Association between the rs1050450 glutathione peroxidase-1 (C > T) gene variant and peripheral neuropathy in two independent samples of subjects with diabetes mellitus.

Glutathione peroxidase-1 (GPx-1) is an endogenous anti-oxidant enzyme. The T allele of the GPx-1 rs1050450 (C > T) gene variant is associated with reduced enzyme activity. Our aim was to examine the association between this gene variant and peripheral neuropathy in two cross-sectional samples of subjects with diabetes: (i) 773 Caucasian subjects were genotyped from the UCL Diabetes and Cardiovascular disease Study (UDACS) and (ii) 382 Caucasian subjects from the Ealing Diabetes Study (EDS). Peripheral neuropathy status (and oxidised-LDL [Ox-LDL:LDL] and plasma Total Ant-ioxidant Status [TAOS] in UDACS), were analysed in relation to genotype. We observed that: (i) In UDACS, the odds ratio (OR) for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.61 [1.10-2.28], p = 0.01. This remained significant after adjustment for other risk factors. Ox-LDL:LDL ratio was significantly elevated in T allele carriers (CC vs. CT/TT: 16.3 ± 2.4 v 18.0 ± 2.9 U/mmol LDL, p = 0.02). (ii) In EDS, the OR for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.95 [1.11-3.42], p = 0.02. This remained significant after adjustment for other risk factors. In conclusion, we observed a significant association between the T allele and peripheral neuropathy and LDL oxidation. This is the first paper to examine the rs1050450 variant in two samples of Caucasian subjects with diabetes. Prospective analysis of the gene variant is required in diabetic and healthy cohorts with measured plasma markers of oxidative stress to investigate the described association further.

Association between the rs4880 superoxide dismutase 2 (C>T) gene variant and coronary heart disease in diabetes mellitus.

Mitochondrial superoxide dismutase 2 (SOD2) is an endogenous anti-oxidant enzyme. The rs4880 gene variant results in a C>T substitution, influencing SOD enzymatic activity. This variant has been associated with micro- and macro-vascular complications in diabetes mellitus. Our aim was to examine the association between this variant and coronary heart disease (CHD) risk in a cross-sectional sample of subjects with diabetes. 776 Caucasian subjects with diabetes were genotyped. CHD risk, oxidised-LDL and plasma total anti-oxidant status (TAOS) were analysed in relation to genotype. In females, the TT genotype was associated with CHD (CC/CT/TT: No CHD vs. CHD: 22.4/56.0/21.6% vs. 12.0/50.0/38.0%, p=0.03; for CC/CT vs. TT, p=0.01). The odds ratio for CHD associated with the TT genotype compared to CC/CT was 2.22 [95%CI: 1.17-4.24], p=0.01. The TT genotype was also associated with significantly lower plasma TAOS. In males, no association was observed between genotype and CHD risk, but CHD was significantly associated with age, lower HDL, higher triglycerides, higher BMI and cigarette smoking. The TT genotype of this variant is associated with increased CHD risk and lower plasma anti-oxidant defences in females with diabetes. This modest genotype-effect is not apparent in males where traditional risk factors may play a greater role.

Randomized controlled trial to assess the impact of continuous glucose monitoring on HbA(1c) in insulin-treated diabetes (MITRE Study).

AIMS: To determine whether continuous glucose information provided through use of either the GlucoWatch G2 Biographer or the MiniMed continuous glucose monitoring system (CGMS) results in improved glycated haemoglobin (HbA(1c)) for insulin-treated adults with diabetes mellitus, relative to an attention control and standard care group. METHODS: Four hundred and four adults taking at least two daily insulin injections and with two consecutive HbA(1c) values > or = 7.5% were recruited to this randomized controlled trial (RCT). All were trained at baseline to use the same monitor for traditional capillary glucose testing throughout the 18-month study. The CGMS group were asked to wear the device three times during the first 3 months of the trial and on another three occasions thereafter. The GlucoWatch group wore the device a minimum of four times per month and a maximum of four times per week during the first 3 months and as desired for the remainder of the trial. Trained diabetes research nurses used downloaded data to guide therapy adjustments. Proportional reduction in HbA(1c) from baseline to 18 months was the primary outcome measure. RESULTS: Neither an intention-to-treat nor per-protocol analysis showed improvement in HbA(1c) in the device groups compared with standard care. For the intention-to-treat analysis, when the standard care group was compared with each of the other groups, this equated to differences in mean relative HbA(1c) reduction (95% confidence interval) from baseline to 18 months of 3.5% (-1.3 to 8.3; GlucoWatch), 0.7% (-4.1 to 5.5; CGMS), and -0.1% (-4.6 to 4.3; attention control). CONCLUSIONS: The additional information provided by these devices did not result in improvements in HbA(1c) in this population.

A randomised controlled trial to compare minimally invasive glucose monitoring devices with conventional monitoring in the management of insulin-treated diabetes mellitus (MITRE).

OBJECTIVES: To evaluate whether the additional information provided by minimally invasive glucose monitors results in improved glycaemic control in people with poorly controlled insulin-requiring diabetes, and to assess the acceptability and health economic impact of the devices. DESIGN: A four-arm randomised controlled trial was undertaken. SETTING: Participants were recruited from secondary care diabetes clinics in four hospitals in England. PARTICIPANTS: 404 people aged over 18 years with insulin-treated diabetes mellitus (types 1 or 2) for at least 6 months who were receiving two or more injections of insulin daily were eligible. Participants had to have had two glycosylated haemoglobin (HbA1c) values > or = 7.5% in the last 15 months. INTERVENTIONS: Participants were randomised to one of four groups. Two groups received minimally invasive glucose monitoring devices [GlucoWatch Biographer or MiniMed Continuous Glucose Monitoring System (CGMS)]. These groups were compared with an attention control group (standard treatment with nurse feedback sessions at the same frequency as those in the device groups) and a standard control group (reflecting common practice in the clinical management of diabetes in the UK). MAIN OUTCOME MEASURES: Change in HbA1c from baseline to 3, 6, 12 and 18 months was the primary indicator of short- to long-term efficacy in this study. Perceived acceptability of the devices was assessed by use and a self-report questionnaire. A health economic analysis was also performed. RESULTS: At 18 months all groups demonstrated a decline in HbA1c levels from baseline. Mean percentage changes in HbA1c were -1.4 for the GlucoWatch group, -4.2 for the CGMS group, -5.1 for the attention control group and -4.9 for the standard care control group. At 18 months the relative percentage reduction in HbA1c in each of the intervention arms was less than that in the standard care control group. In the intention to treat analysis no significant differences were found between any of the groups at any of the assessment times. There was no evidence that the additional information provided by the devices resulted in any change in the number or nature of treatment recommendations offered by the nurses. The health economics analysis indicated no advantage in the groups who received the devices; a lower cost and higher benefit were found for the attention control arm. Assessment of device use and acceptability indicated a decline in use of both devices, which was most marked in the GlucoWatch group by 18 months (20% still using GlucoWatch versus 57% still using the CGMS). The GlucoWatch group reported more side effects, greater interference with daily activities and more difficulty in using the device than the CGMS group. CONCLUSIONS: Continuous glucose monitors do not lead to improved clinical outcomes and are not cost-effective for improving HbA1c in unselected individuals with poorly controlled insulin-requiring diabetes. On acceptability grounds the data suggest that the GlucoWatch will not be frequently used by individuals with diabetes because of the large number of side effects.

Development and piloting of an acceptability questionnaire for continuous glucose monitoring devices.

BACKGROUND: User acceptability of new health technologies is important in determining their widespread use and adoption. The aim of this current study was twofold: first, to investigate the acceptability of two continuous glucose monitoring devices for people with diabetes; and second, to develop a valid questionnaire measure to assess the acceptability of continuous glucose monitoring devices. METHODS: Semi-structured interviews were conducted with six people with diabetes who had previously used the GlucoWatchBiographer (Animas Corp., West Chester, PA) or the CGMS continuous glucose monitoring system (Medtronic MiniMed, Northridge, CA) in order to increase understanding of the issues relating to acceptability of, and satisfaction with, the devices. Interview transcripts were analyzed qualitatively using framework analysis. These analyses, together with consultation with researchers and health professionals in the field, provided the foundation for development of a questionnaire measure that was piloted with 19 individuals. RESULTS: Six broad themes were elicited from the framework analysis: interference with daily activities; reliability and accuracy of the devices; practicality and ease of use; improvements in glycemic control; side effects; and self-consciousness and disclosure. Piloting of the questionnaire arising from this analysis demonstrated face validity. Further psychometric testing of the questionnaire will be conducted as part of a randomized controlled trial evaluating the clinical efficacy and cost-effectiveness of the CGMS and GlucoWatch G2 Biographer. CONCLUSIONS: Ultimately it is the user's preferences and his or her assessment of acceptability that will determine uptake and use of continuous glucose monitoring devices. It is therefore essential to consider and evaluate this alongside clinical efficacy and cost-effectiveness.

Adiponectin and its gene variants as risk factors for insulin resistance, the metabolic syndrome and cardiovascular disease.

The increasing prevalence of obesity and metabolic syndrome/insulin resistance has attracted considerable interest due to their identification as risk factors for cardiovascular disease and, hence, targets for cardiovascular disease prevention. This review focuses on adiponectin, the most profusely secreted protein from adipose tissue, which itself is being increasingly recognised as an important and very active endocrine organ, secreting a wide range of biologically active substances known as adipokines or adipocytokines. Adiponectin has been demonstrated to have insulin sensitising effects, and secretion of adiponectin is reduced as adipose tissue mass increases. Adiponectin has also been demonstrated to have anti-inflammatory and anti-atherogenic properties, and is independently associated with cardiovascular disease. The evidence that suggests adiponectin plays a role in the relationship between obesity and insulin resistance, and also insulin resistance and cardiovascular disease, is examined. Variation in the adiponectin gene is one tool to determine whether this relationship is causal. The association of identified variants with human disease, specifically obesity and its consequences, type 2 diabetes and cardiovascular disease is reviewed. This data may enable patients at greater risk of the adverse effects of obesity to be identified and, as such, benefit from more targeted therapy of its consequences.

Lp-PLA2 activity and PLA2G7 A379V genotype in patients with diabetes mellitus.

Lipoprotein associated phospholipase A2 (Lp-PLA2) modulates low-density lipoprotein (LDL) oxidation by hydrolysing oxidised phospholipids present on particle surfaces. We investigated whether Lp-PLA2 activity and PLA2G7 A379V genotype were related to mediators of atherosclerosis in a diabetic study. Plasma Lp-PLA2 activity (taken in men only) and A379V genotype were investigated with regards to metabolic syndrome (MS), UKPDS risk score, and oxidised LDL (oxLDL/LDL), in a cohort of Caucasian men and women (n=783, age 62.5+/-13.7 years). After adjustment for type of diabetes, CHD status, and statin use, those individuals with features defining the MS (WHO guidelines) had higher Lp-PLA2 activity (35.6+/-11.9 nmol/min/ml) compared to those without (33.0+/-10.8 nmol/min/ml) (p=0.02). Quartiles of UKPDS coronary heart disease (CHD) risk score were also positively associated with Lp-PLA2 activity (p=0.006, p=0.004 linear trend). Those men in the highest quartile of oxLDL/LDL level had the lowest Lp-PLA2 activity (31.3+/-10.5 nmol/min/ml) when compared to the middle two (32.3+/-9.8 and 35.9+/-10.9 nmol/min/ml, respectively) and lowest quartile (35.6 +/-12.5 nmol/min/ml; p=0.03, p=0.004 linear trend). There was no significant association between A379V genotype and Lp-PLA2 enzyme activity (p=0.34) or oxLDL/LDL (p=0.32). Lp-PLA2 activity is an independent predictor of CHD risk and MS in a sample of subjects with diabetes mellitus. The association of Lp-PLA2 activity with oxLDL/LDL suggests that Lp-PLA2 may be a modulating factor in the process of atherosclerosis.

Clinical decision making: managing postprandial hyperglycemia.

The primary objective of treating all patients with diabetes is to establish and maintain near-normal blood glucose levels to prevent microvascular and macrovascular complications. The glycated hemoglobin (HbA(1c)) is the accepted standard for monitoring overall glycemic control with treatments and management strategies traditionally targeting fasting and preprandial glucose levels. However, postprandial glucose levels also contribute to HbA(1c), and optimization of glycemic control may also require targeting these values. Exaggerated postmeal glucose excursions are common in patients with diabetes, and postprandial hyperglycemia (PPHG) is an independent risk factor for cardiovascular disease. Regular self-monitoring of blood glucose concentrations (SMBG) at appropriate times can detect PPHG, provide patient feedback regarding meals and lifestyle, and monitor response to therapy. SMBG can also help detect fluctuations in blood glucose levels, which may be an additional risk factor for complications, independent of HbA(1c). New therapeutic options that specifically target postprandial glucose levels may improve overall glycemic control and reduce the risk of microvascular and macrovascular complications.

The significant increase in cardiovascular disease risk in APOEepsilon4 carriers is evident only in men who smoke: potential relationship between reduced antioxidant status and ApoE4.

Data from 1668 men (316 cardiovascular disease events) from the Framingham Offspring Study was reanalysed, specifically examining APOE:smoking interactions. Overall hazard ratio (HR) for smoking was 1.95 (1.52, 2.50) compared to non-smokers. Using epsilon3/3 as a referent group, in non-smokers HRs for epsilon2 carriers (epsilon2+; 1.04 (0.61, 1.76) and epsilon4 carriers (epsilon4+; 1.04 (0.70, 1.54) showed no major risk increase. In smokers, HRs were 1.96 (1.26, 2.78) in epsilon3epsilon3 men, 3.46 (2.14, 5.60; p = 0.09 for interaction) in epsilon2+ and 3.81 (2.49, 5.84; p = 0.01 for interaction), with a significant interaction between daily cigarette consumption and APOE genotype on risk (p = 0.03). The potential mechanism for this APOEepsilon4:smoking interaction was examined in a second study of 728 Caucasian patients with diabetes, where markers of reactive oxygen species were available. APOE genotype was not associated with plasma OX-LDL or total antioxidant status (TAOS) in non-smokers. However, in smokers epsilon4+ had 26.7% higher plasma OX-LDL than other genotypes (APOE:smoking interaction p = 0.04), while epsilon2+ had 28.4% higher plasma TAOS than epsilon3epsilon3 and epsilon4+ combined (APOE:smoking interaction p = 0.026). Although direct extrapolation needs to be considered with caution, these results identify that the cardiovascular disease risk-raising effect of epsilon4+ is confined to smokers, and a feasible mechanism is presented by the reduced antioxidant capacity/increased OX-LDL of apoE4.

The isolation, identification and molecular analysis of Candida spp. isolated from the oral cavities of patients with diabetes mellitus.

Previous studies have shown a high incidence (77%) of isolation of Candida spp. from the oral cavities of patients with type 1 diabetes mellitus. The aim of the present study was to assess the prevalence of yeast in the oral cavities of patients suffering from type 1 and type 2 diabetes mellitus. The patients were classified according to the level of diabetic control (HbA1c), and further stratified on the presence or absence of dental prosthesis. Oral rinse samples were assessed for the growth of yeast and the degree of colonization. Oral isolates were defined to the species level by both phenotypic and novel molecular methods. The overall proportion (60%) of diabetic patients who had Candida spp. isolated from the oral cavity was similar to that previously reported. Local oral factors, such as the presence of dentures, seemed to have a greater influence than diabetic status on the amount and species of Candida isolated from the oral cavities of diabetic patients. Diabetic patients with dentures had more non-albicans Candida isolated from their mouths than dentate diabetic patients. Candida dubliniensis was isolated from diabetic patients and may have a predilection for dentate patients.

Insulin reduces serum glycosylphosphatidylinositol phospholipase D levels in human type I diabetic patients and streptozotocin diabetic rats.

The enzyme glycosylphosphatidylinositol phospholipase D has a postulated role in the insulin-mimetic signaling pathway of glycosylphosphatidylinositol compounds. We have investigated enzyme activity in the serum of human type I diabetic patients and plasma and tissues of streptozotocin-induced diabetic rats following insulin administration. In the human diabetic patients serum enzyme activity fell by an average of 10.6% (SEM = 2.7; P = 0.008; n = 20) following administration of insulin. In addition serum enzyme activity appeared to be depleted by 27% (SEM = 8.8; P = 0.011; n = 10) compared to nondiabetic controls. In untreated diabetic rats plasma enzyme activity gradually increased 0.3-fold over a 6-week period (P < 0.001; n = 8), this increase was reversed and activity normalized when these animals were treated with insulin. Cloning of the rat glycosylphosphatidylinositol phospholipase D cDNA enabled confirmation of the liver as the principal organ of synthesis. Analysis of mRNA levels in the livers of the diabetic rats showed that gene expression was reduced in the insulin-treated animals compared to the noninsulin-treated controls by 0.7-fold (P = 0.004; n = 4). Tissue enzyme activity was also reduced in the insulin-treated rats; in skeletal muscle enzyme activity was 0.3-fold lower (P = 0.001; n = 4). Insulin therefore decreases glycosylphosphatidylinositol phospholipase D synthesis in diabetic animals resulting in decreased serum enzyme levels, suggesting a relationship between this enzyme and the function of insulin.

Association analysis of the cytotoxic T lymphocyte antigen-4 (CTLA-4) and autoimmune regulator-1 (AIRE-1) genes in sporadic autoimmune Addison's disease.

Although autoimmune Addison's disease (AAD) may occur as a component of the monogenic autoimmune polyendocrinopathy type 1 syndrome (APS1), it is most commonly found as an isolated disorder or associated with the autoimmune polyendocrinopathy type 2 syndrome (APS2). It is likely that sporadic (non-APS1) AAD is inherited as a complex trait; however, apart from the major histocompatibility complex, the susceptibility genes remain unknown. We have examined polymorphisms at two non-major histocompatibility complex candidate susceptibility loci in sporadic (non-APS1) AAD: the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene and the autoimmune regulator (AIRE-1) gene. DNA samples from AAD subjects (n = 90) and local controls (n = 144 for CTLA-4; n = 576 for AIRE-1) were analyzed for the CTLA-4A/G polymorphism in exon 1 of the CTLA-4 gene and for the common mutant AIRE-1 allele (964de113) in United Kingdom subjects with APS1, by using the restriction enzymes Bst7II and BsrBI, respectively. There was an association of the G allele at CTLA-4A/G in AAD subjects (P = 0.008 vs. controls), which was stronger in subjects with AAD as a component of APS2 than in subjects with isolated AAD. In contrast, the mutant AIRE-1 964del13 allele was carried in one each of the 576 (0.2%) control subjects and the 90 (1.1%) AAD subjects as a heterozygote (P = 0.254, not significant), suggesting that this common AIRE-1 gene abnormality does not have a major role in sporadic (non-APS1) AAD.

Relationship of physical exercise and ageing to growth hormone production.

OBJECTIVE: The normal decline in physiological function with ageing is associated with a decrease in bioavailable growth hormone. Growth hormone has been shown to alter body composition and increase fat-free mass in older men. Increased physical fitness is accompanied by an increase in 24-h growth hormone release. The purpose of this study was to examine the effect of exercise on declining growth hormone concentrations with increasing age. DESIGN AND PATIENTS: The growth hormone production of 10 male subjects running over 40 miles per week was compared to 10 healthy age-matched sedentary males (controls 57.7 +/- 2.8 vs. runners 60.5 +/- 3.4 years). All subjects underwent a basal assessment including a two-hour serum growth hormone profile followed by estimation of maximal exercise capacity on a cycle ergometer with growth hormone estimations at peak exercise activity and every five minutes whilst cycling at 40% of maximal exercise capacity. RESULTS: Maximal exercise capacity confirmed the lifestyles of the two groups (VO2 max controls 22.36 +/-6.05 vs. runners 34.91 +/- 13.13 l/min/kg, P = 0.01). The runners had lower body-mass indices than controls (BMI 22. 3 +/- 1.5 vs. 25.5 +/- 2.0 kg/m2, P = 0.002). Peak growth hormone level during a two-hour resting profile was higher in the runners (median (range) controls 2.10 (0.20-12.20) vs. runners 5.25 (0.80-21. 00) mU/l, P = 0.03) as was the average growth hormone level during the two hour profile (mean growth hormone per 2 h median (range): controls 0.54 (0.03-4.88) vs. runners 2.17 (0.25-7.45) mU/l, P = 0. 04). Growth hormone production at maximal exercise capacity was similar. Sex hormone binding globulin and testosterone were significantly higher in the runners. CONCLUSIONS: The results suggest that regular intensive exercise in older male subjects is associated with higher growth hormone and testosterone levels and that exercise may have a role in counteracting the normal decline in growth hormone with ageing.

Metastatic prolactinoma: effect of octreotide, cabergoline, carboplatin and etoposide; immunocytochemical analysis of proto-oncogene expression.

A 49-yr-old woman presented with an extensive prolactinoma (serum PRL > 10,000 mU/L, normal range < 450 mU/L). Over a 5-yr period following transsphenoidal surgery and pituitary irradiation, she became increasingly resistant to high doses of bromocriptine and underwent transfrontal surgery followed by stereotactic radiotherapy. In spite of these treatments, serum prolactin estimations rose progressively to > 100,000 mU/L. Magnetic resonance imaging scanning demonstrated a massive cystic tumor invading the temporal lobes, extending into the cervical and thoracic spine, with metastases to cervical lymph nodes. High-dose cabergoline administration resulted in a 30% decrease in serum PRL. Octreotide was administered as a continuous sc infusion with a profound analgesic effect on facial pain but with no effect on tumor progression. She was treated with a course of chemotherapy consisting of carboplatin and etoposide without any noticeable effect. The patient died 6 months following chemotherapy. Immunocytochemical analysis demonstrated positive nuclear staining for WAF-1, Rb protein, c-myc, and p53 both in the original and metastatic tumors. The metastases but not the primary tumor stained for c-jun. Metastatic prolactinoma remains a therapeutic challenge. It is associated with a variable proto-oncogene expression, which may be coincidental or causal. Cabergoline had no advantage over bromocriptine. Octreotide relieved facial pain but did not alter tumor progression. An effective therapy for metastatic prolactinoma remains to be identified.

Avascular necrosis secondary to postoperative steroid therapy.

Hypothalamic and pituitary tumours may present with vague symptoms owing to excess or lack of hormone production, including diabetes insipidus. Corticosteroids are commonly employed to limit cerebral oedema and at much lower doses to treat secondary hypocorticalism. Continuation of steroids at inappropriately high doses predisposes to the development of avascular necrosis as in the case we describe in a young woman of 34 years. This is a potentially preventable crippling disorder. When prescribing steroids the lowest effective dose should be used.