Terry King-Wing Ma

Effect of using ultrapure dialysate for hemodialysis on the level of circulating bacterial fragment in renal failure patients.

Background: Cardiovascular disease is the major cause of mortality and morbidity in dialysis patients. Recently, circulating endotoxin is found to associate with the systemic inflammatory state and cardiovascular disease of dialysis patients. Previous studies showed that the use of ultrapure dialysate for hemodialysis could reduce the exposure to exogenous endotoxin. We studied the effect of using ultrapure dialysate for hemodialysis on circulating endotoxin and bacterial DNA fragment levels and vascular stiffness. Methods: This is an open-labeled prospective study of 25 patients (14 male). Circulating endotoxin and bacterial DNA level, vascular stiffness as represented by arterial pulse wave velocity (PWV), nutrition and hydration status were monitored before and repeatedly throughout 12 months after the use of ultrapure dialysate for hemodialysis. Results: The average age was 58.9 ± 10.2 years; 21 patients completed the study. Within 4 weeks of conversion to ultrapure dialysate for hemodialysis, the plasma endotoxin level fell from 0.302 ± 0.083 to 0.209 ± 0.044 EU/ml (p < 0.0001) and then remained static, while serum bacterial DNA level remained similar. Furthermore, the time-averaged plasma endotoxin level during the study period significantly correlated with serum C-reactive protein level (r = 0.483, p = 0.017), carotid-femoral PWV (r = 0.455, p = 0.033), and malnutrition inflammation score (r = 0.461, p = 0.031). The time-averaged serum bacterial DNA level significantly correlated with malnutrition inflammation score (r = 0.550, p = 0.008) and inversely with subjective global assessment score (r = -0.543, p = 0.009), but not with PWV. Conclusions: In hemodialysis patients, circulating endotoxin level is associated with vascular stiffness and systemic inflammation. Using ultrapure dialysate for hemodialysis effectively reduces circulating endotoxin level in hemodialysis patients. The long-term benefit of using ultrapure dialysate for hemodialysis requires further study.

Mineralocorticoid receptor antagonist for renal protection.

The renin–angiotensin system (RAS) plays an important role in the pathophysiology of cardiovascular and renal diseases. In chronic kidney disease (CKD), blockade of RAS by angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) has been shown to reduce proteinuria and retard the progression of renal function deterioration. However, aldosterone, another key hormone of the RAS, is not directly targeted by ACEI or ARB. Hyperaldosteronism, apart from promoting sodium and fluid retention, causes inflammation and fibrosis in the heart and kidney. Studies have shown that although plasma aldosterone level shows an initial decrease following ACEI or ARB treatment, it returns to pretreatment level or even increases paradoxically after prolonged treatment. This “aldosterone breakthrough” forms the basis of adding mineralocorticoid receptor (MR) antagonist on top of ACEI or ARB for renal protection. New insights into the pathophysiological role of aldosterone in CKD further expands its potential indications, and there was a growing body of evidence in the past 10 years, which showed a substantial antiproteinuric effect and possibly a considerable renoprotective effect of MR antagonist. Since aldosterone does not act on the efferent glomerular arteriole and has no effect on intraglomerular hemodynamics, the very fact that MR antagonist ameliorates proteinuria sheds light on the physiology of glomerular permeability barrier. This review summarizes the data regarding the theoretical benefit as well as clinical use of MR antagonist in renal diseases.

Peritoneal-dialysis related peritonitis caused by Gordonia species: Report of four cases and literature review

To investigate the clinical course and outcome of peritoneal dialysis‐associated peritonitis secondary to Gordonia species.

Clinical manifestation of macrolide antibiotic toxicity in CKD and dialysis patients

Macrolide antibiotics, erythromycin, clarithromycin and azithromycin are commonly prescribed for upper respiratory infection, and their use has recently been further linked to immunomodulatory effects. With the widespread and expanded use of macrolides, special attention should be paid to their potential adverse effects. We reported two cases of end-stage renal disease (ESRD) patients who developed hallucinations such as vivid images of worms after taking clarithromycin. Similar to previous case reports of clarithromycin neurotoxicity, the visual hallucination resolved upon cessation of clarithromycin. Furthermore, we discussed the pharmacokinetic properties and other toxicities of macrolide antibiotics in patients with chronic kidney disease and ESRD.

Automated peritoneal dialysis in Hong Kong: there are two distinct groups of patients.

To compare the clinical outcome between continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) in specific subgroups of patients.

Newer antibiotics for the treatment of peritoneal dialysis-related peritonitis

Peritonitis is a debilitating infectious complication of peritoneal dialysis (PD). Drug-resistant bacterial peritonitis typically has a lower response rate to antibiotics. In the past 15 years, newer antibiotics with activities against drug-resistant Gram-positive bacteria have been developed. In most circumstances, peritonitis due to methicillin-resistant staphylococci responds to vancomycin. If vancomycin cannot be used due to allergy and/or non-susceptibility, there is increasing evidence that linezolid and daptomycin are the drugs of choice. It is reasonable to start linezolid orally or intravenously, but subsequent dose reduction may be necessary in case of myelosuppression. Daptomycin can be given intravenously or intraperitoneally and has excellent anti-biofilm activity. Other treatment options for drug-resistant Gram-positive bacterial peritonitis include teicoplanin, tigecycline and quinupristin/dalfopristin. Teicoplanin is not available in some countries (e.g. the USA). Tigecycline can only be given intravenously. Quinupristin/dalfopristin is ineffective against Enterococcus faecalis and there is only low-quality evidence to support its efficacy in the treatment of peritonitis. Effective newer antibiotics against drug-resistant Gram-negative bacteria are lacking. Polymyxins can be considered, but evidence on its efficacy is limited. In this review, we will discuss the potential use of newer antibiotics in the treatment of drug-resistant bacterial peritonitis in PD patients.

Intrarenal and Urinary Th9 and Th22 Cytokine Gene Expression in Lupus Nephritis

Objective. We studied the urinary sediment mRNA level of Th9- and Th22-related cytokines in patients with systemic lupus erythematosus (SLE). Methods. We quantified urinary mRNA levels of interleukin (IL) 9, IL-10, IL-22, and their corresponding transcription factors in 73 patients with active lupus nephritis, 13 patients with hypertensive nephrosclerosis (HTN), and 25 healthy subjects. Results. There was no detectable IL-9 mRNA in all samples. Patients with proliferative lupus nephritis had significantly lower urinary IL-22 mRNA levels than those with nonproliferative nephritis (2.2 ± 5.4 vs 8.6 ± 20.0 copies, p = 0.019), and urinary IL-22 mRNA level inversely correlated with the histological activity index (r = −0.427, p < 0.0001). In contrast, patients with lupus nephritis had significantly higher urinary IL-10 mRNA levels than patients with HTN (7.8 ± 18.5 vs 1.9 ± 4.0 copies, p = 0.012), and urinary IL-10 mRNA levels correlated with its intrarenal mRNA levels (r = 0.337, p = 0.004) and SLE disease activity index (r = 0.277, p = 0.018). Urinary IL-10 mRNA level was significantly lower among patients who achieved complete remission than those with partial remission or no response (4.1 ± 6.5 vs 14.1 ± 28.0 copies, p = 0.036). Conclusion. Urinary IL-22 mRNA level is decreased in patients with SLE with proliferative nephritis, while urinary IL-10 mRNA levels correlates with its intrarenal mRNA level and disease activity. Urinary IL-10 mRNA levels may also predict treatment response. These results suggest that urinary mRNA levels of IL-10 and IL-22 might be used as biomarkers for assessing disease activity and risk stratification in lupus nephritis.

Podocyte mRNA in the urinary sediment of minimal change nephropathy and focal segmental glomerulosclerosis.

BACKGROUND Podocyte depletion is a characteristic feature of progressive renal failure. We hypothesize that studying the podocyte mRNA level in urinary sediment may provide diagnostic and prognostic information in adult nephrotic syndrome. METHODS We studied 25 patients with minimal change nephropathy (MCN), 25 with focal segmental glomerulosclerosis (FSGS), and 17 healthy controls. The mRNA levels of nephrin, podocin, and synaptopodin in urinary sediment were quantified. RESULTS There were significant differences in the urinary sediment nephrin and podocin, but not synaptopodin, mRNA levels between diagnosis groups. Post-hoc analysis further showed that urinary nephrin mRNA levels of the MCN group were lower than those in the control and FSGS groups, although the difference between MCN and FSGS groups did not reach statistical significance. The degree of proteinuria inversely correlated with urinary nephrin mRNA levels in the MCN (r = -0.526, p = 0.007) as well as in the FSGS group (r = -0.521, p = 0.008). For the FSGS group, the rate of renal function decline significantly correlated with baseline urinary synaptopodin mRNA levels (r = -0.496, p = 0.012). CONCLUSIONS Urinary nephrin and podocin mRNA levels were reduced in patients with MCN and probably FSGS, and the magnitude of reduction correlated with the degree of proteinuria. Urinary synaptopodin mRNA levels correlated with the subsequent rate of renal function decline in patients with FSGS. Our result indicates that urine sediment podocyte mRNA levels provide novel insights in the pathophysiology of nephrotic syndrome and could be useful for risk stratification.

Causes of nephrotic syndrome and nephrotic-range proteinuria are different in adult Chinese patients: a single centre study over 33 years.

The reported causes of nephrotic syndrome (NS) varies between different countries. Less is known about the causes of nephrotic‐range proteinuria (NPU). We aimed to evaluate the underlying causes of NS and NPU.

Global impact of nephropathies

The global burden of chronic kidney disease (CKD) has increased substantially in recent years, partly attributed to the global epidemic of diabetes mellitus. In many countries including China, glomerulonephritis was the most common cause of end stage renal disease (ESRD). The mortality rate of dialysis patients can be as high as patients with colon, breast and prostate cancers. CKD has important socio‐economic impact on the healthcare system and society. Increasing awareness and early detection of CKD cannot be overemphasized. In places where healthcare resources are limited, peritoneal dialysis first policy has allowed local governments and health authorities to maximize healthcare resources to provide renal replacement therapy for more ESRD patients. In conclusion, management of CKD remains a global health challenge and continued medical research is most important.