Peritoneal clearances in scleroderma and diabetes mellitus: effects of intraperitioneal isoproterenol

Kidney failure after lung transplantation in systemic scleroderma: a case report with literature review

Background

Systemic scleroderma (SSc) involves multiple organs including the skin, the lung, the kidney, and the esophagus. Nowadays, patient life prognosis has substantially improved due to more appropriate management of lung complications, including lung transplantation. However, the extension of their survival may increase SSc patients with chronic kidney diseases and requiring renal replacement therapy (RRT).

Case presentation

A 51-year-old female with SSc who underwent unilateral deceased-donor lung transplantation was referred because of progressive renal dysfunction. Despite no episodes of scleroderma renal crisis, her renal function gradually deteriorated for 2 years with her serum creatinine level increasing from 0.5 mg/dL at transplantation to 4.3 mg/dL. Although we reinforced antihypertensive treatment and reduced calcineurin inhibitor dose, she thereafter developed symptomatic uremia. Due to impaired manual dexterity with contracture of the interphalangeal joints, no caregivers at home, and kidney transplantation donor unavailability, maintenance hemodialysis was chosen as RRT modality. Further, due to the narrowing of superficial vessels in the sclerotic forearm skin and post-transplant immunocompromised status, the native left brachiocephalic arteriovenous fistula was created. Post-operative course was uneventful while any sign of cutaneous infection and pulmonary hypertension was closely monitored. Our literature review also indicates several difficulties with initiating and maintaining RRT in patients with SSc although case reports of kidney failure after lung transplanation in SSc were not accumulated.

Conclusions

With respect to initiating RRT for post-lung transplant patients with SSc, the clinical course of our case exemplifies recent complex trends of renal management. The optimal modality with secured initiation of RRT should be carefully determined based on the severity and risk for the cardiopulmonary, peripheral vascular, cutaneous, and systemic or local infectious complications.

Effects of Intraperitoneal Captopril on Peritoneal Transport in Rats

We studied the effects of various doses of intraperitoneal (I.P.) captopril, (an angiotensin-converting enzyme inhibitor) during peritoneal dialysis, on urea dialysate/plasma (DIP) ratios, dialysate protein (Dpo), dialysate glucose (DG), and drainage volume (VD) in 19 Sprague-Dawley male rats with normal renal function. Similarly, these parameters were measured in five control rats.

Among the study group, 14 rats received 20 to 100 mg/kg of intraperitoneal captopril without effect. Following a larger intraperitoneal dose (75 mg/exchange (ex)) five rats had delayed increases in urea D/P ratios and dialysate protein losses by 30% (p < 0.05) and by 286% (p < 0.025), respectively. During and following intraperitoneal captopril the rats showed enhanced glucose absorption and consequently significant decreases in dialysate glucose concentration. The rats receiving IP captopril, 75 mg/ex remained hypotensive throughout the drug exchanges and three subsequent exchanges.

Increases in dialysate protein concentration and decreases in the dialysate glucose concentration seen with captopril (75 mg/ex) returned to near baseline values only after four to five hours of drug-free exchanges.

These changes, despite systemic hypotension, may reflect an increase in blood flow, capillary permeability and/or surface area subsequent to blockade of the renin-angiotensin system, suggesting some angiotensin II modulation of the peritoneal microcirculation and solute transport during peritoneal dialysis.

Relation of Calcified Macroangiopathy to Peritoneal Small Solute Transport Property

Large interindividual variability in peritoneal solute transfer, determined by the peritoneal equilibration test (PET) at the start of peritoneal dialysis (PD) therapy, has been previously shown (1,2). The contributing factors are not well defined, but may include differences in age, peritoneal surface area, peritoneal permeability, or peritoneal blood flow. The structural or functional changes in peritoneal vasculature produced by systemic atherosclerosis may influence peritoneal solute transport properties. In this study, we quantified the degree of systemic atherosclerosis and investigated its correlation with solute transport in the early phase of PD therapy.

Acute renal failure in the cardiovascular surgical patient

Acute renal failure is a known complication of cardiovascular surgery and is associated with a high mortality. Therapy should be aimed at prevention of oliguric renal failure, or at least its conversion to nonoliguric renal failure. Once renal failure is established, early dialysis with nutritional support probably gives the best chance for survival.

Dialytic therapy in the management of chronic renal failure

The maintenance of life after the development of end-stage renal disease can be achieved by the use of dialytic therapy, either alone as permanent replacement therapy or in conjunction with transplantation. The imperfections of all forms of dialytic therapy leave the nephrologist with the responsibility of recommending to the patient the treatment(s) considered most suitable. Hemodialysis, hemofiltration, and peritoneal dialysis are discussed in this article.

Acceleration of peritoneal mass transport by drugs and hormones

The major restrictions to the transport of solute and solvent across the peritoneum are the limited peritoneal blood flow, area and permeability. Recent investigations have demonstrated that several vasoactive drugs influence transport parameters. Isoproterenol, nitroprusside, dipyridamole and dopamine exemplify drugs that dilate the splanchnic vasculature, thereby augmenting transport, whereas vasoconstriction induced by l-norepinephrine decreases clearances. The tissue prostaglandins affect peritoneal mass transport in accord with their known vasoactive effects, suggesting a role in modulating peritoneal blood flow. The gastrointestinal hormones vasodilate the splanchnic circulation. Exposure of the endothelial surface to glucagon markedly increases peritoneal mass transport, while secretin increases the ultrafiltration rate significantly. These preliminary studies suggest the possible future clinical use of drugs and hormones to augment the efficiency of peritoneal dialysis.

Effects of gastrointestinal hormones on transport by peritoneal dialysis

Because the gastrointestinal hormones are known to dilate the splanchnic vasculature, their effects on transport of water and solutes during peritoneal dialysis were studied in an experimental model, the rabbit. In unanesthetized rabbits, dialysate volume was calculated by isotope dilution, and clearances were estimated by dialysate/plasma concentration ratio factored by minute volume. With isotonic dialysis solution, the mean increment in dialysate volume per minute of intraperitoneal dwell was 0.19 ml/kg/min, and mean clearances of creatinine and urea were 0.71 and 0.90 ml/kg/min, respectively. When administered intravenously, secretin significantly augmented osmotically induced water flux, but not when given intraperitoneally. Neither glucagon nor cholecystokinin affected dialysate volume. Intravenously, but not intraperitoneally, glucagon increased peritoneal clearances of creatinine and urea to more than 150% of control values. Neither cholecystokinin nor secretin augmented significantly peritoneal mass transport when given by either route. The data suggest that the site of acton is the endothelial surface of the membrane, that the mechanisms of augmenting transport involve increased permeability and/or surface area, and that agents which combine an increase in mass transport and capillary filtration coefficient may be clinically useful.

Augmented peritoneal mass transport with intraperitoneal nitroprusside

Lightly restrained, alert New Zealand white rabbits underwent peritoneal dialysis by percutaneous instillation of standard dialysis solution with or without intraperitoneal nitroprusside. Corrected to a mean intraperitoneal dwell time of 36 minutes, mean clearances of creatinine and urea were 0.74 and 0.90 ml/kg/min in six rabbits. With intraperitoneal nitroprusside, 1.13 mg/kg clearances increased to 1.13 and 1.30 ml/kg/min (p less than 0.01) respectively. The 53% increment in creatinine clearance maintained the ratio clearance larger/smaller solute suggesting increased peritoneal permeability and/or area. Lower nitroprusside doses were less effective and not significantly above control. Nitroprusside also increased clearances during hypertonic peritoneal dialysis, but had no effect on osmotically induced water flux. Lavage studies demonstrated a persistent effect of nitroprusside after a single exposure and a sustained effect with repeated use.