Glycosylation of glomerular basement membrane in type 1 (insulin-dependent) diabetic children

Summary Immunoelectrophoresis of glomerular basement membrane antigens in the urine of 20 Type 1 (insulin-dependent) diabetic and 10 healthy children was performed. In 10 of the diabetic children, there was altered -1-mobility, while the other diabetic and normal children showed -2-mobility. After incubation with glucose, glomerular basement membrane antigens in the urine of healthy children showed -1-mobility. Isolated human kidney glomerular basement membrane split products obtained by proteolytic degradation (papain, trypsin, chymotrypsin) were also investigated by immunoelectrophoresis. A difference was observed in the immunoelectrophoretic pattern of native and glycosylated glomerular basement membrane split products. A distinct increase of thiobarbituric acid assay positive glomerular basement membrane structures after incubation with glucose provides suggestive evidence for the occurrence of non-enzymatic glycosylation of glomerular basement membrane proteins. Glycosylated glomerular basement membrane proteins may contribute to both functional and morphological changes in diabetic glomerulosclerosis.     

Apolipoprotein (a) levels in type 1 and type 2 diabetes mellitus

Type 1 and type 2 diabetes mellitus are both characterized by increased cardiovascular mortality and morbidity. Since several reports have indicated that apolipoprotein (a) [apo (a)] levels are positively associated with an increased risk of macrovascular disease, we investigated whether apo (a) levels are elevated in both types of diabetes mellitus and may thus represent an independent risk factor for atherosclerotic disease. Apo(a) concentrations in type 1 diabetic patients were not significantly different from matched controls (276±78 vs 149±46 units/l). Type 2 diabetic patients had considerably higher levels of apo (a) than matched controls (471±89 vs 221±61 units/l,P=0.06), though the difference was not statistically significant. However, concentrations of apo (a) were above 300 units/l in 36% of type 1 and 67% of type 2 diabetic patients, but in only 14% and 25% respectively of matched control subjects. Plasma triglycerides were positively and independently correlated with apo (a) levels in both diabetic and non-diabetic subjects. On the other hand, no significant correlation was found between apo (a) levels and glycosylated haemoglobin, total cholesterol or high density lipoprotein cholesterol in any of the groups studied. In conclusion, apo (a) levels are not significantly elevated either in type 1 or type 2 diabetic patients without proteinuria and in moderate metabolic control; however, levels above 300 units/l were 2.6 times more frequent in both types of diabetes mellitus than in carefully age-, sex-, and weight-matched control subjects.     

2型糖尿病患者肾小球滤过率与尿白蛋白的关系

目的探讨2型糖尿病患者慢性肾脏病(CKD)的患病率及肾小球滤过率与尿白蛋白排泄间的关系。方法收集自2008年1月至2009年12月在江苏省省级机关医院就诊的2型糖尿病患者资料,采用MDRD公式评估肾小球滤过率(eGFR),CKD定义为存在白蛋白尿或者eGFR60 ml/(min·1.73 m2)。白蛋白尿定义为尿白蛋白/肌酐比值(ACR)≥30 mg/g。采用多项式回归及曲线拟合分析eGFR与尿ACR之间的关系。结果研究纳入1521例2型糖尿病患者,平均年龄(63.9±12.0)岁,CKD及白蛋白尿的患病率分别为31.0%和28.9%。eGFR≥90、60~89、30~59、15~29 ml/(min·1.73 m2)患者白蛋白尿的患病率分别为19.9%、34.5%、65.6%和100%。在正常蛋白尿、微量白蛋白尿及大量白蛋白尿患者中,肾功能不全的比率分别为3.0%、9.3%和40.4%。多项式回归分析显示当患者尿ACR90 mg/g时,eGFR下降缓慢且稳定保持在90 ml/(min·1.73 m2)以上,而当尿ACR≥90 mg/g时,eGFR则迅速下降。结论 2型糖尿病患者CKD及白蛋白尿发生率高,对2型糖尿病人群进行CKD的筛查应该同时检测尿白蛋白与eGFR,为了延缓CKD的进展,应尽早对白蛋白尿进行干预治疗。     

Ketone bodies increase glomerular filtration rate in normal man and in patients with Type 1 (insulin-dependent) diabetes mellitus

Summary The purpose of this study was to investigate whether the administration of acetoacetic and hydrochloric acids in a group of control and Type 1 (insulin-dependent) diabetic patients influenced renal haemodynamics. Renal plasma flow increased from 657±88 to 762±81 ml·min^–1. 1.73 m^–2 in diabetic patients (p<0.01) and from 590±71 to 691±135 in control subjects (p<0.01). Glomerular filtration rate increased from 135±9 to 180±8 ml·min^–1·1.73 m^–2 in diabetic patients (p< 0.001) and from 117±8 to 145±7 in control subjects (p<0.01). Similar effects on renal haemodynamics, even if less pronounced, were observed with low dose acetoacetic but not with hydrochloric acid infusion. Total protein, 2-microglobulin but not albumin excretion rates were increased by acetoacetic acid. We conclude that an acute increase in blood concentration of ketone bodies within the range found in diabetic patients with poor metabolic control (1) increases renal plasma flow and glomerular filtration rate both in control subjects and diabetic patients and (2) causes a tubular proteinuria.     

Long-term glycaemic control directly correlates with glomerular filtration rate in early Type 1 diabetes mellitus before the onset of microalbuminuria

Hyperfiltration occurs early in diabetes mellitus and has been implicated in the development of microalbuminuria. Our aim was to re-examine the controversial relationship between glycaemic control and glomerular filtration (GFR) in normoalbuminuric, normotensive, non-obese patients with short duration Type 1 diabetes mellitus (DM). We studied 75 Type 1 DM patients, 35 male, aged 18–42 years, with a duration of diabetes of 4–8 years. GFR was determined by inulin clearance; hyperfiltration was defined as above 145 ml min⁻¹ 1.73 m⁻² (equivalent to 2 SD above mean for a control population). Analysis was by paired Student’s t-testing and linear regression. GFR correlated significantly with HbA_1c (r = 0.47, p < 0.0001) and fructosamine (r = 0.24, p = 0.035). Mean HbA_1c and fructosamine in the 13 patients with hyperfiltration was significantly higher than in the rest of the group (HbA_1c: 9.2 % (95 % C.I. 7.9–10.4 %) vs 7.6 % (7.2–7.9), p = 0.002; fructosamine: 479 μmol l⁻¹ (450–507) vs 410 μmol l⁻¹ (388–432), p = 0.009. This significant difference persisted even when the two highest values of HbA_1c or fructosamine were removed from analysis. Effective renal plasma flow, assessed by PAH clearance, also correlated in all patients with HbA_1c (r = 0.31, p = 0.039). We conclude that poor glycaemic control directly correlates with hyperfiltration and renal hyperperfusion in early Type 1 DM. Copyright © 1998 John Wiley & Sons, Ltd.     

非胰岛素依赖型糖尿病微量白蛋白尿患者红细胞膜ATPases活力的变化

测定非胰岛素依赖型糖尿病(NIDDM)微量白蛋白尿患者20例及NIDDM无微量白蛋白尿患者20例和正常人20例红细胞膜ATPases活力。结果NIDDM微量白蛋白尿患者Na~+-K+ATPase,Ca~(2+)+ATPase活力明显低于正常人(P分别<0.05及0.001),Mg~(2+)ATPase活力无明显改变(P>0.05).NIDDM无微量白蛋白尿患者Ca~(2+)ATPase活力也低于正常人(P<0.01),但不及微量白蛋白尿组明显;无白蛋白尿组Na~+-K~+ATPase活力虽有下降,但P>0.05,Mg~(2+)ATPese活力无明显变化(P>0.05).     

Changing glomerular filtration with progression from impaired glucose tolerance to Type II diabetes mellitus (Short Communications)

Summary Glomerular filtration rate (iothalamate clearance) was measured serially for 48 months in 26 Pima Indians with impaired glucose tolerance and 27 with normal glucose tolerance. At baseline, the mean glomerular filtration rate (SEM) was 133 ± 8 ml/min in subjects with impaired glucose tolerance and 123 ± 5 ml/min in those with normal glucose tolerance (p = 0.12). In the 12 subjects with impaired glucose tolerance who progressed to Type II (non-insulin-dependent) diabetes during follow-up, mean glomerular filtration rate increased by 30 % (p = 0.011). Among the remaining 14 subjects with impaired glucose tolerance, 12 reverted to normoglycaemia. The glomerular filtration rate both at baseline and after 48 months in this subgroup exceeded the values of subjects with normal glucose tolerance by 20 % (p = 0.008) and 14 % (p = 0.013), respectively. A pronounced rise in the glomerular filtration rate occurs at the onset of Type II diabetes but a trend to hyperfiltration is also present in those with impaired glucose tolerance. [Diabetologia (1999) 42: 90–93] Received: 18 May 1998 and in revised form: 21 August 1998     

Proximal glomerulo-tubular balance in patients with Type 1 (insulin-dependent) diabetes mellitus

Summary To evaluate the glomerulo-tubular balance of sodium and water in the proximal tubules of diabetic patients with elevated glomerular filtration rate, the renal plasma clearance of lithium and the glomerular filtration rate (⁵¹Cr-EDTA plasma clearance) were determined simultaneously in 11 ambulatory Type 1 (insulin-dependent) diabetic patients (aged 25–35 years) with no evidence of diabetic nephropathy and in 10 age-matched healthy subjects. The renal plasma clearance of lithium, which is a measure of flow from the proximal tubule into the thin descending limb of the loop of Henle, did not differ between diabetic and control subjects (28.9±4.0 versus 28.3±5.1 ml/min per 1.73m² surface area, mean±SD), whereas the glomerular filtration rate in the diabetic patients was significantly higher than in the control sub jects (136±10.2 versus 108±13.6 ml/min per 1.73m², p< 0.001). The same held true for the fractional reabsorption rate in the proximal tubules (78.7±3.2 versus 73.6±4.9%, p< 0.02). The results indicate that the elevation of the glomerular filtration rate in diabetic patients is associated with a parallel increase in the proximal reabsorption rate. This type of glomeralo-tubular balance implies that the flow of water and flux of sodium to the segments distal to the proximal tubule are kept constant during variations in the glomerular filtration rate.     

Renal excretion of kallikrein and eicosanoids in patients with Type 1 (insulin-dependent) diabetes mellitus. Relationship to glomerular and tubular function

Summary Glomerular filtration rate, renal plasma flow, renal tubular sodium reabsorption (derived from lithium clearance) and renal excretion rates of kallikrein, prostaglandin E₂ and systemic and renally-derived metabolites of prostacyclin and thromboxane A₂ were measured in patients with Type 1 (insulin-dependent) diabetes mellitus and in normal subjects. Diabetic patients with glomerular hyperfiltration had greater active kallikrein and prostaglandin E₂ excretion than patients with normal glomerular filtration rate or than normal control subjects. Both active kallikrein and prostaglandin E₂ excretion correlated directly with glomerular filtration rate. Active kallikrein excretion correlated directly with the reabsorption of sodium in the distal tubule. The excretion rates of 6-keto prostaglandin F₁, 2,3 dinor 6-keto prostaglandin F₁, thromboxane B₂, 2,3 dinor thromboxane B₂ and 11-dehydro thromboxane B₂ excretion were not different between the groups. This study confirms in man our previous finding of increased renal kallikrein production in the hyperfiltering streptozotocin-diabetic rat model. Given that kinins generated by kallikrein are extremely potent vasodilators and stimulate the renal production of eicosanoids that also regulate glomerular function, our findings suggest that increased kallikrein activity and prostaglandin E₂ production may contribute to renal vasodilatation and hyperfiltration in human diabetes. The localization of kallikrein in the distal connecting tubule makes it plausible that altered sodium transport in the distal tubule may be a signal to increase generation of kallikrein.     

Increased prevalence of fetal haemoglobin in Type 1 (insulin-dependent) diabetes mellitus

Summary Fetal haemoglobin levels were measured in 106 patients with Type 1 (insulin-dependent) diabetes mellitus during a period of two to three years. In 15 patients (14.1%) increased fetal haemoglobin levels (>0.5%), determined by high pressure liquid chromatography, were found in contrast to 3% in a healthy control group (n: 100) of equal age distribution. In children aged over 6 years, elevated fetal haemoglobin levels were measured in 13 diabetic patients (13.3%) in contrast to none of the control group. There was no correlation between fetal haemoglobin levels and duration of diabetes, diabetic control (glycated haemoglobin) and dosage of insulin (U·kg^–1, day^–1). The 15 patients had a younger mean age at onset of diabetes (5.6 years) than a sex and age matched control group of diabetic patients without increased fetal haemoglobin levels (7.4 years, p<0.05). Longitudinal assessment revealed a significant decline of fetal haemoglobin levels with age (p<0.005) but a further increase in fetal haemoglobin levels were found in adolescent patients (n: 2). These data indicate a possible effect of insulin-treatment on delaying transition from fetal to adult haemoglobin synthesis or on reactivation of fetal haemoglobin production.     

The impact of a family history of Type II (non-insulin-dependent) diabetes mellitus on the risk of diabetic nephropathy in patients with Type I (insulin-dependent) diabetes mellitus

Aims/hypothesis. There is substantial evidence for a role of genetic factors in the development of diabetic nephropathy. In Pima Indians, a link between susceptibility to diabetic nephropathy and Type II (non-insulin-dependent) diabetes mellitus has been proposed. In this study, our aim was to examine the association between a family history of Type II diabetes and diabetic nephropathy in patients with Type I (insulin-dependent) diabetes mellitus. Methods. In a cross-sectional case-control study, we assessed the prevalence of Type II diabetes in the parents of 137 Type I diabetic patients with diabetic nephropathy (albuminuria > 300 μg/min in two of three overnight urine collections) compared with the parents of 54 Type I diabetic patients without nephropathy (albuminuria < 20 μg/min). Results. Thirty-four (25 %) of the patients with nephropathy compared with five (9 %) of the patients without nephropathy had a parental history of Type II diabetes (p = 0.019). A parental history of Type II diabetes was associated with a three-fold risk [odds ratio 2.95 (95 % confidence interval: 1.03 to 8.40), p = 0.043] of diabetic nephropathy after adjustment for sex, glycaemic control and family history of hypertension. Furthermore, there was an excess of risk factors for development of Type II diabetes (higher fasting plasma glucose concentrations, higher prevalence of hypertension, higher waist-hip ratio and a tendency towards more glucose intolerance) among previously non-diabetic parents of patients with nephropathy. Conclusion/interpretation. Genetic or environmental factors or both related to familial Type II diabetes increase susceptibility to diabetic nephropathy in patients with Type I diabetes. [Diabetologia (1999) 42: 519–526] Received: 30 September 1998 and in final revised form: 28 December 1998     

Different genetic backgrounds for malnutrition-related diabetes and Type 1 (insulin-dependent) diabetes mellitus in South Indians

Summary HLA-DRB, -DQA and -DQB genes were studied in ten South Indian malnutrition-related diabetic patients, ten Type 1 (insulin-dependent) diabetic patients and 45 control subjects, by TaqI restriction fragment length polymorphism analysis. The DR7,DQw9 haplotype was found to be frequent in patients with malnutrition-related diabetes (p<0.01). The DRw17,DQw2 haplotype was overrepresented in the patients with Type 1 diabetes compared to control subjects (p<0.05). In vitro amplification of the polymorphic second exon of DQB genes by the polymerase chain reaction technique was performed on DNA from 10 malnutrition-related diabetic patients, 10 Type 1 diabetic patients and 13 control subjects, as they belong to a new population. Hybridization with sequence-specific oligonucleotide probes for DQB1 alleles showed homozygosity of aspartic acid at position 57 in 7 of 10 malnutrition-related diabetic patients compared to 2 of 10 Type 1 diabetic (p<0.05) and 15 of 45 control subjects (p<0.05). Homozygosity of non-aspartic acid at position 57 was present in 7 of 10 Type 1 diabetic compared to 0 of 10 malnutrition-related diabetic patients (p<0.005) and 3 of 45 control subjects (p<0.05). This study has confirmed the association of DQB1 57 non-asp in South Indians with Type 1 diabetes. In addition, our data clearly show that the genetic background of malnutrition-related diabetes mellitus is different from that of Type 1 diabetes.     

天然免疫细胞在1型糖尿病中的作用

1型糖尿病（T1DM）是一种复杂的自身免疫性疾病,主要是由T、B细胞破坏胰岛β细胞所致.虽然病因不明,但最终一系列天然免疫细胞及特异性免疫细胞相互作用,导致胰岛β细胞损伤和T1DM的发生.对动物模型和T1DM患者的研究发现,单核/巨噬细胞、自然杀伤细胞、自然杀伤T细胞、树突状细胞和淋巴细胞相互作用可影响T1DM的发生、发展.因此,研究天然免疫细胞在T1DM发生、发展中的作用,可能为防治T1DM提供新的方向.     

Decreased hepatic glucagon responses in Type 1 (insulin-dependent) diabetes mellitus

Summary The effect of glucagon infusion on hepatic glucose production during euglycaemia was evaluated in seven Type 1 (insulin-dependent) diabetic patients and in ten control subjects. In the diabetic subjects normoglycaemia was maintained during the night preceding the study by a variable intravenous insulin and glucose infusion. During the study endogenous insulin secretion was suppressed by somatostatin (450 g/h) and replaced by insulin infusion (0.15 mU·kg^–1·min^–1). ³H-glucose was infused for isotopic determination of glucose turnover. Plasma glucose was clamped at 5 mmol/1 for 2 h 30 min and glucagon (1.5 ng· kg^–1·min^–1) was then infused for the following 3 h. Hepatic glucose production and glucose utilisation were measured during the first, second and third hour of the glucagon infusion. Basal hepatic glucose production (just prior to glucagon infusion) was similar in diabetic (1.2±0.3 mg·kg^–1·min^–1) and control (1.6±0.1 mg·kg^–1·min^–1) subjects. In diabetic patients hepatic glucose production rose slowly to 2.1±0.5 mg·kg^–1·min^–1 during the first hours of glucagon infusion and stabilized at this level (2.4±0.5 mg·kg^–1·min^–1) in the third hour. In control subjects hepatic glucose production increased sharply to higher levels than in the diabetic subjects (3.4±0.3 mg·kg^–1·min^–1) during the first and second hour of glucagon infusion (p<0.05) and then gradually fell (2.9±0.4 mg·kg^–1·min^–1) during the third hour. In conclusion, when stimulated with glucagon at a physiologic plasma concentration diabetic patients had 1) an overall reduced hepatic glucose production response and 2) an abnormal sluggish response pattern. These abnormalities may imply inappropriate counter-regulation following a hypoglycaemic episode.     

Changes of the tubular markers in type 2 diabetes mellitus with glomerular hyperfiltration

Aim

To assess whether glomerular hyperfiltration (GHF) could result in renal tubular damage in type 2 diabetes mellitus (T2DM) patients.

Methods

Reference value of estimated glomerular filtration rate (eGFR) was determined in 248 healthy individuals based on serum CysC levels. GHF was defined as an eGFR exceeding the sex-specific 97.5th percentile in non-diabetic individuals. In the present study, 30 with GHF, 58 with norm-GFR T2DM, and 24 healthy controls were recruited. Tubular markers, such as urinary N-acetyl-β-d-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1), as well as serum and urinary neutrophil gelatinase-associated lipocalin (NGAL), were measured and compared. The correlation of these markers with eGFR was analyzed in the GHF group.

Results

The GHF group had higher urinary NGAL and KIM-1 levels but lower serum NGAL level than the norm-GFR and control groups. Slightly decreased serum NGAL and increased urinary NGAL levels were also noted in the norm-GFR group compared with those of the controls. There was no statistical difference in the urinary NAG values among the three groups. Correlation analysis showed that eGFR was positively related to fasting blood glucose (FBG), HbA1c, urinary NGAL, and KIM-1, but negatively with serum NGAL in the GHF group.

Conclusion

Higher urinary tubular damage markers were found in T2DM patients with GHF than the norm-GFR and control groups, probably a direct proof that GHF is a deleterious factor for diabetic nephropathy.     

Lipids,lipoproteins and apolipoproteins in type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus

Summary Total plasma cholesterol, triglycerides, VLDL-C, VLDL-TG, HDL-C and the apoproteins A-I, A-II, B and D were measured in 111 male non-obese diabetic patients and in 90 male control subjects of similar age and body weight distribution. Forty-eight patients had Type 1 (insulin-dependent diabetes) and 63 had Type 2 (non-insulin-dependent diabetes); all were in stable metabolic control while following an appropriate diet and therapy with insulin or oral hypoglycemic agents. HDL-C, apoA-I, apoB and the apoA-I/apoA-II ratio were significantly increased in the Type 1 patients, whereas the VLDL-C/VLDL-TG and LDL-C/apoB ratios were decreased significantly. Type 2 diabetics showed low HDL-C and low apoA-I/apoA-II ratio, while the values of apoA-I, A-II, D and the VLDL-C/VLDL-TG ratio were significantly higher than in controls. Type 1 diabetics in ‘fair’ metabolic control presented higher values of TG, VLDL-C, VLDL-TG and apoB than patients in ‘good’ control: lower values of apoA-I and of the ratios apoA-I/apoA-II, apoA-I/apoB and LDL-C/apoB were recorded in the same subgroup. In Type 2 diabetics no significant differences were observed according to metabolic control, with the exception of a higher apo-D value in subjects in ‘fair’ control. The data obtained support the view that good metabolic control may be important for the prevention of a relevant derangement of lipoprotein components, particularly in Type 1 patients. Partially supported by grant No. 83.02521.56 fromConsiglio Nazionale delle Ricerche (CNR), Roma, Italy (Progetto Finalizzato di Medicina Preventiva e Riabilitativa).     

Fluorescence angiography of the paramacular retinal vessels and altered glomerular basement membrane in children with juvenile onset diabetes mellitus

Summary Eighteen diabetic children aged between 8.5 and 16.5 years (mean 12.5 years) who had been diabetic for 1 to 10 years (mean 4.1 years) were examined for their urinary glomerular basement membrane (GBM) antigen excretion by means of immunoelectrophoresis and for alterations of the retinal vessels by fluorescence angiography. None of these patients showed albuminuria or hypertension. As compared to 40 healthy controls aged between 5 and 17 years, altered GBM antigen mobility (alpha-1) was found in 9 out of these 18 diabetics, whereas the remaining 9 children had normal GBM antigen mobility (alpha-2). Pathological fluorescence angiography findings on the other hand were evident in 7 children with altered GBM mobility, but only in 4 diabetics with normal GBM antigen mobility. This trend reflects the similarity of biochemical and functional characteristics of basement membranes in the retinal and kidney vessels supporting the well established association of vascular changes in both organs in patients with diabetes mellitus. GBM antigen excretion into urine could be useful for detecting early microvascular alterations in the kidneys in juvenile diabetics where diagnosis of early glomerulosclerosis is important.     

Improved metabolic control does not alter the charge-dependent glomerular filtration of albumin in uncomplicated Type 1 (insulin-dependent) diabetes

Summary The selectivity index, i. e. clearance of non glycated albumin/clearance of glycated albumin was studied in fourteen patients with Type 1 (insulin-dependent) diabetes and normal urinary albumin excretion. The index was increased above one in all patients, and correlated significantly to HbA_1c. It was, however, unaffected by 12 weeks of improved metabolic control with a mean decline in HbA_1c of 1.9% in seven patients. We conclude that the increased electronegative charge of the glomerular filtration barrier observed in uncomplicated diabetes is related to long term metabolic control but not reversible during twelve weeks of strict metabolic control. This indicates a slow turnover of the components responsible for the increased charge selectivity in uncomplicated diabetes.