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P Fioretto

Publications and source records attributed to P Fioretto.

At least 19 recordsLinked to original sources
PubMed2006

Remodeling of renal interstitial and tubular lesions in pancreas transplant recipients.

Tubular atrophy and interstitial fibrosis, important in progression of renal diseases, including diabetic (D) and cyclosporine-induced (CSA) nephropathy, have been considered irreversible. Normoglycemia for 10 years following pancreas transplantation alone (PTA) reversed D glomerulopathy lesions. This study quantified tubular, interstitial, and arteriolar parameters in PTA recipients. Kidney function studies and biopsies were performed in eight non-uremic type I D patients (pts) at 5 and 10 years after PTA. Renal biopsies were analyzed by morphometric analysis. All pts were normoglycemic and insulin independent and received CSA during the study. Cortical interstitial volume fraction was increased at 5 years (0.31+/-0.07 vs normal 0.15+/-0.02, P<0.01) and decreased at 10 years post-PTA (0.23+/-0.03, P<0.02 vs 5 years). There was a reduction in the volume fraction of interstitial collagen and cells per cortical tissue, measured using electron microscopy, from 5 (0.126+/-0.061 and 0.103+/-0.026, respectively) to 10 years (0.079+/-0.031, P<0.05, and 0.074+/-0.018, P<0.05, respectively). The volume fraction of tubules which were atrophic (AT) was abnormal at 5 years (0.160+/-0.090) and decreased from 5 to 10 years (0.044+/-0.034, P<0.02), apparently due to AT reabsorption. The index of arteriolar hyalinosis did not change during the study (1.30+/-0.22 and 1.34+/-0.33 at 5 and 10 years, respectively, nonsignificant). This study demonstrates, for the first time in humans, that interstitial expansion is reversible and that atrophic tubules can be reabsorbed. In contrast, there was no improvement in the arteriolar lesions. Whether this is due to long-term normoglycemia, reduction of CSA dose or other mechanisms is unclear.

Adult↗
PubMed2004

Lipoprotein lipase gene variants and progression of nephropathy in hypercholesterolaemic patients with type 2 diabetes.

OBJECTIVE: Recent prospective studies have identified hyperlipidaemia as an independent determinant of diabetic nephropathy. Lipoprotein lipase (LPL) is a key enzyme in the postprandial processing of triglycerides and VLDL. Among a number of common sequence variants of the LPL, HindIII has been associated with coronary heart disease and, more recently, with microalbuminuria in type 2 diabetes. We evaluated the progression of renal disease in hypercholesterolaemic type 2 diabetic patients in relation to this polymorphism. DESIGN AND SUBJECTS: We followed up for 4 years 65 consecutively enrolled microalbuminuric patients with type 2 diabetes; of whom 28 had hypercholesterolaemia (6.62 +/- 0.9 mmol L(-1), group A) and 37 were normocholesterolaemic (4.68 +/- 0.5 mmol L(-1), group B). MAIN OUTCOME MEASURES: After performing the genetic analyses, albumin excretion rate (AER) and estimated glomerular filtration rate (GFR), calculated by the simplified equation of the MDRD Study Group, were repeated every year. RESULTS: In group A, AER increased more (deltaAER: 11 [38] vs. 4 [18] microg min(-1) per year in group B, P < 0.0001) while GFR declined faster (-3.5 +/- 2.1 vs. -2.0 +/- 1.4 mL min(-1) per year, P < 0.02). Patients homozygous for the allele + of HindIII showed a significantly faster decline of GFR and a higher increase of AER (both P = 0.0001) even after adjustment for cholesterol levels and anthropometric variables. CONCLUSIONS: In hypercholesterolaemic type 2 diabetic patients with microalbuminuria, the renal disease has an accelerated course, particularly in those carrying the H+/H+ genotype of the HindIII polymorphism at the LPL locus.

Aged↗
PubMed2004

Effect of lercanidipine compared with ramipril on albumin excretion rate in hypertensive Type 2 diabetic patients with microalbuminuria: DIAL study (diabete, ipertensione, albuminuria, lercanidipina).

Microalbuminuria and hypertension are risk factors for diabetic nephropathy in Type 2 diabetic patients. Recent data suggest that blockade of the renin-angiotensin system slows the progression of diabetic nephropathy; in contrast, the results on the renoprotective effect of calcium channel antagonists are conflicting. We evaluated the effectiveness of lercanidipine, in comparison with ramipril, on the reduction in albumin excretion rate (AER) and blood pressure in mild-to-moderate hypertensive patients with Type 2 diabetes and persistent microalbuminuria. A total of 277 patients were enrolled in a multicentric, randomized, double-blind, active-controlled, parallel-group trial; 180 were randomized to receive 10-20 mg/day of lercanidipine or 5-10 mg/day of ramipril and followed up for 9-12 months. The primary outcome was the change in AER from baseline. After 9-12 months of follow-up, a reduction in AER of -17.4+/-65 microg/min (p<0.05) and -19.7+/-52.5 (p<0.05) in the lercanidipine and ramipril group, respectively, was observed, without differences between the groups. A significant reduction in systolic and diastolic blood pressure was observed in both the lercanidipine and ramipril-based treatment groups (p<0.0001 for both). This study demonstrated that treatment with lercanidipine 10-20 mg/day does not worsen albuminuria in microalbuminuric Type 2 diabetic patients with hypertension. Indeed, both lercanidipine and ramipril treatments resulted in a significant reduction in AER without a statistically significant difference between the two groups.

Adult↗
PubMed2001

Risk predictors in patients with diabetic nephropathy.

Diabetic nephropathy is currently the most common cause of end-stage renal disease in the Western countries. Only approximately one third of patients with type 1 diabetes develop nephropathy; thus, because it is not feasible to aggressively treat all patients, it becomes very important to find early markers in order to identify patients at high nephropathy risk. To date the best available predictor of overt nephropathy is microalbuminuria. In this article we review the validity of microalbuminuria as a predictor of overt nephropathy and consider other markers of nephropathy risk.

Albuminuria↗
PubMed2001

A defect in glycogen synthesis characterizes insulin resistance in hypertensive patients with type 2 diabetes.

A subgroup of patients with type 2 diabetes shows a clustering of abnormalities such as peripheral insulin resistance, hypertension, and microalbuminuria. To evaluate whether these traits reflect intrinsic disorders of cell function rather than in vivo environmental effects, we studied a group of 7 nondiabetic hypertensive subjects with an altered albumin excretion rate (AER) (HyMA+) and 3 groups of patients with type 2 diabetes: 7 with normal blood pressure and normal AER (DH-MA-), 7 with high blood pressure and normal AER (DH+MA-), and 7 with both high blood pressure and altered AER (DH+MA+). Glucose disposal was measured during an hyperinsulinemic clamp (40 mU. m(2)(-1). min(-1)) with primed deuterated [6.6 (2)H(2)] glucose infusion. In the same subjects, a skin biopsy was performed and the following parameters were investigated: glucose transport (as determined by [(3)H]2-deoxyglucose uptake); glycogen synthase activity (as determined by [(14)C] glucose incorporation from UDP-[U-(14)C] glucose into glycogen); glycogen phosphorylase activity (as measured by the incorporation of [U-(14)C]glucose 1-phosphate into glycogen); and total glycogen content. In vivo glucose disposal was significantly reduced in DH+MA- and DH+MA+, with respect to DH-MA-, HyMA+, and controls. Insulin-stimulated glucose transport was similar in the 3 groups of patients with diabetes. A significant reduction of intracellular glycogen content was observed in DH+MA- and DH+MA+ compared with DH-MA- in both basal and insulin-stimulated conditions, probably because of a major impairment of glycogen synthase activity. Glycogen phosphorylase activity did not show differences between the groups. These results suggest that (1) the combination of type 2 diabetes with hypertension and altered AER is associated with impaired insulin sensitivity, and (2) intrinsic, possibly genetic, factors may account for increased peripheral insulin resistance in hypertensive microalbuminuric patients with type 2 diabetes, pointing to the reduction of glycogen synthase activity as a shared common defect.

Albuminuria↗
PubMed2001

Early ACE-i intervention in microalbuminuric patients with type 1 diabetes: effects on albumin excretion, 24 h ambulatory blood pressure, and renal function.

OBJECTIVES: To study the effects of ACE-i in type 1 diabetic patients with early microalbuminuria with regard to: i) UAE, ii) 24 h AMBP, including the effect on diurnal BP variation, and iii) renal haemodynamics. MATERIAL AND METHODS: 58 patients with urinary albumin excretion (UAE) between 20-70 microg/min were treated for two years with either the ACE inhibitor (ACE-i) lisinopril (20 mg od) or placebo in two randomised placebo controlled double blind studies. In a subgroup of patients (n=22) we performed 24 h ambulatory blood pressure measurements (AMBP) and renal function tests (constant infusion technique). RESULTS: i) Changes in UAE over the two years were significantly different (p<0.01) in the two groups with final UAE in the lisinopril group of 19.1 microg/min x/divide 2.5 (geometric mean x/divide tolerance factor) and 44.1 microg/min x/divide 2.8 in the placebo group. In the lisinopril group 20 patients (60.6%) reversed to normoalbuminuria compared to 6 patients (24%) in the placebo group (p<0.02). ii) Clinical BP measurements revealed no differences between groups, but by AMBP significant reductions were detectable in the lisinopril group, primarily in night AMBP (systolic/diastolic: - 6.9 +/- 8.6/- 6.0 +/- 5.3 mmHg, p<0.01) as opposed to increases in the placebo group (3.1 +/- 9.3/1.9 +/- 7.3 mmHg). iii) Changes in UAE and changes in filtration fraction (FF) were positively correlated in the intervention group (r=0.9, p<0.01), i.e. the patients who showed the greatest fall in UAE were the ones with the greatest fall in FF. CONCLUSIONS: ACE-i treatment in patients with low-grade microalbuminuria reduces 24 h AMBP without attenuating diurnal blood pressure variation, reduces UAE significantly, with changes in UAE being strongly associated with changes in FF. Furthermore, compared to placebo, ACE-i reverses micro- to normoalbuminuria in a significant fraction of patients.

Adult↗
PubMed2000

Gliclazide modified release: its place in the therapeutic armamentarium.

The constraints of intensive multifactorial management of type 2 diabetes dictate a need for effective, well-tolerated agents with simple administration regimens. Sulfonylureas remain the most frequently used agents, and represent a rational approach when consideration is given to the pathophysiology of this common condition. Trials of gliclazide modified release in varied populations have yielded very acceptable clinical results that support its first-line use in type 2 diabetes, including obese, elderly, and mild-to-moderate renal insufficient patients. The simplicity of its dose regimen and its efficacy and tolerance profile may significantly contribute to improving compliance.

Diabetes Mellitus↗
PubMed2000

Course of renal function in type 2 diabetic patients with abnormalities of albumin excretion rate.

Heterogeneity in renal structure has been described in type 2 diabetic patients with both microalbuminuria and proteinuria; in fact, only a subset of type 2 diabetic patients have the typical diabetic glomerulopathy. However, it is currently unknown whether abnormalities in albumin excretion rate (AER) have a different renal prognostic value depending on the underlying renal structure. Aims of this study were: 1) to study the course of renal function in type 2 diabetic patients with altered AER; 2) to evaluate the relationship between the course of glomerular filtration rate (GFR) and renal structure; and 3) to evaluate the relationship between the course of GFR and baseline AER levels, metabolic control, and blood pressure levels during a follow-up period of 4 years. A total of 108 type 2 diabetic patients, 74 with microalbuminuria (MA) and 34 with proteinuria (P), were recruited into a prospective study that encompassed: 1) a baseline kidney biopsy with morphometric measurements of glomerular parameters; 2) intensified antihypertensive treatment for an average 4-year period (blood pressure target <140/90 mmHg); and 3) determinations of GFR at baseline and every 6 months. Mean (+/- SD) GFR significantly decreased from baseline in both MA (-1.3+/-9.4 [95% CI -3.51 to +0.86], P < 0.05) and P (-3.0+/-13.0 ml x min(-1) x 1.73 m(-2) per year [-7.71 to +1.61], P < 0.01). However, the changes in GFR were quite heterogeneous. Thus, on the basis of percent GFR change per year from baseline (delta%GFR), both MA and P patients were defined as progressors or nonprogressors when they were below or above the median, respectively. Baseline parameters of glomerular structure had a strong influence on the course of GFR. Indeed, the odds ratios of being progressors significantly increased across the quartiles of baseline glomerular basement membrane (GBM) width and mesangial fractional volume [Vv(mes/glom)], being 2.71 and 2.85 higher, respectively, in the fourth quartile than in the first quartile (P < 0.01 for both). Conversely, nonprogressors outnumbered progressors in the first quartile of GBM width (odds ratio: 2.14, P < 0.05) and in the first quartile of Vv(mes/glom) (odds ratio: 2.28, P < 0.01). Baseline albumin excretion rate (AER) did not influence delta%GFR; in fact, the number of progressors did not increase across quartiles of baseline AER among either MA or P. Similarly, mean blood pressure levels during follow-up (and intensified antihypertensive therapy) did not affect the course of GFR: the number of progressors and nonprogressors did not change across quartiles of mean blood pressure. In contrast, HbA1c during follow-up had an impact on delta%GFR: the odds ratio for being a progressor increased across quartiles of HbA1c, particularly for the highest quartile (HbA1c >9.0%). In conclusion, the course of renal function is heterogeneous in type 2 diabetic patients with microalbuminuria or proteinuria. In fact, a subset of patients has a rapid decline in GFR over a 4-year follow-up period; these patients have more advanced diabetic glomerulopathy and worse metabolic control than the remaining patients, whose GFR remains stable. These two cohorts are otherwise undistinguishable as regards the degree of AER at baseline and tight blood pressure control. Kidney biopsy has an important prognostic role in these patients. Thus, tight blood pressure control, when not associated with satisfactory glycemic control, is unable to prevent rapid GFR decline in type 2 diabetic patients with typical diabetic glomerulopathy.

Adult↗
PubMed2000

The need for early predictors of diabetic nephropathy risk: is albumin excretion rate sufficient?

Initial studies showing an approximately 80% rate of progression from microalbuminuria (MA) to proteinuria in type 1 diabetic patients led to the broad acceptance of MA as a useful clinical predictor of increased diabetic nephropathy (DN) risk. Some MA patients, however, have quite advanced renal structural changes, and MA may, in these cases, be a marker rather than a predictor of DN. More recent studies have observed only about a 30-45% risk of progression of MA to proteinuria over 10 years, while about 30% of type 1 diabetic patients with MA became normoalbuminuric and the rest remained microalbuminuric. The finding that some MA patients have only mild diabetic renal lesions is consistent with the lower than originally estimated risk of progression from MA to proteinuria and with the notion that some MA patients revert to normoalbuminuria. To increase the complexity of the scenario, some normoalbuminuric long-standing type 1 diabetic patients have well-established DN lesions and approximately 40% of all patients destined to progress to proteinuria are normoalbuminuric at initial screening, despite many years of diabetes. A similar picture is emerging in type 2 diabetic patients, although fewer studies have been conducted. Thus, the predictive precision for MA to progress to overt nephropathy over the subsequent decade or so is considerably less than originally described. It is unclear whether this is due to changes in the natural history of DN resulting from improved glycemia and blood pressure control, or whether there were overestimates of risk in the original studies due to the small sample sizes, post hoc analyses, and variable MA definitions. Albumin excretion rate (AER) remains the best available noninvasive predictor of DN risk and should be regularly measured according to established guidelines. However, AER may be unable to define patients who are safe from or at risk of DN with an accuracy that is adequate for optimal clinical decision making or for the design of certain clinical trials. Investigations into new risk markers or into the combined use of several currently available predictive parameters are needed.

Albuminuria↗
PubMed2000

Structural involvement in type 1 and type 2 diabetic nephropathy.

Structural changes underlying diabetic nephropathy in Type 1 diabetes are prodominant in the glomerulus [thickening of glomerular basement membrane (GBM) and mesangial expansion], but also include arteriolar, tubular and interstitial lesions. The structural measure that correlates best with all renal functional parameters in Type 1 diabetes is mesangial fractional volume [Vv(mes/glom)], an estimate of mesangial expansion. Structural-functional relationships in Type 2 diabetes are much less known. These studies investigated renal structure in the early stages of nephropathy [microalbuminuria (MA)] in patients with Type 1 and Type 2 diabetes. Diabetic glomerulopathy was quite advanced in Type 1 diabetic patients with MA, and both Vv (mes/glom) and GBM width were increased as compared to normoalbuminuric (NA) patients when the albumin excretion rate (AER) was > 30 microgram/min. Serial renal biopsies were performed 5 years apart in 11 Type 1 diabetic patients to evaluate whether glomerular and interstitial lesions progress jointly. AER increased significantly in 5 years, while the glomerular filtration rate remained unchanged. All structural parameters were initially abnormal. Vv(mes/glom) and mean glomerular volume increased significantly, whereas GBM width and the interstitial volume fraction were unchanged. Moreover, the change in Vv (mes/glom) was correlated with the change in AER (r =0.64, p <0.05). Thus, at the disease stage during which some patients progress to MA or proteinuria, continuing mesangial expansion is the main variable, whereas further interstitial expansion does not occur. A large number of Type 2 patients were also studied. Early diabetic glomerulopathy was detected by electron microscopy in NA patients and found to be more advanced in those with MA and proteinuria. However, lesions were milder than in Type 1 diabetic patients, and there was considerable overlap between groups. Morphometric results by electron microscopy were similar to those by light microscopy, demonstrating the heterogeneity of renal structure in Type 2 diabetic patients. In fact, only 30% of MA patients had typical diabetic glomerulopathy, while 40% had more advanced tubulo-interstitial and/or vascular lesions and 30% had normal renal structure.

Basement Membrane↗
PubMed1999

Polymorphisms of angiotensin-converting enzyme and angiotensinogen genes in type 2 diabetic sibships in relation to albumin excretion rate.

Familial clustering of altered albumin excretion and nephropathy risk has been described in both type 1 and type 2 diabetes; moreover, an association of micro-macroalbuminuria and diabetic retinopathy has been recently reported in a large number of white families with type 2 diabetes. Conflicting reports, mainly comparing affected with unaffected unrelated subjects, have suggested a possible role of some genotypes of the renin-angiotensin system in conferring nephropathy risk in type 2 diabetes. To examine the role of genetic factors in influencing albuminuria in families, we studied the relation of angiotensin-converting enzymes (ACE) and angiotensinogen (AGN) genotypes with albumin excretion rate in a population of affected siblings of type 2 diabetic probands. We determined ACE insertion/deletion polymorphism and two polymorphisms of the AGN gene (T174M and M235T) in 160 families with at least one affected member. Defining proband as the patient with the longest known duration of diabetes, we compared the allelic distribution in diabetic probands with and without altered albumin excretion and in their siblings. Allelic distribution of these polymorphisms was similar in the two groups of probands, as well as in their siblings. Identity-by-State (IBS) analysis showed a link between AGN locus and arterial hypertension in these siblings, which was independent from the degree of renal involvement. Thus, our findings suggest that in white families with type 2 diabetes, there is no linkage between the degree of albumin excretion and ACE and AGN polymorphisms, whereas the latter is related to arterial hypertension, as previously found in patients without diabetes but with essential hypertension.

Albuminuria↗
PubMed1999

Insulin-dependent diabetic sibling pairs are concordant for sodium-hydrogen antiport activity.

UNLABELLED: Insulin-dependent diabetic sibling pairs are concordant for sodium-hydrogen antiport activity. BACKGROUND: Recent findings of enhanced Na+/H+ antiport activity in cultured fibroblasts and immortalized lymphoblasts from type 1 diabetic patients with nephropathy support the view that a phenotypic or genotypic factor(s) underlies nephropathy risk. This study evaluated the kinetic properties of Na+/H+ antiporter in cultured fibroblasts from families with two siblings affected by type 1 (insulin-dependent) diabetes. METHODS: Seventeen diabetic sibling pairs were studied. The age was 38 +/- 10 years (mean +/- SD) in probands, the first to develop diabetes, and 39 +/- 7 in siblings; the duration of diabetes was, by definition, longer in probands (24 +/- 12 vs. 17 +/- 8 years in siblings). Na+/H+ antiport activity was determined using a microfluorometric technique with the pH sensitive dye 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein in skin fibroblasts cultured for at least six passages. RESULTS: There were no significant differences between probands and siblings for the following parameters: glycated hemoglobin, 8.3 +/- 0.8% in probands and 8.6 +/- 1.4% in siblings; creatinine clearance, 103 +/- 24 ml/min/1.73 m2 in probands and 103 +/- 25 in siblings; albumin excretion rate, 6.8 (1 to 860) microgram/min (median and range) in probands and 4.9 (2 to 1334) in siblings. Intracellular pH and buffering capacity were superimposable in the sibling pairs. The Vmax for the antiport was 39.2 +/- 14.7 mmol/liter cell/min in probands and 40.3 +/- 17.6 in siblings. The internal pH for half-maximal activation (Km) and Hill coefficient was also similar in probands and siblings. There were correlations between probands and siblings in values for intracellular pH (r = 0.51, P < 0.04), Vmax (r = 0.84, P < 0.0001), and buffering capacity (r = 0.53, P < 0. 03). Glycated hemoglobin values over five years were not significantly correlated in the sibling pairs (r = 0.3, P > 0.1). Vmax was related with the albumin excretion rate (r = +0.49, P = 0. 005) and glycated hemoglobin (r = +0.41, P = 0.017) in the total cohort of sibling pairs. However, multiple regression analysis, using Vmax as the dependent variable, found no correlations between any of the subjects' clinical and demographic variables. CONCLUSIONS: Familial concordance for Na+/H+ antiport activity in long-term cultured skin fibroblasts from type 1 diabetic siblings suggests that at least some of the in vitro phenotypical characteristics of these cells are likely to be genetically determined and to be, at least in part, independent of in vivo metabolic control.

Adult↗
PubMed1999

Is diabetic nephropathy inherited? Studies of glomerular structure in type 1 diabetic sibling pairs.

Only a minority of patients with type 1 diabetes develop diabetic nephropathy (DN). Poor glycemic control cannot fully explain DN risk, and family studies suggest genetic susceptibility factors. To understand familial DN concordance, we evaluated glomerular structure in families with type 1 diabetic sibling pairs. Kidney function and biopsy studies were performed in 21 probands (P) (first to develop diabetes) and 21 siblings (S) (second to develop diabetes), most with normal urinary albumin excretion rates (UAER). Glomerular structure was measured by morphometry. Intrafamilial correlation was estimated by one-way random-effects ANOVA and by mixed-effects ANOVA, adjusting for age and duration of diabetes. Diabetes duration was, by definition, longer in P than in S, while age and sex were similar. HbA1c over 5 years and blood pressure were not different in P and S and were without familial effect. UAER was greater in P than in S (P < 0.05), with strong familial effect (P = 0.03). A strong concordance among siblings for mesangial fractional volume (P < or = 0.01) remained significant after adjustment for diabetes duration and age (P = 0.04). Results were similar for mesangial cell (P = 0.01; adjusted P = 0.04) and mesangial matrix fractional volumes (P < 0.01; adjusted P = 0.06). There was also clustering of the patterns of glomerular lesions. For example, if P had relatively marked glomerular basement membrane thickening compared with mesangial matrix expansion, S had a similar pattern (chi2, P < 0.025). Strong concordance in severity and patterns of glomerular lesions in type 1 diabetic siblings, despite lack of concordance in glycemia, supports an important role for genetic factors in DN risk.

Adult↗
PubMed1998

Reversal of lesions of diabetic nephropathy after pancreas transplantation.

BACKGROUND: In patients with type I diabetes mellitus who do not have uremia and have not received a kidney transplant, pancreas transplantation does not ameliorate established lesions of diabetic nephropathy within five years after transplantation, but the effects of longer periods of normoglycemia are unknown. METHODS: We studied kidney function and performed renal biopsies before pancreas transplantation and 5 and 10 years thereafter in eight patients with type I diabetes but without uremia who had mild to advanced lesions of diabetic nephropathy at the time of transplantation. The biopsy samples were analyzed morphometrically. RESULTS: All patients had persistently normal glycosylated hemoglobin values after transplantation. The median urinary albumin excretion rate was 103 mg per day before transplantation, 30 mg per day 5 years after transplantation, and 20 mg per day 10 years after transplantation (P=0.07 for the comparison of values at base line and at 5 years; P=0.11 for the comparison between base line and 10 years). The mean (+/-SD) creatinine clearance rate declined from 108+/-20 ml per minute per 1.73 m2 of body-surface area at base line to 74+/-16 ml per minute per 1.73 m2 at 5 years (P<0.001) and 74+/-14 ml per minute per 1.73 m2 at 10 years (P<0.001). The thickness of the glomerular and tubular basement membranes was similar at 5 years (570+/-64 and 928+/-173 nm, respectively) and at base line (594+/-81 and 911+/-133 nm, respectively) but had decreased by 10 years (to 404+/-38 and 690+/-111 nm, respectively; P<0.001 and P=0.004 for the comparisons with the base-line values). The mesangial fractional volume (the proportion of the glomerulus occupied by the mesangium) increased from base line (0.33+/-0.07) to 5 years (0.39+/-0.10, P=0.02) but had decreased at 10 years (0.27+/-0.02, P=0.05 for the comparison with the baseline value and P=0.006 for the comparison with the value at 5 years), mostly because of a reduction in mesangial matrix. CONCLUSIONS: Pancreas transplantation can reverse the lesions of diabetic nephropathy, but reversal requires more than five years of normoglycemia.

Adult↗
PubMed1998

Heterogeneous nature of microalbuminuria in NIDDM: studies of endothelial function and renal structure.

Microalbuminuria (MA) is associated with microangiopathy (renal and retinal lesions) in insulin-dependent diabetic (IDDM) patients. In contrast MA does not reflect microvascular damage in a substantial number of non-insulin-dependent diabetic (NIDDM) patients. MA predicts cardiovascular disease in NIDDM patients with increased von Willebrand factor (vWF) plasma levels which are hypothesized to reflect endothelial dysfunction. However, it is not known whether MA is consequent to generalised endothelial dysfunction or to renal injury. Thus, this study evaluated vWF plasma levels in relation to renal and retinal structural abnormalities in NIDDM patients with MA. Kidney biopsies, fundoscopy and measures of vWF plasma levels were performed in 32 NIDDM patients with MA. These patients were allocated to two renal structural categories: A) Without renal structural abnormalities (C I, n = 10): normal or near-normal renal structure, and B) With renal structural abnormalities (n = 22), further divided into: C II (n = 12) with typical diabetic nephropathology, predominantly glomerulopathy, and C III (n = 10) with atypical patterns of renal injury (more advanced tubulo-interstitial and arteriolar than glomerular changes). vWF plasma levels were significantly higher in category B (C II: 195+/-49% and C III: 161+/-46%) than in category A (C I: 119+/-42%), (chi-square, p < 0.05). Diabetic retinopathy was also related to vWF plasma levels (ANOVA, p < 0.05). These data suggest that there are two types of MA in NIDDM: one associated with increased vWF levels, established renal injury and frequently retinopathy, and the other characterized by normal vWF levels, normal renal structure and absent or mild diabetic retinopathy. We propose that vWF plasma levels in NIDDM patients with MA may help to identify patients with important renal structural changes, increased retinopathy risk and, perhaps, generalised endothelial dysfunction. Whether vWF plasma levels predict end-stage renal disease and cardiovascular events deserves longitudinal studies.

Adult↗
PubMed1998

Proximal tubular basement membrane width in insulin-dependent diabetes mellitus.

Although glomerular structure has been studied, careful evaluation of tubular basement membrane (TBM) structure in diabetes in humans has not been done. We measured proximal TBM width, glomerular basement membrane (GBM) width, mesangial fractional volume [Vv(Mes/glom)], mesangial matrix fractional volume [Vv(MM/glom)], and cortical interstitial fractional volume [Vv(Int/cortex)] in 35 insulin-dependent diabetic (IDDM) patients and 20 controls. The patients' mean age was 28 +/- 10 years (X +/- SD) and IDDM duration was 17 +/- 8 years. Twenty-five patients were normoalbuminuric, four microalbuminuric, and six had overt proteinuria. Tubular basement membrane and GBM widths were measured by the orthogonal intercept method and mesangial and interstitial parameters by point counting. The TBM width was 915 +/- 320 nm in IDDM patients and 558 +/- 116 nm in controls (P = 0.0005); the TBM width was also increased in normoalbuminuric patients (849 +/- 297 nm, P = 0.0005). The TBM width was strongly directly related to GBM width (r = 0.67, P < 0.001), Vv(Mes/glom) (r = 0.52, P < 0.01), and Vv(MM/glom) (r = 0.61, P < 0.001), but only weakly to Vv(Int/cortex) (r = 0.29, NS). The TBM width (r = 0.65, P < 0.001) and GBM width (r = 0.65, P < 0.001) were strongly related to hemoglobin A1C (HbA1C), while the Vv(Mes/glom) (r = 0.35, P < 0.05) and Vv(Int/cortex) (r = 0.30, NS) were only weakly related to HbA1C. Thus, increased proximal TBM width is an integral component of early nephropathology in IDDM patients. This study suggests that the metabolic disturbances of diabetes are strong determinants of the constellation of structural abnormalities occurring in human diabetic nephropathy.

Adolescent↗
PubMed1998

Relationships of cell proliferation and expression of integrin subunits and type I collagen in skin fibroblasts with renal lesions in patients with IDDM.

Previous studies have shown that cultured skin fibroblasts (SFs) from insulin-dependent diabetic mellitus (IDDM) patients with diabetic nephropathy (DN) exhibit both increased proliferation and Na+/H+ antiporter activity. The present study correlated the growth rate and mRNA expression of integrin subunits, extracellular matrix molecules, and transforming growth factor-beta in cultured SFs, with the biopsy determined rate of development of DN lesions ranging from slow to rapid in nine IDDM patients. These varying rates of development of DN lesions were expressed by a mesangial expansion score as estimated by the rate of change in mesangial fraction volume per year. Cultured SF proliferation by direct cell counts positively correlated with mesangial expansion score (r = 0.65; P < 0.05). Expression of cultured SF alpha3 integrin subunit mRNA levels, as well as type I collagen mRNA (P < 0.05 for both), but not transforming growth factor-beta mRNA levels (Northern blot analysis), were also positively correlated with mesangial expansion score. We postulate that these observations of correlations between activities of cultured SFs and the rate of progression of DN lesions may be predictive of the risk to develop clinical DN in IDDM, may be in part genetically regulated, and may be of pathogenetic importance.

Adult↗