Effects of bariatric surgery on telomere length and T-cell aging.

BACKGROUND: Obesity adversely affects health and is associated with subclinical systemic inflammation and features of accelerated aging, including the T-cell immune system. The presence of metabolic syndrome (MetS) may accelerate, while bariatric surgery might reverse these phenomena. To examine the effects of MetS and bariatric surgery on T-cell aging, we measured relative telomere length (RTL) and T-cell differentiation status in obese patients before and after bariatric surgery. METHODS: WHO II/III classified obese patients scheduled for bariatric surgery were included: 41 without MetS and 67 with MetS. RTL and T-cell differentiation status were measured in circulating CD4+ and CD8+ T cells via flow cytometry. T-cell characteristics were compared between patients with and without MetS prior to and at 3, 6, and 12 months after surgery considering effects of age, cytomegalovirus-serostatus, and weight loss. RESULTS: Thymic output, represented by numbers of CD31-expressing naive T cells, showed an age-related decline in patients with MetS. MetS significantly enhanced CD8+ T-cell differentiation. Patients with MetS had significant lower CD4+ RTL than patients without MetS. Within the first 6 months after bariatric surgery, RTL increased in CD4+ T cells after which it decreased at month 12. A decline in both thymic output and more differentiated T cells was seen following bariatric surgery, more pronounced in the MetS group and showing an association with percentage of body weight loss. CONCLUSIONS: In obese patients, MetS results in attrition of RTL and accelerated T-cell differentiation. Bariatric surgery temporarily reverses these effects. These data suggest that MetS is a risk factor for accelerated aging of T cells and that MetS should be a more prominent factor in the decision making for eligibility for bariatric surgery.

Systematic Review and Meta-Analysis of the Impact of Computed Tomography-Assessed Skeletal Muscle Mass on Outcome in Patients Awaiting or Undergoing Liver Transplantation.

Liver transplant outcome has improved considerably as a direct result of optimized surgical and anesthesiological techniques and organ allocation programs. Because there remains a shortage of human organs, strict selection of transplant candidates remains of paramount importance. Recently, computed tomography (CT)-assessed low skeletal muscle mass (i.e. sarcopenia) was identified as a novel prognostic parameter to predict outcome in liver transplant candidates. A systematic review and meta-analysis on the impact of CT-assessed skeletal muscle mass on outcome in liver transplant candidates were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Nineteen studies, including 3803 patients in partly overlapping cohorts, fulfilled the inclusion criteria. The prevalence of sarcopenia ranged from 22.2% to 70%. An independent association between low muscle mass and posttransplantation and waiting list mortality was described in 4 of the 6 and 6 of the 11 studies, respectively. The pooled hazard ratios of sarcopenia were 1.84 (95% confidence interval 1.11-3.05, p = 0.02) and 1.72 (95% confidence interval 0.99-3.00, p = 0.05) for posttransplantation and waiting list mortality, respectively, independent of Model for End-stage Liver Disease score. Less-consistent evidence suggested a higher complication rate, particularly infections, in sarcopenic patients. In conclusion, sarcopenia is an independent predictor for outcome in liver transplantation patients and could be used for risk assessment.

Improving the outcome of kidney transplantation by ameliorating renal ischemia reperfusion injury: lost in translation?

Kidney transplantation is the treatment of choice in patients with end stage renal disease. During kidney transplantation ischemia reperfusion injury (IRI) occurs, which is a risk factor for acute kidney injury, delayed graft function and acute and chronic rejection. Kidneys from living donors show a superior short- and long-term graft survival compared with deceased donors. However, the shortage of donor kidneys has resulted in expansion of the donor pool by using not only living- and brain death donors but also kidneys from donation after circulatory death and from extended criteria donors. These grafts are associated with an increased sensitivity to IRI and decreased graft outcome due to prolonged ischemia and donor comorbidity. Therefore, preventing or ameliorating IRI may improve graft survival. Animal experiments focus on understanding the mechanism behind IRI and try to find methods to minimize IRI either before, during or after ischemia. This review evaluates the different experimental strategies that have been investigated to prevent or ameliorate renal IRI. In addition, we review the current state of translation to the clinical setting. Experimental research has contributed to the development of strategies to prevent or ameliorate IRI, but promising results in animal studies have not yet been successfully translated to clinical use.

Systematic review of sarcopenia in patients operated on for gastrointestinal and hepatopancreatobiliary malignancies.

BACKGROUND: Preoperative risk assessment in cancer surgery is of importance to improve treatment and outcome. The aim of this study was to assess the impact of CT-assessed sarcopenia on short- and long-term outcomes in patients undergoing surgical resection of gastrointestinal and hepatopancreatobiliary malignancies. METHODS: A systematic search of Embase, PubMed and Web of Science was performed to identify relevant studies published before 30 September 2014. PRISMA guidelines for systematic reviews were followed. Screening for inclusion, checking the validity of included studies and data extraction were carried out independently by two investigators. RESULTS: After screening 692 records, 13 observational studies with a total of 2884 patients were included in the analysis. There was wide variation in the reported prevalence of sarcopenia (17.0-79 per cent). Sarcopenia was independently associated with reduced overall survival in seven of ten studies, irrespective of tumour site. Hazard ratios (HRs) of up to 3.19 (hepatic cancer), 1.63 (pancreatic cancer), 1.85 (colorectal cancer) and 2.69 (colorectal liver metastases, CLM) were reported. For oesophageal cancer, the HR was 0.31 for increasing muscle mass. In patients with colorectal cancer and CLM, sarcopenia was independently associated with postoperative mortality (colorectal cancer: odds ratio (OR) 43.3), complications (colorectal cancer: OR 0.96 for increasing muscle mass; CLM: OR 2.22) and severe complications (CLM: OR 3.12). CONCLUSION: Sarcopenia identified before surgery by single-slice CT is associated with impaired overall survival in gastrointestinal and hepatopancreatobiliary malignancies, and increased postoperative morbidity in patients with colorectal cancer with or without hepatic metastases.

PROMISE: effect of protein supplementation on fat-free mass preservation after bariatric surgery, a randomized double-blind placebo-controlled trial.

INTRODUCTION: Protein malnutrition after bariatric surgery is a severe complication and leads to significant morbidity. Previous studies have shown that protein intake and physical activity are the most important factors in the preservation of fat-free mass during weight loss. Low protein intake is very common in patients undergoing bariatric surgery despite dietary counseling. Protein powder supplements might help patients to achieve the protein intake recommendations after bariatric surgery and could therefore contribute to preserve fat-free mass. This double-blind randomized placebo-controlled intervention study aims to assess the effect of a daily consumed clear protein powder shake during the first 6 months after bariatric surgery on fat-free mass loss in the first 12 months after laparoscopic Roux-en-Y gastric bypass (LRYGB). METHODS AND ANALYSIS: Inclusion will take place at the outpatient clinic of the bariatric expertise center for obesity of the Maasstad Hospital. Patients will be randomly assigned to either the intervention or control group before surgery. The intervention group will receive a clear protein powder shake of 200 ml containing 20 g of whey protein dissolved in water which should be taken daily during the first 6 months after LRYGB on top of their normal postoperative diet. The control group will receive an isocaloric, clear, placebo shake containing maltodextrine. Postoperative rehabilitation and physiotherapeutical guidance will be standardized and similar in both groups. Also, both groups will receive the same dietary advice from specialized dieticians. The main study parameter is the percentage of fat-free mass loss 6 months after surgery, assessed by multi-frequency bioelectrical impedance analysis (MF-BIA). ETHICS AND DISSEMINATION: The protocol, version 2 (February 20, 2022) has been approved by the Medical Research Ethics Committees United (MEC-U) (NL 80414.100.22). The results of this study will be submitted to peer-reviewed journals. TRIAL REGISTRATION: ClinicalTrials.gov NCT05570474. Registered on October 5, 2022.

T and B Cell Composition and Cytokine Producing Capacity Before and After Bariatric Surgery.

Morbid obesity is associated with a chronic state of low-grade inflammation, which may lead to accelerated differentiation of T and B cells. These differentiated immune cells are strongly cytotoxic and have an increased pro-inflammatory cytokine producing capacity. Furthermore, the anti-inflammatory function of the T and B cells decreases. The aim of this study was to evaluate the effect of morbid obesity on the subset profile and cytokine producing capacity of T and B cells. Subsequently, we assessed whether bariatric surgery affected the subset profile and cytokine producing capacity of these cells. We determined the proportion of T and B cell subsets and their cytokine producing capacity in peripheral blood collected from 23 morbidly obese patients before and three months after bariatric surgery using flow-cytometry. We compared this with the results of 25 lean controls. Both CD4+ and CD8+ T cells showed a more differentiated subset profile in morbidly obese patients as compared to lean controls, which was not recovered three months after bariatric surgery. The B cell composition of morbidly obese patients after bariatric surgery adjusted towards the profile of lean controls. However, the IL-2 and IFN-γ producing capacity of CD8+ T cells and the IL-2, IFN-γ, TNF-α and IL-10 producing capacity of B cells was not restored three months after bariatric surgery. In conclusion, the data suggest that the immune system has the capacity to recover from the detrimental effects of morbid obesity within three months after bariatric surgery in terms of cell composition; however, this was not seen in terms of cytokine producing capacity. The full restoration of the immune system after bariatric surgery may thus take longer.

The importance of portal venous blood flow in ischemic-type biliary lesions after liver transplantation.

Ischemic-type biliary lesions (ITBL) are the most frequent cause of nonanastomotic biliary strictures after liver transplantation. This complication develops in up to 25% of patients, with a 50% retransplantation rate in affected patients. Traditionally, ischemia-reperfusion injury to the biliary system is considered to be the major risk factor for ITBL. Several other risk factors for ITBL have been identified, including the use of liver grafts donated after cardiac death, prolonged cold and warm ischemic times and use of University of Wisconsin preservation solution. In recent years however, impaired microcirculation of the peribiliary plexus (PBP) has been implicated as a possible risk factor. It is widely accepted that the PBP is exclusively provided by blood from the hepatic artery, and therefore, the role of the portal venous blood supply has not been considered as a possible cause for the development of ITBL. In this short report, we present three patients with segmental portal vein thrombosis and subsequent development of ITBL in the affected segments in the presence of normal arterial blood flow. This suggests that portal blood flow may have an important contribution to the biliary microcirculation and that a compromised portal venous blood supply can predispose to the development of ITBL.

Safety and feasibility of 2 h of normothermic machine perfusion of donor kidneys in the Eurotransplant Senior Program.

BACKGROUND: The 5-year graft survival rate of donor kidneys transplanted in the Eurotransplant Senior Program (ESP) is only 47 per cent. Normothermic machine perfusion (NMP) may be a new preservation technique that improves graft outcome. This pilot study aimed to assess safety and feasibility of this technique within the ESP. METHODS: Recipients were eligible for inclusion if they received a donor kidney within the ESP. Donor kidneys underwent 2 h of oxygenated NMP with a red cell-based solution at 37°C, additional to standard-of-care preservation (non-oxygenated hypothermic machine perfusion). The primary outcome was the safety and feasibility of NMP. As a secondary outcome, graft outcome was investigated and compared with that in a historical group of patients in the ESP and the contralateral kidneys. RESULTS: Eleven patients were included in the NMP group; the function of eight kidneys could be compared with that of the contralateral kidney. Fifty-three patients in the ESP, transplanted consecutively between 2016 and 2018, were included as controls. No adverse events were noted, especially no arterial thrombosis or primary non-function of the transplants. After 120 min of oxygenated NMP, median flow increased from 117 (i.q.r. 80-126) to 215 (170-276) ml/min (P = 0.001). The incidence of immediate function was 64 per cent in the NMP group and 40 per cent in historical controls (P = 0.144). A significant difference in graft outcome was not observed. DISCUSSION: This pilot study showed NMP to be safe and feasible in kidneys transplanted in the ESP. A well powered study is warranted to confirm these results and investigate the potential advantages of NMP on graft outcome.

Inhibition of activin-like kinase 4/5 attenuates cancer cachexia associated muscle wasting.

Cancer mediated activation of the ActRIIB-ALK4/5 heterodimer by myostatin is strongly associated with muscle wasting. We investigated in vitro and in vivo the efficacy of ALK4/5 receptor blockers SB431542 and GW788388 in preventing muscle wasting, and explored synergy with IGF-I analogue LONG R3 (LR3) IGF-I. In vitro, C2C12 skeletal muscle cells were treated with vehicle, SB431542, GW788388 and LR3 IGF-I. A C26-CD2F1 cachexia model was used to induce cachexia in vivo. Mice were allocated as non-tumour bearing (NTB) or C26 tumour-bearing (C26 TB) vehicle control, treated with SB431542, LR3 IGF-I, SB431542 and LR3 IGF-I, or GW788388 (intraperitoneally or orally). In vitro, differentiation index and mean nuclei count increased using SB431542, GW788388, LR3 IGF-I. In vivo, GW788388 was superior to SB431542 in limiting loss of bodyweight, grip-strength and gastrocnemius weight. and downregulated Atrogin-1 expression comparable to NTB mice. LR3 IGF-I treatment limited loss of muscle mass, but at the expense of accelerated tumour growth. In conclusion, treatment with GW788388 prevented cancer cachexia, and downregulated associated ubiquitin ligase Atrogin-1.

Anastomotic leakage, the search for a reliable biomarker. A review of the literature.

BACKGROUND: Colorectal anastomotic leakage (AL) is a severe complication leading to severe infection, sepsis and sometimes death. At present the diagnosis is made clinically, usually at 6-8 days after surgery. An objective biomarker reflecting the intra-abdominal milieu surrounding the anastomosis would be a useful additional diagnostic tool to make the diagnosis of AL before its clinical presentation. This review aims to assess the current status of the search for such a biomarker in peritoneal fluid. METHOD: A literature search was carried out, using MEDLINE, PubMed and the Cochrane library, for all publications concerning human peritoneal fluid in relation to postoperative complications in general, and, more specific, anastomotic leakage after colorectal surgery. RESULTS: Analysis of several immune parameters, tissue repair parameters, parameters for ischaemia and microbiological composition of peritoneal fluid show that these can be determined reliably in the fluid, albeit with a large variance. Furthermore the data show that changes in concentration of these parameters precede AL and other postoperative complications by several days. CONCLUSION: The results of the review demonstrate that it is possible to distinguish between patients with and without AL by measuring biomarkers in fluid from the peritoneal drain. Prospective studies with larger numbers of patients should, however, be performed and additional biomarkers should be studied to explore the full diagnostic potential of this approach.

Muscle wasting and survival following pre-operative chemoradiotherapy for locally advanced rectal carcinoma.

BACKGROUND & AIMS: Neoadjuvant chemoradiotherapy (NACRT) has increased local control in locally advanced rectal cancer. Reduced skeletal muscle mass (sarcopenia), or ongoing muscle wasting, is associated with decreased survival in cancer. This study aims to assess the change in body composition during NACRT and its impact on outcome using computed tomography (CT) imaging in locally advanced rectal cancer (LARC) patients. METHODS: LARC patients treated with NACRT were selected from a prospectively maintained database and retrospectively analyzed. One-hundred twenty-two patients who received treatment between 2004 and 2012 with available diagnostic CT imaging obtained before and after NACRT were identified. Cross-sectional areas for skeletal muscle was determined, and subsequently normalized for patient height. Differences between skeletal muscle areas before and after NACRT were computed, and their influence on overall and disease-free survival was assessed. RESULTS: A wide distribution in change of body composition was observed. Loss of skeletal muscle mass during chemoradiotherapy was independently associated with disease-free survival (HR0.971; 95% CI: 0.946-0.996; p = 0.025) and distant metastasis-free survival (HR0.942; 95% CI: 0.898-0.988; p = 0.013). No relation was observed with overall survival in the current cohort. CONCLUSIONS: Loss of skeletal muscle mass during NACRT in rectal cancer patients is an independent prognostic factor for disease-free survival and distant metastasis-free survival following curative intent resection.

A signature of renal stress resistance induced by short-term dietary restriction, fasting, and protein restriction.

During kidney transplantation, ischemia-reperfusion injury (IRI) induces oxidative stress. Short-term preoperative 30% dietary restriction (DR) and 3-day fasting protect against renal IRI. We investigated the contribution of macronutrients to this protection on both phenotypical and transcriptional levels. Male C57BL/6 mice were fed control food ad libitum, underwent two weeks of 30%DR, 3-day fasting, or received a protein-, carbohydrate- or fat-free diet for various periods of time. After completion of each diet, renal gene expression was investigated using microarrays. After induction of renal IRI by clamping the renal pedicles, animals were monitored seven days postoperatively for signs of IRI. In addition to 3-day fasting and two weeks 30%DR, three days of a protein-free diet protected against renal IRI as well, whereas the other diets did not. Gene expression patterns significantly overlapped between all diets except the fat-free diet. Detailed meta-analysis showed involvement of nuclear receptor signaling via transcription factors, including FOXO3, HNF4A and HMGA1. In conclusion, three days of a protein-free diet is sufficient to induce protection against renal IRI similar to 3-day fasting and two weeks of 30%DR. The elucidated network of common protective pathways and transcription factors further improves our mechanistic insight into the increased stress resistance induced by short-term DR.

Effect of prolonged warm ischemia and pneumoperitoneum on renal function in a rat syngeneic kidney transplantation model.

BACKGROUND: Laparoscopic donor nephrectomy is associated with several advantages for the donor. However, graft function may be impaired due to use of pneumoperitoneum and prolonged warm ischemia. This study investigated the impact of pneumoperitoneum and prolonged warm ischemia on long-term graft function in a syngeneic rat renal transplant model. METHODS: A total of 27 Brown Norway rats were randomized for transplantation of kidneys after three different procedures: no insufflation and no warm ischemia (group 1), no insufflation with 20 min of warm ischemia (group 2), and CO2 insufflation and 20 min of warm ischemia (group 3). Glomerular filtration rate (GRF), serum creatinine, urine volume, urine creatinine, and proteinuria were determined monthly for 1 year. One year after transplantation, the grafts were removed for histomorphologic analysis. RESULTS: No significant differences in GRF, serum creatinine, urine volume, and proteinuria were found among the three groups. Histologic analysis also showed no differences between the groups. CONCLUSION: Warm ischemia in combination with CO2 pneumoperitoneum, as used in laparoscopic donor nephrectomy, does not result in a negative effect on long-term graft function.

Fate and Effect of Intravenously Infused Mesenchymal Stem Cells in a Mouse Model of Hepatic Ischemia Reperfusion Injury and Resection.

Liver ischemia reperfusion injury (IRI) is inevitable during transplantation and resection and is characterized by hepatocellular injury. Therapeutic strategies to reduce IRI and accelerate regeneration could offer major benefits. Mesenchymal stem cells (MSC) are reported to have anti-inflammatory and regeneration promoting properties. We investigated the effect of MSC in a model of combined IRI and partial resection in the mouse. Hepatic IRI was induced by occlusion of 70% of the blood flow during 60 minutes, followed by 30% hepatectomy. 2 × 10(5) MSC or PBS were infused 2 hours before or 1 hour after IRI. Six, 48, and 120 hours postoperatively mice were sacrificed. Liver damage was evaluated by liver enzymes, histology, and inflammatory markers. Regeneration was determined by liver/body weight ratio, proliferating hepatocytes, and TGF-ß levels. Fate of MSC was visualized with 3D cryoimaging. Infusion of 2 × 10(5) MSC 2 hours before or 1 hour after IRI and resection showed no beneficial effects. Tracking revealed that MSC were trapped in the lungs and did not migrate to the site of injury and many cells had already disappeared 2 hours after infusion. Based on these findings we conclude that intravenously infused MSC disappear rapidly and were unable to induce beneficial effects in a clinically relevant model of IRI and resection.

Late graft dysfunction after prolonged cold ischemia of the donor kidney: inhibition by cyclosporine.

BACKGROUND: The present study was devised to elucidate the influence of prolonged cold ischemia on the development of chronic transplant dysfunction (CTD) in kidney isografts (Brown Norway-->Brown Norway; BN-->BN) and in kidney allografts (BN-->Wistar Agouti/ Rij [WAG]) under temporary cyclosporine (CsA) therapy. METHODS: To induce ischemic injury, BN donor kidneys were preserved for 24 hr in 4 degrees C University of Wisconsin solution before transplantation. Renal function (proteinuria), histomorphology according to the BANFF criteria for CTD, and infiltrating cells were assessed. Grafts were examined both early at days 2, 3, 6, and 10, and late at week 26 (allografts) or at week 52 (isografts). RESULTS: Nonischemic isografts preserved a normal function and morphology. Ischemic isografts developed a progressive proteinuria over time and demonstrated significantly more glomerulopathy with macrophage (Me) infiltration and intimal hyperplasia than nonischemic controls at week 52. During the initial 10 days, there was an increased infiltration of MHC class II+ cells, predominantly CD4+ cells and Mphi, coinciding with up-regulated intercellular adhesion molecule-1 expression. CsA treatment in ischemic isografts inhibited infiltration of MHC II+ cells in the early stage, which was accompanied by significantly less renal damage at week 52 compared with untreated controls (proteinuria: 59+/-8 vs. 134+/-19 mg/24 hr; BANFF score: 2.8+/-0.4 vs. 4.3+/-1.0). Under CsA therapy, 24-hr cold ischemia of the allograft affected neither the onset or progress of proteinuria, nor the histomorphology (BANFF score: 7.8+/-2.4 vs. 7.3+/-1.9). In both ischemic and nonischemic allografts, intercellular adhesion molecule-1 expression and mononuclear cell infiltration (CD4, CD8, Mphi was abundantly present during the first 10 days and function deteriorated rapidly. CONCLUSIONS: Prolonged cold ischemia plays a role in the induction of CTD, but its deleterious effect can be successfully inhibited by CsA. Therefore, the alloantigeneic stimulus is the overriding component in the multifactorial pathogenesis of CTD.

Moderate effect of preoperative blood transfusions on pancreas allograft survival in rats and dogs.

Treatment of type I diabetes by early pancreas transplantation requires the availability of a safe and effective transplantation technique. With the currently available immunosuppressive drugs it is difficult to obtain long-term pancreatic allograft survival. In this respect pancreas grafts compare unfavorably with heart or kidney grafts. Using a relatively simple and safe subcutaneous transplantation technique we investigated the effect of blood transfusions combined with low-dose immunosuppressive drugs in rats and dogs in order to attain an immunosuppressive schedule of low toxicity. Subcutaneous pancreas transplantation appeared to be a feasible technique, with long-term graft survival in syngeneically transplanted rats and autotransplanted dogs. Only a moderate prolongation of pancreatic allograft survival by blood transfusions was demonstrated in both models. In rats one or three preoperative donor-specific blood transfusions significantly prolonged pancreas graft survival to 23 +/- 15 and 29 +/- 15 days, respectively, compared with 12 +/- 2 days in untreated controls. Low-dose cyclosporine (15 mg/kg on the day of operation) led to improved graft survival in nontransfused recipients (17 +/- 4 days), however, this treatment could not further prolong graft survival in transfused animals (34 +/- 20 days). In dogs, treated postoperatively with azathioprine and prednisolone, three preoperative third-party blood transfusions led to 29 +/- 19 days of pancreas graft survival, which was not significantly different from nontransfused controls (17 +/- 5 days). These results indicate that, in rats as well in dogs, pancreatic allografts are less sensitive to the immunomodulating effect of blood transfusions than heart and kidney grafts.

Small bowel transplantation in rats. The effect of pretransplant donor-specific blood transfusions on various segments of small bowel grafts.

The effects of pretransplant donor-specific blood transfusion on the survival of orthotopic small bowel transplants in rats were investigated in the fully allogeneic BN (Rt1n) to WAG (Rt1u) donor-host combination. Previous studies show that in this combination DSTs lead to permanent survival of heterotopically transplanted hearts, marked prolongation of kidney grafts, and moderate prolongation of pancreas grafts but have no effect on skin grafts. Without pretreatment, total small bowel grafts (+/- 45 cm) were rejected in 12.2 +/- 1.8 days (mean +/- SD), and 10-cm segments of jejunum or ileum in 11.2 +/- 4.0 and 11.6 +/- 0.5 days, respectively. Three DSTs given on days -21, -14, and -7 before transplantation had no effect on graft survival in any of the groups tested. Total small bowel grafts were rejected in 12.8 +/- 2.5 days, and 10-cm-long segments or jejunum or ileum in 17.0 +/- 7.2 days and 11.5 +/- 2.7 days, respectively. Graft-versus-host disease, which was mild and transient, occurred in 50% of the nontreated rats engrafted with a total small bowel, in 40% of the animals transplanted with an ileum segment, and in none of the rats that received a jejunal transplant. In the DST-pretreated groups, none of the animals transplanted with a total small bowel or ileum segment and 16.6% of the animals transplanted with a jejunum segment showed clinical signs of GVHD. When DST pretreatment was combined with cyclosporine, grafts did not survive any longer than with cyclosporine treatment alone. It is concluded that DSTs ameliorate GVHD but do not prolong the survival of small bowel allografts nor act additively with cyclosporine treatment.

The limited efficacy of cyclosporine in preventing rejection and graft-versus-host disease in orthotopic small bowel transplantation in rats.

The effect of different schedules of cyclosporine treatment on the survival of small bowel allografts was studied in rats. The administration of a short course of CsA (15 mg/kg on days 0, 1, 2, 4, and 6) had no beneficial effect on graft-vs.-host disease and survival time of the recipient compared with untreated controls. CsA, 25 mg/kg for 1 or 2 weeks prolonged survival significantly (38.3 +/- 3.8 and 42.5 +/- 2.7 vs. 16.6 +/- 2.7, P less than 0.01). When combined with maintenance therapy, 15 mg/kg of CsA 3 times weekly until day 100, only 7 of 30 rats survived more than 100 days. In addition, GVHD was not consistently abrogated in these groups. Only high doses of CsA (25 mg/kg on days 0-6, 15 mg/kg on days 7-13, followed by maintenance therapy) could prevent the onset of GVHD, although the survival time of the transplants was not prolonged compared with untreated controls due to a toxic side effect of CsA on the transplants. It can be concluded that CsA used as monotherapy is ineffective in consistently ameliorating GVHD and rejection in the WAG-BN rat model. This model exhibits at least some of the immunological problems seen in large animal models and can be useful in studying combinations of immunosuppressive drugs or methods that may be applicable to small bowel transplantation in man.

Total orthotopic allogeneic small bowel transplantation in rats. Attempts to ameliorate the graft-versus-host disease by irradiation and transfusions of the donor.

The effect of pretransplant specific blood transfusions and irradiation of the donor were studied in total orthotopic small bowel transplantation in rats, with the aim of ameliorating the graft-versus-host reaction. Syngeneic transplantation with or without irradiation of the donor with 10 Gy showed that small bowel transplantation is compatible with a normal nutritional status, when no rejection is involved. Transplantation in the histoincompatible WAG-to-BN combination without pretreatment resulted in rejection of the small bowel grafts in 16.6 +/- 2.7 days. Pretreatment with 3 BN blood transfusions to the WAG donor did not prolong the survival time; surprisingly, the transfusions induced a more-severe GVH reaction. Irradiation of the donor with 10 Gy was very effective in ameliorating the GVH disease, but the absence of the immunosuppressive effect of the GVH disease did lead to an accelerated graft rejection (7.5 +/- 0.9 days).

Suppression of acute rejection prevents graft arteriosclerosis after allogeneic aorta transplantation in the rat.

Rat aortic allografts develop arteriosclerotic alterations in the vascular wall that are histologically similar to those observed in chronic rejecting vascular allografts. We used cyclosporine and rapamycin (RAPA) in two different rat strain aorta transplantation models to investigate the effect of immunosuppression on posttransplant graft arteriosclerosis. High dose CsA (25 mg/kg, 3 times/week) treatment significantly inhibited intimal proliferation in the "strong" WAG-BN model (P < 0.01) as well as in the "weak" BN-WAG combination (P < 0.001), compared with untreated allogeneic controls. In the latter combination, even fewer intimal lesions were present than in WAG autotransplants, suggesting that CsA may also inhibit the arteriosclerotic response to mechanical injury. RAPA (3 mg/kg, 3 times/week) was as effective as CsA in reducing intimal lesions (P < 0.01 and P < 0.001 in the BN-WAG and WAG-BN models, respectively). Low dose CsA (5 mg/kg, 3 times/week) was only partially effective in preventing intimal lesions. Histology of the nontreated allografts showed ongoing acute rejection in the adventitial layer. The degree of cellular infiltration correlated with the severity of arteriosclerotic lesions. High dose CsA and RAPA treatment prevented adventitial infiltration in both models, while low dose CsA was only moderately effective. In conclusion, in the present study, the degree of arteriosclerotic involvement after allogeneic aorta transplantation was related to the severity of cellular adventitial infiltration. The myointimal thickening was inhibited by effective immunosuppressive treatment. These observations may imply that chronic rejection develops after ineffective immunosuppression.