The role of endothelin in early renal cortical reperfusionin renal transplantation

Preservation Solutions for Kidney Transplantation: History, Advances and Mechanisms

Solid organ transplantation was one of the greatest medical advances during the past few decades. Organ preservation solutions have been applied to diminish ischemic/hypoxic injury during cold storage and improve graft survival. In this article, we provide a general review of the history and advances of preservation solutions for kidney transplantation. Key components of commonly used solutions are listed, and effective supplementations for current available preservation solutions are discussed. At cellular and molecular levels, further insights were provided into the pathophysiological mechanisms of effective ingredients against ischemic/hypoxic renal injury during cold storage. We pay special attention to the cellular and molecular events during transplantation, including ATP depletion, acidosis, mitochondrial dysfunction, oxidative stress, inflammation, and other intracellular mechanisms.

Correlation between endothelin expression in early post-transplant biopsy specimens and long-term allograft function in living-related renal transplantation

OBJECTIVE

We investigated whether degree of immunohistochemically evident endothelin (ET) expression in early post-transplant biopsy specimens could predict long-term allograft function in living-related renal transplantation.

METHODS

Allograft biopsy specimens obtained from 40 patients with living-related transplants were studied. Cases with episodes of acute rejection or calcineurin inhibitor toxicity were excluded. We immunostained graft biopsy specimens obtained at pre-transplantation (PRE) and at 3 months (3M) afterward with anti-ET antibody. The number of stained tubular epithelial cells per 1000 tubular cells was defined as the staining index (SI). In the 21 patients whom we could assess at 3 yr (3Y) after transplantation, the correlation between ET expression and long-term graft function was examined.

RESULTS

Anti-ET antibody staining was appreciable in tubular epithelium but not in glomeruli. Tubular SI at PRE and at 3M were 10.6 +/- 15.3 and 32.0 +/- 35.6 (mean +/- SD) respectively (p < 0.01). When patients were classified according to SI (group A, SI < 25; group B, SI > 25), declining ratio in creatinine clearance at 3Y after transplantation for groups A and B with respect was 21.8% +/- 15.4% and 41.9% +/- 21.6% (p < 0.05).

CONCLUSION

High ET expression in early post-transplantation, biopsy specimens was related to poor long-term allograft function following living-related renal transplantation.

Effects of immunosuppressant FTY720 on renal and hepatic hemodynamics in the rat

BACKGROUND

FTY720 is a novel immunomodulator that may provide an opportunity for a reduction in calcineurin inhibitor dosage in transplant recipients with renal/hepatic side effects. However, the effects of FTY720 on renal or hepatic hemodynamics are unknown. The aim of this study was to establish the hemodynamic and renal actions of FTY720 at therapeutically relevant dosages.

METHODS

The effects of acute and repeat oral administration of FTY720 on systemic, renal, and hepatic hemodynamics were investigated in the anesthetized male Lewis rat. Renal function and renal tubular parameters were examined in animals that received repeat high dosage of FTY720.

RESULTS

Seven-day oral administration of FTY720 did not cause any significant changes in markers of hepatocyte injury, nor did it cause any reduction in renal function (elevated urea and creatinine). Histological examination of liver and kidney from animals treated with repeat FTY720 for 1 or 3 weeks did not reveal any sclerosis, tubular changes, infiltrates, or fibrosis. Hepatocyte, vascular, and biliary structures were normal. Compared with the vehicle (saline), oral administration of FTY720 at dosages up to 5 mg/kg/day for 1 week did not have any significant effects on systemic, hepatic, or renal hemodynamics. Five min after intravenous FTY720 administration (1 mg/kg), mean arterial pressure (MAP) rose to 114+/-3.3% of baseline (P <0.01) before returning to the normal range within 30-45 min. Lower doses of FTY720 (0.3 and 0.5 mg/kg, i.v.) did not affect MAP. Renal cortical perfusion, renal artery blood flow, and renal vascular resistance were not altered by FTY720 at i.v. doses up to 1 mg/kg. Animals that received FTY720 (5 mg/kg/day) for 3 weeks showed a significant reduction in body weight (-4.8+/-1% of baseline at 3 weeks, P <0.001); however, weight-adjusted creatinine clearance, 24 h urine production, and urine osmolality were not different from those in control animals (0.71+/-0.1 vs. 0.74+/-0.1 ml/min/100 g, 2.63+/-0.2 vs. 3.12+/-0.2 ml/100 g, and 2003+/-33 vs. 1966+/-56 mOsm/kg, respectively). FTY720 at the same repeat oral dosage was, nevertheless, associated with a significantly lower 24 h sodium excretion and a significantly lower fractional excretion of sodium compared with those in control animals (223.4+/-35 vs. 304.5+/-50 micromol/100 g and 1.75+/-0.3 vs. 2.23+/-0.3%, respectively; P <0.05).

CONCLUSIONS

Our data indicate that, at least in the short term, oral FTY720 does not cause any significant adverse effects on renal or hepatic hemodynamics, nor does it cause any reduction in glomerular perfusion and thus may provide reasonable rescue/add-on therapy in calcineurin-inhibitor treated transplant recipients. At high repeat oral dosages, however, FTY720 may alter renal handling of sodium.