Prognostic role of serum ACE activity on outcome of type 2 diabetic patients on chronic ambulatory peritoneal dialysis

Inflammation and myocardial damage markers influence loss of residual renal function in peritoneal dialysis patients

BACKGROUND

Residual renal function (RRF) has been identified as the most important component in dialysis adequacy and has a strong effect on clinical outcomes. This justifies any effort in understanding the mechanism behind the preservation or decline in RRF. The aim of this study was to analyze the possible association of components of cardio-renal syndrome with the rate of decline in RRF.

METHODS

A retrospective cohort study was performed in a group of prevalent adult patients on continuous ambulatory peritoneal dialysis (CAPD). Patients were analyzed at baseline and after a 30-month follow-up. Evaluations included measurements of residual renal function, dialysis adequacy parameters, cardiovascular comorbidity, and measurements of biochemical markers of cardiovascular disease (CVD) and inflammation, as well as resting electrocardiography.

RESULTS

We included 129 patients in the study who were divided into groups according to loss of RRF, considering the cut-off point as 100 mL/day of 24 h urine volume. At baseline, there were no differences between groups: patients who lost RRF showed low values of 24 h urine volume, higher levels of systolic blood pressure, N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), IL-6, and low values of serum albumin. In the multivariate analysis, age, albumin, CRP, and NT-proBNP were significant risk factors for the loss of RRF.

CONCLUSIONS

Data indicate a close relationship between heart and kidney function where chronic kidney disease (CKD) affects and is an effect of, heart function, indicative of a bi-directional influence that leads to a vicious cycle, promoting deleterious effects on both systems.

Update on potential medical treatments for encapsulating peritoneal sclerosis; human and experimental data

Encapsulating peritoneal sclerosis (EPS) is an infrequent but serious complication of peritoneal dialysis (PD). The pathogenesis is unknown but speculation is ongoing. The current management of EPS focuses on prevention and treatment of the inflammatory and fibrotic changes at the level of the peritoneal membrane with immunosuppressive and antifibrotic agents, respectively. This article reviews the currently available human and animal data on potential agents to prevent and/or treat EPS. We propose a strategy for early diagnose EPS in an attempt to avoid the development of the full-blown and potentially life-threatening clinical syndrome of EPS. Future research should focus on studying potential prophylactic and therapeutic agents in humans in large, multicenter, randomized trials but also on early detection of EPS in the inflammatory phase by means of biomarkers and the establishment of a composite EPS score.

Applying Translational Research in Understanding Complications and Defining Targets for Intervention: Inflammation in PD as a Model

The bench-to-bedside approach to translational research is becoming increasingly important to efficiently advance understanding of the mechanisms underlying disease and to improve the quality of patient care. Although this investigation model has been practiced since the early days of the therapy, robust research platforms built to practice translational research have only recently been structured in the field of peritoneal dialysis. Experience with a translational research environment that generated most of the information cited in this overview is the core of this manuscript. The central investigation theme described is how to approach the cardiovascular complications of peritoneal dialysis. The research question was, could the continuous activation of inflammatory pathways be central in this process and represent a relevant target for interventions?

Inflammation, blood pressure, and stroke: an opportunity to target primary prevention?

Promising findings suggest that systemic inflammation and neuroinflammation are central features in cerebrovascular disease. Inflammatory mechanisms are also important participants in the pathophysiology of hypertension. Markers of inflammation have been shown to be upregulated in different forms of cerebrovascular disease, and to correlate with vascular risk. The inhibitor nuclear factor-kB/nuclear factor-kB system is considered a major intracellular inflammatory pathway, mediating most of the vascular inflammatory responses. Increasing evidence indicates that hypertension, through the vasoactive peptides angiotensin and endothelin-1, promotes and accelerates the atherosclerotic process via inflammatory mechanisms. Proinflammatory properties of angiotensin II have been demonstrated. The identification of useful markers of inflammation, of new therapeutic targets to interfere with these mechanisms, and the evaluation of the efficacy of anti-inflammatory treatments will allow progress in our ability to combat cerebrovascular disease and the complications of hypertension. Whether these targets will be useful in the development of risk prediction strategies or therapies for the treatment of stroke in humans is far from clear.

Hypertension and dialysis

The high mortality rate seen in dialysis patients is related to long-standing high blood pressure and the presence of other traditional as well as non-traditional risk factors for cardiovascular disease. Hypertension is associated with increased risk for left ventricular hypertrophy, coronary artery disease, congestive heart failure and cerebrovascular complications. High blood pressure is frequent and difficult to control in the dialysis population. Available therapeutic options to normalize blood pressure in these patients include dietary salt and fluid restriction in combination with reduction of dialysate sodium concentration. A possible treatment option for these patients may be long, slow hemodialysis (3 x 8 h per week); short daily hemodialysis (2-3 h 7 times per week); nocturnal hemodialysis (6-7 times overnight per week). Reduction of residual renal function is a major cause of blood pressure increase in the peritoneal dialysis patient population. Therefore, hyperhydration should be avoided. If antihypertensive medication is needed, ACE inhibitors, beta-blockers and/or calcium channel blockers are recommended. Optimal blood pressure in dialysis patients is not different from recommendations for the general population.

Pharmacogenomics of angiotensin converting enzyme inhibitors in renal disease--pathophysiological considerations

Angiotensin converting enzyme (ACE) inhibitors preserve native kidney function in patients with renal disease better than other antihypertensive drugs, most likely because they more effectively reduce proteinuria. The plasma concentration of the ACE inhibitors target is, at least in part, under genetic control. A polymorphism of the ACE gene based on the presence or absence of a 287 base pair element in intron 16 accounts for 47% of the total phenotypic variance in the plasma ACE levels of healthy individuals. Unfortunately, pharmacogenetic studies performed so far do not provide a clear answer as to whether the efficacy of the reduction of proteinuria by ACE inhibitors is influenced by the ACE genotype - probably because these studies were not primarily designed to answer this question. This paper will try to outline some aspects that should be considered before an appropriate study on this topic is initiated.