Low-level BK polyomavirus (BKPyV) shedding is seen in at least 10% of seropositive immunocompetent adults. Moreover, BKPyV infection is highly prevalent amongst immunocompromised populations, yet little is known on its relationship with malignancy. We studied a female patient with BKPyV-associated and donor-derived de novo high-grade sarcomatoid urothelial carcinoma developed 8 years after kidney transplantation from a male donor. Through whole-genome sequencing, we discovered integration of genotype IV BKPyV genome into the non-coding RNA (ncRNA) intronic region of human chromosome 18. The two breakpoints in the virus genome were located at the non-coding control region (NCCR) and large T antigen (TAg) coding region, respectively. Nevertheless, the TAg was overexpressed. We, therefore, inferred that the BKPyV was clonally integrated into the human genome in the form of concatemers, facilitating the expression of the TAg. The patient presented with multiorgan metastases, which were reduced in size and number throughout the body after removal of the graft and cessation of immunosuppressants. The few remaining lesions located in the liver were identified, through biopsy to be necrotic tumor tissue with TAg detected; additionally, genomic sequencing of the liver mass found Y chromosome. In conclusion, we propose that integration of the BKPyV genome is closely related to oncogenesis in this patient; while oncogenesis occurred when host immunity was impaired, recovery of the patient’s native immunity effectively curbed viral replication and eliminated the metastatic lesions.

The present study aimed to: (i) identify the exogenous factors that allow in vitro differentiation of mouse spermatogonial stem cells (SSCs) from embryonic stem cells (ESCs); (ii) evaluate the effects of Sertoli cells in SSC enrichment; and (iii) assess the success of transplantation using in vitro differentiated SSCs in a mouse busulfan-treated azoospermia model. A 1-day-old embryoid body (EB) received 5 ng/ml of bone morphogenetic protein 4 (BMP4) for 4 days, 3 µM retinoic acid (RA) in a SIM mouse embryo-derived thioguanine and ouabain resistant (STO) co-culture system for 7 days, and was subsequently co-cultured for 2 days with Sertoli cells in the presence or absence of a leukaemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF) and RA composition, and in the presence of these factors in simple culture medium. Higher viability, proliferation and germ cell gene expression were seen in the presence of the LIF, bFGF and RA composition, on top of Sertoli cells. Immunocytochemistry results showed higher CDH1 expression in this group. Sertoli co-culture had no effects on SSC proliferation. Eight weeks after transplantation, injected cells were observed at the base of the seminiferous tubules and in the recipient testes. The number of spermatogonia and the mass of the testes were higher in transplanted testes relative to the control group. It seems that transplantation of these cells can be useful in infertility treatment.

Interleukin 1 (IL-1) family is a group of cytokines with multiple local and systemic effects, which regulates both innate and adaptive immune responses. Generally, most IL-1 family cytokines express prevailing pro-inflammatory activities (IL-1α, IL-1β, IL-18, IL-33, IL-36 α, β, γ), whereas others are anti-inflammatory (IL-1Ra (IL-1 receptor antagonist), IL-36Ra, IL-38, IL-37). In addition to their immunomodulatory roles, some of them are also involved in the physiological modulation of homeostatic processes and directly affect mRNA transcription. IL-1 family cytokines bind to specific receptors composed of a ligand-binding chain and an accessory chain. The pro-inflammatory effects of IL-1 family cytokines are regulated on the level of transcription, enzymatic processing of precursors, release of soluble antagonists, and expression of decoy receptors. Members of the IL-1 family regulate the recruitment and activation of effector cells involved in innate and adaptive immunity, but they are also involved in the pathogenesis of chronic disorders, including inflammatory bowel disease, rheumatoid arthritis, and various autoimmune and autoinflammatory diseases. There are only limited data regarding the role of IL-1 cytokines in transplantation. In recent years, targeted therapeutics affecting IL-1 have been used in multiple clinical studies. In addition to the recombinant IL-1Ra, anakinra (highly effective in autoinflammatory diseases and tested for other chronic diseases), the monoclonal antibodies canakinumab, gevokizumab, and rilonacept (a long-acting IL-1 receptor fusion protein) provide further options to block IL-1 activity. Furthermore, new inhibitors of IL-18 (GSK 1070806, ABT-325, rIL-18BP (IL-18 binding protein)) and IL-33 (CNTO-7160) are presently under clinical studies and other molecules are being developed to target IL-1 family cytokines.

Hepatic microcirculatory dysfunction due to cold storage and warm reperfusion (CS+WR) injury during liver transplantation is partly mediated by oxidative stress and may lead to graft dysfunction. This is especially relevant when steatotic donors are considered. Using primary cultured liver sinusoidal endothelial cells (LSECs), liver grafts from healthy and steatotic rats, and human liver samples, we aimed to characterize the effects of a new recombinant form of human manganese superoxide dismutase (rMnSOD) on hepatic CS+WR injury. After CS+WR, the liver endothelium exhibited accumulation of superoxide anion (O 2 − ) and diminished levels of nitric oxide (NO); these detrimental effects were prevented by rMnSOD. CS+WR control and steatotic rat livers exhibited markedly deteriorated microcirculation and acute endothelial dysfunction, together with liver damage, inflammation, oxidative stress, and low NO. rMnSOD markedly blunted oxidative stress, which was associated with a global improvement in liver damage and microcirculatory derangements. The addition of rMnSOD to CS solution maintained its antioxidant capability, protecting rat and human liver tissues. In conclusion, rMnSOD represents a new and highly effective therapy to significantly upgrade liver procurement for transplantation.

Stem cell therapy has emerged as a promising strategy for cardiac and vascular repair. The ultimate goal is to rebuild functional myocardium by transplanting exogenous stem cells or by activating native stem cells to induce endogenous repair. CS/PCs (cardiac stem/progenitor cells) are one type of adult stem cell with the potential to differentiate into cardiac lineages (cardiomyocytes, smooth muscle cells and endothelial cells). iPSCs (induced pluripotent stem cells) also have the capacity to differentiate into necessary cells to rebuild injured cardiac tissue. Both types of stem cells have brought promise for cardiac repair. The present review summarizes recent advances in cardiac cell therapy based on these two cell sources and discusses the advantages and limitations of each candidate. We conclude that, although both types of stem cells can be considered for autologous transplantation with promising outcomes in animal models, CS/PCs have advanced more in their clinical application because iPSCs and their derivatives possess inherent obstacles for clinical use. Further studies are needed to move cell therapy forward for the treatment of heart disease.

In the present Hypothesis article, we summarize and present data from the literature that support our hypothesis on the potential mechanisms by which UPS (ubiquitin–proteasome system) inhibitors reduce I/R (ischaemia/reperfusion) injury in the liver. I/R is the main cause of primary liver failure and, consequently, minimizing the detrimental effects of this process could increase the number of suitable transplantation grafts and also enhance the survival rate of patients after liver transplantation. A potential strategy to reduce I/R injury is the use of UPS inhibitors either as additives to preservation solutions or as drugs administered to patients. However, there is still controversy over whether the use of UPS inhibitors is beneficial or deleterious with regard to liver injury. From our experience and the few studies that have investigated the role of UPS in hepatic I/R, we believe that the use of UPS inhibitors is a potential strategy to reduce I/R injury in liver transplantation and graft preservation. We hypothesize that one of the main mechanisms of action of UPS inhibitors may be the up-regulation of AMPK (AMP-activated protein kinase) activity and the consequent down-regulation of mTOR (mammalian target of rapamycin), which may finally influence autophagy and preserve the energy state of the cell.

With the already heightened demand placed on organ donation, stem cell therapy has become a tantalizing idea to provide glucose-responsive insulin-producing cells to Type 1 diabetic patients as an alternative to islet transplantation. Multiple groups have developed varied approaches to create a population of cells with the appropriate characteristics. Both adult and embryonic stem cells have received an enormous amount of attention as possible sources of insulin-producing cells. Although adult stem cells lack the pluripotent nature of their embryonic counterparts, they appear to avoid the ethical debate that has centred around the latter. This may limit the eventual application of embryonic stem cells, which have already shown promise in early mouse models. One must also consider the potential of stem cells to form teratomas, a complication which would prove devastating in an immunologically compromised transplant recipient. The present review looks at the progress to date in both the adult and embryonic stem cells fields as potential treatments for diabetes. We also consider some of the limitations of stem cell therapy and the potential complications that may develop with their use.

Arginine is an important substrate in health and disease. It is a commonly held view that arginase-1 release from injured erythrocytes and hepatocytes leads to arginine breakdown; however, the true relationship between plasma arginase-1 concentration and activity has remained unaddressed. In the present study, blood was sampled from patients undergoing liver resection, a known cause of hepatocyte injury and arginase-1 release, to determine arginase-1, arginine and ornithine plasma levels. Arginase activity was assessed in vitro by measuring changes in arginine and ornithine plasma levels during incubation of plasma and whole-blood samples at 37 °C. Arginase-1 plasma levels increased 8–10-fold during liver resection, whereas arginine and ornithine levels remained unchanged. In accordance with these in vivo findings, arginine and ornithine levels remained unchanged in plasma incubated at 37 °C irrespective of the arginase-1 concentration. In contrast, arginine plasma levels in whole blood decreased significantly during incubation, with ornithine increasing stoichiometrically. These changes were irrespective of arginase-1 plasma levels and were explained by arginase activity present in intact erythrocytes. Next, plasma samples with 1000-fold normal arginase-1 concentrations were obtained from patients undergoing cadaveric liver transplantation. A significant decrease in arginine plasma levels occurred in vivo and in vitro . In contrast with commonly held views, moderately increased arginase-1 plasma levels do not affect plasma arginine. Very high plasma arginase-1 levels are required to induce potential clinically relevant effects.

Endothelin-1 (ET-1) is believed to play an important role in cardiac ischaemia/reperfusion injury. ET-1 is synthesized from preproET-1 by the action of ET-converting enzyme (ECE). It is unclear to what extent the ET system is activated following prolonged ischaemia. In this study we used a model mimicking the conditions of the donor heart during transplantation. Isolated rat hearts perfused with Krebs–Henseleit buffer were subjected to 30min of normothermic perfusion, then 4h of cardioplegic arrest at 4°C with St Thomas' Hospital solution, followed by reperfusion for 2h. Hearts were freeze-clamped at different time points during the protocol. Using quantitative reverse transcription–PCR, relative levels of ET-1 and ECE mRNA expression were measured and compared with a housekeeping gene (ribosomal protein L32). During reperfusion there was a consistent decrease in coronary flow to approx. 85–90% of pre-ischaemic flow. There was no significant alteration in preproET-1 mRNA expression during 2h of reperfusion. However, ECE mRNA expression was increased by 77.5% at 1h and by 74.6% at 2h following ischaemia compared with pre-ischaemic values ( P <0.05). Thus we conclude that ECE mRNA expression is increased following prolonged hypothermic cardioplegic arrest. Elevations in the expression of this enzyme may help to explain the role of the ET system in the pathogenesis of ischaemia/reperfusion injury following cardiac surgery and transplantation.

C-type natriuretic peptide (CNP) is a potent, endothelial-derived relaxant and growth-inhibitory factor. Accelerated vascular disease is an important cause of morbidity in cardiac transplant recipients, and endothelial dysfunction is now well recognized in patients with cardiovascular disease. CNP has not previously been investigated following cardiac transplantation. We therefore studied plasma levels of immunoreactive CNP in patients early and late after heart transplantation, compared with levels in healthy subjects. We measured CNP in extracted human plasma using an antibody against human CNP-(1–22). CNP levels were significantly elevated in 13 cardiac recipients 2 weeks post-transplant [2.64±0.26 pmol/l (mean±S.E.M.)] compared with those in the normal healthy subjects (0.62±0.04 pmol/l; n = 20, P < 0.001). Plasma levels of CNP were also significantly elevated in a second group of established cardiac transplant recipients (1.15±0.07 pmol/l; n = 46) studied 1–13 years post-transplant when compared with the healthy subjects ( P < 0.001). In the group studied later after transplantation, CNP levels were significantly associated with systolic blood pressure ( P < 0.05) and were higher in patients with angiographic post-transplant coronary artery disease ( P = 0.032). In conclusion, these findings clearly demonstrate that CNP is elevated soon after cardiac transplantation and remains raised in patients even several years post-transplant. CNP may be important as a circulating or local hormone involved in vascular contractile function and in the pathophysiology of cardiac allograft vasculopathy following heart transplantation.

Cyclosporin A (CsA) may exert its cytotoxic effects by altering the activity of different plasma membrane transport systems. Although CsA may act at the gene level, it has been also suggested that it can directly alter transport processes at the plasma membrane. To examine this possibility in a physiological context, we determined Na + /K + -ATPase activity in erythrocytes from two groups of subjects receiving CsA treatment: group I consisted of kidney transplant patients, and group II comprised patients with steroid-resistant idiopathic nephrotic syndrome. Group I patients showed a marked decrease (35%) in the activity of the Na + /K + -ATPase in erythrocytes immediately after surgery, before the initiation of CsA treatment. The activity remained low 2 days after the introduction of CsA, but had recovered to the original (pre-surgery) value 1 month later. Group II patients showed the same pattern of erythrocyte Na + /K + -ATPase activity as those in group I. When the blood CsA levels from all patients were plotted against the corresponding erythrocyte Na + /K + -ATPase transport activity, a significant linear correlation was found. Higher levels of CsA in the blood were correlated significantly with increased Na + /K + -ATPase activities. The blood sodium concentration was also correlated positively with both erythrocyte Na + /K + -ATPase activity and blood CsA concentration. Thus CsA treatment is not associated with inhibition of the Na + /K + -ATPase in erythrocytes.

1. Living-related liver transplantation has some advantages in the evaluation of novel clinical protocols, since many complicated factors affecting initial graft function are almost uniform in grafts obtained from healthy donors. 2. To compare histidine—tryptophan—ketoglutarate (HTK) and University of Wisconsin (UW) solution in terms of tissue oxygenation in living-related liver transplantation, oxygen saturation of haemoglobin (SO 2 ) in hepatic tissue and its heterogeneity (CV, coefficient of variation) were measured by near-infrared spectroscopy. The HTK and UW groups consisted of 15 and 49 successful transplants respectively, in which no statistical differences in background were observed. 3. In the HTK group, hepatic SO 2 after portal vein reflow was higher ( P <0.01) than that in the UW group, as was that after hepatic artery reflow ( P <0.05). In the UW group, hepatic SO 2 remained at the lower level at the end of the operation. 4. Furthermore, the increase in CV after portal vein reflow was normalized after hepatic artery reflow in the HTK group. However, the CV remained at a high level at the end of the operation in the UW group. 5. Postoperative peak aspartate aminotransferase level in the HTK group was lower than that in the UW group ( P <0.05). 6. In cadaveric liver transplantation, higher hepatic SO 2 and lower CV of hepatic SO 2 in the early phase after reperfusion compared with the UW group ( n = 18) were also observed in the HTK group ( n = 30) ( P <0.05). 7. In conclusion, recovery of tissue oxygenation and its heterogeneity after reperfusion in HTK-preserved livers were more rapid and homogeneous than in UW-preserved livers in living-related liver transplantation. Accordingly, HTK solution may be a potential alternative to UW solution.

1. Multiple sclerosis is characterized by areas of demyelination spread throughout the central nervous system, in which the myelin sheaths surrounding axons are destroyed. While therapies aimed at suppressing the autoimmune response, such as β-interferon, may prevent further damage, they cannot repair or replace the lost myelin. To this end, an additional therapy has been proposed, which involves transplanting cells of the oligodendrocyte lineage into the central nervous system. 2. The cell of interest for transplantation is the oligodendrocyte precursor because, unlike the differentiated cell, it is an intrinsically migratory and proliferative cell. In order to optimize the transplant strategy we have investigated the molecular mechanisms that control migration in vitro , so that these mechanisms might be upregulated to maximize cell migration in vivo. We have focused on the integrin family of cell adhesion molecules, known to play a fundamental role in the regulation of migration in other cell types. 3. These studies show that oligodendrocytes express a limited repertoire of integrins consisting of α 6 β 1 and three different α v integrins. α 6 β 1 is expressed throughout development but α v integrins show developmental regulation; differentiation is accompanied by loss of α v β 1 and upregulation of α v β 5 . 4. Function-blocking studies show that oligodendrocyte precursor migration in vitro is mediated primarily by the developmentally regulated α v β 1 integrin, but not α 6 β 1 or α v β 3 . Taken together with previous evidence that cell migration can be regulated by altering integrin expression, this work suggests that modifying expression levels of α v β 1 on oligodendrocyte precursors may increase the migratory capacity of these cells. If so, this would support a future therapeutic strategy aimed at transplanting genetically modified oligodendrocyte precursors to repair widespread demyelinated lesions.

1. Lung transplantation causes a total interruption of the innervation and vascularization within the transplanted organ, followed by repair processes. This is frequently associated with bronchial hyper-responsiveness. A common feature of tissue repair is an increase in the number of mast cells. Three phenotypically distinct mast cell subsets, with respect to their protease content, have been identified in rat lung, and it is probable that mast cells of differing protease phenotype fulfil different functions. 2. We have compared the number, protease phenotype and distribution of mast cells in left lung from transplanted and control Lewis rats 1 month after syngeneic unilateral left lung transplantation, without interference of inflammation, graft rejection or of any treatment. Connective and mucosal-type mast cell phenotypes were characterized using antibodies directed against their specific rat mast cell proteases, RMCPI and RMCPII, respectively. 3. After transplantation, RMCPI and RMCPII tissue concentrations increased by 172% and 239%, respectively, compared with controls (13.1 ± 1.2 and 5.6±1.0 μg/g). 4. Localization of mast cell phenotypes was studied by immunohistochemistry after double immunostaining. The number of mast cells increased after transplantation: the increase in the number of RMCPI-immunoreactive mast cells (RMCPI + ) was significant around bronchioles and arterioles, around large vessels and in the pleura. The number of RMCPII + mast cells also significantly increased around bronchioles and arterioles, as well as in the smooth muscle layer of large airways. Some mast cells stained for the presence of both RMCPI and RMCPII, supporting the existence of co-expressing phenotype in rat lung. The number of mast cells of the RMCPI + /H + phenotype significantly increased around bronchioles and arterioles and in the pleura. Moreover, the distribution of the mast cell phenotypes was modified in the different areas after transplantation. 5. This indicates a local differentiation/maturation of mast cells after transplantation.

1. The preservation of hypoxic pulmonary vasoconstriction (HPV) in the denervated lung was studied in five human heart–lung transplant recipients. 2. AH five patients showed significant increases in mean pulmonary artery pressure and pulmonary vascular resistance during hypoxic exposure, returning toward normoxic values during recovery. Aside from P ao 2 and P ao 2 , other factors known to influence pulmonary vascular resistance did not change significantly during the hypoxic period. 3. There was no relation between the length of the post-transplantation period and the intensity of HPV, suggesting that reinnervation of the pulmonary vascular bed did not account for persistent HPV and that HPV persists in the human transplanted lung despite the loss of autonomic neural innervation.

1. Rabbits were anaesthetized and kidneys removed directly with no flush (group NF), or alternatively kidneys were flushed (group F) with sodium phosphate buffered 140 mmol/1 sucrose (PBsuc 140), Collins C 2 (C 2 ) or Euro-Collins (EC) transplant preservation solutions and stored at 4°C for 0–4, 24 or 48 h. Mid-cortical proximal convoluted tubule (PCT) segments were dissected from all groups and set up for microperfusion in vitro. Observations were made of tubule morphology, fluid reabsorption rate ( J v ), bath leak of the glomerular marker iothalamate and transmural potential difference (p.d.), both at 37°C and at 15–20°C, in order to compare the relative effectiveness of the solutions in the preservation of tubule integrity and immediate function. 2. Tubules from kidneys flushed with EC and C 2 contained luminal debris and frequently had high bath leaks of iothalamate, both indicative of poor preservation of tubule integrity. In contrast, tubules from NF kidneys and PBsuc140-flushed kidneys were free of luminal debris with a lower incidence of high iothalamate leaks. 3. Tubules from PBsuc140-flushed and EC-flushed kidneys after 0–4 and 24 h storage had J v that were similar to those of NF kidneys. Tubules from all groups of flushed kidneys after 48 h cold storage and all tubules from C 2 -flushed kidneys showed reduced J v values. In all cases J v was reduced to approximately zero when the temperature was lowered to 15–20°C. 4. Transmural p.d. was similar in all groups except for particularly low p.d. values observed in tubules from C 2 -flushed kidneys after 48 h storage. 5. These observations suggest that PBsuc140 is more effective in the preservation of tubule function during prolonged cold storage than the glucose-based Collins solutions. The marked difference in the effectiveness of C 2 and EC contra-indicates the inclusion of magnesium (present in C 2 ) for preservation of kidneys, as judged by experiments on the rabbit.

1. Changes in plasma renin activity, plasma noradrenaline, pulse rate and blood pressure after tilting were measured in normal subjects and in patients with renal transplants. 2. There was a marked difference between the renin responses in the two groups, the increases in plasma renin activity in the control subjects being much greater than those in the transplanted patients. 3. Activation of the sympathetic nervous system after tilting, as indicated by changes in pulse rate, blood pressure and plasma noradrenaline, was similar in the two groups. 4. We conclude that the ability of the transplanted kidney to increase plasma renin activity after tilting is impaired, probably as a result of sympathetic denervation of the kidney during transplantation. The results suggest a dominant role of the sympathetic nervous system in the mediation of renin release after tilting.

1. Patients with cadaveric renal transplants and plasma creatinine less than 177 μmol/l who had their own kidneys removed were studied. 2. The renin—angiotensin system appeared to behave in a normal fashion in response to alterations in sodium intake and posture. 3. The renin—angiotensin system had no major role in the establishment or maintenance of hypertension. 4. Mean arterial pressure was directly related to expansion of the extracellular fluid volume.

1. The adrenal response to a reduction in extracellular fluid volume (ECFV), sodium depletion, intravenous adrenocorticotrophic hormone (ACTH) and angiotensin II was assessed from changes in plasma aldosterone and plasma cortisol in eleven nephrectomized patients. Five patients were also studied before nephrectomy and six after successful renal transplantation. 2. Before nephrectomy, the resting concentrations of plasma aldosterone were usually raised. In the three patients out of five tested, the response to intravenous ACTH was marked. In two out of four patients, there was a good response to angiotensin II infusion. In one of two patients, there was a good response to a reduction in ECFV and sodium depletion. 3. After nephrectomy, the resting concentrations of plasma aldosterone were negligible or uniformly reduced and the response to ECFV reduction, sodium depletion, ACTH and angiotensin II was universally poor. 4. In all cases there was a normal plasma cortisol response to ACTH. 5. After renal transplantation in six patients, the four to whom an infusion of angiotensin II was given showed a return to a normal aldosterone response and all six showed a normal response to ACTH. 6. No clear correlation was shown between resting concentrations of plasma aldosterone and plasma potassium after nephrectomy. 7. It was concluded that the kidney, through the renin-angiotensin system, may play its main part by sensitizing the zona glomerulosa to other stimuli, but an alternative kidney-dependent mechanism cannot be excluded.