Indefinite Survival of Rat Islet Allografts following Infusion of Donor Bone Marrow without Cytoablation

We have tested the effect of donor bone marrow cell (DBMC) infusion on the survival of pancreatic islet allografts in the rat, without the use of cytoablative recipient conditioning. Lewis and diabetic Brown Norway rats were used as donors and recipients, respectively. Donor islets were placed beneath the left renal capsule. Infusion of DBMC and temporary immunosuppression followed by delayed islet transplantation resulted in indefinite survival of all islet grafts (MST >180 days). Control animals demonstrated recurrent hyperglycemia (islet allografts rejection). Donor bone marrow derived cells were detected in the spleen and cervical lymph nodes of BN recipients of LEW bone marrow but not in the recipients of islet transplants alone. Second set full thickness skin grafts were performed in normal BN and in recipients of a previously successful ITX. Donor specific skin grafts were accepted in the animals that had received DBMC 40 days before the islet allograft, while animals receiving DBMC at the time of the islet allograft rejected the donor specific skin graft similarly to the controls. However, these animals did not reject a second set donor-specific islet transplant. The results indicate that radiation conditioning of the recipients was not necessary to induce microchimerism and graft acceptance in this rodent model of islet allotransplantation.

Thomas Starzl, Video Interview for His Living Legend Award at the ISBTS 2015

At the 14th International Small Bowel Transplant Symposium, (ISBTS2015) held in Buenos Aires, a session to recognize the pioneers that have dedicated their lives to make our current field possible was organized. Dr Thomas Starzl received the first Living Legend Award. A video interview was obtained at his office, edited, and later presented during the scientific meeting. More than 600 people saw Dr Starzl's interview, which captivated the audience for 40 minutes, before smiles, tears and the final applause erupted at the conclusion. We would like to share this video with all of you to inspire the current generations and the generations to come. The manuscript has the main parts of the interview, which can also be accessed at http://isbts2015.tts.org/starzl.mp4.

Liver-specific deletion of augmenter of liver regeneration accelerates development of steatohepatitis and hepatocellular carcinoma in mice

BACKGROUND & AIMS

Augmenter of liver regeneration (ALR, encoded by GFER) is a widely distributed pleiotropic protein originally identified as a hepatic growth factor. However, little is known about its roles in hepatic physiology and pathology. We created mice with liver-specific deletion of ALR to study its function.

METHODS

We developed mice with liver-specific deletion of ALR (ALR-L-KO) using the albumin-Cre/LoxP system. Liver tissues were collected from ALR-L-KO mice and ALR(floxed/floxed) mice (controls) and analyzed by histology, reverse-transcription polymerase chain reaction, immunohistochemistry, electron microscopy, and techniques to measure fibrosis and lipids. Liver tissues from patients with and without advanced liver disease were determined by immunoblot analysis.

RESULTS

Two weeks after birth, livers of ALR-L-KO mice contained low levels of ALR and adenosine triphosphate (ATP); they had reduced mitochondrial respiratory function and increased oxidative stress, compared with livers from control mice, and had excessive steatosis, and hepatocyte apoptosis. Levels of carbamyl-palmitoyl transferase 1a and ATP synthase subunit ATP5G1 were reduced in livers of ALR-L-KO mice, indicating defects in mitochondrial fatty acid transport and ATP synthesis. Electron microscopy showed mitochondrial swelling with abnormalities in shapes and numbers of cristae. From weeks 2-4 after birth, levels of steatosis and apoptosis decreased in ALR-L-KO mice, and numbers of ALR-expressing cells increased, along with ATP levels. However, at weeks 4-8 after birth, livers became inflamed, with hepatocellular necrosis, ductular proliferation, and fibrosis; hepatocellular carcinoma developed by 1 year after birth in nearly 60% of the mice. Hepatic levels of ALR were also low in ob/ob mice and alcohol-fed mice with liver steatosis, compared with controls. Levels of ALR were lower in liver tissues from patients with advanced alcoholic liver disease and nonalcoholic steatohepatitis than in control liver tissues.

CONCLUSIONS

We developed mice with liver-specific deletion of ALR, and showed that it is required for mitochondrial function and lipid homeostasis in the liver. ALR-L-KO mice provide a useful model for investigating the pathogenesis of steatohepatitis and its complications.

Human dominant-negative class II transactivator transgenic pigs - effect on the human anti-pig T-cell immune response and immune status

Swine leucocyte antigen (SLA) class II molecules on porcine (p) cells play a crucial role in xenotransplantation as activators of recipient human CD4(+) T cells. A human dominant-negative mutant class II transactivator (CIITA-DN) transgene under a CAG promoter with an endothelium-specific Tie2 enhancer was constructed. CIITA-DN transgenic pigs were produced by nuclear transfer/embryo transfer. CIITA-DN pig cells were evaluated for expression of SLA class II with/without activation, and the human CD4(+) T-cell response to cells from CIITA-DN and wild-type (WT) pigs was compared. Lymphocyte subset numbers and T-cell function in CIITA-DN pigs were compared with those in WT pigs. The expression of SLA class II on antigen-presenting cells from CIITA-DN pigs was significantly reduced (40-50% reduction compared with WT; P < 0·01), and was completely suppressed on aortic endothelial cells (AECs) even after activation (100% suppression; P < 0·01). The human CD4(+) T-cell response to CIITA-DN pAECs was significantly weaker than to WT pAECs (60-80% suppression; P < 0·01). Although there was a significantly lower frequency of CD4(+) cells in the PBMCs from CIITA-DN (20%) than from WT (30%) pigs (P < 0·01), T-cell proliferation was similar, suggesting no significant immunological compromise. Organs and cells from CIITA-DN pigs should be partially protected from the human cellular immune response.

Fifty years later

That concludes my remarks. If I have not made my purpose clear, let me summarize simply. I, like all others gathered here, have come to pay homage to Paul Terasaki, a man who bent in the winds of his time but never broke. Over the last 50 years, I have worked with many people. No collaboration has been dearer than that with Paul (Fig. 7).

The first report of orthotopic liver transplantation in the Western world

Until the present time, the first experimental liver transplant which led to the development of human liver transplantation is attributed to C. Stuart Welch who performed a heterotopic transplant in the canine species in 1955. In 1956, Jack Cannon is credited with the first animal orthotopic liver transplant although the species was not disclosed. This report is intended to set the historical record straight by acknowledging that Vittorio Staudacher in 1952 was the first to perform a liver transplant in a large animal model.

Treprostinil, a prostacyclin analog, ameliorates ischemia-reperfusion injury in rat orthotopic liver transplantation

Prostaglandins have been evaluated for their ability to reduce IRI after liver transplantation; however, poor stability, side effects and the inability to show a significant difference in primary endpoint have limited their clinical application. Treprostinil, a prostacyclin (PGI(2) ) analog, has a higher potency and longer elimination half-life than other commercially available PGI(2) analogs. We examined the efficacy of treprostinil to prevent IRI during OLT. OLT was performed in syngeneic Lewis rats after 18 h of cold preservation (4°C) in the UW solution. IRI significantly increased serum ALT and AST levels, neutrophil infiltration, hepatic necrosis and mRNA levels of proinflammatory cytokines post-OLT, while treatment with treprostinil decreased all the parameters. Cold storage of liver grafts significantly reduced ATP levels and treprostinil restored energy levels in liver grafts early postreperfusion. In addition, treprostinil preserved the sinusoidal endothelial cell lining and reduced platelet deposition early post-transplantation compared to placebo. Hepatic tissue blood flow was significantly compromised in the placebo group, whereas treprostinil maintained blood-flow similar to normal levels. Treprostinil protected the liver graft against IRI during OLT. Treprostinil has the potential to serve as a therapeutic option to protect the liver graft against I/R injury in patients undergoing OLT.

Themes of liver transplantation

Liver transplantation was the product of five interlocking themes. These began in 1958-1959 with canine studies of then theoretical hepatotrophic molecules in portal venous blood (Theme I) and with the contemporaneous parallel development of liver and multivisceral transplant models (Theme II). Further Theme I investigations showed that insulin was the principal, although not the only, portal hepatotrophic factor. In addition to resolving long-standing controversies about the pathophysiology of portacaval shunt, the hepatotrophic studies blazed new trails in the regulation of liver size, function, and regeneration. They also targeted inborn metabolic errors (e.g., familial hyperlipoproteinemia) whose palliation by portal diversion presaged definitive correction with liver replacement. Clinical use of the Theme II transplant models depended on multiple drug immunosuppression (Theme III, Immunology), guided by an empirical algorithm of pattern recognition and therapeutic response. Successful liver replacement was first accomplished in 1967 with azathioprine, prednisone, and antilymphoid globulin. With this regimen, the world's longest surviving liver recipient is now 40 years postoperative. Incremental improvements in survival outcome occurred (Theme IV) when azathioprine was replaced by cyclosporine (1979), which was replaced in turn by tacrolimus (1989). However, the biologic meaning of alloengraftment remained enigmatic until multilineage donor leukocyte microchimerism was discovered in 1992 in long-surviving organ recipients. Seminal mechanisms were then identified (clonal exhaustion-deletion and immune ignorance) that linked organ engraftment and the acquired tolerance of bone marrow transplantation and eventually clarified the relationship of transplantation immunology to the immunology of infections, neoplasms, and autoimmune disorders. With this insight, better strategies of immunosuppression have evolved. As liver and other kinds of organ transplantation became accepted as healthcare standards, the ethical, legal, equity, and the other humanism issues of Theme V have been resolved less conclusively than the medical-scientific problems of Themes I-IV.

Cholera toxin-sensitive GTP-binding protein-coupled activation of augmenter of liver regeneration (ALR) receptor and its function in rat kupffer cells

Mitogenic effect of augmenter of liver regeneration (ALR), a protein produced and released by hepatocytes, on hepatocytes in vivo but not in vitro suggests that the effect is mediated by nonparenchymal cells. Since mediators produced by Kupffer cells are implicated in hepatic regeneration, we investigated receptor for ALR and its functions in rat Kupffer cells. Kupffer cells were isolated from rat liver by enzymatic digestion and centrifugal elutriation. Radioligand ([(125)I] ALR) receptor binding, ALR-induced GTP/G-protein association, and nitric oxide (NO), tumor necrosis factor (TNF)-alpha, and interleukin-6 (IL-6) synthesis were determined. High-affinity receptor for ALR, belonging to the G-protein family, with K(d) of 1.25 +/- 0.18 nM and B(max) of 0.26 +/- 0.02 fmol/microg DNA was identified. ALR stimulated NO, TNF-alpha, and IL-6 synthesis via cholera toxin-sensitive G-protein, as well as p38-MAPK activity and nuclear translocation of NFkappaB. While inhibitor of NFkappaB (MG132) inhibited ALR-induced NO synthesis, MG132 and p38-MAPK inhibitor (SB203580) abrogated ALR-induced TNF-alpha and IL-6 synthesis. ALR also prevented the release of mediator(s) from Kupffer cells that cause inhibition of DNA synthesis in hepatocytes. Administration of ALR to 40% partially hepatectomized rats increased expression of TNF-alpha, IL-6, and inducible nitric oxide synthase (iNOS) and caused augmentation of hepatic regeneration. These results demonstrate specific G-protein coupled binding of ALR and its function in Kupffer cells and suggest that mediators produced by ALR-stimulated Kupffer cells may elicit physiologically important effects on hepatocytes.

Species-dependent hepatic metabolism of immunosuppressive agent tacrolimus (FK-506)

The current study aims to investigate species-related differences in the in-vitro hepatic metabolism of tacroliums using liver microsomes obtained from rat, hamster, guinea pig, rabbit, pig, dog, baboon and humans. Tacrolimus metabolism was characterized using high-performance liquid chromatography- ultraviolet light (HPLC-UV) and two soft ionization mass spectrometric techniques; matrix-assisted lasers desorption/ionization (MALDI) and time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The extent of tacrolimus metabolism, when normalized to the cytochrome P-450 content, was in the order: rat < hamster < rabbit < pig < guinea pig < dog < human < baboon. Tacrolimus metabolism exhibited significant qualitative and quantitative differences between the animal species tested. Desmethyl- (MI-MIII), didesmethyl- (MIV-MVI), monohydroxy- (MVII), dihydroxy- (MVIII), epoxide- (MIX), dihydrodiol- (MX), monodesmethyl and monohydroxy- (MXI-MXIII), and didesmethyl and monohydroxy- (MXIV-MXVI) tacroliums metabolites were identified in the species tested. MI-MX were identified in all the species tested; MXI-MXVI were identified in all species except rat, rabbit and guinea pig; and MXIV-MXVI were identified only in baboon. The current investigation was unable to detect any phase II metabolites due to the limitations of the test system used. The analytical methods were not able to differentiate optical and positional isomers of metabolites due to the nature of the analytical tools used, therefore groups of metabolites were identified based on their molecular weights and available information. From the current in-vitro metabolism studies, the pattern of tacroliums metabolism in baboons closely resembled that in humans and thus it is ideal for studying tacroliums metabolism-related work of clinical relevance.

Complications of right lobe living donor liver transplantation

BACKGROUND/AIMS

Right lobar living donor liver transplantation (LDLT) has been controversial because of donor deaths and widely variable reports of recipient and donor morbidity. Our aims were to ensure full disclosure to donors and recipients of the risks and benefits of this procedure in a large University center and to help explain reporting inconsistencies.

METHODS

The Clavien 5-tier grading system was applied retrospectively in 121 consecutive adult right lobe recipients and their donors. The incidence was determined of potentially (Grade III), actually (Grade IV), or ultimately fatal (Grade V) complications during the first post-transplant year. When patients had more than one complication, only the seminal one was counted, or the most serious one if complications occurred contemporaneously.

RESULTS

One year recipient/graft survival was 91%/84%. Within the year, 80 (66%) of the 121 recipients had Grade III (n=54) Grade IV (n=16), or Grade V (n=10) complications. The complications involved the graft's biliary tract (42% incidence), graft vasculature (15%), or non-graft locations (9%). Complications during the first year did not decline with increased team experience, and adversely affected survival out to 5 years. All 121 donors survive. However, 13 donors (10.7%) had Grade III (n=9) or IV (n=4) complications of which five were graft-related.

CONCLUSIONS

Despite the satisfactory recipient and graft survival at our and selected other institutions, and although we have not had a donor mortality to date, the role of right lobar LDLT is not clear because of the recipient morbidity and risk to the donors.

Kidney after nonrenal transplantation-the impact of alemtuzumab induction

BACKGROUND

Calcineurin inhibitor nephrotoxicity in nonrenal allograft recipients can lead to end-stage renal disease and the need for kidney transplantation. We sought to evaluate the role of alemtuzumab induction in this population.

PATIENTS AND METHODS

We evaluated 144 patients undergoing kidney transplantation after nonrenal transplantation between May 18, 1998, and October 8, 2007. Seventy-two patients transplanted between January 15, 2003, and October 8, 2007, received alemtuzumab induction and continued their pretransplant immunosuppression. Seventy-two patients transplanted between May 18, 1998, and July 21, 2007, did not receive alemtuzumab induction, but received additional steroids and maintenance immunosuppression. Donor and recipient demographics were comparable.

RESULTS

Overall, 1- and 3-year patient survival and renal function were comparable between the two groups. One- and 3-year graft survival was 93.0% and 75.3% in the alemtuzumab group and 83.3% and 68.7% in the no alemtuzumab group, respectively (P=0.051). The incidence of acute rejection was lower in the alemtuzumab group, 15.3%, than in the no alemtuzumab group, 41.7% (P=0.0001). The incidence of delayed graft function was lower in the alemtuzumab group, 9.7%, than in the no alemtuzumab group, 25.0% (P=0.003). The incidence of viral complications was comparable.

CONCLUSION

Alemtuzumab induction with simple resumption of baseline immunosuppression in patients undergoing kidney transplantation after nonrenal transplantation represents a reasonable immunosuppressive strategy.

The origin of clinical organ transplantation revisited

A patient whose illness had begun with edema and hypertension was found to have extreme atrophy of both kidneys. Because of the steady worsening of the condition and the appearance of uremia with other unfavorable diagnostic signs, transplantation of 1 kidney from the patient's identical healthy twin brother was undertaken. Preparations included collection of evidence of monozygosity and experimental transplantation of a skin graft from the twin. During the transfer of the healthy kidney, it was totally ischemic for 82 minutes. Evidence of functional activity in the transplanted kidney was obtained. The hypertension persisted until the patient's diseased kidneys were both removed. The homograft has survived for 11 months, and the marked clinical improvement in the patient has included disappearance of the signs of malignant hypertension.

Successful salvage of mucormycosis infection of the forearm and osteomyelitis of the ulna

A 6-month-old child developed cutaneous mucormycosis of the forearm 5 weeks after liver transplantation, which progressed to osteomyelitis of the proximal ulna. Aggressive treatment, which included serial radical debridements, intravenous administration of amphotericin B, and eventually split thickness skin graft coverage resulted in successful functional salvage of the forearm, wrist, and hand. Of the nine previously reported cases of mucormycosis affecting the forearm or hand in immunocompromised patients, all either required amputation of the hand or below elbow amputation, or resulted in the patient's death. Definitive early diagnosis and serial radical debridements may allow salvage of a functional hand.

A hundred years of the hepatotrophic controversy

Venous blood returning from the splanchnic viscera has liver-supporting (hepatotrophic) qualities not found to the same degree in other kinds of arterial or venous blood. The effects of portal blood have been noted in animals with two livers (or a differential portal blood supply to different regions of one liver) to include hypertrophy, glycogen storage, hyperplasia, capacity for regeneration, increase of several synthetic functions, and maintenance of normal structure. The main splanchnic venous hepatotrophic factors are endogenous hormones of which the single most important is insulin. Thus, the foregoing portal hepatotrophic effects are largely eliminated with the diabetes produced by alloxan or total pancreatectomy. The injury of portacaval shunt is caused by the diversion of the hormones around the liver. Accordingly, the atrophy, injury to the organelles, and loss of the capacity for cell renewal is minimized if insulin is infused into the portally deprived liver. In these and other experiments, exogenous glucagon alone or the addition of glucagon to insulin has had no effect, but this may be because of the masking presence of gut glucagon and other hormonal or non-hormonal substances in our models. At present, the effects on the liver of exogenous insulin, glucagon, epidermal growth factor, and numerous other hormones are being determined by their intraportal infusion into eviscerated dogs in which other endogenous splanchnic factors have been eliminated.

Portacaval shunt for glycogen storage disease and hyperlipidaemia

Complete portacaval shunt was used to treat 10 patients with glycogen storage disease. A favourable effect was noted on body growth and a number of metabolic abnormalities. More recently, continous night feedings with an intermittently placed gastric tube or through a gastrostomy has been shown to be helpful either before or after portacaval shunts. Such alimentation techniques may eliminate the need for shunts in some patients and be of adjuvant benefit in others. Portacaval shunt was also used for three children who had homozygous Type II hyperlipidaemia. Substantial reductions in serum cholesterol concentration were observed, as well as resorption of xanthomas. Reversal of some cardiovascular lesions has been documented. The benefits of portacaval shunt in these disorders is probably due to the change in the hormone climate of the liver and the whole organism brought about by diversion of the hormone-rich splanchnic venous blood around the liver.

Alemtuzumab preconditioning with tacrolimus monotherapy-the impact of serial monitoring for donor-specific antibody

BACKGROUND

Antibody preconditioning with tacrolimus monotherapy has allowed many renal allograft recipients to be maintained on spaced weaning.

METHODS

Of 279 renal allograft recipients transplanted between March 2003 and December 2004, 222 (80%) had spaced weaning (i.e., reduction of tacrolimus monotherapy dosing to every other day, three times a week, twice a week, or once a week) attempted. Routine monitoring for donor-specific antibody (DSA) was begun in September 2004. Mean follow-up is 34+/-6.5 months after transplantation and 26+/-8.1 months after the initiation of spaced weaning.

RESULTS

One hundred and twenty-two (44%) patients remained on spaced weaning. One- and 2-year actual patient/graft survival was 99%/99%, and 97%/96%. Fifty-six (20%) patients experienced acute rejection after initiation of spaced weaning. One- and 2-year actual patient/graft survival was 100%/98%, and 94%/78%. Forty-two (15%) patients with stable renal function had spaced weaning stopped because of the development of DSA, which disappeared in 17 (40%). One- and 2-year actual patient and graft survival was 100% and 100%.

CONCLUSION

Adult renal transplant recipients who are able to be maintained on spaced weaning have excellent outcomes. Patients with stable renal function who have reversal of weaning because of the development of DSA also have excellent outcomes. Routine monitoring for DSA may allow patients to avoid late rejection after spaced weaning.

Augmenter of liver regeneration: an important intracellular survival factor for hepatocytes

BACKGROUND/AIMS

Augmenter of liver regeneration (ALR), a protein synthesized and stored in hepatocytes, is associated with mitochondria, and possesses sulfhydryl oxidase and cytochrome c reductase activities. We sought to determine the effects of ALR depletion in hepatocytes by antisense oligonucleotide transfection.

METHODS

Rat hepatocytes in primary culture were transfected with antisense oligonucleotide for ALR mRNA (ALR-AS) or scrambled oligonucleotide. Various analyses were performed at times up to 24h after transfection.

RESULTS

Treatment with ALR-AS caused a decrease in ALR mRNA, cellular depletion of ALR protein primarily from mitochondria, and decreased viability. Flow cytometric analysis of ALR-AS-transfected hepatocytes stained with annexin-Vcy3 and 7-aminoactinomycin D revealed apoptosis as the predominant cause of death up to 6h; incubation beyond this time resulted in necrosis in addition to apoptosis. ALR-AS-transfection caused release of mitochondrial cytochrome c, activation of caspase-3, profound reduction in the ATP content, and cellular release of LDH. Inhibition of caspase-3 inhibited the early phase of ALR-AS-induced death but not the late phase that included ALR and LDH release.

CONCLUSIONS

These results suggest that ALR is critically important for the survival of hepatocytes by its association with mitochondria and regulation of ATP synthesis.

Relative contribution of direct and indirect allorecognition in developing tolerance after liver transplantation

The interaction of donor passenger leukocytes and host leukocytes in recipient secondary lymphoid tissues during the early posttransplantation period is crucial in directing host immune reactions toward allograft rejection or acceptance. Responsible T cell clones could be activated through the direct and indirect pathways of allorecognition. We examined the role of the indirect pathway in liver transplantation (LT) tolerance by depleting host antigen-presenting cells (APC) with phagocytic activity [e.g., cluster domain (CD)68+/CD163+ macrophages, CD11c+ dendritic cells (DC)] using liposome-encapsulating clodronate (LP-CL). After Lewis rat cell or liver graft transplantation, Brown Norway (BN) rat recipients pretreated with LP-CL showed a significantly reduced type 1 helper T cell cytokine up-regulation than control-LP-treated recipients. In the LT model, LP-CL treatment and host APC depletion abrogated hepatic tolerance; Lewis liver grafts in LP-CL-treated-BN recipients developed mild allograft rejection, failed to maintain donor major histocompatibility complex (MHC) class II+ leukocytes, and developed chronic rejection in challenged donor heart allografts, while control-LP-treated BN recipients maintained tolerance status and donor MHC class II+ hepatic leukocytes. Furthermore, in the BN to Lewis LT model, LP-CL recipient treatment abrogated spontaneous hepatic allograft acceptance, and graft survival rate was reduced to 43% from 100% in the control-LP group. In conclusion, the study suggests that host cells with phagocytic activity could play significant roles in developing LT tolerance.

Alemtuzumab pre-conditioning with tacrolimus monotherapy in pediatric renal transplantation

We employed antibody pre-conditioning with alemtuzumab and posttransplant immunosuppression with low-dose tacrolimus monotherapy in 26 consecutive pediatric kidney transplant recipients between January 2004 and December 2005. Mean recipient age was 10.7 +/- 5.8 years, 7.7% were undergoing retransplantation, and 3.8% were sensitized, with a PRA >20%. Mean donor age was 32.8 +/- 9.2 years. Living donors were utilized in 65% of the transplants. Mean cold ischemia time was 27.6 +/- 6.4 h. The mean number of HLA mismatches was 3.3 +/- 1.3. Mean follow-up was 25 +/- 8 months. One and 2 year patient survival was 100% and 96%. One and 2 year graft survival was 96% and 88%. Mean serum creatinine was 1.1 +/- 0.6 mg/dL, and calculated creatinine clearance was 82.3 +/- 29.4 mL/min/1.73 m(2). The incidence of pre-weaning acute rejection was 11.5%; the incidence of delayed graft function was 7.7%. Eighteen (69%) of the children were tapered to spaced tacrolimus monotherapy, 10.5 +/- 2.2 months after transplantation. The incidence of CMV, PTLD and BK virus was 0%; the incidence of posttransplant diabetes was 7.7%. Although more follow-up is clearly needed, antibody pre-conditioning with alemtuzumab and tacrolimus monotherapy may be a safe and effective regimen in pediatric renal transplantation.

Renal transplantation in children managed with lymphocyte depleting agents and low-dose maintenance tacrolimus monotherapy

OBJECTIVE

Describe the safety and efficacy of antithymocyte globulin or alemtuzumab preconditioning, steroid avoidance and reduced calcineurin inhibitor (CNI) immunosuppression in 34 children undergoing renal transplantation.

METHODS

ATG (n=8) or alemtuzumab (n=26) were infused at the time of transplantation. This was followed by low-dose twice a day tacrolimus monotherapy with consolidation to once daily dosing by 6 months and once every other day dosing by 12 months. Follow-up ranged from 0.5-2.9 years (mean 1.33 years), with a minimum of 6 months.

RESULTS

Both ATG and alemtuzumab were well tolerated. Lymphopenia occurred routinely and resolved after 3-6 months. Acute cellular rejection occurred in 9%; it was related to medical nonadherence in two patients and resulted in one graft loss at 1.5 years. Important adverse events included transient neutropenia in 10 children (none with serious infection), and autoimmune hemolytic anemia in two (resolved with a steroid course in both and conversion to sirolimus in one). Estimated glomerular filtration rate (e-GFR) was stable and averaged 88 mL/min/1.73 m2 at latest follow-up. Fifteen preadolescents had a greater increase in height Z-score at 1 year (1.3 vs. 0.5, P=0.001), and a higher e-GFR (94.8+/-21 vs. 76.6+/-20 ml/min/1.73 m2, P<0.05), when compared to case-matched historical controls who were weaned off steroids by 6 months after transplantation and received twice daily tacrolimus monotherapy.

CONCLUSION

This simple regimen appears safe, has a low risk for acute cellular rejection or other adverse effects, and is associated with excellent growth and renal function. Such a regimen may also improve compliance and limit CNI nephrotoxicity.

World's longest surviving liver-pancreas recipient

In July 1988, the liver and pancreas of a cadaveric donor were transplanted separately into a man with type 1 diabetes with end-stage chronic hepatitis B virus. Two features of the operation may help explain the patient's current status as the longest-lived liver-pancreas recipient. One was enteric drainage of pancreatic exocrine secretions. The other was delivery of the pancreas venous effluent to the host portal system and then directly to the hepatic allograft.

Cold heparinized lactated Ringers with procaine (HeLP) preservation fluid in 266 living donor kidney transplantations

Since the 1960s simple inexpensive cold lactated Ringers with additives has been used for short-term cold preservation of kidneys from living donors. We performed 266 living donor kidney transplantations from January 22, 2003 to October 30, 2006. Donor allografts were recovered laparoscopically and flushed with cold heparin, lactated Ringer's and procaine (HeLP) solution. Warm and cold ischemic times were typically <45 min and <90 min, respectively. The mean follow up was 21.6+/-12.2 months. There was no delayed graft function. Actuarial 1-year patient and graft survival were 98.6% and 98.1%, respectively. The creatinine at 1 year was 1.46+/-0.51 mg/dL. The cumulative incidences of acute cellular rejection at 6, 12, 18, and 24 months were 3.0%, 7.1%, 10.2%, and 11.7%. There were no identifiable side effects attributed to the HeLP solution. This study documents the effectiveness of cold HeLP as a flushing and short-term preservation fluid for living donor kidney transplantation with excellent results and significant cost benefit because of its low cost.

Chronic allograft nephropathy score before sirolimus rescue predicts allograft function in renal transplant patients

Chronic allograft nephropathy (CAN) is a major indication for initiation of sirolimus (SRL) in renal transplantation (TX) to prevent deterioration of renal function. We evaluated whether the CAN score at time of sirolimus rescue (SRL-R) predicts renal allograft function. CAN score is the sum of the following 4 categories: glomerulopathy (cg, 0-3), interstitial fibrosis (ci, 0-3), tubular atrophy (ct, 0-3), and vasculopathy (cv, 0-3). This is a retrospective cohort study of renal transplant recipients from July 2001 to March 2004. Immunosuppression consisted of preconditioning with rabbit anti-thymocyte globulin or alemtuzumab and maintenance with tacrolimus (TAC) monotherapy with spaced weaning, if applicable, SRL-R was achieved by conversion from TAC, or by addition to reduced doses of TAC. Ninety patients received SRL. Thirty-three of these patients met the inclusion criteria of the following: (1) receipt of SRL for >6 months, and (2) follow-up of > or =6 months. There were 16 patients in the low-CAN (0-4) group and 17 patients in the high-CAN (>4) group. Cockcroft-Gault (C-G) glomerular filtration rate (GFR) was calculated at SRL-R and at 1, 3, 6, and 12 months. The DeltaGFR was significantly better in the low-CAN group at 1, 3, and 6 months. A trend toward an improved DeltaGFR was present at 12 months in the low-CAN group (P = .16). CAN scoring at the time of SRL-R predicts recovery of renal allograft function (as measured using DeltaGFR), and should be used in preference to biochemical markers (Cr and C-G GFR), which may not be reliable predictors.

Alemtuzumab induction and tacrolimus monotherapy in pancreas transplantation: One- and two-year outcomes

BACKGROUND

Alemtuzumab (Campath-1H) induction with tacrolimus monotherapy has been shown to provide effective immunosuppression for kidney, liver, lung, and small bowel transplantation. This drug combination was evaluated in pancreas transplant recipients.

METHODS

Sixty consecutive pancreas transplants (30 simultaneous pancreas-kidney, 20 pancreas after kidney, and 10 pancreas alone) were carried out under this protocol between July 2003 to January 2005. The mean follow-up was 22 months (range 17-33).

RESULTS

One-year patient, pancreas, and kidney allograft survival were 95%, 93%, and 90%, respectively. With 22 months follow-up, patient, pancreas, and kidney survival were 94%, 89%, and 87%, respectively. The rejection rate was 30% (18/60), with four patients (7%) experiencing steroid-resistant rejection. Major infection occurred in three (5%) patients resulting in two (3.3%) deaths from disseminated histoplasmosis and a herpes virus infection. One patient with cryptococcal meningitis was successfully treated. Seven (11.7%) patients experienced cytomegalovirus infection, all of whom responded to treatment with ganciclovir. One (1.7%) case of polymorphic posttransplant lymphoproliferative disease was seen, which regressed with a temporary discontinuation of tacrolimus and high-dose ganciclovir. The mean serum creatinine of the 30 simultaneous pancreas-kidney transplants at one year posttransplant was 1.37+/-0.33 mg/ml. The preexisting creatinine in pancreas after kidney transplants was not adversely affected by this immunosuppressive protocol.

CONCLUSION

A single dose of perioperative alemtuzumab followed by daily tacrolimus monotherapy provides effective immunosuppression for pancreas transplantation, but the optimal use of this drug combination is not yet clear.

Functionally important glycosyltransferase gain and loss during catarrhine primate emergence

A glycosyltransferase, alpha1,3galactosyltransferase, catalyzes the terminal step in biosynthesis of Galalpha1,3Galbeta1-4GlcNAc-R (alphaGal), an oligosaccharide cell surface epitope. This epitope or antigenically similar epitopes are widely distributed among the different forms of life. Although abundant in most mammals, alphaGal is not normally found in catarrhine primates (Old World monkeys and apes, including humans), all of which produce anti-alphaGal antibodies from infancy onward. Natural selection favoring enhanced resistance to alphaGal-positive pathogens has been the primary reason offered to account for the loss of alphaGal in catarrhines. Here, we question the primacy of this immune defense hypothesis with results that elucidate the evolutionary history of GGTA1 gene and pseudogene loci. One such locus, GGTA1P, a processed (intronless) pseudogene (PPG), is present in platyrrhines, i.e., New World monkeys, and catarrhines but not in prosimians. PPG arose in an early ancestor of anthropoids (catarrhines and platyrrhines), and GGTA1 itself became an unprocessed pseudogene in the late catarrhine stem lineage. Strong purifying selection, denoted by low nonsynonymous substitutions per nonsynonymous site/synonymous substitutions per synonymous site values, preserved GGTA1 in noncatarrhine mammals, indicating that the functional gene product is subjected to considerable physiological constraint. Thus, we propose that a pattern of alternative and/or more beneficial glycosyltransferase activity had to first evolve in the stem catarrhines before GGTA1 inactivation could occur. Enhanced defense against alphaGal-positive pathogens could then have accelerated the replacement of alphaGal-positive catarrhines by alphaGal-negative catarrhines. However, we emphasize that positively selected regulatory changes in sugar chain metabolism might well have contributed in a major way to catarrhine origins.

Acquired immunologic tolerance: with particular reference to transplantation

The first unequivocally successful bone marrow cell transplantation in humans was recorded in 1968 by the University of Minnesota team of Robert A. Good (Gatti et al. Lancet 2: 1366-1369, 1968). This achievement was a direct extension of mouse models of acquired immunologic tolerance that were established 15 years earlier. In contrast, organ (i.e. kidney) transplantation was accomplished precociously in humans (in 1959) before demonstrating its feasibility in any experimental model and in the absence of a defensible immunologic rationale. Due to the striking differences between the outcomes with the two kinds of procedure, the mechanisms of organ engraftment were long thought to differ from the leukocyte chimerism-associated ones of bone marrow transplantation. This and other concepts of alloengraftment and acquired tolerance have changed over time. Current concepts and their clinical implications can be understood and discussed best from the perspective provided by the life and times of Bob Good.

Living donor renal transplantation using alemtuzumab induction and tacrolimus monotherapy

Alemtuzumab was used as an induction agent in 205 renal transplant recipients undergoing 207 living donor renal transplants. All donor kidneys were recovered laparoscopically. Postoperatively, patients were treated with tacrolimus monotherapy, and immunosuppression was weaned when possible. Forty-seven recipients of living donor renal transplants prior to the induction era who received conventional triple drug immunosuppression without antibody induction served as historic controls. The mean follow-up was 493 days in the alemtuzumab group and 2101 days in the historic control group. Actuarial 1-year patient and graft survival were 98.6% and 98.1% in the alemtuzumab group, compared to 93.6% and 91.5% in the control group, respectively. The incidence of acute cellular rejection (ACR) at 1 year was 6.8% in the alemtuzumab group and 17.0% (p < 0.05) in the historic control group. Most (81.3%) episodes of ACR in the alemtuzumab group were Banff 1 (a or b) and were sensitive to steroid pulses for the treatment of rejection. There was no cytomegalovirus disease or infection. The incidence of delayed graft function was 0%, and the incidence of posttransplant insulin-dependent diabetes mellitus was 0.5%. This study represents the largest series to date of live donor renal transplant recipients undergoing alemtuzumab induction, and confirms the short-term safety and efficacy of this approach.

Antilymphoid antibody preconditioning and tacrolimus monotherapy for pediatric kidney transplantation

OBJECTIVE

Heavy post-transplant immunosuppression may contribute to long-term immunosuppression dependence by subverting tolerogenic mechanisms; thus, we sought to determine if this undesirable consequence could be mitigated by pretransplant lymphoid depletion and minimalistic post-transplant monotherapy.

STUDY DESIGN

Lymphoid depletion in 17 unselected pediatric recipients of live (n = 14) or deceased donor kidneys (n = 3) was accomplished with antithymocyte globulin (ATG) (n = 8) or alemtuzumab (n = 9). Tacrolimus was begun post-transplantation with subsequent lengthening of intervals between doses (spaced weaning). Maintenance immunosuppression, morbidity, graft function, and patient/graft survival were collated.

RESULTS

Steroids were added temporarily to treat rejection in two patients (both ATG subgroup) or to treat hemolytic anemia in two others. After 16 to 31 months (mean 22), patient and graft survival was 100% and 94%, respectively. The only graft loss was in a nonweaned noncompliant recipient. In the other 16, serum creatinine was 0.85 +/- 0.35 mg/dL and creatinine clearance was 90.8 +/- 22.1 mL/1.73 m2. All 16 patients are on monotherapy (15 tacrolimus, one sirolimus), and 14 receive every other day or 3 times per week doses. There were no wound or other infections. Two patients developed insulin-dependent diabetes.

CONCLUSION

The strategy of lymphoid depletion and minimum post-transplant immunosuppression appears safe and effective for pediatric kidney recipients.

Simultaneous bone marrow and intestine transplantation promotes marrow-derived hematopoietic stem cell engraftment and chimerism

Organ allografts have been shown to provide a syngeneic microenvironment for organ-based donor hematopoietic stem cells to maintain long-lasting chimerism after transplantation. We hypothesized that organ allografts would also support engraftment and hematopoiesis of adjunctively infused donor marrow stem cells, syngeneic to organ grafts, in nonmyeloablated recipients. In BN-to-LEW and GFP-to-ACI rat combinations, donor bone marrow (BM) infusion together with small intestine transplantation (SITx) under short-course tacrolimus immunosuppression resulted in persistent macrochimerism (more than 5%) for 150 days. In contrast, after BM infusion or SITx alone, chimerism was temporary and disappeared by day 100. Y-chromosome polymerase chain reaction (PCR) in sex-mismatched male BM plus female intestine or female BM plus male intestine transplantation into female recipients suggested that persistent macrochimerism was derived from infused BM. BM infusion together with lymphoid-depleted intestine grafts also supported macrochimerism development; however, third-party intestine grafts did not. After GFP-positive BM plus wild-type (WT) SITx into ACI, large numbers of GFP-positive leukocytes were found in WT intestine grafts. Isolated cells from WT intestine grafts developed GFP-positive CFU-Cs and propagated multilineage GFP-positive leukocytes when adoptively transferred into lethally irradiated WT recipients. These findings suggest that intestine allograft supports simultaneously infused donor (syngeneic to organ grafts) marrow stem cell engraftment, differentiation, and persistence of chimerism.