Glycaemic control in diabetic nephropathy.

To investigate the quality of glycaemic control that is achievable in diabetic patients with persistent proteinuria and asymptomatic but declining renal function three matched groups of patients were studied. The first comprised diabetics with proteinuria receiving continuous subcutaneous insulin infusion; the second, diabetics without proteinuria receiving continuous subcutaneous insulin infusion; and the third, diabetics with proteinuria receiving conventional insulin treatment. Glycaemic control in patients receiving continuous subcutaneous insulin infusion was shown to be appreciably worse during the daytime in diabetics with proteinuria than in diabetics without proteinuria, although greatly superior to that in diabetics with proteinuria receiving conventional insulin treatment. The loss of glycaemic control in patients with proteinuria receiving continuous subcutaneous insulin infusion probably occurred as a response to daytime hypoglycaemia and a consequent reduction in the proportion of the total insulin dose given prandially. Difficulty in controlling blood glucose concentrations may be a factor in the failure of intensified insulin regimens to influence the progression of diabetic renal disease.     

Reversal of insulin resistance in type I diabetes after treatment with continuous subcutaneous insulin infusion.

Insulin responsiveness was studied with the euglycaemic glucose clamp technique in seven patients with type I diabetes and in six control subjects matched for age and weight. The glucose disposal rate was significantly reduced in the diabetic subjects when they were receiving conventional insulin treatment compared with the control group, showing insulin resistance in the diabetics. The diabetic patients were again studied after eight days of intensified metabolic control achieved with continuous subcutaneous insulin infusion. During the infusion a more physiological insulin regimen was used compared with their regular treatment, less of the total insulin dose being given as continuous infusion and more as bolus doses before meals. The insulin resistance in the diabetics was largely reversed after this improved metabolic control. Dose response studies showed an increased glucose disposal rate at all plasma insulin concentrations, including the maximum insulin concentration, indicating a predominant effect of the continuous infusion regimen at the postreceptor level. The improved insulin effect seen with continuous subcutaneous insulin infusion could be due to the improved metabolic control achieved as well as the more physiological regimen.     

Effect of antihypertensive treatment on kidney function in diabetic nephropathy.

The effect of long term, aggressive antihypertensive treatment on kidney function in diabetic nephropathy was studied prospectively in 11 insulin dependent diabetics (mean age 30). During the mean pretreatment period of 32 (range 23-66) months the glomerular filtration rate decreased significantly and albuminuria and the arterial blood pressure increased significantly. During the 72 (range 32-91) month period of antihypertensive treatment the average arterial blood pressure fell from 143/96 mm Hg to 129/84 mm Hg and albuminuria decreased from 1038 micrograms/min to 504 micrograms/min. The rate of decline in the glomerular filtration rate decreased from 0.89 (range 0.44-1.46) ml/min/month before treatment to 0.22 (range 0.01-0.40) ml/min/month during treatment. The rate of decline in the glomerular filtration rate was significantly smaller during the second three years compared with the first three years in patients who received long term antihypertensive treatment (greater than or equal to 6 years). One patient died from acute myocardial infarction (glomerular filtration rate 46 ml/min/1.74 m2). Effective antihypertensive treatment postpones renal insufficiency in diabetic nephropathy.     

Effect of optimal glycaemic control with continuous subcutaneous insulin infusion on energy expenditure in type I diabetes mellitus.

To assess the role of insulin in the control of body weight energy expenditure was measured by indirect calorimetry in eight patients of normal weight with type I diabetes initially while poorly controlled during conventional insulin treatment and later during optimal glycaemic control achieved by using the continuous subcutaneous insulin infusion pump. Their response to seven days of fat supplementation was also assessed and the results compared with those in eight non-diabetic subjects. After a mean of 5.3 months of continuous subcutaneous insulin infusion the diabetic subjects had gained on average 3.5 kg. In the poorly controlled diabetic state the resting metabolic rate was raised but decreased by a mean of 374 kJ (90 kcal) per 24 hours with optimal glycaemic control. The thermic response to infused noradrenaline was reduced by 59% in the diabetic subjects, was not improved by continuous subcutaneous insulin infusion, but was improved when three of the subjects were given metformin in addition. The diabetic subjects had no abnormality in the thermic response to a meal while taking their usual diabetic diet. During fat supplementation, however, this thermic response was reduced when glycaemic control was poor but not when control was precise. Fat supplementation did not alter the resting metabolic rate or the reduced noradrenergic thermic response in the diabetic subjects. These findings suggest that precise glycaemic control could produce weight gain if energy intake remained unaltered, for diabetic subjects do not compensate for the decrease in metabolic rate by an increase in noradrenergic and dietary thermic responses. Also precise glycaemic control using continuous subcutaneous insulin infusion does not correct all the metabolic abnormalities of diabetes mellitus.     

Effect of captopril on blood pressure and kidney function in normotensive insulin dependent diabetics with nephropathy.

OBJECTIVE--To assess whether inhibition of angiotensin converting enzyme protects kidney function in diabetic nephropathy. DESIGN--Open, randomised follow up study of normotensive insulin dependent diabetics with nephropathy either treated or not with captopril for one year. SETTING--Outpatient diabetic clinic in a tertiary referral centre. PATIENTS--32 Normotensive patients with insulin dependent diabetes complicated by nephropathy who were randomised either to the treatment group (n = 15) or to the control group (n = 17). INTERVENTIONS--The treatment group was given captopril (25-100 mg/day) for 12 months, the average dose during the second six months of the study being 40 mg daily. Controls were not treated. MAIN OUTCOME MEASURES--Albuminuria, arterial blood pressure, and the glomerular filtration rate. RESULTS--Mean arterial blood pressure fell by 3 (SE 2) mm Hg in the captopril treated group and rose by 6 (1) mm Hg in the controls. In addition, albuminuria declined by 11% in the captopril treated group and rose by 55% in the controls, fractional albumin clearance fell by 17% in the captopril treated group and increased by 66% in the controls, and the glomerular filtration rate declined by 3.1 (2.8)ml/min/1.73 m2 with captopril and by 6.4 (3.1) ml/min/1.73 m2 in the controls. CONCLUSION--Inhibition of angiotensin converting enzyme arrests the progressive rise in albuminuria in normotensive insulin dependent diabetics with nephropathy.     

Protection of kidney function and decrease in albuminuria by captopril in insulin dependent diabetics with nephropathy.

STUDY OBJECTIVE--To assess whether long term inhibition of angiotensin converting enzyme with captopril and frusemide or bendrofluazide protects kidney function in diabetic nephropathy. DESIGN--Non-randomised controlled before-after trial of matched hypertensive insulin dependent diabetics with nephropathy treated with captopril and frusemide or bendrofluazide. SETTING--Outpatient diabetic clinic in tertiary referral centre. PATIENTS--Treatment group of 18 hypertensive insulin dependent diabetics with nephropathy (mean age 33), who had not been treated previously. Control group of 13 patients (mean age 32) fulfilling the same entry criteria from a prospective study. INTERVENTIONS--Treatment group was given daily captopril 37.5-100.0 mg and frusemide (mean) 98 mg (10 patients) or bendrofluazide (mean) 4 mg (seven). Treatment was continued for about two and a half years. Controls were not treated. END POINT--Measurement of arterial blood pressure, albuminuria, and glomerular filtration. MEASUREMENTS AND MAIN RESULTS--Baseline values were identical in treated and untreated groups respectively: mean blood pressure 146/93 (SE 3/1) mm Hg v 137/95 (2/1) mm Hg; geometric mean albuminuria 982 (antilog SE 1.2) micrograms/min v 936 (1.2) micrograms/min; and mean glomerular filtration rate 98 (SE 5) ml/min/1.73 m2 v 96 (6) ml/min/1.73 m2. Mean arterial blood pressure fell by 8.7 (1.3) mm Hg with captopril and rose by 6.6 (1.5) mm Hg in controls, (p less than 0.001); Albumin excretion decreased to 390 (1.1) micrograms/min with captopril and rose to 1367 (1.3) micrograms/min in controls (p less than 0.001). The rate of decrease in glomerular filtration rate was lower with captopril (5.8 (0.7) ml/year v 10.0 (1.3) ml/year) (p less than 0.01). Rate of fall in glomerular filtration rate and mean arterial blood pressure were significantly correlated (n = 31, r = 0.37, p less than 0.05). CONCLUSIONS--Captopril is a valuable new drug for treating hypertension in insulin dependent diabetics with nephropathy.     

Rapid tightening of blood glucose control leads to transient deterioration of retinopathy in insulin dependent diabetes mellitus: the Oslo study.

In a study of retinopathy during one year of tight blood glucose control 45 type I (insulin dependent) diabetics without proliferative retinopathy were randomised to receive either continuous subcutaneous insulin infusion, multiple insulin injections, or conventional insulin treatment (controls). Near normoglycaemia was achieved with continuous infusion and multiple injections but not with conventional treatment. Blind evaluation of fluorescein angiograms performed three monthly showed progression of retinopathy in the control group, transient deterioration in the continuous infusion group, and no change in the multiple injection group. Half the patients receiving continuous infusion and multiple injections developed retinal cotton wool spots after three to six months. These changes regressed in all but four patients after 12 months. Control patients did not develop cotton wool spots. Patients who developed cotton wool spots are characterised by a larger decrement in glycosylated haemoglobin and blood glucose values, more frequent episodes of hypoglycaemia, a longer duration of diabetes, and more severe retinopathy at onset. A large and rapid fall in blood glucose concentration may promote transient deterioration of diabetic retinopathy.     

Effect of deletion polymorphism of angiotensin converting enzyme gene on progression of diabetic nephropathy during inhibition of angiotensin converting enzyme: observational follow up study.

OBJECTIVE: To evaluate the concept that an insertion/deletion polymorphism of the angiotensin converting enzyme gene predicts the therapeutic efficacy of inhibition of angiotensin converting enzyme on progression of diabetic nephropathy. DESIGN: Observational follow up study of patients with insulin dependent diabetes and nephropathy who had been treated with captopril for a median of 7 years (range 3-9 years). SETTING: Outpatient diabetic clinic in a tertiary referral centre. PATIENTS: 35 patients with insulin dependent diabetes and nephropathy were investigated during captopril treatment (median 75 mg/day (range 12.5 to 150 mg/day)) that was in many cases combined with a loop diuretic, 11 patients were homozygous for the deletion allele and 24 were heterozygous or homozygous for the insertion allele of the angiotensin converting enzyme gene. MAIN OUTCOME MEASURES: Albuminuria, arterial blood pressure, and glomerular filtration rate according to insertion/deletion polymorphism. RESULTS: The two groups had comparable glomerular filtration rate, albuminuria, blood pressure, and haemoglobin A1c concentration at baseline. Captopril induced nearly the same reduction in mean blood pressure in the two groups-to 103 (SD 5) mm Hg in the group with the deletion and 102 (8) mm Hg in the group with the insertion-and in geometric mean albumin excretion-573 (antilog SE 1.3) micrograms/min and 470 (1.2) micrograms/min, respectively. The rate of decline in glomerular filtration rate (linear regression of all glomerular filtration rate measurements during antihypertensive treatment) was significantly steeper in the group homozygous for the double deletion allele than in the other group (mean 5.7 (3.7) ml/min/year and 2.6 (2.8) ml/min/year, respectively; P = 0.01). Multiple linear regression analysis showed that haemoglobin A1c concentration, albuminuria, and the double deletion genotype independently influenced the sustained rate of decline in glomerular filtration rate (R1 (adjusted) = 0.51). CONCLUSION: The deletion polymorphism in the angiotensin converting enzyme gene reduces the long term beneficial effect of angiotensin converting enzyme inhibition on the progression of diabetic nephropathy in patients with insulin dependent diabetes.     

Abnormal Glomerular Filtration Rate,Renal Plasma Flow,and Renal Protein Excretion in Recent and Short-term Diabetics

Glomerular filtration rate and renal plasma flow were simultaneously determined in comparable groups of 43 diabetics less than 40 years of age and with a duration of diabetes less than 10 years and 32 control subjects. The average glomerular filtration rate in the diabetic group was significantly higher than that in the control group (P <0·01). The average renal plasma flow in the diabetic group was found to be significantly lower than that in the control group (P <0·05). The filtration fraction in both male and female diabetics was significantly higher than in the male and female control groups (P <0·001). These changes were found to be present even in recent juvenile diabetics with disease of a duration of less than one year. No correlation was apparent between the average levels of serum growth hormone and glomerular filtration rate.The urinary protein excretion was determined in 36 diabetic and 38 healthy subjects comparable with regard to glomerular filtration rate. In the diabetic group there was a greater frequency of cases with higher protein excretion rates (P <0·02). The average protein excretion rate was increased even in diabetics with less than one year''s duration of the disease.The results of the changes in renal haemodynamics in subjects with recent and short-term diabetes are compatible with the presence of a constrictive state of the vas efferens leading to an increase in the filtration pressure. The increase in protein excretion rate may similarly be a consequence of this process or of an increase in the glomerular permeability with augmented molecular sieving of proteins or both.     

Glomerular filtration and renal volume in type II diabetes (non-insulin-dependent): study in normal and microalbuminuria patients]

In type 2 diabetes elevated glomerular filtration rate (GFR) and increased renal volume (RV), often accompanied to normo or microalbuminuria, were demonstrated. This condition is considered a pathogenetic factor for clinical nephropathy. As this topic is little studied in type 2 diabetes, we have investigated 73 type 2 diabetic patients (34 normo and 39 microalbuminuric), looking for a correlation between GFR, RV, hypertension, duration of diabetes and indexes of metabolic control. GFR was measured by a scintigraphy, after infusion of 99Tc-DTPA. Renal volume was determined by ultrasound scanning. Between the groups GFR and RV weren't different; elevated GFR was demonstrated in 3 patients; increased RV in 1 patient. In the hypertensive group GFR was lower than in normotensive group and in controls. Multivariate analysis in stepwise demonstrated that GFR presents a negative correlation to systolic blood pressure as in normo as in microalbuminuric patients. In the normotensive group GFR didn't correlate to the other variables. The present data suggest that in type 2 diabetes there is a little prevalence of glomerular hyperfiltration and increased renal volume and that hypertension plays a role on GFR of hypertensive diabetic patients.     

Continuous subcutaneous insulin infusion: an approach to achieving normoglycaemia.

A study was performed to examine the feasibility of achieving long periods of near-normoglycaemia in patients with diabetes mellitus by giving a continuous subcutaneous infusion of insulin solution from a miniature, battery-driven, syringe pump. Twelve insulin-dependent diabetics had their insulin pumped through a subcutaneously implanted, fine nylon cannula; the basal infusion rate was electronically stepped up eightfold before meals. The blood glucose profile of these patients was closely monitored during the 24 hours of the subcutaneous infusion and compared with the profile on a control day, when the patients were managed with their usual subcutaneous insulin. Diet and exercise were standardised on both days. In five out of 14 studies the subcutaneous insulin infusion significantly lowered the mean blood glucose concentration without producing hypoglycaemic symptoms; in another six patients the mean blood glucose concentration was maintained. As assessed by the M value the level of control was statistically improved in six out of 14 studies by the infusion method and maintained in six other patients. To assess the effects of blood glucose control on diabetic microvascular disease it will be necessary to achieve long-term normoglycaemia in selected diabetics. The results of this preliminary study suggest that a continuous subcutaneous insulin infusion may be a means of maining physiological glucose concentrations in diabetics. Though several problems remain--for example, in determining the rate of infusion--longer-term studies with the miniature infusion pumps are now needed.     

Management of severely brittle diabetes by continuous subcutaneous and intramuscular insulin infusions: evidence for a defect in subcutaneous insulin absorption.

Severely brittle diabetes is defined as a rare subtype of insulin-dependent diabetes with wide, fast, unpredictable, and inexplicable swings in blood glucose concentration, often culminating in ketoacidosis or hypoglycaemic coma. To assess the role of inappropriate type, amount, or timing of insulin treatment and the route of administration as a cause of severe brittleness six patients with continuous subcutaneous insulin infusion, which provides a high degree of optimisation of dosage with exogenous insulin in stable diabetics. The glycaemic control achieved during continuous subcutaneous insulin infusion was compared with that during continuous intramuscular insulin infusion. Six patients with non-brittle diabetes were also treated by continuous subcutaneous insulin infusion. These patients achieved the expected improvement in glycaemic control (mean +/- SD plasma glucose concentration 5.1 +/- 2.3 mmol/l (92 +/- 41 mg/100 ml)), but not the patients with brittle diabetes remained uncontrolled with continuous subcutaneous infusion (13.6 +/- 5.8 mmol/1 (245 +/- 105 mg/100 ml) compared with 10.3 +/- 4.1 mmol/l (186 +/- 74 mg/100 ml) during treatment with optimised conventional subcutaneous injections). During continuous intramuscular infusion, however, glycaemic control in five of the patients with brittle diabetes was significantly improved (7.7 +/- 2.6 mmol/l (139 +/- 47 mg/100 ml). The remaining patient with brittle diabetes, previously safely controlled only with continuous intravenous insulin, did not respond to continuous intramuscular infusion. It is concluded that in five of the six patients with brittle diabetes studied here impaired or irregular absorption of insulin from the subcutaneous site played a more important part in their hyperlability than inappropriate injection strategies. This absorption defect was presumably bypassed by the intramuscular route.     

Long-term antihypertensive treatment inhibiting progression of diabetic nephropathy

Six men aged 26-35 years with proteinuria due to insulindependent juvenile-onset diabetes were treated for moderate hypertension (mean blood pressure 162/103 mm Hg) and studied for a mean of 73 months for the effect on the progression of nephropathy. All patients were of normal weight. During a mean control period of 28 months before treatment the mean glomerular filtration rate (three or four measurements) was 86·1 ml/min and mean 24-hour urinary albumin excretion (also three or four measurements) 3·9 g (range 0·5-8·8 g).During antihypertensive treatment the mean systolic blood pressure fell to 144 mm Hg and mean diastolic pressure to 95 mm Hg. In the control period five patients had shown a mean monthly decline in glomerular filtration rate of 1·23 ml/min; with antihypertensive treatment, however, this decline fell to 0·49 ml/min (2p=0·042). In the remaining patient the glomerular filtration rate was 137 ml/min before treatment and 135 ml/min at the end of the treatment period. In all patients the mean yearly increase in albumin clearance (expressed as a percentage of the glomerular filtration rate) fell from 107% before treatment to 5% during treatment (2p=0·0099).This small study indicates that antihypertensive treatment slows the decline in renal function in diabetic nephropathy. Clinical trials beginning treatment in the incipient phase of diabetic nephropathy will define the optimal modality of treatment in this large patient population.     

Effect of captopril on kidney function in insulin-dependent diabetic patients with nephropathy.

The influence of angiotensin II on kidney function in diabetic nephropathy was assessed by studying the effect of 12 weeks'' monotherapy with captopril (25-50 mg twice a day) in 16 hypertensive insulin dependent diabetic patients with persistent albuminuria. In an initial one week randomised single blind trial of captopril versus placebo, captopril (for nine patients) reduced arterial blood pressure from 148/94 (SD11/6) to 135/88 (8/7) mm Hg (p less than 0.05) and albuminuria from 1549 (range 352-2238) to 1170 (297-2198) micrograms/min (p less than 0.05), while glomerular filtration rate remained stable. No significant changes occurred in seven patients treated with placebo. During the 12 weeks of captopril treatment arterial blood pressure in all patients fell from 147/94 (11/6) to 135/86 (13/7) mm Hg (p less than 0.01), albuminuria fell from 1589 (range 168-2588) to 1075 (35-2647) micrograms/min (p less than 0.01), and glomerular filtration rate fell from 99 (SD19) to 93 (25) ml/min/1.73 m2 (p less than 0.01). The renin-angiotensin system showed suppressed plasma concentrations of angiotensin II and increased concentrations of angiotensin I and renin. The study showed that glomerular filtration rate is not dependent on angiotensin II, that captopril reduces albuminuria, probably by lowering glomerular hypertension, and that captopril represents a valuable new drug for treating hypertension in diabetics dependent on insulin with nephropathy.     

Beneficial effects of angiotensin converting enzyme inhibition on renal function in patients with diabetic nephropathy.

The effects of angiotensin converting enzyme inhibition with captopril were investigated in patients with diabetic nephropathy and hypertension. After nine days'' treatment with captopril glomerular filtration rate was unchanged in 13 patients, whereas renal plasma flow had increased from 265 to 302 ml/min/1.73 m2 body surface area (p less than 0.05) and the filtration fraction had decreased from 14.3 to 12.8% (p less than 0.025). During two years'' treatment with captopril in 14 patients the mean arterial blood pressure had fallen by 5 mm Hg (p less than 0.005) and the deterioration in glomerular filtration rate had decreased from 10.3 to 2.4 ml/min/year (p less than 0.005). There was no correlation between the fall in blood pressure and the reduction in the deterioration of glomerular filtration rate. These findings suggest that the effects of angiotensin converting enzyme inhibition on renal haemodynamics protect renal function. Inhibitors of angiotensin converting enzyme should be considered for lowering blood pressure in patients with diabetic nephropathy.     

Diabetic nephropathy: the central role of renal proximal tubular cells in tubulointerstitial injury

Diabetic nephropathy is now the commonest cause of end stage renal disease and accounts for 30-40% of all patients requiring renal replacement therapy. Furthermore, the incidence of diabetic nephropathy continues to increase, in part due to the improved survival of type 2 diabetic patients as the cardiovascular mortality in this group declines (Ritz and Stefanski, 1996). Clinically incipient nephropathy is first manifest by the onset of persistent microalbuminuria, after which, overt diabetic nephropathy is heralded by the appearance of persistent proteinuria. Subsequently, there is a progressive decline in glomerular filtration rate (GFR) resulting, within 5 years, in end stage renal disease in 50% of patients (Hasslacher et al., 1989). The pathology of the renal lesions are similar in type I and II diabetes (Taft et al., 1994), although it has been suggested that there is more heterogeneity in type II diabetes (Chihara et al., 1986). Studies analysing structural-functional relationships have demonstrated that the development of proteinuria correlates with the degree of mesangial expansion (Mauer et al., 1984; White and Bilous, 2000). Although diabetic nephropathy was traditionally considered a primarily glomerular disease, it is now widely accepted that the rate of deterioration of function correlates best with the degree of renal tubulointerstitial fibrosis (Mauer et al., 1984, Bohle et al., 1991). This suggests that although in the majority of patients the primary event is a condition manifest by glomerular changes resulting in proteinuria, the long-term outcome is determined by events in the renal interstitium. With the increasing awareness of the importance of these pathological interstitial changes, interest has focused on the role of cells, such as the epithelial cells of the proximal tubule (PTC) or the interstitial myofibroblast, in the initiation of fibrosis. The aim of the present review is to analyse the available data supporting the role for the PTC in orchestrating renal interstitial fibrosis in diabetic nephropathy as a result of glucose-dependent alterations in PTC function. The potential for subsequent effects on PTC-fibroblast cross-talk will also be considered.     

终末期糖尿病肾病的血液透析与腹膜透析的比较研究

目的:探讨终末期糖尿病肾病患者接受不同透析方法的临床疗效。方法:40例终末期糖尿病肾病患者,按照透析方式分为血液透析和腹膜透析组,回顾性分析其临床资料。结果:血液透析与腹膜透析在血压控制,血糖,白蛋白、血总蛋白,肌酐、尿素氮水平,甘油三酯以及出血发生率等各项指标有其各自的优劣性,但是均可使患者获益,提高生存率,生存率比较无统计学差异。结论:及时、恰当的选择肾脏替代治疗,并在治疗过程中及时调整,甚或更换方案对终末期糖尿病肾病患者是有益的。     

Cross sectional longitudinal study of spot morning urine protein:creatinine ratio, 24 hour urine protein excretion rate,glomerular filtration rate,and end stage renal failure in chronic renal disease in patients without diabetes.

OBJECTIVE: To evaluate whether the protein:creatinine ratio in spot morning urine samples is a reliable indicator of 24 hour urinary protein excretion and predicts the rate of decline of glomerular filtration rate and progression to end stage renal failure in non-diabetic patients with chronic nephropathy. DESIGN: Cross sectional correlation between the ratio and urinary protein excretion rate. Univariate and multivariate analysis of baseline predictors, including the ratio and 24 hour urinary protein, of decline in glomerular filtration rate and end stage renal failure in the long term. SETTING: Research centre in Italy. SUBJECTS: 177 non-diabetic outpatients with chronic renal disease screened for participation in the ramipril efficacy in nephropathy study. MAIN OUTCOME MEASURES: Rate of decline in filtration rate evaluated by repeated measurements of unlabelled iohexol plasma clearance and rate of progression to renal failure. RESULTS: Protein:creatinine ratio was significantly correlated with absolute and log transformed 24 hour urinary protein values (P = 0.0001 and P < 0.0001, respectively.) Ratios also had high predictive value for rate of decline of the glomerular filtration rate (univariate P = 0.0003, multivariate P = 0.004) and end stage renal failure (P = 0.002 and P = 0.04). Baseline protein:creatinine ratios and rate of decline of the glomerular filtration rate were also significantly correlated (P < 0.0005). In the lowest third of the protein:creatinine ratio (< 1.7) there was 3% renal failure compared with 21.2% in the highest third (> 2.7) (P < 0.05). CONCLUSIONS: Protein:creatinine ratio in spot morning urine samples is a precise indicator of proteinuria and a reliable predictor of progression of disease in non-diabetic patients with chronic nephropathies and represents a simple and inexpensive procedure in establishing severity of renal disease and prognosis.     

Evidence of apoptosis in human diabetic kidney

Diabetic nephropathy is characterized by an early period of renal growth with glomerular and tubular cell hypertrophy, but this is followed by progressive glomerulosclerosis and tubulointerstitial fibrosis, associated with loss of renal tissue. We studied whether apoptotic cell death occurs in human diabetic nephropathy. Percutaneous renal biopsy samples were obtained from five patients with diabetic nephropathy who were receiving insulin and/or angiotensin-converting enzyme inhibitor therapy. Apoptosis was determined by the presence of DNA fragmentation, detected by in situ TUNEL staining, and by characteristic features on electron microscopy, such as chromatin condensation. Apoptosis was present in all five biopsy specimens, either in epithelial cells of the proximal or distal tubules, or in endothelial cells or interstitial cells. No apoptosis was detected in cells of the glomeruli. The present study provides evidence for apoptosis in human diabetic kidney, and suggests a role for apoptosis in the gradual loss of renal mass.     

Glomerular hemodynamic and structural alterations in experimental diabetes mellitus

Elevated glomerular filtration rate (GFR) is a frequent finding in patients with early insulin-dependent diabetes mellitus (IDDM). The mechanisms responsible for this glomerular hyperfiltration in IDDM are unclear. Rats made diabetic with alloxan or streptozotocin, and treated daily with supplemental insulin, have moderate hyperglycemia and elevated GFR, and thus have been used to study mechanisms of glomerular hyperfiltration in diabetes. Renal micropuncture techniques have shown that single-nephron GFR (SNGFR) is elevated in moderately hyperglycemic diabetic rats. In some cases, this is because of elevated glomerular capillary pressure (Pgc), but in other cases, Pgc is normal despite elevated SNGFR. Several potential mediators of increased SNGFR have been examined, including hyperglycemia, increased glomerular prostaglandin production, and decreased sensitivity of the tubuloglomerular feedback mechanism. Renal failure is a common complication of human IDDM. Diabetic rats with long-term moderate hyperglycemia have been used to study the mechanism by which glomerular injury develops in diabetes mellitus. It has been postulated that glomerular hyperfiltration or some determinant of elevated GFR in early diabetes may ultimately cause glomerular damage, leading to a progressive loss of renal function (diabetic nephropathy). Diabetic rats with long-term moderate hyperglycemia, however, do not develop characteristic glomerular lesions of human diabetic nephropathy and, in fact, develop only minimal glomerular injury even after 1 year of diabetes. Thus, although the diabetic rat with moderate hyperglycemia may be useful to study the mechanisms of glomerular hyperfiltration in early diabetes, it may not be an appropriate model of renal failure in IDDM.