Association between expanded criteria for living kidney donors and renal biopsy findings.

BACKGROUND: There are certain criteria for selecting living kidney donors. However, the association between clinical characteristics of these criteria and kidney biopsy findings in living kidney donors have not yet been elucidated. Thus, we investigated the association between kidney biopsy findings and clinical characteristics defined in the Japanese guidelines for living kidney donors. METHODS: A retrospective multicentre study was conducted on donors and their recipients who underwent kidney transplantation between July 2014 and June 2017. Multiple linear regression analysis and multiple logistic regression analysis were performed to investigate the association between biopsy findings and clinical characteristics. RESULTS: A total of 240 donors and 240 recipients were included. Age was significantly correlated with global glomerulosclerosis and intimal thickening in multiple linear regression analysis and multiple logistic regression analysis, whereas diabetes was correlated with tubular atrophy in multiple linear regression analysis after multiple imputation and multiple logistic regression analysis. CONCLUSIONS: Amongst the clinical factors investigated in our study, age was positively correlated and diabetes was possibly correlated with kidney tissue injury in living kidney donors. Age and diabetes may be more important for selecting suitable living kidney donors than other clinical factors.

Massive Ascites in a Renal Transplant Patient after Laparoscopic Fenestration of a Lymphocele.

Retroperitoneal lymphocele is a common complication of renal transplantation. Here, we report the case of a 67-year-old woman with massive ascites after fenestration surgery for a lymphocele that developed following renal transplantation. She had been on continuous ambulatory peritoneal dialysis for 9 years. Living donor renal transplantation was performed and an intrapelvic lymphocele subsequently developed. The lymphocele did not resolve after aspiration therapy; therefore, laparoscopic fenestration was performed. Although the lymphocele disappeared, massive ascites appeared in its stead. Half a year later, the ascites was surgically punctured, which then gradually resolved and disappeared 6 weeks later. Aspiration therapy should be considered in patients on long-term peritoneal dialysis, although laparoscopic fenestration is safe and effective.

Successful percutaneous revascularization in a patient with a chronic totally occluded renal artery in an atrophied kidney.

A 57-year-old man presented with renovascular hypertension with chronic kidney disease. 16-Multi-detector row computed tomography (MDCT) showed that the left renal artery was totally occluded and the left kidney was atrophied. The left atrophied kidney was hormonally active despite the desolation of glomerular filtration function. Percutaneous renal revascularization was successful for stenting this lesion. The renin activity in the left renal vein was decreased immediately after the procedure. He remained healthy with adequate blood pressure for three years. In this case, MDCT and renal vein renin measurement provided useful information for the decision to perform percutaneous renal revascularization.

Effects of uroguanylin, an intestinal natriuretic peptide, on tubuloglomerular feedback.

Uroguanylin is an endogenous peptide that stimulates cyclic guanosine monophosphate (cGMP) production via the activation of guanylate cyclase C (GC-C) in the intestine and kidney. A high salt diet, but not intravenous salt load, enhances the secretion of biologically active uroguanylin from the intestine and increases its concentration in plasma and urine. Our purpose is to clarify the effect of uroguanylin on renal microcirculation and the tubuloglomerular feedback (TGF) mechanism. Clearance and micropuncture experiments were performed in anesthetized rats. TGF responsiveness was assessed in superficial nephrons by measuring the changes of early proximal flow rate (EPFR) in response to orthograde loop perfusion at 40 nl/min with artificial tubular fluid (ATF). Reductions in EPFR induced by loop perfusion during intravenous infusion of uroguanylin at the rate of 10 and 50 nmol/kg/h were similar yet significantly less than that during the control period (33+/-3% and 35+/-3% vs. 47+/-3%, p<0.05). Intraluminal application of uroguanylin at 10(-7) and 10(-5) mol/l in ATF decreased EPFR by 40+/-3% and 33+/-7%, respectively, with the latter value being significantly less than the control (p<0.05). Intravenous infusion of uroguanylin did not significantly change whole kidney function. Administration of atrial natriuretic peptide (ANP), which activates GC-A and B, significantly suppressed TGF-mediated EPFR reduction either intravenously (10 nmol/kg/h) or intraluminally (10(-5) mol/l in ATF) (9+/-3% and 13+/-2% vs. 47+/-3% of the control, p<0.05). In conclusion, uroguanylin clearly suppresses TGF both through intravenous and intraluminal routes, although the effects on glomerular microcirculation and whole kidney function are far less than those of ANP.

Effects of a nucleoside transporter inhibitor, dilazep, on renal microcirculation in rats.

Adenosine, one of the endogenous modulators in renal hemodynamics, has recently been shown to be a mediator of tubuloglomerular feedback (TGF). Dilazep augments endogenous adenosine actions by blocking its cellular uptake. Our purpose in the present study was to clarify the effects of dilazep on renal microcirculation and the TGF mechanism. Clearance and micropuncture experiments were performed in anesthetized rats. TGF responsiveness was assessed in superficial nephrons by measuring the changes of early proximal flow rate (EPFR) in response to loop perfusion at 0-40 nl/min with artificial tubular fluid (ATF). Under dilazep administration (0.3 mg/kg+0.3 mg/kg/h i.v.) systemic BP and GFR were decreased and renal plasma flow was unaltered; as a result, the filtration fraction tended to decrease (p=0.076). Renal vascular resistance was reduced, but not to a significant degree. The reduction in EPFR by loop perfusion was similar between controls (47 +/- 2%) and rats administered dilazep i.v. (44 +/- 5%). Intraluminal application of dilazep in ATF suppressed TGF-mediated EPFR reduction to by 46 +/- 4%, 43 +/- 7%, and 37 +/- 3% at dilazep concentrations of 10(-6), 10(-5), and 10(-4) mol/l, respectively. TGF suppression with 10(-4) mol/l dilazep was reversed by co-perfusion of 10(-5) mol/l DMPX, a selective adenosine A2 receptor antagonist. DMPX alone did not affect TGF response. In conclusion, these results indicate that systemic dilazep dilates postglomerular arterioles and does not affect TGF, and thus reduces GFR. A pharmacological concentration of dilazep applied to single nephrons clearly attenuates TGF, indicating afferent arteriolar vasodilatation. Extracellular adenosine augmented by dilazep dilates glomerular vessels at both afferent and efferent sites, probably via the activation of A2 receptors.