Autonomic and peripheral nerve function in early diabetic neuropathy. Possible influence of a novel aldose reductase inhibitor on autonomic function

Autonomic and peripheral nerve functions as well as the possible short-term effect of a novel aldose reductase inhibitor (ARI) on neuropathy were evaluated in 30 male type I diabetics (age 25-44 years, mean 34; duration of diabetes 10-20 years, mean 34) with neurographic signs of peripheral neuropathy (PN). Autonomic neuropathy (AN) was established by the heart rate reactions to deep breathing (E/I ratio = vagal function) and to tilt (acceleration index = sympathetic and vagal functions; the brake index = vagal function). Twenty-nine patients, 13 with AN, completed the study. Among neurographic variables, only sural nerve function tests correlated with autonomic functions. Patients with AN showed significantly lower mean sensory action potential amplitudes (SAPA) sural, indicating axonal losses, than patients without AN (3.58 +/- 0.79 microV v. 7.34 +/- 1.12 microV; p less than 0.01). PN as measured by neurography did not improve during ARI treatment. On the other hand, vagal function (brake indices) improved (p less than 0.05) during ARI in AN patients.     

Irreversible progression of severe retinopathy in young type I insulin-dependent diabetes mellitus patients after improved metabolic control.

The impact of metabolic control on the development of rapidly progressive severe retinopathy was studied in 14 young type I insulin-dependent diabetes mellitus (IDDM) patients. Glycosylated hemoglobin (HbAlc) levels 45 months prior to and 12 months after the diagnosis of retinopathy were compared with HbAlc levels in 17 type I IDDM patients with no or minimal background retinopathy, matched for age and duration of diabetes. HbAlc levels were generally higher in patients with severe retinopathy (p less than 0.05) from 39 months until 6 months before the diagnosis of retinopathy. Thereafter, there was a gradual decrease in HbAlc levels reaching the same level as in control patients 6 months after diagnosis of retinopathy. Patients with severe retinopathy required higher doses of insulin prior to the diagnosis of retinopathy (p less than 0.05), but the insulin requirement decreased, and 12 months afterward, the insulin dosage was similar to patients with background retinopathy. Systolic blood pressure levels were slightly increased and higher in patients with severe retinopathy compared with control patients from 18 months before to diagnosis of retinopathy (p less than 0.05). Diastolic blood pressure levels likewise differed at 18 and 12 months before and at the time of diagnosis of retinopathy as well as 12 months afterward (p less than 0.05); however, no differences were seen in urinary albumin or serum creatinine levels between the groups. Thus, years of poor metabolic control, drastically improved, preceded the development of irreversible severe retinopathy in these young type I IDDM patients.     

Circulating anti-pericyte autoantibodies are present in Type 2 diabetic patients and are associated with non-proliferative retinopathy

AIMS/HYPOTHESIS: This study aims to determine the prevalence of anti-pericyte autoantibodies in Type 2 diabetes and to characterize these autoantibodies as new markers of disease activity in diabetic retinopathy. METHODS: A total of 299 patients with Type 2 diabetes participated in this study. Retinopathy was assessed by 7-field stereo fundus photography and was graded according to the ETDRS scale. Serum anti-pericyte autoantibodies were detected by immunofluorescence on tissue cultured bovine retinal pericytes. RESULTS: The prevalence of anti-pericyte autoantibodies in Type 2 diabetic patients was 54% and was approximately equal in men and women. The prevalence was approximately 55% with retinopathy at grades from 10 to 53. At grades above 53 the prevalence declined to 23% ( p<0.0001). The highest prevalence by duration of diabetes, 70%, was found at 0 to 5 years and the lowest, 25% at more than 25 years duration ( p<0.0001). CONCLUSION/INTERPRETATION: Anti-pericyte autoantibodies are present at high prevalence in Type 2 diabetes. Their presence during earlier stages of retinopathy could be due to a reaction with antigens expressed by "activated" pericytes. The decline in antibody prevalence in advanced retinopathy could mark pericyte loss and progression to an angiogenic retinal milieu.     

Test–retest variability for standard automated perimetry and short‐wavelength automated perimetry in diabetic patients

Purpose: To assess limits for significant improvement or deterioration of visual fields in diabetic patients based on short‐term test–retest variability in subjects with different degrees of retinopathy. Methods: Fifty patients with diabetic retinopathy ranging from level 10 to 75 [according to the Early Treatment Diabetic Retinopathy Study (ETDRS) severity scale] were tested repeatedly with both standard automated perimetry (SAP) and short‐wavelength automated perimetry (SWAP) with short intervals. The association between visual field loss and degree of retinopathy outside fovea was analysed. Test–retest variability of global and local visual field indices and prediction limits for significant change were calculated. Results: The amount of visual field loss was significantly associated to the degree of retinopathy, with a correlation coefficient of ?0.51 for SAP (P = 0.0003) and ?0.45 for SWAP (P = 0.002). Global test–retest variability was smaller with SAP than with SWAP (P < 0.0001). For both SAP and SWAP, local test–retest variability was considerably smaller at test points with normal sensitivity than at test points with reduced sensitivity (P < 0.0001). Paracentral test points within 10° of eccentricity had less variability than peripheral points (P < 0.0001), implying that smaller change is required to reach statistically significant improvement or deterioration at initially normal and paracentral points than at depressed points and peripherally located test points. Conclusion: Our results propose that SAP, as well as SWAP, can be useful for monitoring visual function outside fovea in diabetic patients with various degrees of retinopathy. We report a preference for SAP because of less variability generally. Limits for significant improvement or deterioration have been assessed but need future validation in a longitudinal study.     

Type 1 diabetes patients with severe non-proliferative retinopathy may benefit from panretinal photocoagulation

PURPOSE: To examine whether panretinal photocoagulation for severe non-proliferative retinopathy in type 1 diabetes patients could halt the progression of retinopathy with subsequent vitreous haemorrhages and visual impairment. METHODS: During a 10-year follow-up study period of 344 type 1 diabetes patients, 81 subjects went through panretinal photocoagulation. Forty patients were treated for severe non-proliferative retinopathy (age at onset of diabetes 14 +/- 8 years, diabetes duration 18 + 10 years) and 41 for proliferative retinopathy (age at onset 15 +/- 10 years, diabetes duration 22 + 13 years). One randomly selected eye per patient forms the basis for the study. Metabolic control, systolic and diastolic blood pressure, serum creatinine and urinary albumin levels were measured and analysed yearly during the follow-up period. RESULTS: A total of 35% (14/40) of eyes treated for severe non-proliferative retinopathy developed neovascularizations during a mean time of 2.9 +/- 1.5 years. Vitreous haemorrhages were more frequent in eyes with proliferative retinopathy at treatment than in eyes with severe non-proliferative retinopathy (12/41 versus 2/40; p = 0.007). The number of vitrectomies due to vitreous haemorrhages in eyes treated for severe non-proliferative retinopathy tended to be lower (1/40 versus 6/41; p = 0.052). Before photocoagulation, visual acuity (VA) was similar in eyes with severe non-proliferative retinopathy and in those with proliferative retinopathy (1.0, 0.4-1.0 versus 1.0, 0.1-1.0; median and range). Visual impairment and blindness tended to develop more often in eyes treated for proliferative retinopathy compared to those treated for severe non-proliferative retinopathy (10/40 versus 4/40; p = 0.056). Eyes with neovascularizations at follow-up were more often visually impaired (VA < 0.5) than eyes without neovascularizations (15/55 versus 1/26; p = 0.016). CONCLUSION: In type 1 diabetes, panretinal photocoagulation may be beneficial even at the severe non-proliferative retinopathy stage in terms of preventing vitreous haemorrhage, subsequent vitrectomy and visual impairment.     

Diabetes duration may modify the association between genetic variation in the glycoprotein Ia subunit of the platelet collagen receptor and risk of severe diabetic retinopathy: a working hypothesis

Genetic factors appear to contribute to the severity and progression of diabetic retinopathy. We assessed the associations of the C807T and Glu505Lys variants of the glycoprotein Ia (alpha(2) integrin) subunit of the platelet/endothelial collagen receptor and risk of retinopathy in a population-based survey of 288 diabetic patients in one Swedish community. Neither variant was associated with retinopathy risk overall. However, the 807T variant was associated with increased risk of severe retinopathy, and the association was modified by diabetes duration. Among patients with diabetes of longer duration (>/=25 years), the 807T variant was strongly associated with risk of severe retinopathy (odds ratio 7.49, 95% confidence interval 1.75 to 32.1). There was no association between the 807T variant and risk of severe retinopathy among patients with diabetes duration <25 years. The Lys505 variant of glycoprotein Ia was associated with an odds ratio for severe retinopathy of 1.88 (95% confidence interval 0.83 to 4.24). Overall, there was a significant interaction between glycoprotein Ia genotype and duration of diabetes on the risk of retinopathy (P-value for interaction = 0.019). These results suggest the hypothesis that genetic variation of platelet glycoprotein Ia may play a particularly important role during the advanced stages of diabetic retinopathy.     

A screening procedure detecting high-yield candidates for OGTT. The Women's Health in the Lund Area (WHILA) study: a population based study of middle-aged Swedish women

The objective was to evaluate a screening procedure for detecting high-yield candidates for an OGTT, in a population of middle-aged Swedish women. A two-step screening procedure was performed in 6917 subjects. Women with a positive screening outcome, i.e. increased non-fasting capillary blood glucose, serum triglycerides, BMI, WHR, blood pressure or a family history of diabetes, pharmacological treatment of hypertension or hyperlipidaemia at the primary screening underwent a 75-g OGTT. A control group of women with negative screening outcome (n = 221) also underwent an OGTT. In 2923 women with positive screening outcome, 517 (17.7%) had NFG/IGT (normal fasting venous blood glucose <5.6 mmol/l and 2h-glucose 6.7–9.9 mmol/l), 109 (3.7%) IFG/IGT (fasting 5.6–6.0 and 2h 6.7–9.9 mmol/l) and 223 (7.6%) diabetes (fasting 6.1 or 2h 10.0 mmol/l). These figures were three, five and four times higher, respectively, than in the control group with negative screening outcome (p < 0.001 for all); no differences were found for IFG/NGT (fasting 5.6–6.0 and normal 2h < 6.7 mmol/l) (4.6% vs. 7.2%). For predicting impaired glucose metabolism (IFG/NGT, NFG/IGT, IFG/IGT, diabetes), the screening instrument showed an estimated sensitivity of 70%, specificity of 55%, positive predictive value of 34% and negative predictive value of 85%, based on findings in the control sample. The odds ratio for NFG/IGT increased with the numbers of risk factors from 2.8 to 7.7, for IFG/IGT from 5.7 to 55.0 and for diabetes from 2.5 to 18.1. High B-glucose, WHR and BMI were the three most important factors associated with an increased risk for NFG/IGT, IFG/IGT and diabetes. In subjects with IFG/NGT, none of the screening variables was associated with an increased risk. In summary, the results show a population screening method focused on features of the metabolic syndrome that discloses high-yield candidates for OGTT. A high prevalence of unknown impaired glucose metabolism was found in middle-aged women with a positive screening profile.     

Retinopathy and Nephropathy in Insulin-dependent Diabetics: An Inconsistent Relationship?

The association between retinopathy and nephropathy was investigated in a retrospective study of 52 insulin-dependent diabetics with preproliferative or proliferative retinopathy and in 48 patients without or with background retinopathy. The duration of diabetes was 23.2 +/- 1.0 years (mean +/- SEM) and 22.0 +/- 1.2 years in the two groups. Patients in the retinopathy group showed a higher frequency of detectable nephropathy and were more often treated with antihypertensive drugs. However, a high proportion (35%) of patients with proliferative retinopathy did not show any detectable signs of nephropathy. Furthermore, nephropathy did not seem to develop in patients with retinopathy during an observation period of up to 9 years. The data suggest that the factors underlying the development of retinal and renal microangiopathy might be of different origin.