Robert A. Sells

Adenosine triphosphate regeneration and function in the rat kidney following warm ischaemia.

SUMMARY Tissue levels of adonosine triphosphate (ATP) have been measured in rat kidneys following periods of warm ischaemia: (1) immediately after the ischaemic period and (2) after the kidney had been reperfused with blood for 10 min. ATP levels at the end of the period of ischaemia are similar for ischaemic periods of 10 to 60 min and give no indication of the kidneys subsequent functional ability. The amount of ATP regenerated in 10 min of reperfusion correlates both with the duration of the period of ischaemia and with the subsequent functional ability of the kidney.

Clinical outcome of cadaveric renal allografts contaminated before transplantation

This analysis was performed to define the incidence of pretransplant microbial contamination of donor kidneys, and to assess the resultant morbidity including infections requiring therapy, and graft loss. Case records of all 638 renal allograft recipients patients transplanted in our centre during the period June 1990 to October 2000 were studied. All the recipients were given a single dose of intravenous antibiotics at the time of induction of anaesthesia. A total of 775 microbiology reports on perfusion fluid, kidney swabs and ureteric tissue were retrieved. Fifty‐eight of 638 (9.1%) patients were transplanted with a graft that showed preoperative contamination. 18 of these 58 patients (31%) subsequently required antibiotic treatment. Thirty of 32 patients who received kidney contaminated with skin flora had a benign course (i.e. no unexplained, no positive blood cultures or graft infection). By contrast, seven of nine recipients with grafts whose perfusion fluid yielded lactose fermenting coliforms (LFCs) required antibiotics and three of nine of them suffered graft loss as a result. Two of these patients had bacteraemia caused by LFC, and one died. Three of five patients with positive cultures due to yeast required treatment with antifungals. None of the four patients who had graft contaminated by Staphylococcus aureus became infected. One‐year 49/58 (85%) of these patients survived with functioning graft. Overall 1‐year patient survival was 53/55 (92%). These data suggest that contamination of renal allografts by LFCs or yeasts need to be treated preemptively before the onset of clinical manifestations. By contrast, contamination with skin contaminants does not pose a risk to the graft.

Localization of C-X-C and C-C chemokines to renal tubular epithelial cells in human kidney transplants is not confined to acute cellular rejection.

Chemokines are important mediators of leucocyte chemoattraction to inflammatory sites. Previous work has shown that the expression of some chemokines is upregulated during renal transplant rejection. The objectives of the present study were to determine whether chemokine expression is increased during renal transplant rejection. Immunohistochemistry was used to localize the C-X-C (alpha) chemokine interleukin-8 (IL-8) and the C-C (beta) chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1beta (MIP-1beta) in 30 needle biopsies of human kidney transplants taken for diagnosis of renal dysfunction. Urine samples from transplant patients taken immediately prior to biopsy were assayed for chemokine content using enzyme-linked immunosorbent assays (ELISAs). Results from groups of patients having different clinicopathological diagnoses were then compared. All three chemokines were detected in most renal transplant biopsies showing acute cellular rejection but, although infiltrating leucocytes were often positive, staining was predominantly localized to renal tubular epithelium. Staining for MCP-1 was generally weaker than for the other chemokines, and collecting tubules were usually stained more strongly than proximal convoluted tubules. Tubular epithelial staining was also found in biopsies from patients without signs of acute cellular rejection. There were significantly higher amounts of IL-8 in the urine of patients with acute cellular rejection, even when patients with urinary tract infections were excluded, but mean titres of urinary MIP-1beta did not differ between patient groups. This was also found when titres were normalized for urine volume and creatinine levels. Production of IL-8, MCP-1 and MIP-1beta is not confined to kidney transplants showing acute cellular rejection, and may be a relatively nonspecific response of tubular epithelial cells to renal damage.

Cardiovascular complications following renal transplantation

Summary CAD is an important risk after renal transplantation and increases the death rate to a level many times higher than in individuals who do not suffer renal failure. Two prophylactic interventions are of proven value in the general patient population and for which there is indirect evidence of some survival benefit in pre- and posttransplant patients. They are: 1. Coronary revascularisation in appropriate patients identified by angiography; 2. “Statin” treatment in those experiencing posttransplant hypercholesterolaemia. The former is known to provide improved patient survival in diabetics, and by implication also non-diabetic renal transplant recipients. The latter is associated with a reduction of blood cholesterol levels towards normal, and with an improvement in the “atherogenic” fraction to levels which are associated with fewer myocardial infarctions and cardiac deaths in other large epidemiological studies. We may conclude that applying at least these two prophylactic steps would reduce the presently high death rate in the mid and long term after renal transplantation. Pre-transplant cardiac scintigraphy, with pharmacological stress, predicts reasonably accurately those individuals in whom coronary arteriography is indicated. Suitable patients may then have their coronary stenoses dealt with surgically to good effect. Normocholesterolaemia induced in selected patients by “statin” prescription seems logical, on hypothetical grounds, although there is need for a multi-centre trial involving 10 year follow-up to elucidate this effect. Recently licensed new immunosuppressives (FK506, MMF) seem to have little elevating effect on blood cholesterol levels, though more long-term data are needed. In the meantime, altering cyclosporine and steroid dosage with newer agents in susceptible recipients (hypercholesterolaemics, cardiopaths) or substitutive therapy, would seem a wise management strategy, the new drugs give future hope for even better control of cholesterol metabolism, and thus vascular disease.

RENAL TUBULAR PEPTIDE CATABOLISM IN CHRONIC VASCULAR REJECTION

Chronic vascular rejection (CR) is the commonest cause of renal transplant loss, with few clues to etiology, but proteinuria is a common feature. In diseased native kidneys, proteinuria and progression to failure are linked. We proposed a pathogenic role for this excess protein at a tubular level in kidney diseases of dissimilar origin. We demonstrated in both nephrotic patients with normal function and in those with failing kidneys increased renal tubular catabolisman and turnover rates of a peptide marker, Aprotinin (Apr), linked to increased ammonia excretion and tubular injury. These potentially injurious processes were suppressed by reducing proteinuria with Lisinopril. Do similar mechanisms of renal injury and such a linkage also occur in proteinuric transplanted patients with CR, and if so, is Lisinopril then of beneficial value? We now examine these aspects in 11 patients with moderate/severe renal impairment (51CrEDTA clearance 26.2 ± 3.3 mL/min/1.73m2), proteinuria (6.1 ± 1.5 g/24 h) and biopsy proven CR. Lisinopril (10–40 mg) was given daily for 2 months in 7 patients. Four others were given oral sodium bicarbonate (Na HCO3) for 2 months before adding Lisinopril. Renal tubular catabolism of intravenous 99mTc-Apr (Apr* 0.5 mg, 80 MBq), was measured before and after Lisinopril by γ-ray renal imaging and urinary radioactivity of the free radiolabel over 26 h. Fractional degradation was calculated from these data. Total 24 h urinary N-acetyl-β-glucoaminidase (NAG) and ammonia excretion in fresh timed urine collections were also measured every two weeks from two months before treatment. After Lisinopril proteinuria fell significantly (from 7.8 ± 2.2 to 3.4 ± 1.9 g/24 h, p < 0.05). This was associated with a reduction in metabolism of Apr* over 26 h (from 0.5 ± 0.05 to 0.3 ± 0.005% dose/h, p < 0.02), and in fractional degradation (from 0.04 ± 0.009 to 0.02 ± 0.005/h, p <0.01). Urinary ammonia fell, but surprisingly not significantly and this was explained by the increased clinical acidosis after Lisinopril, (plasma bicarbonate fell from 19.1 ± 0.7 to 17.4 ± 0.8 mmol/L, p <0.01), an original observation. Total urinary NAG did fall significantly from a median of 2108 (range 1044–3816) to 1008 (76–2147) μmol/L, p < 0.05. There was no significant change in blood pressure or in measurements of glomerular hemodynamics. In the 4 patients who were given Na HCO3 before adding Lisinopril, both acidosis (and hyperkalemia) were reversed and neither recurred after adding Lisinopril. These observations in proteinuric transplanted patients after Lisinopril treatment have not been previously described.

Core Needle Biopsy in Renal Transplantation

Core biopsies have been done by ultrasound assisted 18-G disposable needles with a spring loaded gun (Biopty) system in 140 renal transplant cases either for investigation of an early non-functioning graft or evaluation of deteriorating graft functions. The biopsy procedure was successfully completed in 99.5% and sufficient amount of renal tissue was obtained in 88% of cases. The pathological diagnoses were confirmed 100% by the other clinical parameters of cases with acute cellular rejection, pyelonephritis, acute tubular necrosis and there was disease recurrence. In another 8 patients (6%) where the pathological picture was showing either no or nonspecific changes there was no major change in clinical outcome. In addition, clinical diagnoses of chronic vascular rejection and Cyclosporin A toxicity were confirmed in 93.7% and 91.7%, respectively, in biopsies of these cases. Complications were seen in 3 patients as a bowel perforation, intra-abdominal bleeding and formation of an intrarenal arterio-venous fistula. In former two complicated cases there was no need for any extra treatment but the arterio-venous fistula was successfully embolized through an angiography catheter without losing the graft. We conclude that the Biopty system is more efficient than the fine needle aspiration biopsy especially when the pathological diagnosis can be made upon tissue components rather than cells alone.

The chyloesophageal fistula. A new approach to thoracic duct drainage.

: The main reason for the virtual abandonment of external thoracic duct drainage as an immunosuppressive measure is not its lack of efficacy, but the time-consuming technical problems of maintaining cannula patency and replacing the large obligatory losses of fluid and protein. In an effort to overcome these problems we have devised a method of diverting thoracic duct lymph internally into the esophagus of the sheep, our hypothesis being that fluid and protein should be resorbed, but lymphocytes and antibodies destroyed. By isolating that part of the venous system into which the thoracic duct drains and anastomosing this conduit to the cervical esophagus a chyloesophageal fistula was created. A mean patency of 19 days was demonstrated radiologically and there was a reproducible peripheral blood lymphopenia of over 50% of preoperative values at 4 weeks. Although plasma albumin levels fell from 37 g/L to 29 g/L at 1 week, they remained stable thereafter. No parenteral fluid or protein was administered, yet the animals remained well with no significant weight loss or overt signs of dehydration or hypoproteinemia. Skin allograft mean survival time was prolonged from 9 to 11.8 days (P less than 0.01).The main; reason for the virtual abandonment of external thoracic duct drainage as an immunosuppressive measure is not its lack of efficacy, but the time-consuming technical problems of maintaining cannula patency and replacing the large obligatory losses of fluid and protein. In an effort to overcome these problems we have devised a method of diverting thoracic duct lymph internally into the esophagus of the sheep, our hypothesis being that fluid and protein should be resorbed, but lymphocytes and antibodies destroyed. By isolation that part of the venous system into which the thoracic duct drains and anastomosing this conduit to the cervical esophagus a chyloesophageal fistula was created. A mean patency of 19 days was demonstrated radiologically and there was a reproducible peripheral blood lymphopenia of over 50% of preoperative values at 4 weeks. Although plasma ablbumin levels fell from 37 g/L to 29 g/L at 1 week, they remained stable thereafter. No parenteral fluid or protein was administered, yet the animals remained well with no significant weight loss or overt signs of dehydration or hypoproteinemia. Skin allograft mean survival time was prolonged from 9 to 11.8 days (P<0.01).

Occult donor malignancy in pancreas transplantation.

Tumor of the pancreas allograft is extremely rare. We report a case of an occult donor malignant undifferentiated tumor arising in a pancreas allograft. A 42-year-old female with Type 1 diabetes received a macroscopically normal pancreas allograft. The donor was a 22-year-old male who died of spontaneous intracerebral hemorrhage. She underwent transplant pancreatectomy, the histology of the pancreas allograft demonstrated a tumor measuring 5 mm in diameter, and a diagnosis of malignant undifferentiated tumor was made. In a different transplant center, the recipient of the left kidney transplant from the same donor had a nephrectomy, and the recipient of the liver transplant died of metastatic disease. Microscopic examination of the liver and kidney allografts subsequently revealed histological features identical to the pancreas tumor. Tumor transmission in transplantation may occur from an organ that contains metastatic cells or, less commonly, from the transmission of an unrecognized or occult primary tumor. A report from the United Network for Organs Sharing transplant data 1997–2002 is illustrated and discussed. This case illustrates the difficulties associated with identifying donors with occult primary tumor or metastases.

T-cell receptor Vβ gene usage by lymphocytes infiltrating human renal allografts

T cell lines have been derived from human kidney allograft biopsies using mitogenic stimulation. Southern blotting using a T-cell receptor (TCR) Cβ probe revealed an oligoclonal pattern of rearranged bands in all 12 samples analysed. In some cases, differences in band patterns were noted between independent cultures from the same biopsy. Most T-cell clones derived from 2 biopsies showed different patterns of rearranged bands. The polymerase chain reaction (PCR) was used to study TCR Vβ gene usage in allograft-derived T-cell cultures. This was more sensitive and more informative than Southern blotting and revealed that most TCR Vβ genes were expressed in T cells from biopsies showing cellular rejection. The potential usefulness of this technique to quantify TCR V gene usage in allospecific T-cell populations is discussed.