Anil K. Mandal

Endothelial cell injury by high glucose and heparanase is prevented by insulin, heparin and basic fibroblast growth factor

BackgroundUncontrolled hyperglycemia is the main risk factor in the development of diabetic vascular complications. The endothelial cells are the first cells targeted by hyperglycemia. The mechanism of endothelial injury by high glucose is still poorly understood. Heparanase production, induced by hyperglycemia, and subsequent degradation of heparan sulfate may contribute to endothelial injury. Little is known about endothelial injury by heparanase and possible means of preventing this injury.ObjectivesTo determine if high glucose as well as heparanase cause endothelial cell injury and if insulin, heparin and bFGF protect cells from this injury.MethodsCultured porcine aortic endothelial cells were treated with high glucose (30 mM) and/or insulin (1 U/ml) and/or heparin (0.5 μ g/ml) and /or basic fibroblast growth factor (bFGF) (1 ng/ml) for seven days. Cells were also treated with heparinase I (0.3 U/ml, the in vitro surrogate heparanase), plus insulin, heparin and bFGF for two days in serum free medium. Endothelial cell injury was evaluated by determining the number of live cells per culture and lactate dehydrogenase (LDH) release into medium expressed as percentage of control.ResultsA significant decrease in live cell number and increase in LDH release was found in endothelial cells treated with high glucose or heparinase I. Insulin and/or heparin and/or bFGF prevented these changes and thus protected cells from injury by high glucose or heparinase I. The protective ability of heparin and bFGF alone or in combination was more evident in cells damaged with heparinase I than high glucose.ConclusionEndothelial cells injured by high glucose or heparinase I are protected by a combination of insulin, heparin and bFGF, although protection by heparin and/or bFGF was variable.

Renal protection in diabetes : Is it affected by glucose control or inhibition of the renin-angiotensin pathway?

BACKGROUND Recent reports indicate increased risk of renal failure with long-term use of angiotensin-converting enzyme inhibitors (ACEI) in diabetes. End-stage renal disease (ESRD) in diabetes has increased despite ACEI and angiotensin receptor blocker (ARB) use. This study questions renal protection by ACEI or ARB. Our hypothesis is that uncontrolled hyperglycemia is central to diabetic ESRD while tight glucose control is renoprotective. Cultured endothelial cells show morphological damage that increases with duration of exposure to high glucose and is prevented by insulin and more so by a combination of insulin and heparin. METHODS Findings from individual patients are compared to clinical trial results wherein ACEI or ARB was emphasized as the prime therapy to prevent progression of diabetic nephropathy to ESRD. Serum creatinine (Scr) changes were the main indicator of renoprotective effects in clinical trials. Creatinine clearance (Ccl), an important marker of glomerular filtration rate, was seldom reported. RESULTS Our observations show that ACEI-treated patients develop progressive renal failure, whereas renal function remains stable with optimum glucose control. Clinical trials showed that reduction of proteinuria, with ACEI, reduces the risk of ESRD. Our studies show that reduction of proteinuria with use of ACEI or ARB parallels a reduction in Ccl, suggesting that a change in proteinuria is related to Ccl changes. Scr changes are small, giving a deceptive view of renal protection. CONCLUSIONS Our observations find no evidence of renal protection with ACEI or ARB use in diabetes. Laboratory studies and clinical observations suggest that adequate glucose control is the key to renal protection in diabetes.

dGlucose is linked to renal function changes in diabetes

AIMS This study examines if dglucose, two-hour postprandial (2 hPP) minus fasting glucose (F), predicts glycemic control better than F or 2 hPPglucose. METHODS F and 2 hPPglucose, and renal function variables; BUN, serum creatinine (Scr), and estimated GFR (eGFR), were obtained from 56 insulin treated diabetic adults. 2 hPP-F(d) was calculated. Variables were compared when 2 hPPglucose was <200 (n=23) or >200 mg/dL (n=33). Correlation coefficients were calculated for F, 2 hPP or 2 hPP-F(d) renal function variables versus those for glucose. RESULTS Variables differed significantly between F and 2 hPP (t-test, p<0.05) for all patients and when 2 hPPglucose was < or >200 mg/dL, except dBUN at <200 mg/dL. When F, 2 hPP or 2 hPP-F(d) variables between 2 hPPglucose< and >200 mg/dL were compared, dScr was significant (p=0.0327). Correlation coefficients between dglucose and dScr or deGFR, were significant for all patients (r=0.420, p=0.0013, and r=-0.434, p=0.0008, respectively) and for 2 hPPglucose >200 mg/dL (r=0.523, p=0.0018 and r=-0.513, p=0.0023, respectively) but not 2 hPPglucose <200 mg/dL. When dglucose increased by 100 mg/dL, dScr increased by 0.08 and 0.11 mg/dL, and deGFR decreased by 2.73 and 3.73 mL/min for all patients and >200 mg/dL, respectively. CONCLUSIONS dGlucose better predicts renal function changes than F or 2 hPPglucose. Postprandial hyperglycemia (<200 mg/dL) control is crucial for renal protection in diabetes.

Renal Disease Is a Prodrome of Multiple Myeloma: An Analysis of 50 Patients from Eastern India

This study describes a spectrum of renal diseases that can precede the diagnosis of multiple myeloma (MM). Patients presenting manifestations of renal disease were recorded as individual patients of MM. Fifty patients (male 41; female 9) were included in this study. Diagnosis of MM was confirmed by two or more of the following four features: lytic bone lesions, serum or urine monoclonal peak, Bence Jones proteinuria, and greater than 20% plasma cells in bone marrow. Renal disease was present in 42 of 50 (84%) patients before MM was diagnosed. In only eight of 50 (16%) patients, diagnosis of MM preceded the detection of renal disease. Renal diseases consisted of acute renal failure in 26 patients (52%), chronic renal failure in 15 patients (30%) and nephrotic syndrome in 9 patients (18%). Some of the patients with acute or chronic renal failure also had heavy proteinuria. Percutaneous renal biopsy was done in 17 patients. Renal histopathology showed amyloidosis (n = 10), cast nephropathy (n = 5), nodular glomerulosclerosis (n = 1), and mesangioproliferative glomerulonephritis with plasma cell infiltration (n = 1). Hypercalcemia (calcium 11–13.8 mg/dL) was the most common precipitating factor for acute renal failure. All 50 patients received combination chemotherapy of melphalan and prednisolone or vincristine, Adriamycin, and dexamethasone. More than half of the total number of patients did not complete chemotherapy because of death or lost to follow-up. Nineteen patients with acute renal failure and eight patients with chronic renal failure were treated with hemodialysis. Fourteen patients (28%) with acute renal failure had recovery of renal function. Twenty-three patients (46%) were lost to follow-up. Seven patients (14%) died from sepsis, uremia, or hyperkalemia. Remission of MM was found in 9 of 21 (42.8%) patients who completed chemotherapy. Thus, acute renal failure is the most common renal disease preceding the diagnosis of MM. Reversal of renal function is achieved with chemotherapy and hemodialysis treatment.

Transmission Electron Microscopy of Urinary Sediment in Aminoglycoside Nephrotoxicity

Urinary sediment from 20 patients treated with aminoglycosides (AG) was studied using transmission electron microscopy. For the purpose of comparison, urinary sediment was also studied (control) from an additional 9 patients who had acute renal failure (ARF) but who did not receive AG (5 posttransplant, 4 postsurgical). Urinary myeloid bodies and renal tubule cells were analyzed semiquantitatively. The diagnosis of AG nephrotoxicity (or ARF) was made on the basis of a rise in serum creatinine greater than or equal to 0.5 mg/dL from the baseline levels. Among 20 patients, 12 developed AG-ARF, and 11 of these 12 showed myeloid bodies and necrotic renal tubule cells in their urinary sediment. Of the 8 patients that did not develop AG-ARF, 5 showed myeloid bodies and 2 of these also showed renal tubule cells in their urinary sediment. This incidence of necrotic renal tubule cells in the nephrotoxic group is significantly higher than in the nonnephrotoxic group (p less than 0.01). Although no statistical difference was found in the incidence of myeloid bodies between the two groups, the number of myeloid bodies was significantly (p less than 0.05) greater in the nephrotoxic group than in the nonnephrotoxic group. Furthermore, consecutive sediment studies revealed that the appearance of necrotic renal tubule cells (and not of myeloid bodies) coincided with the increase in serum creatinine. All control patients showed necrotic renal tubule cells but no myeloid bodies in their urinary sediment. Thus this study suggests that the presence of necrotic renal tubule cells signifies ARF, and when preceded or accompanied by large numbers of myeloid bodies that it indicates AG-ARF.