H. H. P. J. Lemkes

Effect of simultaneous pancreas-kidney transplantation on mortality of patients with type-1 diabetes mellitus and end-stage renal failure

BACKGROUND Long-term prognosis of patients with type-1 diabetes mellitus and end-stage renal failure appears to be better after kidney transplantation compared with dialysis. Controversy exists about the additional benefit of a simultaneously transplanted pancreatic graft. We studied the effect on mortality of simultaneous pancreas-kidney transplantation compared with kidney transplantation alone from regional differences in transplantation protocols. METHODS All 415 patients with type-1 diabetes (aged 18-52 years) who started renal-replacement therapy in the Netherlands between 1985 and 1996 were included in the analysis. Patients were allocated to a centre based on their place of residence at onset of renal failure. In the Leiden area, the primary intention to treat was with a simultaneous pancreas-kidney transplantation, whereas in the non-Leiden area, kidney transplantation alone was the predominant type of treatment. All patients were followed up to July, 1997. Analyses, mortality, and graft failure were by Cox proportional-hazard model adjusted for age and sex. FINDINGS Simultaneous pancreas-kidney transplantation was done in 41 (73%) of 56 transplanted patients in the Leiden area compared with 59 (37%) of 158 transplanted patients in the non-Leiden area (p<0.001). The hazard ratio for mortality after the start of renal-replacement therapy was 0.53 (95% CI, 0.36-0.77, p<0.001) in the Leiden area compared with the non-Leiden area. When just the transplanted patients were analysed the mortality ratio was 0.4 (95% CI 0.20-0.77, p=0.008) and was independent of duration of dialysis and early transplant-related deaths. Equal survival was found for patients on dialysis only. INTERPRETATION These data support the hypothesis that simultaneous pancreas-kidney transplantation prolongs survival in patients with diabetes and end-stage renal failure.

Maternally inherited diabetes and deafness is a distinct subtype of diabetes and associates with a single point mutation in the mitochondrial tRNA Leu(UUR) gene

We have recently reported an A to G transition at nucleotide position 3243 in the mitochondrial DNA (mtDNA) tRNALeu(UUR)) gene in a large family with non-insulin-dependent diabetes mellitus (NIDDM). Characteristic was its maternal transmission and an associated sensorineural hearing loss. In a screening of a Dutch and French NIDDM population for the presence of the tRNALeu(UUR)) mutation we identified two new pedigrees in which NIDDM is present in combination with deafness. The mode of inheritance agrees with a maternal one. This result shows that patients with a phenotype of NIDDM and deafness can be identified within groups of NIDDM patients based on the tRNALeu(UUR)) mutation. The same mutation has also been linked to the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). How the same mutation can give rise to different clinical phenotypes is not clear. We obtained the complete mtDNA sequence from our initial pedigree and identified a number of additional mutations that could confer the phenotype of the tRNA(Leu(UUR)) mutation to diabetes. We examined the presence of these additional, potentially pathogenic mutations in the mtDNA from the two new pedigrees and from a previously described British pedigree. The absence of these mutations in all three pedigrees shows that the tRNALeu(UUR)) mutation alone associates with the phenotype of NIDDM and deafness. We conclude that maternally inherited diabetes and deafness is a distinct subtype of diabetes that is associated with a single mitochondrial tRNALeu(UUR) mutation. We propose the abbreviation MIDD for this particular subtype.

Expression of glomerular extracellular matrix components in human diabetic nephropathy: decrease of heparan sulphate in the glomerular basement membrane.

SummaryDiabetic nephropathy is characterized by albuminuria which proceeds to overt proteinuria. The highly negatively stained HS side chain of heparan sulphate proteoglycan (HSPG) is a major determinant of the charge-dependent permeability of the GBM. We set out to study the presence of HS and HSPG in the GBM of patients with diabetic nephropathy using newly developed monoclonal antibodies, and to compare HSPG expression to the expression of other previously investigated glomerular extracellular matrix compounds. Immunohistochemically, glomerular extracellular matrix components were analysed in 14 renal biopsies of patients with diabetic nephropathy and compared with those of normal control subjects. Monoclonal antibodies used were: JM403 against the HS side chain of GBM HSPG and JM72 against the HSPG-core protein. Also, a polyclonal antiserum (B31) against human GBM-HSPG-core protein was used. Additionally, antibodies were used against collagen types I, III, IV and against α1(IV)NC, α3(IV)NC and fibronectin. Staining was scored for intensity and for staining pattern by four independent observers who had no previous knowledge of the sample origin. No glomerular staining was seen for collagen type I. Collagen type III was present in some diabetic nodules. Anti-collagen type IV showed a decreased GBM staining in patients with diabetic nephropathy (p = 0.04). With anti-α1(IV)NC no changes in GBM staining intensity were observed; with anti-α3(IV)NC brilliant GBM staining was seen in both groups. Increased mesangial staining (p = 0.003) was seen with anti-collagen type IV in biopsies with nodular lesions. No differences were observed for fibronectin although it was abundantly present in the mesangial area of biopsies from patients with diabetic nephropathy. In biopsies with mesangial expansion and in biopsies with diabetic nodules, we observed a decreased GBM (p = 0.001) HS side chain staining (JM403) without changes in HSPG-core protein staining (JM72,B31). The HS staining pattern regularly changed from a linear to a more granular and irregular pattern. In patients with a creatinine clearance of more than 15 ml/min, the intensity of GBM HS staining showed an inverse correlation with the rate of proteinuria (r = -0.85, p = 0.004), suggesting a functional relationship. The decreased HS staining in the GBM may reflect the potentially disrupted charge barrier in diabetic nephropathy.

Heteroplasmy levels of a mitochondrial gene mutation associated with diabetes mellitus decrease in leucocyte DNA upon aging

We showed previously that a mutation in the mitochondrial tRNALeu(UUR) gene at position 3243 associates with maternally inherited diabetes and deafness (MIDD). This mutation shows heteroplasmy in DNA from peripheral blood and other tissues. To examine whether heteroplasmy levels in peripheral blood DNA change upon aging, heteroplasmy levels were determined in DNA samples from peripheral blood, collected recently and 1.5–6 years ago, from 18 individuals carrying the 3243 mutation. It was found that 17 out of 18 carriers showed a decrease upon aging (P = 0.001), the average change being −0.69 ± 0.61% per year. These data indicate a continuous selection against haematopoietic (precursor) cells carrying high levels of the 3243 mutation. Moreover, they imply that heteroplasmy levels may decrease below the detection limit if DNA from peripheral blood is analyzed from elderly individuals. DNA from oral mucosa cells was found to be a good alternative as heteroplasmy levels for the 3243 mutation are on the average 1.7 fold higher than in DNA from peripheral blood.

Large electrodes improve nerve conduction repeatability in controls as well as in patients with diabetic neuropathy

Recording site is an important cause of variability of compound muscle action potential (CMAP) and conduction parameters, which can be reduced by using large electrodes. Repeatability of CMAP and conduction parameters of conventional and large electrodes was compared in 16 controls and 17 diabetic neuropathic patients, using defined recording sites linked to anatomical landmarks. Right‐sided median, peroneal, and tibial nerves were investigated twice by the same examiner, with a 1–2 week interval. Compared to previous studies, conventional electrodes on strictly defined recording sites resulted in better repeatability: intraindividual coefficients of variation (CV) varied between 4% and 14.4% for all parameters. CV of conduction parameters, not published previously, was smaller than CV of CMAP parameters. The use of large electrodes improved repeatability further: large electrodes resulted in substantially smaller CV for duration, amplitude, area, and changes of amplitude and area over a length of nerve, which were reduced by 10%, 31%, 29%, 27%, and 16%, respectively. Patients had higher CV than controls; large electrodes reduced patient CV more than control CV, resulting in less contrast between groups. Strictly defined recording sites and large electrodes improve repeatability of motor conduction studies to relevant degrees: all CMAP and conduction parameters are suitable for longitudinal studies of neuropathic patients.

Mitochondrial diabetes and its lessons for common Type 2 diabetes

Multiple pathogenic pathways are able to deregulate glucose homoeostasis leading to diabetes. The 3243A>G mutation in the mtDNA (mitochondrial DNA)-encoded tRNALeu,UUR gene was found by us to be associated with a particular diabetic subtype, designated MIDD (maternally inherited diabetes and deafness). This mutation causes an imbalance in the mitochondrion between proteins encoded by the nuclear and mitochondrial genomes, resulting in a gradual deterioration of glucose homoeostasis during life. Remarkably, carriers of the 3243A>G mutation are generally not obese. The mutation also results in enhanced radical production by mitochondria. We propose that this mutation leads to the development of diabetes due to an inappropriate storage of triacylglycerols within adipocytes. The result is a fatty acid-induced deterioration of pancreatic beta-cell function. In combination with an enhanced radical production in the beta-cell due to the mutation, this leads to an age-dependent, accelerated decline in insulin production. In common Type 2 (non-insulin-dependent) diabetes, which is generally associated with obesity, a decline in mitochondrial function in adipose cells seems to result in an inappropriate scavenging of fatty acids by beta-oxidation. As a consequence, a systemic overload with fatty acids occurs, leading to an enhanced decline in beta-cell function due to lipotoxicity.

Effect of danaparoid sodium on hard exudates in diabetic retinopathy

BACKGROUND In diabetes mellitus, both retinopathy and nephropathy represent specific microvascular disease with increased capillary permeability resulting in hard exudates, foveal oedema, and albuminuria. The decrease of heparan-sulphate content of the glomerular-basement membrane is quantitatively related to the rate of proteinuria in nephropathy associated with insulin-dependent diabetes mellitus (IDDM). Several short-term studies in patients with IDDM and non-IDDM have shown that a reduction of microalbuminuria and macroalbuminuria can be achieved with the supplementation of glycosaminoglycans. After completion of a study on the effect of danaparoid sodium on albumin excretion in patients with IDDM and macroalbuminuria, we hypothesised that treatment with danaparoid sodium also influenced retinal leakage in the patients in that trial. METHODS In this retrospective study nine patients with nephropathy received 750 anti-Xa units danaparoid sodium once a day for 6 weeks in a placebo-controlled double-blind cross-over study. Fundus photographs, done at baseline and at the end of the study, were semiquantitatively scored for the severity of hard exudates. FINDINGS At baseline 14 eyes had grade 1 to 5 severity of hard exudates and four eyes were without hard exudates (grade 0). There was no progression in the latter four eyes. In ten eyes an improvement was observed: four patients showed a favourable response to treatment in both eyes and two patients showed improvement in one eye. We found improvement of hard exudates after 6 weeks of treatment with danaparoid sodium. INTERPRETATION Our uncontrolled observation indicates that the supplementation of danaparoid sodium influences both the permeability of retinal vessels as well as of glomerular vessels. Danaparoid-sodium therapy as a systemic adjuvant is worth considering for treatment strategies for foveal oedema and hard exudates in diabetic maculopathy.

HLA-DQ polymorphism and degree of heteroplasmy of the A3243G mitochondrial DNA mutation in maternally inherited diabetes and deafness

SUMMARY

Effects of supine blood pressure on interpretation of standing up test in 500 patients with diabetes mellitus

The relationship between fall in blood pressure (BP) on standing and supine BP before standing up was studied in 75 healthy controls and in 500 patients with diabetes mellitus (DM) using conventional BP measurements. The influences of physiological (sex, age, height) and DM-related factors (type, duration, HbA1c-level, use of insulin, oral antidiabetic and anti-hypertensive medication) on BP-fall were assessed. The effects of using a fixed abnormality threshold and a new supine BP-related abnormality definition on interpretation of the test were determined. Highly significant relationships of BP-fall with supine BP were found in control and DM subjects. Slopes did not differ between these groups. Slopes for systolic BP-fall were steeper in type 1 than in type 2 DM patients. A forward stepwise regression procedure revealed that supine BP (explaining 24% of variance) and HbA1c (explaining 1%) had significant influences on systolic BP-fall. Diastolic supine BP explained 14% of diastolic BP-fall, age 3%, and sex 2%. Only supine BP was thus of practical relevance in explaining BP-fall. Taking supine BP into consideration affected test results: of 74 subjects with an abnormal conventional systolic BP-fall, 10 (13.5%) had been misclassified according to the new method, and 4 additional patients had been misclassified as normal. Classification changes were much larger for diastolic BP-fall (63% of conventionally abnormal results were reclassified as normal), but the range of diastolic BP is smaller than for systolic BP, meaning that the measurement error interferes with its clinical utility.(ABSTRACT TRUNCATED AT 250 WORDS)

Function and survival of intrasplenic islet autografts in dogs

SummarySuccessful transplantation of isolated islets of Langerhans has been reported in large mammals, including man, but metabolic control has not been well-established. We studied the glucose and islet hormone response to fasting, i. v. glucose bolus infusion, i.v. arginine bolus infusion during a 35-mmol/l hyperglycaemic clamp, mixed meals, and i. v. insulin-induced hypoglycaemia up to 3 years after intrasplenic islet autotransplantation in six pancreatectomised dogs. The individual postprandial insulinogenic index (ratio of 2-h postprandial insulin to glucose levels) at 1 month post-transplant, predicted (r=0.99) the time to functional graft failure (6–175 weeks). Metabolic studies at 6 months post-transplant in four dogs demonstrated normal fasting glucose and hormone levels, except for reduced pancreatic polypeptide levels. Intravenous glucose and arginine-stimulated insulin were reduced to 15% of preoperative values. In contrast, postprandial normoin-sulinaemia was observed — albeit with moderate hyperglycaemia (approximately 10 mmol/l). Postprandial glucagon and glucose-dependent insulinotropic polypeptide (GIP) had increased. Comparison of the post-transplant insulin responses to a meal and to intravenous challenges demonstrated maximal stimulation of the graft by the meal. Post-transplant pancreatic polypeptide responses to a meal and i.v. arginine were severely reduced, and no pancreatic polypeptide response to i.v. insulin-induced hypoglycaemia was observed — indicating absence of cholinergic reinnervation. Thus, glucose regulation and both the insulin secretory capacity and life expectancy of islet grafts were best documented by meal testing. Tentatively, a postprandial hyperglycaemia-enhanced incretin effect of glucose-dependent insulinotropic polypeptide and other gut hormones may account for the difference in the insulin response to i. v. glucose and a meal. Aside from the reduced insulin secretory capacity, both a deranged pulsatile delivery of insulin, hyperglucagonaemia, and pancreatic polypeptide deficiency may have been conducive to glucose intolerance.