Nonenzymatically glucosylated serum proteins in patients with end-stage renal disease

Diabetes mellitus in chronic kidney disease: Biomarkers beyond HbA1c to estimate glycemic control and diabetes-dependent morbidity and mortality

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). Optimal glycemic control contributes to improved outcomes in patients with DM, particularly for microvascular damage, but blood glucose levels are too variable to provide an accurate assessment and instead markers averaging long-term glycemic load are used. The most established glycemic biomarker of long-term glycemic control is HbA1c. Nevertheless, HbA1c has pitfalls that limit its accuracy to estimate glycemic control, including the presence of altered red blood cell survival, hemoglobin glycation and suboptimal performance of HbA1c assays. Alternative methods to evaluate glycemic control in patients with DM include glycated albumin, fructosamine, 1-5 anhydroglucitol, continuous glucose measurement, self-monitoring of blood glucose and random blood glucose concentration measurements. Accordingly, our aim was to review the advantages and pitfalls of these methods in the context of CKD.

Hemoglobin A1c levels in non-diabetic patients with end-stage renal disease (ESRD) receiving hemodialysis

Hemoglobin A1c (HbA1c) level represents an established tool to monitor glycemic control in diabetic patients, but the previous commonly used tests of HbA1c in patients with end-stage renal disease (ESRD) may not be reliable because of the presence of anemia, assay interference from uremia, and decreased red blood cell (RBC) life span. HbA1c level measured by turbidimetric immunoassay method is not affected by the above factors. We enrolled 40 non-diabetic ESRD patients receiving hemodialysis and 55 non-diabetic patients without ESRD for this study. HbA1c was analyzed by turbidimetric immunoassays with Synchron CX system. We found that the average HbA1c level in non-diabetic ESRD patients receiving hemodialysis was 5.99% and in the control group was 5.45% (p<0.05). There was no significant difference in fasting glucose levels and Hct % between the two groups (p>0.05). Our limited data indicate that HbA1c levels are elevated in nondiabetic ESRD patients receiving hemodialysis. We propose that the elevated HbA1c level may be due to the repetitive exposure of patients' RBCs to the high glucose level in dialysate (200 mg/dl) or may reflect true glucose intolerance in non-diabetic patients with ESRD.

Low water-soluble uremic toxins

The uremic syndrome is the result of the retention of solutes, which under normal conditions are cleared by the healthy kidneys. Uremic retention products are arbitrarily subdivided according to their molecular weight. Low-molecular-weight molecules are characterized by a molecular weight below 500 D. The purpose of the present publication is to review the main water soluble, nonprotein bound uremic retention solutes, together with their main toxic effects. We will consecutively discuss creatinine, glomerulopressin, the guanidines, the methylamines, myo-inositol, oxalate, phenylacetyl-glutamine, phosphate, the polyamines, pseudouridine, the purines, the trihalomethanes, and urea per se.

Dermal angiopathy in hemodialysis patients: the effect of time

We studied skin biopsies from 14 patients after 6 months to 18 years on hemodialysis (HD) to discern any effect of duration of treatment on skin and dermal capillaries. Patients selected for biopsy were without evidence of other diseases known to affect vasculature such as diabetes mellitus. Pathological changes compared with duration of HD were: capillary wall thickening, endothelial proliferation and new capillary formation, lipid content, and epidermal atrophy. Severity of morphologic changes were graded from 0 to 4+ by a pathologist who had no knowledge of HD duration. The earliest change observed was reduplication of the capillary basement membrane. Narrowing of capillary lumina due to endothelial cell proliferation and new capillary formation were noted after five years of HD; lipid droplets were noted in capillaries by five years; and epidermal atrophy by 10 years. Progressive severity of each finding was associated with length of time on HD. Neither amyloid nor Ca++ deposits were observed in any specimens. By clinical observation, easy bruisability and increased skin fragility were worse the longer the patient was on HD. Capillary occlusion inducing tissue ischemia could be a cause of the atrophic skin changes noted. However, no patient manifested dermal necrosis. While pathogenesis of the capillary changes in uremic skin is unknown, the changes have been shown to stabilize following successful kidney transplantation.