Proteinuria, but Not eGFR, Predicts Stroke Risk in Chronic Kidney Disease: Chronic Renal Insufficiency Cohort Study

Efficacy and safety of calcineurin inhibitor treatment for IgA nephropathy: a meta-analysis

Background

IgA nephropathy is the most common progressive glomerular disease to end stage renal failure worldwide. Calcineurin inhibitors (CNIs) is a selective immunosuppressant widely used in organ transplantation. The efficacy and safety of calcineurin inhibitors for the treatment of IgA nephropathy remain uncertain.

Methods

We performed a systematic literature search using the PubMed, Embase, Science Citation Index, Ovid evidence-based medicine, Chinese Biomedical Literature (CBM) and Chinese science and technology periodicals (CNKI, VIP, and Wan Fang) for randomized, controlled trials of CNIs therapy of IgA nephropathy. Complete remission rate (CR) was defined as proteinuria less than 0.5 or 0.3 g/d. Partial remission rate (PR) was defined as proteinuria reduced to at least half of the baseline measurement and an absolute value of >0.5 or 0.3 g/d.

Results

Seven relevant trials were conducted with 374 patients enrolled. CNIs plus medium/low-dose steroid had a higher CR (RR = 2.51 [95% CI,1.25 to 5.04], P = 0.02) compared to therapy with steroid alone or placebo, but were not significant on PR (RR = 0.87 [95% CI,0.32 to 2.38]; P = 0.78). Also, significant alterations were observed in proteinuria (weighted mean difference, −0.46 g/d,[95% CI:-0.55 to −0.24], P < 0.01) with no differences were found in serum creatinine (SCr) (weighted mean difference, 0.57,95% CI:-4.05 to 5.19; P = 0.78) and estimated glomerular filtration rate (eGFR) (weighted mean difference, 1.13,95% CI:-4.05 to 6.32; P = 0.34) level between the two groups. CNI therapy was associated with an increased risk for adverse events (RR = 2.21,95% CI:1.52 to 3.21, P < 0.01), such as gastrointestinal and neurological symptoms or hirsutism.

Conclusions

CNIs might provide renal protection in patients with IgAN, but at an increased risk of adverse events. Reliably defining the efficacy and safety of CNIs in IgAN requires a high-quality trial with a large sample size.

Mycophenolate mofetil prevents cerebrovascular injury in stroke-prone spontaneously hypertensive rats

Stroke-prone spontaneously hypertensive rats (SHR-A3) develop strokes and progressive kidney disease as a result of naturally occurring genetic variations. We recently identified genetic variants in immune signaling pathways that contribute to end-organ injury. The present study was designed to test the hypothesis that a dysregulated immune response promotes stroke susceptibility. We salt-loaded 20 wk old male SHR-A3 rats and treated them with the immunosuppressant mycophenolate mofetil (MMF, 25 mg/kg/day po) (n = 8) or vehicle (saline) (n = 9) for 8 wk. Blood pressure (BP) was measured weekly by telemetry. Compared with vehicle-treated controls, MMF-treated SHR-A3 rats had improved survival and lower neurological deficit scores (1.44 vs. 0.125; P < 0.02). Gross morphology of the brain revealed cerebral edema in 8 of 9, and microbleeds and hemorrhages in 5 of 9 vehicle-treated rats. These lesions were absent in MMF-treated rats. Brain CD68 expression, indicating macrophage/microglial activation, was upregulated in vehicle-treated rats with microbleeds and hemorrhages but was undetectable in the brains of MMF-treated rats. MMF also prevented renal injury in SHR-A3 rats, evidenced by reduced proteinuria (albumin:creatinine) from 7.52 to 1.05 mg/mg (P < 0.03) and lower tubulointerstitial injury scores (2.46 vs. 1.43; P < 0.01). Salt loading resulted in a progressive increase in BP, which was blunted in rats receiving MMF. Our findings provide evidence that abnormal immune activation predisposes to cerebrovascular and renal injury in stroke-prone SHR-A3 rats.

[Chronic kidney disease and dyslipidaemia]

Chronic kidney disease (CKD) has to be considered as a high, or even very high risk cardiovascular risk condition, since it leads to an increase in cardiovascular mortality that continues to increase as the disease progresses. An early diagnosis of CKD is required, together with an adequate identification of the risk factors, in order to slow down its progression to more severe states, prevent complications, and to delay, whenever possible, the need for renal replacement therapy. Dyslipidaemia is a factor of the progression of CKD that increases the risk in developing atherosclerosis and its complications. Its proper control contributes to reducing the elevated cardiovascular morbidity and mortality presented by these patients. In this review, an assessment is made of the lipid-lowering therapeutic measures required to achieve to recommended objectives, by adjusting the treatment to the progression of the disease and to the characteristics of the patient. In CKD, it seems that an early and intensive intervention of the dyslipidaemia is a priority before there is a significant decrease in kidney function. Treatment with statins has been shown to be safe and effective in decreasing LDL-Cholesterol, and in the reduction of cardiovascular events in individuals with CKD, or after renal transplant, although there is less evidence in the case of dialysed patients.

Prognostic value of urine dipstick proteinuria on mortality after acute ischemic stroke

BACKGROUND AND AIMS

Proteinuria is a marker of kidney disease and a strong risk factor for cardiovascular diseases including stroke. This study was aimed at investigating the prognostic value of proteinuria measured by urine dipstick in patients with acute ischemic stroke.

METHODS

This post-hoc analysis of a prospective cohort study included 3404 consecutive patients who had been admitted for acute ischemic stroke between November 2005 and June 2013. Proteinuria was defined as a trace or more of protein on a urine dipstick test routinely performed at admission. Date and cause of death until December 31, 2013 were collected. We investigated the association of proteinuria with all-cause mortality, cardiovascular mortality (defined as ICD-10 codes I00-I99), and non-cardiovascular mortality.

RESULTS

Proteinuria was present in 12.8% of the 3404 patients. During the mean follow-up period of 3.56 ± 2.22 years, there were 681 cases of all-cause mortality (460 cardiovascular deaths and 221 non-cardiovascular deaths). Multivariate Cox regression analysis showed that the presence of proteinuria was an independent risk factor for all-cause mortality (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.40-2.04), cardiovascular mortality (adjusted HR 1.65, 95% CI 1.31-2.08), and non-cardiovascular mortality (adjusted HR 1.59, 95% CI 1.13-2.23). Adding proteinuria to the multivariate Cox models moderately improved the model performance for all-cause mortality (integrated area under curve [95% CI]: from 0.800 [0.784-0.816] to 0.803 [0.788-0.818], p = 0.026).

CONCLUSIONS

Proteinuria, which was detected on a urine dipstick test, was a significant predictor of mortality after acute ischemic stroke.

Relationship between Kidney Dysfunction and Ischemic Stroke Outcomes: Albuminuria, but Not Estimated Glomerular Filtration Rate, Is Associated with the Risk of Further Vascular Events and Mortality after Stroke

Background and Objective

Estimated glomerular filtration rate (eGFR) and albuminuria are known to be associated with ischemic stroke outcomes. In this study, we investigated the longitudinal relationships of the two markers with mortality, vascular events and functional outcomes in a stroke cohort.

Methods

A total of 295 patients with acute ischemic stroke were prospectively recruited in a single center between May 2012 and February 2015. Renal dysfunction was defined as a decreased eGFR (<60 mL/min/1.73 m²) or albuminuria (urine albumin-to-creatinine ratio ≥ 30 mg/g). Good functional outcome at 6 months was defined as a modified Rankin scale score ≤ 2, and the occurrence of major vascular events (stroke, acute coronary syndrome or peripheral artery occlusion) or death was monitored. The associations between renal dysfunction and mortality, major vascular events, and 6-month functional outcome were evaluated by the Cox proportional hazards model and logistic regression analysis. Unadjusted and adjusted hazards ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs) were obtained. A Kaplan–Meier survival curve for composite adverse events (major vascular events or death) was also computed according to the presence or absence of albuminuria.

Results

Albuminuria, not eGFR, was significantly associated with mortality (P = 0.028; HR 2.15; 95% CI 1.09–4.25) and major vascular events (P = 0.044; HR 2.24; 95% CI 1.02–4.94) in the multivariate Cox proportional hazards models adjusting for age, sex, diabetes, hypertension, current smoking, atrial fibrillation, previous stroke, alcohol history, initial National Institutes of Health Stroke Scale (NIHSS) score and eGFR. In addition, albuminuria was negatively associated with 6-month functional outcome in the multivariate logistic regression analysis adjusting for age, sex, diabetes, hypertension, current smoking, atrial fibrillation, previous stroke, alcohol history and eGFR (P = 0.001; OR 0.36; 95% CI 0.20–0.65), but the association disappeared when NIHSS score was additionally adjusted (P = 0.519; OR 0.79; 95% CI 0.39–1.60). Furthermore, the patients with albuminuria had a significantly higher rate of composite adverse events than the patients without albuminuria (P < 0.001 by log-rank test).

Conclusions

Albuminuria seems a more useful clinical indicator than eGFR in evaluating the risk of adverse outcomes including further vascular events and death in patients with ischemic stroke.

Extracellular purines' action on glomerular albumin permeability in isolated rat glomeruli: insights into the pathogenesis of albuminuria

Purinoceptors (adrengeric receptors and P2 receptors) are expressed on the cellular components of the glomerular filtration barrier, and their activation may affect glomerular permeability to albumin, which may ultimately lead to albuminuria, a well-established risk factor for the progression of chronic kidney disease and development of cardiovascular diseases. We investigated the mechanisms underlying the in vitro and in vivo purinergic actions on glomerular filter permeability to albumin by measuring convectional albumin permeability (Palb) in a single isolated rat glomerulus based on the video microscopy method. Primary cultured rat podocytes were used for the analysis of Palb, cGMP accumulation, PKG-Iα dimerization, and immunofluorescence. In vitro, natural nucleotides (ATP, ADP, UTP, and UDP) and nonmetabolized ATP analogs (2-meSATP and ATP-γ-S) increased Palb in a time- and concentration-dependent manner. The effects were dependent on P2 receptor activation, nitric oxide synthase, and cytoplasmic guanylate cyclase. ATP analogs significantly increased Palb, cGMP accumulation, and subcortical actin reorganization in a PKG-dependent but nondimer-mediated route in cultured podocytes. In vivo, 2-meSATP and ATP-γ-S increased Palb but did not significantly affect urinary albumin excretion. Both agonists enhanced the clathrin-mediated endocytosis of albumin in podocytes. A product of adenine nucleotides hydrolysis, adenosine, increased the permeability of the glomerular barrier via adrenergic receptors in a dependent and independent manner. Our results suggest that the extracellular nucleotides that stimulate an increase of glomerular Palb involve nitric oxide synthase and cytoplasmic guanylate cyclase with actin reorganization in podocytes.

Proteinuria Is an Independent Risk Factor for First Incident Stroke in Adults Under Treatment for Hypertension in China

Background

Conflicting evidence exists regarding whether reduced estimated glomerular filtration rate (eGFR) and proteinuria are independent risk factors for stroke and its subtypes in hypertensive patients. This study investigated the association of these renal measures with first incident stroke in adults under treatment for hypertension in China.

Methods and Results

The study included 19 599 adults aged 45 to 75 years who participated in the China Stroke Primary Prevention Trial. Baseline eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration creatinine equation. Proteinuria was assessed by qualitative dipstick urinalysis and in a subset by the quantitative albumin–creatinine ratio method. Cox regression analysis was used to examine the effects of eGFR and proteinuria on the risk of first incident stroke. During a median of 4.5 years of follow‐up, a total of 585 first strokes (472 ischemic strokes) were identified. Compared to participants without proteinuria, participants with proteinuria (trace or more by dipstick) had a 35% increased risk of first stroke: the adjusted hazard ratio (HR) (95% CI) was 1.35 (1.09–1.66, P=0.005). The results were robust in subgroup analyses. In a subset with data on proteinuria measured by quantitative albumin–creatinine ratio, a similar association was found. In both independent and combined analyses with proteinuria, eGFR was not significantly associated with stroke.

Conclusions

In adults under treatment for hypertension in China, baseline proteinuria measured by dipstick or quantitative albumin–creatinine ratio, but not reduced eGFR, was found to be an independent risk factor for first incident stroke and ischemic stroke.