaps the most important question facing the transplant community due to the shortage of organs and also preservation time. 101 00:10:36,320 --> 00:10:42,650 The incidence of post reperfusion syndrome. So that's a measure of the degree of hemodynamic instability that a recipient suffers 102 00:10:42,650 --> 00:10:48,590 after the transplant and that limits the organs that many recipients can be eligible for. 103 00:10:48,590 --> 00:10:55,400 Early allograft dysfunction, which is another measure of early graft function that correlates with the later graft survival biliary injury, 104 00:10:55,400 --> 00:11:02,870 which in DCD organs is really what limits their usage because many of those organs suffer biliary injury and biliary strictures. 105 00:11:02,870 --> 00:11:06,500 And then the other aspects listed here, 106 00:11:06,500 --> 00:11:14,270 the way the trial worked was that once an eligible liver was matched to a recipient who was consented for the trial, then the liver was randomised. 107 00:11:14,270 --> 00:11:16,250 It was randomised to cold storage. 108 00:11:16,250 --> 00:11:22,010 Then the organ retrieval, preservation and transplant process all happened according to conventional standard practise. 109 00:11:22,010 --> 00:11:29,900 It was randomised to machine perfusion. Then, a researcher and the device travelled out to the donor hospital, and once the liver was out, 110 00:11:29,900 --> 00:11:39,410 it was placed on the machine where it remained until it was transplanted, and all of post-operative care was continued as per normal practise. 111 00:11:39,410 --> 00:11:45,440 So the the way normal stomach perfusion works, the mechanics of it are shown here. 112 00:11:45,440 --> 00:11:51,980 You, you have a liver in a bowl and that liver is calculated. So there's a cannula in the portal vein hepatic artery and vena cava. 113 00:11:51,980 --> 00:11:57,800 There's a blood based profuse eight which flows out of the vena cava to this pump, which pumps it up to a heat exchanger, 114 00:11:57,800 --> 00:12:02,420 an oxygen oxygenated, and this warms up a fuse eight to 37 degrees and oxygenates it. 115 00:12:02,420 --> 00:12:08,600 And then from there, it's either pumped directly into their Patek vein, and that's a high pressure, low flow system. 116 00:12:08,600 --> 00:12:15,050 So, yeah, high pressure, low flow, or it's pumped up to the reservoir from where it drains under gravity into the portal vein. 117 00:12:15,050 --> 00:12:21,220 And so that's a low pressure, high flow system sort of mimicking your normal physiology. 118 00:12:21,220 --> 00:12:26,720 But it's taken a few years to develop that circuit or to develop the final looking circuit. 119 00:12:26,720 --> 00:12:34,130 This was about 20 years ago, although it looks like it's from the 1920s. But but it's actually essentially the same circuit. 120 00:12:34,130 --> 00:12:38,690 We've got the liver in a bowl, you've got an oxygen tank and various other tubes and so on. 121 00:12:38,690 --> 00:12:45,110 And that appearance has been gradually refined, refined until we've ended up with the device we used in the trial. 122 00:12:45,110 --> 00:12:47,180 But it has exactly the same circuit I described. 123 00:12:47,180 --> 00:12:52,370 The perfused that comes out of the vena cava to this pump travels up to the heat exchanger, an oxygen heater, 124 00:12:52,370 --> 00:12:58,010 and then either goes straight into the hepatic artery or up to a reservoir from where it drains antigravity. 125 00:12:58,010 --> 00:13:03,470 We've got continuous infusions of heparin, insulin, foster cycling and bath salts. 126 00:13:03,470 --> 00:13:13,340 And this display gives continuous, real time information about the metabolic, synthetic and flow dynamic characteristics of the liver. 127 00:13:13,340 --> 00:13:19,470 Once we had travelled out to the donor hospital with the machine. And once the liver was out of the donor. 128 00:13:19,470 --> 00:13:22,470 And so once we got to the hospital, we had to set up the device that come. 129 00:13:22,470 --> 00:13:31,950 There's a naked chassis and a and a disposable set, which is then mounted on the chassis and find with blood to end up with this appearance. 130 00:13:31,950 --> 00:13:38,010 And then once the mother was out of the donor, we have to prepare it. So this is where there's a change in normal practise. 131 00:13:38,010 --> 00:13:43,040 So once the levers that we have our own kit we take with us, we first have to close off. 132 00:13:43,040 --> 00:13:46,110 This is the vena cava with the caudate lobe of the liver there. 133 00:13:46,110 --> 00:13:54,210 So we close off the top end of the vena cava with a stapler and then calculates the bottom and as shown here. 134 00:13:54,210 --> 00:14:09,430 We then calculates the portal vein, the hepatic artery, the bile duct and then transfer that liver into the bowl on the machine and connected up. 135 00:14:09,430 --> 00:14:19,510 And this shows that process, so in the poll here, we got a piece which we remove initially. 136 00:14:19,510 --> 00:14:24,310 And we've then got these and pieces onto which we can connect the countries that are already in the liver, 137 00:14:24,310 --> 00:14:33,370 so this yellow one connects to the portal vein red ones of the plastic artery blue and here will connect to the to the IVC. 138 00:14:33,370 --> 00:14:38,290 And we should have a liver that we prepared earlier coming into screen now. 139 00:14:38,290 --> 00:14:49,660 So this is a healthy looking liver rather than the some of the larger toxic ones we sometimes end up with. 140 00:14:49,660 --> 00:14:59,700 Again, here you can see behind my hand the vena cava travelling through the caudate lobe, which has been kind of lighted. 141 00:14:59,700 --> 00:15:08,390 And we first take some time to arrange the candidates and then get rid of any air that's left just at the end of the tubing. 142 00:15:08,390 --> 00:15:13,410 And connect those Kenya is up. 143 00:15:13,410 --> 00:15:20,490 With the portal vein, there have been cases where there's there have been twists in the portal vein that have been missed. 144 00:15:20,490 --> 00:15:39,870 So we take some time to make sure that is correctly positioned. 145 00:15:39,870 --> 00:15:50,490 And then finally, we connect the hepatic artery. So we're just twisting the port to win here. 146 00:15:50,490 --> 00:16:02,500 So finally, connecting up the hepatic artery and again, removing any gas that's left in the end of the tubing. 147 00:16:02,500 --> 00:16:24,450 And then once that's all done, we open these clamps. And that final tube were just manipulating, is the silicone tube sitting in the bile duct? 148 00:16:24,450 --> 00:16:26,520 And then once that's done, we start the perfusion. 149 00:16:26,520 --> 00:16:32,340 And the first thing you see is flow going into the affected artery and then coming out of the vena cava. 150 00:16:32,340 --> 00:16:35,520 And then finally going in through the portal vein. 151 00:16:35,520 --> 00:16:43,200 And if it's if it's a nice liver, it will profuse, fairly homogenous Lee and it will pink up relatively quickly, 152 00:16:43,200 --> 00:16:46,620 as this one is doing if it's not as nice a liver. 153 00:16:46,620 --> 00:16:52,680 It may be far more patchy the perfusion than it may take a good while for it to have a nice appearance. 154 00:16:52,680 --> 00:16:57,630 But the other good thing about this setup is if there is any, any vessels you've missed, such as here, 155 00:16:57,630 --> 00:17:05,250 there'll be some bleeding in a moment from an adrenal vein that's been missed that can then be addressed and and tied off. 156 00:17:05,250 --> 00:17:10,800 So this it's possible to do further backbench work and preparation of the liver during machine perfusion, 157 00:17:10,800 --> 00:17:17,610 as well as potentially do other therapeutic interventions. 158 00:17:17,610 --> 00:17:22,680 So the way in which the trial panned out in the end was we needed to randomise many more livers than expected, 159 00:17:22,680 --> 00:17:27,930 so we ended up randomising of over 300 livers, of which 62 were withdrawn. 160 00:17:27,930 --> 00:17:31,980 This was mainly because the deceased donors, those who die after circulatory death, 161 00:17:31,980 --> 00:17:36,030 they didn't actually die in the required time period, so couldn't be included. 162 00:17:36,030 --> 00:17:44,760 And that's not uncommon. So we ended up with 270 livers that were included in the trial, approximately 50 50 split between the two arms. 163 00:17:44,760 --> 00:17:51,930 But then there was a notable disparity between the number of organs that went on to be discarded after inclusion in the trial. 164 00:17:51,930 --> 00:17:58,860 So after they'd been retrieved, let's say 32 were discarded in the cold storage, 16 were discarded in the machine perfused arm. 165 00:17:58,860 --> 00:18:05,310 So we ended up with a difference in the number of livers that ultimately went on to be transplanted. 166 00:18:05,310 --> 00:18:13,020 In terms of the results, our donors and our recipients were well matched in all characteristics. 167 00:18:13,020 --> 00:18:16,360 The primary outcome from the trial, as I said, was the peak transfer mannies levels. 168 00:18:16,360 --> 00:18:21,210 So this was sort of the headline outcome, and we powered the trial for a 33 per cent reduction. 169 00:18:21,210 --> 00:18:27,960 And in the end, we saw more than 50 percent reduction in the peak transfer monies, and that was statistically significant. 170 00:18:27,960 --> 00:18:31,440 When this was broken down by donor type thought for brain dead donors. 171 00:18:31,440 --> 00:18:34,410 So they said better quality organs. 172 00:18:34,410 --> 00:18:44,550 The the reduction in PTSD was about 40 percent for DCD organs, which by their nature, are extended criteria or much more marginal types of livers. 173 00:18:44,550 --> 00:18:53,910 That reduction was was over 70 percent, so we saw a much greater improvement in that in that group of donor organs. 174 00:18:53,910 --> 00:19:00,030 Moving on to organ utilisations, and this was the number of livers that were retrieved that ultimately went on to be transplanted, as I said, 175 00:19:00,030 --> 00:19:04,530 there was a notable difference in the number of livers that were discarded in both arms, 176 00:19:04,530 --> 00:19:10,140 with 24 percent discarded and cold and 11 percent in the in the normal thermic arms. 177 00:19:10,140 --> 00:19:14,400 There was better organ utilisation in the normal thermic group. 178 00:19:14,400 --> 00:19:19,590 And this was probably a reflection of the number of toxic livers that were utilised in each group. 179 00:19:19,590 --> 00:19:27,330 So fatty livers have a much higher rate of of non-functional after transplantation, so surgeons tend to be much more hesitant to use them. 180 00:19:27,330 --> 00:19:34,500 But we noticed that in the normal thing, they come, about a quarter of the livers that went on to be transplanted were moderately or severely toxic, 181 00:19:34,500 --> 00:19:40,020 compared to just over 10 percent in the coastal group. And when you look at the characteristics of the discarded livers, 182 00:19:40,020 --> 00:19:47,530 it was notable that many more of those that were discarded in the cold were still toxic. 183 00:19:47,530 --> 00:19:55,120 One of the other problems in transplantation is that the longer an organ is preserved for the poor, the outcomes after transplantation. 184 00:19:55,120 --> 00:20:00,040 So here and here, we've got all the livers in the trial ranked according to their preservation time. 185 00:20:00,040 --> 00:20:02,290 Every red bar represents enormous liver. 186 00:20:02,290 --> 00:20:07,090 Every blue blue bar represents a coastal liver, and they're ranked according to their duration of preservation. 187 00:20:07,090 --> 00:20:11,650 And you can see that in the normal swimming group, the duration of preservation was much longer, 188 00:20:11,650 --> 00:20:15,040 and that was shown in the in the findings from the trial. 189 00:20:15,040 --> 00:20:20,140 And we know that many centres started to organise their theatre logistics, according to whether the liver was on the machine. 190 00:20:20,140 --> 00:20:23,230 So even if we had two livers arriving at the same time, 191 00:20:23,230 --> 00:20:29,800 they simply cued them up rather than trying to open additional theatres and sort of in other cases. 192 00:20:29,800 --> 00:20:34,150 Some of the centres also rescheduled transplants, so rather than doing them in the middle of the night, 193 00:20:34,150 --> 00:20:43,890 they moved the operating time to daylight hours, which again, we know has logistical benefits for the way the theatre departments are run. 194 00:20:43,890 --> 00:20:51,510 As you may remember, temporary perfusion syndrome measured the degree of hemodynamic instability in recipients after their transplantation. 195 00:20:51,510 --> 00:20:57,690 And again, here we saw a 33 percent rate in the coastal group, compared to 12 percent in the normal thermic group. 196 00:20:57,690 --> 00:21:03,930 So there was a measurable improvement in the hemodynamic characteristics of recipients after transplantation, 197 00:21:03,930 --> 00:21:15,000 which correlates with graft injury and also is likely to increase the number of organs that can be considered for some of the sickest recipients. 198 00:21:15,000 --> 00:21:21,720 Another measure of early graft function is early allograft dysfunction, which correlates with later survival. 199 00:21:21,720 --> 00:21:31,950 Here we saw rates of 30 percent in the coastal group, which is similar to those quoted elsewhere with much lower rates than our normal thermic livers. 200 00:21:31,950 --> 00:21:36,120 In D.C. organs, as I mentioned, the big factor that is limited, 201 00:21:36,120 --> 00:21:46,620 more widespread utilisation of such organs is the risk of bile duct complications with as many as one in three patients getting biliary strictures. 202 00:21:46,620 --> 00:21:53,490 As part of this study, all patients underwent an MRI scan at six months after transplantation, regardless of whether they had symptoms. 203 00:21:53,490 --> 00:21:57,270 And this is actually something that had never been done before in any previous study. 204 00:21:57,270 --> 00:22:05,460 So the radiological rate of Billy restrictions in otherwise asymptomatic individuals has not previously been described. 205 00:22:05,460 --> 00:22:11,910 And what we found was that in about 10 percent of the normal thermic DCD livers, 206 00:22:11,910 --> 00:22:17,010 there was evidence of biliary structuring, compared to about 26 percent in the coastal group. 207 00:22:17,010 --> 00:22:24,480 However, this did not translate into any into clinical findings with with only one patient in each arm of the 208 00:22:24,480 --> 00:22:29,760 trial actually suffering significant clinical consequences as a result of these biliary strictures. 209 00:22:29,760 --> 00:22:36,930 So actually, the clinical relevance of these MCP findings is not clear. 210 00:22:36,930 --> 00:22:42,210 And then finally, graft and patient survival we've gone out to two years now. 211 00:22:42,210 --> 00:22:49,010 There's there's no measurable difference in graft survival at two years. 212 00:22:49,010 --> 00:22:57,050 Perhaps the greatest benefit from machine perfusion will be the ability to assess organ viability and to help guide organ utilisation. 213 00:22:57,050 --> 00:23:09,590 And as I said, during machine perfusion, you can measure metabolic, synthetic or hepatocellular characteristics, as well as perfusion flow dynamics. 214 00:23:09,590 --> 00:23:16,040 With regards to restructuring, there's many groups that have tried to look into this during machine perfusion to determine if there's anything 215 00:23:16,040 --> 00:23:20,510 that can be measured while the liver is on the machine that may predict the likelihood of strictures. 216 00:23:20,510 --> 00:23:24,080 It doesn't look like bile production shows any relationship, 217 00:23:24,080 --> 00:23:32,030 but the group from Cambridge have shown that bile P.H. does appear to potentially predict the likelihood of developing 218 00:23:32,030 --> 00:23:42,910 later strictures with patients that had more acid acidic bile later going on to develop ischaemic angioplasty. 219 00:23:42,910 --> 00:23:46,600 Other groups fear that lactate clearance may be a better marker of viability. 220 00:23:46,600 --> 00:23:50,440 We saw that in pretty much all the livers that went on to be successfully transplanted. 221 00:23:50,440 --> 00:23:58,930 Lactate was cleared very quickly from the circuit, although again the group in Cambridge feel that it may not be as good a predictor with some, 222 00:23:58,930 --> 00:24:04,100 but they've had one liver that didn't function after transplantation that did manage to clear lactate. 223 00:24:04,100 --> 00:24:09,010 But I'm going to give a few exact case examples now that will show how the assessment 224 00:24:09,010 --> 00:24:15,040 of organ viability has been used to guide organ utilisation in real clinical practise. 225 00:24:15,040 --> 00:24:24,580 So here we had a severely fatty liver from a 72 year old DCD donor, so poor quality donor, which at the time of the retrieval, 226 00:24:24,580 --> 00:24:29,920 the retrieval surgeon said this liver is awful as perfused, very poorly in situ is not usable. 227 00:24:29,920 --> 00:24:33,340 He phoned the transplant surgeon, who said, I don't want it, 228 00:24:33,340 --> 00:24:37,930 but we were there at the donor hospital already with the machine set up and so on the phone, 229 00:24:37,930 --> 00:24:40,600 we just said, why don't we put it on the machine and see what happens? 230 00:24:40,600 --> 00:24:45,010 And he said, OK, so we put it on the machine, and to our surprise, it started functioning. 231 00:24:45,010 --> 00:24:48,580 So we phoned the transplant surgeon and said the liver is functioning well. 232 00:24:48,580 --> 00:24:52,570 And he said, OK, we'll come to the Royal Free Hospital and we'll see what happens when we arrive there. 233 00:24:52,570 --> 00:24:56,560 About 2:00 a.m. And the surgeon was in his suit and he said, Look, I'm going home now. 234 00:24:56,560 --> 00:24:57,700 You can do what you want. 235 00:24:57,700 --> 00:25:03,400 But if if when I come back in eight o'clock in the morning, you've still got a functioning liver, then come back and talk to me. 236 00:25:03,400 --> 00:25:08,500 So then at 8:00. But he didn't quite say like that, but it's 8:00. 237 00:25:08,500 --> 00:25:12,280 When he came back, the liver being on the machine for 11 hours and 10 minutes, 238 00:25:12,280 --> 00:25:20,110 it had 500 miles a minute going through the artery, a little a minute going through the portal vein that was normal for a liver. 239 00:25:20,110 --> 00:25:27,940 It was making bile at 10 miles an hour. It was using glucose nicely and it appeared healthier than we'd expected. 240 00:25:27,940 --> 00:25:34,120 And the surgeon was surprised, but he said, OK, let's give it a shot. 241 00:25:34,120 --> 00:25:38,860 So we had a patient who was consented for the trial, had a discussion with him. 242 00:25:38,860 --> 00:25:42,520 He was happy to proceed. So we performed the transplant. 243 00:25:42,520 --> 00:25:47,350 When the liver came off the machine, it looked awful again and I got shouted out to bits. 244 00:25:47,350 --> 00:25:51,790 And then once he got transplanted, it also didn't look very pretty inside you, 245 00:25:51,790 --> 00:25:58,390 but it functioned perfectly from as soon as it was Ripa fused and that recipient who went on to make a good recovery. 246 00:25:58,390 --> 00:26:01,030 With that liver still functioning two years later, 247 00:26:01,030 --> 00:26:07,000 that was maybe the clearest example of a liver that would not have been used that went on to be used, 248 00:26:07,000 --> 00:26:14,410 who had other cases, such as a 55 year old's brain dead donor who was quite overweight, who again had quite a fatty liver. 249 00:26:14,410 --> 00:26:18,430 But in this case, what happened was at the time of retrieval, it wasn't noted that if you look over here, 250 00:26:18,430 --> 00:26:26,410 you can see a little vessel that's a left hepatic artery that had been inadvertently divided, not noticed at the time of retrieval. 251 00:26:26,410 --> 00:26:29,830 And the significance of that artery is often unknown. Sometimes these can be tied off. 252 00:26:29,830 --> 00:26:33,550 Sometimes they are important for perfusion of the left side of the liver. 253 00:26:33,550 --> 00:26:35,920 So this liver on the machine? 254 00:26:35,920 --> 00:26:42,580 And it was notable quite early on that the left lobe was very patchy in the way it perfused, although the liver appeared to be functioning nicely. 255 00:26:42,580 --> 00:26:45,580 But we got to the transplanting centre in Addenbrooke's, 256 00:26:45,580 --> 00:26:51,820 and the surgeons there looked at the liver and decided to try and reconstruct that artery during machine perfusion. 257 00:26:51,820 --> 00:26:58,840 So they used the donor only Akashi, which you can see here, the external and internal to reconstruct it. 258 00:26:58,840 --> 00:27:01,840 You can't really see it well, but onto the left hepatic artery. 259 00:27:01,840 --> 00:27:07,780 And and as the perfusion continued, after that reconstruction had been performed, actually, 260 00:27:07,780 --> 00:27:12,730 the liver went from functioning well to functioning very well, with the flows improving further, 261 00:27:12,730 --> 00:27:18,580 the lactate dropped further and that liver again ultimately went on to be transplanted and and 262 00:27:18,580 --> 00:27:26,470 functioned well without any problems that could have been related to impaired perfusion of one lobe. 263 00:27:26,470 --> 00:27:32,710 And then the final case I'm going to present this was a 51 year old. This was a liver from a 51 year old DCD donor, 264 00:27:32,710 --> 00:27:41,620 so poor quality donor who had a very large fatty liver that had been declined for transplant by all centres in the UK. 265 00:27:41,620 --> 00:27:44,230 So this was then offered up nationally for research, 266 00:27:44,230 --> 00:27:50,440 and the group in Birmingham had a research study going on where they could put these livers on the on the machine. 267 00:27:50,440 --> 00:27:53,470 So we travelled up there with the machine and put this liver on, 268 00:27:53,470 --> 00:27:58,570 and this was a fatty liver that had been on ice for eight hours by the time we got to it. 269 00:27:58,570 --> 00:28:04,630 And this is why we went on the machine and it perfused, nice and homogeneously after one minute. 270 00:28:04,630 --> 00:28:11,350 As you'd expect, it was very acidic, with only 200 meals a minute through the through the artery. 271 00:28:11,350 --> 00:28:19,570 And, you know, looked not very good. By one hour, the arterial flows had improved a bit. 272 00:28:19,570 --> 00:28:26,980 That should come come up of its own accord, but it still wasn't a great liver by two hours. 273 00:28:26,980 --> 00:28:36,070 The flows were still a right that was improving further. The liver had started to produce bile at six miles an hour and was starting to look better. 274 00:28:36,070 --> 00:28:41,490 And then by four and a half hours, the flows were better still. That was better still bile. 275 00:28:41,490 --> 00:28:49,770 And. Should it continue to improve and it was now using glucose, so the glucose a drop from 20 to 11 MetaMaus. 276 00:28:49,770 --> 00:28:53,160 So the team went on to transplant that liver and again, 277 00:28:53,160 --> 00:29:00,420 that liver function well after after transplantation and is still functioning well two years later. 278 00:29:00,420 --> 00:29:02,520 So in summary, from the clinical studies we've done, 279 00:29:02,520 --> 00:29:10,020 we've shown that normal perfusion is associated with less early graft injury after transplantation, 280 00:29:10,020 --> 00:29:18,660 and this is despite higher organ utilisation in the normal thermic groups and substantially longer preservation times. 281 00:29:18,660 --> 00:29:27,540 And we've also shown that it appears to be the case that we can use normal perfusion to assess organ quality to help guide clinical decision making. 282 00:29:27,540 --> 00:29:32,730 And these findings have gone on to be published recently in Nature. 283 00:29:32,730 --> 00:29:39,780 I'm now going to hand over to my colleague Colin. Thank you very much, David. 284 00:29:39,780 --> 00:29:46,280 And so, as you've already heard, machine provisions been implemented successfully in the clinical context. 285 00:29:46,280 --> 00:29:50,750 But one key thing that I was looking to investigate was whether you could recondition 286 00:29:50,750 --> 00:29:54,830 organs and improve organs or organs that may be and weren't functioning. 287 00:29:54,830 --> 00:30:00,740 Could you actually further enhance them? And fatty livers, as we've heard, do particularly poorly when transplanted. 288 00:30:00,740 --> 00:30:06,530 These are a very good type of organ to try and reconditioned and enhance. 289 00:30:06,530 --> 00:30:12,140 So why did fatty livers do so badly and fatty liver basically when it was transplanted? 290 00:30:12,140 --> 00:30:16,340 And if there's more than 30 percent of large fat droplets, as you can see, 291 00:30:16,340 --> 00:30:22,610 the white circles here within the liver that's been shown to decrease post-transplant survival by up to 70 percent. 292 00:30:22,610 --> 00:30:25,880 And this is largely attributable to ischaemia reperfusion injury. 293 00:30:25,880 --> 00:30:31,820 So these livers have a much more exuberant inflammatory response increased neutrophil infiltration, 294 00:30:31,820 --> 00:30:38,690 reduced ATP production, mitochondrial dysfunction and impaired blood blood flow, which lead to these poor outcomes. 295 00:30:38,690 --> 00:30:44,810 And as a result, a large number of these livers are discarded and a thousand fatty liver is in the states are discarded each year. 296 00:30:44,810 --> 00:30:48,410 That's in the context of 6000 transplants a year in the UK. 297 00:30:48,410 --> 00:30:53,060 Half of all discarded livers are due to stay at horses. So it's a big problem. 298 00:30:53,060 --> 00:30:56,690 The problems made worse by fat donors, which are increasing. 299 00:30:56,690 --> 00:31:03,350 So obesity is a risk factor for fatty liver disease, and no quarter of donors in the UK are clinically obese. 300 00:31:03,350 --> 00:31:13,520 So in the context of not enough organs available for transplantation, we try and optimise the ones that are available to us. 301 00:31:13,520 --> 00:31:18,050 So as David's already presented us and the clinical trial, 302 00:31:18,050 --> 00:31:26,180 we looked at a subset subset of fatty livers that were transplanted and matched them to lean livers that were all normal, famiglie, perfused. 303 00:31:26,180 --> 00:31:29,180 And what you can see here is fatty livers, unsurprisingly, 304 00:31:29,180 --> 00:31:38,570 mobilise more fat into the circuit during preservation and also have more fatty acid oxidation and as measured by three hydroxybutyrate. 305 00:31:38,570 --> 00:31:45,350 But if we looked at the degree of state forces over the preservation, unlike what had been shown in animal models, 306 00:31:45,350 --> 00:31:53,840 actually the total amount of fat before preservation, after preservation and after reperfusion remained largely unchanged. 307 00:31:53,840 --> 00:31:59,360 But if you compare the post-transplant outcomes in these livers from a state Typekit compared to lean liver, 308 00:31:59,360 --> 00:32:07,340 actually the still toxic liver has had more preservation injury in terms of Peaks University than their lean counterparts. 309 00:32:07,340 --> 00:32:15,830 So the question is, can we get these livers to perform as well as these livers by enhancing them during preservation in order to do this, 310 00:32:15,830 --> 00:32:21,160 a brief understanding of liver fat metabolism and was important for me anyway. 311 00:32:21,160 --> 00:32:31,430 And so the liver gets fat from various sources, from diet, from a mobilisation of subcutaneous fat or visceral fat, as known as terrified fatty acids. 312 00:32:31,430 --> 00:32:37,430 And these all contribute to the fatty acid pool within the liver, as well as de novo life of genesis within the liver. 313 00:32:37,430 --> 00:32:41,690 They can either be stored or follow two pathways either oxidation. 314 00:32:41,690 --> 00:32:43,850 So that's via beta and beta. 315 00:32:43,850 --> 00:32:52,910 Tradition into mitochondria are very low density lipoprotein and secretion is a certification which then gets restored again peripherally. 316 00:32:52,910 --> 00:32:59,120 But actually in the ex H2 circuit, there's no diet, there's no subcutaneous fat and there's no visceral fat. 317 00:32:59,120 --> 00:33:03,590 So the only source of fat within the liver is the normal life biogenesis pathway. 318 00:33:03,590 --> 00:33:11,180 So this is where the liver makes fat from non-living precursors, mostly glucose and the end product as palmitic acid or palmitate. 319 00:33:11,180 --> 00:33:18,770 And this process is stimulated by insulin. So basically, I took all livers that were discarded because of steatosis. 320 00:33:18,770 --> 00:33:23,300 All seven UK transplant centre said, No, it's too fatty. We don't want to transplant it. 321 00:33:23,300 --> 00:33:27,350 They came to Oxford, recalculated and perfused on the circuit. 322 00:33:27,350 --> 00:33:33,690 Labelled water was added, and this allows us to quantify newly synthesised fatty acids via gas chromatography. 323 00:33:33,690 --> 00:33:44,660 Mass spectroscopy and livers were perfused for 48 hours, with frequent gas sampling, perfusion analysis and 12 hour leak or biopsies. 324 00:33:44,660 --> 00:33:51,920 So a total of 21 livers were taken during this period. Three were excluded as they didn't demonstrate any any evidence of function. 325 00:33:51,920 --> 00:33:54,500 So this allowed 18 40 hour perfusion. 326 00:33:54,500 --> 00:34:03,020 Six livers were perfused on the machine by itself, six levels with an perfused on the machine with the addition of this LDL apheresis filter. 327 00:34:03,020 --> 00:34:07,910 So these are filters are used in patients with very high cholesterol that's refractory to medical 328 00:34:07,910 --> 00:34:14,420 treatment and essentially mechanically filters out lipoproteins in the final group as well as a filter. 329 00:34:14,420 --> 00:34:16,130 We added some drugs. 330 00:34:16,130 --> 00:34:25,700 So for school and increases, it's tariffication and v LDL secretion L-carnitine and shifts to fatty acids to the mitochondria for beta oxidation. 331 00:34:25,700 --> 00:34:33,050 And then we tried to reduce the normal life of Genesis by reducing the amount of insulin and glucose that were delivered to the liver. 332 00:34:33,050 --> 00:34:37,790 This is my wife and her. I think I was able to confirm. 333 00:34:37,790 --> 00:34:46,790 Her coming in at 3:00 a.m. Saturday morning to the spending quality time together, and it paid just about to save the relationship. 334 00:34:46,790 --> 00:34:52,530 So if you look at the demographics of the lovers, there were six in each group and actually they were quite similar. 335 00:34:52,530 --> 00:34:59,270 And there were four DVDs and two decades within each group. And and yeah, they were otherwise well matched. 336 00:34:59,270 --> 00:35:06,750 The cold ischaemia times were up in the region of around 12 hours of news lovers of a UK tour before they finally made it to Oxford. 337 00:35:06,750 --> 00:35:12,530 And so that that you actually had quite a lot of injury already sustained before they arrived. 338 00:35:12,530 --> 00:35:21,230 If we look at the basic function in terms of page normalisation, lactate clearance and glucose metabolism, the liver performed in a similar way. 339 00:35:21,230 --> 00:35:27,350 And this is important in the context of comparing metabolic function that their baseline function was quite similar. 340 00:35:27,350 --> 00:35:33,710 Unsurprisingly, the glucose of the third intervention group was lower, which is what we targeted. 341 00:35:33,710 --> 00:35:41,990 Looking at, the elite transmitted and the perfused itself actually all increases, but only increased significantly significantly. 342 00:35:41,990 --> 00:35:44,360 In Group one, there are new interventions. 343 00:35:44,360 --> 00:35:51,680 The baseline A.L.S. level is a reflection on the amount of energy it is already being sustained in the liver at any ongoing enzyme releases, 344 00:35:51,680 --> 00:36:00,140 probably reflective of ongoing injury. So that seems to have been attenuated in the second two groups compared to the first 345 00:36:00,140 --> 00:36:04,700 hepatic arterial flow was also significantly higher in our intervention groups, 346 00:36:04,700 --> 00:36:12,330 potentially here. Reversing the impaired sinusoidal blood flow that is no one's occurrence did talk to Glovers and an end and PLO, 347 00:36:12,330 --> 00:36:21,840 and indeed there was a reduction in arterial flow during preservation. Porterville remained unchanged in the groups by adding this filter. 348 00:36:21,840 --> 00:36:25,550 We were successful in mechanically removing triglyceride from the circuit, 349 00:36:25,550 --> 00:36:31,430 and this in theory could reduce the amount of Lypertek scarcity, which has also been shown to impair liver function. 350 00:36:31,430 --> 00:36:38,300 The same was true for cholesterol, and we also show a shift in fatty acid partitioning when L-carnitine was added towards 351 00:36:38,300 --> 00:36:44,600 the oxidation pathway to those fatty acids rather than being stored or being oxidised. 352 00:36:44,600 --> 00:36:48,500 So how does this actually result in the amount of fat within the liver? 353 00:36:48,500 --> 00:36:50,600 And by measuring the biochemically, 354 00:36:50,600 --> 00:36:59,060 then by homogenising the liver tissue and measuring the triglyceride was a slight increase in the livers and employment group, 355 00:36:59,060 --> 00:37:02,570 actually a 45 percent reduction in our treatment group. 356 00:37:02,570 --> 00:37:07,850 And I suppose the change was significant compared to the slight increase. Here you can see, I'm not sure if you can see it very well, 357 00:37:07,850 --> 00:37:17,380 but lots of large lipid droplets at time zero and have more or less either become very, very small or disappeared by 48 hours. 358 00:37:17,380 --> 00:37:25,660 And this was actually associated with a significant reduction 48 hours and the amount of daily fatty acids, namely palmitate. 359 00:37:25,660 --> 00:37:30,010 So this is by reducing glucose and insulin, we actually reduced to normal for Genesis, 360 00:37:30,010 --> 00:37:35,320 and that probably accounts for the reduction of fat within the liver. 361 00:37:35,320 --> 00:37:41,470 So to conclude, there's demonstrate that we can successfully manipulate hepatic metabolism and excite you. 362 00:37:41,470 --> 00:37:47,770 Setting the addition of the Selter improves function of the liver, but don't change them at a site within the liver. 363 00:37:47,770 --> 00:37:52,330 However, by adding L-carnitine, altering insulin and glucose and function, 364 00:37:52,330 --> 00:38:01,000 improved fatty acid oxidation increased and there was a reduction in de novo Lt. Gen. Terrestres actually moving on from using the device. 365 00:38:01,000 --> 00:38:08,860 As it is, there's potential to exploit things even further to try and transplant even more livers with with good outcomes. 366 00:38:08,860 --> 00:38:15,080 I know that Prof. Who's going to wrap this up? Thank you very much. 367 00:38:15,080 --> 00:38:15,440 So really, 368 00:38:15,440 --> 00:38:26,530 just just to finish on this theme of using normal thermic perfusion as a platform to treat a liver rather than simply a means of preserve the liver. 369 00:38:26,530 --> 00:38:33,400 This is clearly an opportunity, and it's an opportunity which has been more or less not exploited so far. 370 00:38:33,400 --> 00:38:43,570 It's very exciting. We could give drugs. We just heard Carlos excellent work looking at approaches to reduce the fat content of livers. 371 00:38:43,570 --> 00:38:51,390 There are other drugs which we can use, which will mitigate the effects of the inflammatory effects of ischaemia reperfusion. 372 00:38:51,390 --> 00:38:59,080 There's some very nice work just beginning to emerge using nanoparticle technology to deliver drugs to endothelium. 373 00:38:59,080 --> 00:39:04,210 There was a lot of interest in the use of cell therapy imaging kind of stem cells, 374 00:39:04,210 --> 00:39:13,600 which have natural and anti-inflammatory properties, regulatory T cells, which which reduce the immediate necessity of an organ. 375 00:39:13,600 --> 00:39:24,430 And gene therapy there is there is evidence experimentally of giving, for example, IL 10 as a gene therapy to reduce the inflammation in a graft. 376 00:39:24,430 --> 00:39:33,760 This experience of giving CTLA four IgG, which is one of the immunomodulators to make the organ less likely to reject these, are just some examples. 377 00:39:33,760 --> 00:39:38,470 Many of these have been done in clinical practise. Yet these are all experimental studies. 378 00:39:38,470 --> 00:39:45,040 They're all waiting to be done, and there are many, many more. That's just a few as it were picked out of the literature. 379 00:39:45,040 --> 00:39:52,810 This is this is this is an illustration of why normal seeming perfusion might enable this. 380 00:39:52,810 --> 00:39:55,480 It doesn't matter which gene was being used as it happens, 381 00:39:55,480 --> 00:40:04,150 it was an oligonucleotide caught in reverse and which is a strategy which might prevent hepatitis C re-infection of livers. 382 00:40:04,150 --> 00:40:12,460 That doesn't matter. What's important is in the graph, which shows just how much more effectively the gene is delivers enormous, 383 00:40:12,460 --> 00:40:17,140 I think, a warm fusion environment compared to cold storage. 384 00:40:17,140 --> 00:40:22,770 So is this going to change the future? Is it going to change how we look at organ preservation? 385 00:40:22,770 --> 00:40:28,360 Is organ preservation going to become a much more active process than it currently is? 386 00:40:28,360 --> 00:40:33,610 One might envisage a time in the future where organ donation of course still happens, 387 00:40:33,610 --> 00:40:37,240 where it happens in hospitals, all over the country, all over the world. 388 00:40:37,240 --> 00:40:43,390 And if the organs are completely straightforward, there's no reason perhaps why they shouldn't be simply transferred to transplant. 389 00:40:43,390 --> 00:40:46,810 Hospitals in transplant is pretty much as they are now. 390 00:40:46,810 --> 00:40:55,580 But what about delivering the high risk organs to specialist reconditioning centres where the organs are placed on perfusion devices? 391 00:40:55,580 --> 00:41:04,450 They're assessed, and depending on that assessment, they may be treated with interventions as yet unspecified and then tested again. 392 00:41:04,450 --> 00:41:09,040 If they pass the criteria, they then get transferred for transplantation. 393 00:41:09,040 --> 00:41:13,720 And if they don't, they're discarded or more likely used for research. 394 00:41:13,720 --> 00:41:17,650 Well, that all sounds like quite an exciting possibility for the future. 395 00:41:17,650 --> 00:41:21,400 Of course, the future is often a lot closer than we think. 396 00:41:21,400 --> 00:41:27,880 This is a small organisation as a small company called Lung Bioengineering, based in Maryland in Silver Spring, 397 00:41:27,880 --> 00:41:36,280 Maryland, this building has been built with the express and sole purpose of reconditioning lungs for transplantation. 398 00:41:36,280 --> 00:41:43,750 So lungs which fail to meet the criteria for lung transplantation are flown into this institution 399 00:41:43,750 --> 00:41:49,270 that put on a machine that treated if they if the gas exchange and other parameters improve, 400 00:41:49,270 --> 00:41:53,710 they're taken off the machine and sent out somewhere to be transplanted. 401 00:41:53,710 --> 00:41:57,970 So this is perhaps the vision of the future. And is this perhaps a new science? 402 00:41:57,970 --> 00:42:06,380 Is this a new and new set? Of course, this is going to evolve in perhaps the same way that tissue typing did in the 1960s and 1970s. 403 00:42:06,380 --> 00:42:11,380 It remains to be seen, but it would seem to me a very likely possibility. 404 00:42:11,380 --> 00:42:15,990 And remember, what we're dealing with at the moment is essentially first generation to. 405 00:42:15,990 --> 00:42:22,050 Mythology, we all know what happens to technology. Thank you very much indeed for your attention. 406 00:42:22,050 --> 00:42:31,292 Very happy to take any questions, as are the others.