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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kidney is a site of insulin-like growth factor I (IGF-I) production and IGF-I mediates effects on kidney growth and function. Diabetes is associated with kidney growth in man and the rat and, in the latter, commences within 48 h of induction of diabetes. Levels of kidney IGF-I are increased during the first 2-3 days of diabetes and this is at least partially due to increased production. Additionally, IGF-I binding is increased in diabetic rat kidney, due to increased binding to the IGF-I receptor and induction of proximal tubular binding protein expression. These changes are attenuated in prepubertal rats suggesting hormonal regulation. Further studies suggest that the changes are partly GH-dependent but independent of direct sex steroid effects. As kidney growth has been implicated in the subsequent development of diabetic nephropathy, further exploration of the close association between diabetes-related kidney growth and IGF-I accumulation may lead to an improved understanding of this complication.
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PMID:IGF-I and IGF binding proteins in diabetes-related kidney growth. 128 98

Recent studies indicate the important roles of mesangial cell dysfunction and insulin-like growth factor I (IGF-I) in the development of diabetic nephropathy. In order to know whether hyperglycemia could alter IGF-I action on mesangial cells, we examined mitogenic and metabolic effects of IGF-I on mesangial cells. Mesangial cells revealed to express considerable numbers of receptors specific to IGF-I will relatively small numbers of insulin receptors. The uptake of [3H]-2-deoxy-glucose, [3H]-aminoisobutyric acid (AIB), or [3H]-thymidine into mesangial cells was stimulated by IGF-I at physiological concentrations. Under high concentrations of glucose (55 mM), the stimulation of thymidine uptake by IGF-I was significantly suppressed from 5863 +/- 549 (at 11 mM glucose) to 1731 +/- 146 DPM/100 micrograms/prot. On the contrary, AIB incorporation by IGF-I was significantly enhanced in the cells cultured under high concentration of glucose, as 2.03 +/- 0.03n mol/mg protein/15 min at 55 mM glucose vs 0.59 +/- 0.01 at 11 mM glucose. In conclusion; 1) IGF-I had metabolic and mitogenic effects on rat mesangial cells at physiological concentrations. 2) under excess glucose conditions, mitogenic action of IGF-I on rat mesangial cells was suppressed, while amino acid incorporation was enhanced. These results suggest that modulation of IGF-I effects on mesangial cell by glucose could be associated with mesangial cell dysfunction in diabetes.
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PMID:[Metabolic and mitogenic effects of insulin-like growth factor I on rat glomerular mesangial cells cultured under high concentration of glucose]. 205 39

In order to explore the possible contribution of insulin-like growth factor I to the development of diabetic nephropathy, the effect of glucose on the mitogenic and metabolic actions of insulin-like growth factor I in cultured rat glomerular mesangial cells was examined. The stimulation of [3H]-thymidine incorporation by insulin-like growth factor I in the cells exposed to high concentrations (55 mmol/l) of glucose (4.6 +/- 1.3 fold stimulation) was significantly suppressed as compared with that in the cells cultured in 11 mmol/l glucose (17.5 +/- 0.8 fold). In contrast, [3H]-amino-isobutylic acid uptake into the mesangial cells was significantly enhanced by glucose (2.03 +/- 0.03 nmol.mg protein-1. 15 min-1 at 55 mmol/l glucose vs 0.59 +/- 0.01 at 11 mmol/l glucose), while 2-deoxyglucose uptake remained unchanged. [125I]-insulin-like growth factor I binding was slightly but significantly increased in the cells exposed to high concentrations of glucose. Thus, glucose may modulate the mitogenic and metabolic actions of insulin-like growth factor I differently in cultured mesangial cells probably at the post-insulin-like growth factor I receptor level. These results may indicate that the differential modulation of the actions of insulin-like growth factor I by glucose could result in the increase in amino acid uptake and decrease in the cell proliferation in the mesangial cells, possibly leading to enhanced mesangial matrix synthesis with a relatively small increase in mesangial cell volume as seen in diabetic nephropathy.
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PMID:Differential modulation of mitogenic and metabolic actions of insulin-like growth factor I in rat glomerular mesangial cells in high glucose culture. 847 71

The aim of this study was to determine the clinical significance of serum and urinary insulin-like growth factor I (IGF-I) in renal disease and diabetes mellitus. In renal portion, we measured their concentrations in patients with chronic renal disease (serum creatinine < 2.0 mg/dl) (CRD. n = 22) and those with chronic renal failure (serum creatinine > or = 2.0 mg/dl) (CRF, n = 26) and compared with normal healthy controls (C. n = 20). Serum concentrations growth hormone (GH) and IGF-I did not differ among these groups. Urinary IGF-I level was significantly increased in CRF (4.0 +/- 0.5 ng/mg creatinine) compared with CRD (2.8 +/- 0.6 ng/mg creatinine) and C (1.8 +/- 1.0 ng/mg) creatinine). Urinary IGF-I did not correlate with either serum GH or serum IGF-I. Urinary IGF-I, but not serum IGF-I, demonstrated a significant negative correlation with creatinine clearance. In diabetic portion, 29 patients with noninsulin dependent diabetes mellitus (NIDDM), whose serum creatinine were within normal range, and age-matched 12 subjects were enrolled. Serum IGF-I in NIDDM (130 +/- 11 ng/ml) was significantly lower than that in controls (201 +/- 11 pg/ml). In contrast, urinary IGF-I level in NIDDM (1.93 +/- 0.31 ng/mg creatinine) did not differ from that in controls (2.00 +/- 0.31 ng/mg creatinine). In NIDDM, urinary IGF-I had poor correlation with both serum IGF-I and albuminuria. The data in renal patients suggest the possible participation of renal IGF-I in the progression of renal disease, while in NIDDM with normal serum creatinine the role of renal IGF-I may be less in the early diabetic nephropathy.
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PMID:Serum and urinary levels of insulin-like growth factor I in patients with chronic renal disease and diabetes mellitus: its clinical implication. 879 28

To evaluate the protecting effect of camostat mesylate, N,N-dimethylcarbamoylmethyl-p-(p-guanidinobenzoyloxy)phenylacetate methanesulfonate, one of the synthetic trypsin inhibitors, on diabetic nephropathy, urinary albumin excretion was measured in streptozotocin-induced (50 mg/kg, i.p.) diabetic rats treated with oral camostat mesylate for 12 weeks. The rats were divided into three groups: (1) nondiabetic control rats; (2) diabetic rats, and (3) diabetic rats received rat chow containing 0.1% camostat mesylate (PI rats). After induction of diabetes, the ratio of kidney weight to body weight and urinary albumin excretion (UAE) were significantly increased. However, the ratio of kidney weight to body weight in PI rats was significantly lower than that in diabetic rats, and UAE in PI rats was also significantly lower than that in diabetic rats at 4, 8 and 12 weeks. Kidney tissue insulin-like growth factor I (IGF-I) contents were significantly reduced in diabetic rats, and there were no significant differences in kidney tissue IGF-I contents between diabetic and PI rats. These results suggest that camostat mesylate reduces the UAE probably through an inhibitory effect on initial diabetic renal hypertrophy and that camostat mesylate is available for diabetic nephropathy.
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PMID:An inhibition of urinary albumin excretion by protease inhibitor in streptozotocin-diabetic rats. 895 6

The renal kallikrein-kinin system and the renin-angiotensin system are implicated in the pathogenesis of diabetic nephropathy. We have shown that renal kallikrein and renin gene expression are altered by diabetes. To investigate the cellular mechanisms responsible for these changes, we examined the effects of acute insulin and insulin-like growth factor I (IGF-I) treatment on renal kallikrein-kinin and renin-angiotensin system components. Three weeks after induction of diabetes, we measured renal kallikrein and renin mRNA levels, renal kallikrein and renal renin activity, and plasma renin activity in control and diabetic rats and diabetic rats treated with insulin or IGF-I for 2 or 5 h. In diabetic rats, kallikrein and renin mRNA levels were reduced >50% compared with control rats. Renal tissue kallikrein levels and plasma renin activity were decreased, whereas renal renin content was unchanged. Insulin increased kallikrein and renin mRNA levels after 2 h. IGF-I, at a dosage that stimulated kallikrein mRNA levels in control rats, had no effect on renal kallikrein and renin content or mRNA levels in diabetic rats. However, infusion of a fivefold higher IGF-I dosage resulted in a two- to threefold increase in kallikrein and renin mRNA levels in 2 h. These data suggest that 1) diabetes suppresses kallikrein and renin gene expression, and these abnormalities are reversed by insulin or IGF-I; and 2) the diabetic state produces resistance to IGF-I induction of kallikrein and renin gene expression. These changes in regulated synthesis of kallikrein and renin in the kidney may underlie renal vascular changes that develop in diabetes.
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PMID:Induction of renal kallikrein and renin gene expression by insulin and IGF-I in the diabetic rat. 939 95

Among other neuropeptides and neurohormones, growth hormone (GH) and somatostatin (SRIF) have been shown to modulate the development of glomerular injury in various renal diseases. In particular, GH is implicated in the induction of glomerular hypertrophy and sclerosis in partial nephrectomy and diabetic nephropathy. While GH effects on glomerular hypertrophy are likely mediated by insulin-like growth factor I (IGF-I), GH effects on glomerular sclerosis are independent of IGF-I. Those effects rather require multiple signaling pathways functioning in series, e.g. angiotensin II binding preceding transforming growth factor beta (TGF-beta) release, or pro-inflammatory factor release preceding repair/scarring processes. In contrast with GH, SRIF administration prevents the development of glomerular lesions in experimental diabetes, partial nephrectomy and immune glomerulonephritis. Inhibitory effects of SRIF on glomerular hypotrophy may be through a decrease in GH secretion and/or IGF-I expression or through a direct blockade of glomerular cell proliferation. The mechanisms underlying the anti-inflammatory effects of SRIF are most likely a deactivation of inflammatory cells related in part to an upregulated response of these cells to glucocorticoids. Additional studies will be required to further define the role of GH and SRIF in the development of glomerular injury and, hence, to identify new targets for a therapeutic approach in glomerular diseases.
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PMID:Growth hormone and somatostatin in glomerular injury. 1020 98

Thirty-three patients with type 2 diabetes mellitus (16 men, 17 women) were divided into 3 groups based on urinary excretion of albumin (U-Alb)--group A: U-Alb < 30 mg/d; group B: 30 mg/d < or = U-Alb < or = 300 mg/d; and group C: 300 mg/d < U-Alb. Serum creatinine levels were lower than 2.0 mg/dL in all the subjects. There was no difference in age, sex, therapy, body weight, body mass index (BMI), lean body mass (LBM), or hemoglobin A(1c) (HbA(1c)) levels among the 3 groups. Resting metabolic rate (RMR) (kJ/h/m(2)) and adjusted RMR for lean body mass (kJ/h/m(2)) were significantly increased in group C compared with groups A and B. Hb concentrations, serum albumin levels, and creatinine clearance were much lower in group C than in groups A and B (P < .001). There were no difference in serum urea nitrogen, total cholesterol, cholinesterase and free thyroxine, or plasma insulin-like growth factor I (IGF-I) levels among the 3 groups. Linear regression analysis revealed an inverse correlation between RMR and serum albumin levels, correlation between RMR and U-Alb, and inverse correlation between RMR and Hb concentrations, respectively, in these patients. In conclusion, RMR in diabetic patients correlated directly with U-Alb and inversely with serum albumin and Hb concentration. These findings suggest that RMR is related with urinary albumin loss and anemia in patients with type 2 diabetes mellitus accompanied by diabetic nephropathy.
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PMID:Increased resting metabolic rate in patients with type 2 diabetes mellitus accompanied by advanced diabetic nephropathy. 1553 91

Microalbuminuria is the earliest detectable clinical abnormality in diabetic glomerulopathy. On a molecular level, metabolic pathways activated by hyperglycemia, glycated proteins, hemodynamic factors, and oxidative stress are key players in the genesis of diabetic kidney disease. A variety of growth factors and cytokines are then induced through complex signal transduction pathways. Transforming growth factor-beta 1 (TGF-beta1) has emerged as an important downstream mediator for the development of renal hypertrophy and the accumulation of mesangial extracellular matrix components, but there is limited evidence to support its role in the development of albuminuria. The loss of proteoglycans in the glomerular basement membrane (GBM) has been recently questioned as causative of the albuminuria, and current research has focused on the podocyte as a central target for the effects of the metabolic milieu in the development and progression of diabetic albuminuria. Podocyte-derived vascular endothelial growth factor (VEGF), a permeability and angiogenic factor whose expression is increased in diabetic kidney disease, is perhaps a major mediator of the increased protein filtration. Decreased podocyte number and/or density as a result of apoptosis or detachment, GBM thickening with altered matrix composition, and a reduction in nephrin protein in the slit diaphragm with podocyte foot process effacement, all comprise the principal features of diabetic podocytopathy that clinically manifests as albuminuria and proteinuria. Many of these events are mediated by angiotensin II whose local concentration is stimulated by high glucose, mechanical stretch, and proteinuria itself. Angiotensin II in turn stimulates podocyte-derived VEGF, suppresses nephrin expression, and induces TGF-beta1 leading to podocyte apoptosis and fostering the development of glomerulosclerosis. Proteinuria can then induce in tubular cells a genetic program leading to tubulointerstitial inflammation, fibrosis and tubular atrophy. Besides direct effects of albuminuria on tubular cells, pathophysiological changes in the ultrafiltration barrier lead to an increased tubular filtration of various growth factors (TGF-beta1, insulin-like growth factor I) that may further alter the function of tubular cells. Moreover, angiotensin II also stimulates uptake of ultrafiltered proteins into tubular cells and enhances the production of proinflammatory and profibrotic cytokines within the cells. Migration of macrophages and other inflammatory cells into the tubulointerstitium occurs. Increased synthesis and decreased turnover of extracellular matrix proteins in tubular cells and interstitial fibroblasts contribute to interstitial fibrosis. In addition, under locally high concentrations of angiotensin II and TGF-beta1, tubular cells may change their phenotype and become fibroblasts by a process called epithelial to mesenchymal transition (EMT) which contributes to interstitial fibrosis and tubular atrophy because of vanishing epithelia cells. An alternative explanation for the development of albuminuria in diabetic nephropathy that involves primarily an abnormality in tubular handling of ultrafiltered proteins has also been suggested, but these changes are not necessarily exclusive of the altered properties of glomerular ultrafiltration barrier.
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PMID:Pathogenesis of the podocytopathy and proteinuria in diabetic glomerulopathy. 1822 Jun 94