Glomerular cell number in normal subjects and in type 1 diabetic patients

Glomerular cell number in normal subjects and in type 1 diabetic patients.BackgroundThe number of cells in glomeruli has been a challenging measure, especially in human kidneys, with only a small amount of tissue obtained by biopsy. However, the number of cells and their function are important determinants of renal function in health and disease.MethodsModern morphometric techniques have now provided the means to determine the numerical density (Nv) and number (with a measure of glomerular volume) of endothelial cells, mesangial cells, and podocytes in plastic-embedded renal tissue biopsied from nondiabetic subjects (N = 36) and type 1 diabetic patients (N = 46) over an extended age range from childhood through late adult.ResultsNv values for all glomerular cells varied only slightly with age and did not change within the range of glomerular lesions of diabetes studied. Thus, the increase in glomerular volume during childhood to a steady level thereafter was the primary determinant of total glomerular cell number. The number of mesangial cells and endothelial cells increased with age, reflecting the increase in all cells, while the podocytes remained unchanged in number over all ages studied (10 to 69 years). Numbers of total glomerular cells, mesangial cells, and endothelial cells were not changed with diabetes, while podocytes were fewer in number in diabetic patients of all ages, with reduced podocyte numbers even in diabetes of short duration.ConclusionsThe essentially constant glomerular cell density in nondiabetic and diabetic subjects under different circumstances possibly indicates an underlying propensity for the glomerulus to regulate its architecture to maintain a constant number of cells per volume, no matter the size of the glomerulus or the severity of diabetic nephropathy studied in this set of patients. The reductions in podocyte numbers in both younger and older diabetic patients indicate a significant risk for functional abnormalities as diabetic nephropathy progresses. Moreover, these observations do not support the suggestion of marked increases in glomerular cell number (and especially mesangial cells) with the development and progression of diabetic nephropathy

Studies of renal autoregulation in pancreatectomized and streptozotocin diabetic rats

Studies of renal autoregulation in pancreatectomized and streptozotocin diabetic rats. We studied renal autoregulation in pancreatectomized Munich-Wistar diabetic rats and in their sham-operated controls. In a second experiment we studied renal autoregulation in untreated and insulin treated streptozotocin diabetic Munich-Wistar rats and their nondiabetic controls. In the first experiment the diabetic rats had higher baseline renal blood flows (RBF). There was a fall in renal vascular resistance (RVR) and sustained RBF in both diabetic and control rats as renal perfusion pressures (RPP) was reduced from 130 and 110mm Hg. As RPP was reduced from 110 and 80mm Hg, there was no significant change in RVR in control rats and RBF began to fall. Below RPP of 80mm Hg RVR rose and RBF fell sharply in these rats. In contrast, there was a progressive fall in RVR as RPP was lowered to 60mm Hg in the diabetic rats and, thus, RBF was much better sustained in these animals. In the second experiment the plasma glucose level was 502 ± 52 mg/dl (X ± SD) in the untreated diabetic rats and only modestly reduced to 411 ± 49 mg/dl in the insulin treated animals. Untreated streptozotocin diabetic rats had moderately reduced and insulin-treated diabetic rats had mildly reduced baseline RVR and RBF. However, in these animals as in the pancreatectomized rats the increases in RVR noted in control rats at subautoregulatory RPPs were not seen. Thus, regardless of whether baseline RBFs were increased or decreased, diabetic rats sustained RBF at markedly reduced RPPs far more efficiently than did nondiabetic rats. The pathogenesis of these abnormalities in diabetic rats was not learned in these studies. However, it is likely that further study of autoregulation in diabetic rats could uncover factors influencing renal vascular tone which would be helpful in understanding the renal hemodynamic perturbations which may attend this experimental model

Performance of A1C for the Classification and Prediction of Diabetes

OBJECTIVE Although A1C is now recommended to diagnose diabetes, its test performance for diagnosis and prognosis is uncertain. Our objective was to assess the test performance of A1C against single and repeat glucose measurements for diagnosis of prevalent diabetes and for prediction of incident diabetes. RESEARCH DESIGN AND METHODS We conducted population-based analyses of 12,485 participants in the Atherosclerosis Risk in Communities (ARIC) study and a subpopulation of 691 participants in the Third National Health and Nutrition Examination Survey (NHANES III) with repeat test results. RESULTS Against a single fasting glucose ≥126 mg/dl, the sensitivity and specificity of A1C ≥6.5% for detection of prevalent diabetes were 47 and 98%, respectively (area under the curve 0.892). Against repeated fasting glucose (3 years apart) ≥126 mg/dl, sensitivity improved to 67% and specificity remained high (97%) (AUC 0.936). Similar results were obtained in NHANES III against repeated fasting glucose 2 weeks apart. The accuracy of A1C was consistent across age, BMI, and race groups. For individuals with fasting glucose ≥126 mg/dl and A1C ≥6.5% at baseline, the 10-year risk of diagnosed diabetes was 88% compared with 55% among those individuals with fasting glucose ≥126 mg/dl and A1C 5.7–<6.5%. CONCLUSIONS A1C performs well as a diagnostic tool when diabetes definitions that most closely resemble those used in clinical practice are used as the “gold standard.” The high risk of diabetes among individuals with both elevated fasting glucose and A1C suggests a dual role for fasting glucose and A1C for prediction of diabetes. Although A1C is now recommended for the diagnosis of diabetes (1,2), its precise test performance is uncertain. The lack of a single, clear “gold standard” poses a challenge for determining the performance of A1C. Previous diagnostic studies of A1C have relied exclusively on a single elevated fasting or 2-h glucose values as gold standards (3–5). However, because glucose determinations are inherently more variable than A1C (6), these convenient gold standards are likely to reduce the apparent accuracy of A1C as a diagnostic test. A stronger gold standard would rely on repeated glucose determinations on different days (2), i.e., the recommended approach to diagnosis of diabetes in clinical practice. Alternatively, A1C and fasting glucose can be compared head-to-head against the subsequent development of clinically diagnosed diabetes as the gold standard. We hypothesized that 1) A1C would perform well as a diagnostic and prognostic test for diabetes across its full range and at the American Diabetes Association–recommended threshold of 6.5% and 2) that its performance would be best when judged against stronger, most clinically relevant gold standards

Albuminuria Changes and Cardiovascular and Renal Outcomes in Type 1 Diabetes: The DCCT/EDIC Study.

Background and objectives In trials of people with type 2 diabetes, albuminuria reduction with renin-angiotensin system inhibitors is associated with lower risks of cardiovascular events and CKD progression. We tested whether progression or remission of microalbuminuria is associated with cardiovascular and renal risk in a well characterized cohort of type 1 diabetes. Design, setting, participants, & measurements We studied 1441 participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study. Albumin excretion rate (AER) was quantified annually or biennially for up to 30 years. For each participant, albuminuria status was defined over time as normoalbuminuria (AER continuously \u3c30 mg/d), sustained microalbuminuria (AER, 30–299 mg/d on two consecutive visits), macroalbuminuria (AER≥300 mg/d), or remitted microalbuminuria (transition from sustained microalbuminuria to AER\u3c30 mg/d on two consecutive visits). We tested associations of time-updated albuminuria status with adjudicated clinical cardiovascular events, the development of reduced GFR (\u3c60 ml/min per 1.73 m2 on two consecutive visits), and subclinical cardiovascular disease. Results At least one cardiovascular event occurred in 184 participants, and 98 participants developed reduced eGFR. Compared with normoalbuminuria, sustained microalbuminuria, remitted microalbuminuria, and macroalbuminuria were each associated with higher risk of cardiovascular events (adjusted hazard ratios [HRs] and 95% confidence intervals [95% CIs]: 1.79 [1.13 to 2.85], 2.62 [1.68 to 4.07], and 2.65 [1.68 to 4.19], respectively) and reduced eGFR (adjusted HRs [95% CIs], 5.26 [2.43 to 11.41], 4.36 [1.80 to 10.57], and 54.35 [30.79 to 95.94], respectively). Compared with sustained microalbuminuria, remission to normoalbuminuria was not associated with reduced risk of cardiovascular events (adjusted HR, 1.33; 95% CI, 0.68 to 2.59) or reduced eGFR (adjusted HR, 1.75; 95% CI, 0.56 to 5.49). Compared with normoalbuminuria, sustained microalbuminuria, remitted microalbuminuria, and macroalbuminuria were associated with greater carotid intima-media thickness, and macroalbuminuria was associated with a greater degree of coronary artery calcification. Conclusions In type 1 diabetes, microalbuminuria and macroalbuminuria are associated with higher risks of cardiovascular disease and reduced eGFR, but achieving a remission of established microalbuminuria to normoalbuminuria does not appear to improve outcomes

Ritonavir blocks AKT signaling, activates apoptosis and inhibits migration and invasion in ovarian cancer cells

<p>Abstract</p> <p>Background</p> <p>Ovarian cancer is the leading cause of mortality from gynecological malignancies, often undetectable in early stages. The difficulty of detecting the disease in its early stages and the propensity of ovarian cancer cells to develop resistance to known chemotherapeutic treatments dramatically decreases the 5-year survival rate. Chemotherapy with paclitaxel after surgery increases median survival only by 2 to 3 years in stage IV disease highlights the need for more effective drugs. The human immunodeficiency virus (HIV) infection is characterized by increased risk of several solid tumors due to its inherent nature of weakening of immune system. Recent observations point to a lower incidence of some cancers in patients treated with protease inhibitor (PI) cocktail treatment known as HAART (Highly Active Anti-Retroviral Therapy).</p> <p>Results</p> <p>Here we show that ritonavir, a HIV protease inhibitor effectively induced cell cycle arrest and apoptosis in ovarian cell lines MDH-2774 and SKOV-3 in a dose dependent manner. Over a 3 day period with 20 μM ritonavir resulted in the cell death of over 60% for MDAH-2774 compared with 55% in case of SKOV-3 cell line. Ritonavir caused G1 cell cycle arrest of the ovarian cancer cells, mediated by down modulating levels of RB phosphorylation and depleting the G1 cyclins, cyclin-dependent kinase and increasing their inhibitors as determined by gene profile analysis. Interestingly, the treatment of ritonavir decreased the amount of phosphorylated AKT in a dose-dependent manner. Furthermore, inhibition of AKT by specific siRNA synergistically increased the efficacy of the ritonavir-induced apoptosis. These results indicate that the addition of the AKT inhibitor may increase the therapeutic efficacy of ritonavir.</p> <p>Conclusion</p> <p>Our results demonstrate a potential use of ritonavir for ovarian cancer with additive effects in conjunction with conventional chemotherapeutic regimens. Since ritonavir is clinically approved for human use for HIV, drug repositioning for ovarian cancer could accelerate the process of traditional drug development. This would reduce risks, limit the costs and decrease the time needed to bring the drug from bench to bedside.</p