Nutritional antioxidants as antidegenerative agents

In this study, primary cultures of cerebellar granule neurons were prepared from eight-day-old Wistar rats, and maintained in an appropriate medium containing a high (25 mM) concentration of KCl. All experiments were performed with fully differentiated neurons (eight days). To induce apoptosis, culture medium was replaced with a serum-free medium (containing 5 mM KCl) eight days after plating. In another series of experiments, apoptosis was induced by application of glutamate (50 microM) to the cell cultures. Apoptosis was measured by flow cytometry, the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick end-labeling) method, and by the classical method of DNA fragmentation. Since there is evidence that an increased formation of reactive oxygen species (ROS) is involved in the apoptosis induced by both low K(+) concentrations and glutamate, a series of natural antioxidants and a red wine lyophilized extract (which is rich in antioxidant compounds) were tested in our experimental model. It was found that ascorbic acid (30 microM) and a red wine lyophilized extract (5 microgram/ml) were capable of blocking the apoptotic process. Addition of the following natural antioxidants did not have any protective effect on apoptosis induced by low K(+) concentrations: trans- and cis-resveratrol (5-200 microM), alpha-tocopherol (100-200 microM), reduced glutathione (100-400 microM), 3-hydroxytirosol (25-100 microM), epicatechin (25-100 microM), or quercetin (25-50 miroM). It is concluded that only a limited number of natural antioxidants are provided with antiapoptotic activity in cultured cerebellar granule neurons. This effect is probably exerted by reducing ROS formation, and by blocking caspase-3 activity.     

Could a rural lifestyle decrease the prevalence of erectile dysfunction?

OBJECTIVE: To determine the prevalence of erectile dysfunction (ED) in a specific population and explore potential correlates with lifestyle. SUBJECTS AND METHODS: This prospective observational study, covering a population of a very small rural town, included 2000 men aged > or = 20 years from a total population of 121 831 (51% female and 49% male). The International Index of Erectile Function was completed by each of the 2000 men at their homes over a 1-year period. Another questionnaire assessing socio-economic status and health-related determinants of ED were also completed. RESULTS: All 2000 men completed the questionnaires; overall, only 34 reported ED (1.7%). The frequency of mild, mild to moderate, moderate and severe ED was 12%, 29%, 20% and 38%, respectively. Significantly more men aged > 51 years had ED than those aged <41 years (0.05% and 0.45%, respectively; P < 0.001). There was no difference in ED with salary levels. CONCLUSION: The prevalence of ED in this particular rural population of Brazil was very low, at only 1.7%. Although ED increases with age, this association was not apparent for all age groups. It seems that several others factors, e.g. lifestyle, culture and diet, could be important for the onset of ED.     

Tailored echocardiographic interventricular delay programming further optimizes left ventricular performance after cardiac resynchronization therapy.

BACKGROUND: The aim of cardiac resynchronization therapy is correction of left ventricular (LV) dyssynchrony. However, little is known about the optimal timing of LV and right ventricular (RV) stimulation. OBJECTIVES: The purpose of this study was to evaluate the acute hemodynamic effects of biventricular pacing, using a range of interventricular delays in patients with advanced heart failure. METHODS: Twenty patients with dilated ischemic (n = 12) and idiopathic (n = 8) cardiomyopathy (age 66 +/- 6 years, New York Heart Association class III-IV, LV end-diastolic diameter >55 mm, ejection fraction 22% +/- 18%, and QRS 200 +/- 32 ms) were implanted with a biventricular resynchronization device with sequential RV and LV timing (VV) capabilities. Tissue Doppler echocardiographic parameters were measured during sinus rhythm before implantation and following an optimal AV interval with both simultaneous and sequential biventricular pacing. The interventricular interval was modified by advancing the LV stimulus (LV first) or RV stimulus (RV first) up to 60 ms. For each stimulation protocol, standard echocardiographic Doppler and tissue Doppler imaging (TDI) echo were used to measure the LV outflow tract velocity-time integral, LV filling time, intraventricular delay, and interventricular delay. RESULTS: The highest velocity-time integral was found in 12 patients with LV first stimulation, 5 patients with RV first stimulation, and 3 patients with simultaneous biventricular activation. Compared with simultaneous biventricular pacing, the optimized sequential biventricular pacing significantly increased the velocity-time integral (P <.001) and LV filling time (P = .001) and decreased interventricular delay (P = .013) and intraventricular delay (P = .010). The optimal VV interval could not be predicted by any clinical nor echocardiographic parameter. At 6-month follow-up, the incidence of nonresponders was 10%. CONCLUSION: Optimal timing of the interventricular interval results in prolongation of the LV filling time, reduction of interventricular asynchrony, and an increase in stroke volume. In patients with advanced heart failure undergoing cardiac resynchronization therapy, LV hemodynamics may be further improved by optimizing LV-RV delay.     

Heterogeneity of Patients With Latent Autoimmune Diabetes in Adults: Linkage to Autoimmunity Is Apparent Only in Those With Perceived Need for Insulin Treatment: Results from the Nord-Tr?ndelag Health (HUNT) study

OBJECTIVE—Subjects with the diagnosis of latent autoimmune diabetes in adults (LADA) are more prone to need insulin treatment than those with type 2 diabetes. However, not all patients with LADA develop the need for insulin treatment, indicating the heterogeneity of LADA. We investigated this heterogeneity by comparing phenotypes of LADA with and without perceived need for insulin treatment (data obtained at times when diagnosis of LADA was not investigated) and also compared LADA and type 2 diabetes phenotypes.RESEARCH DESIGN AND METHODS—We used data from the all population–based Nord-Trøndelag Health study (n = 64,931), performed in 1995–1997. Data were assembled for individuals with LADA (n = 106) and type 2 diabetes (n = 943).RESULTS—In the comparison of individuals with LADA both with and without the need for insulin, insulin-treated subjects had higher titers of GAD antibodies (P < 0.001) and lower fasting C-peptide levels (P < 0.001). GAD antibodies and C-peptide correlated negatively (r = −0.40; P = 0.009). In the comparison of individuals with LADA and type 2 diabetes, all without the need for insulin, markers of metabolic syndrome were equally prevalent and pronounced. Age, C-peptide, and glucose levels were also similar. In the comparison of insulin-treated individuals with LADA and type 2 diabetes, more patients with LADA received insulin (40 vs. 22%, P < 0.001) and C-peptide levels were lower (P < 0.001). Patients with LADA were leaner but were still overweight (mean BMI 28.7 vs. 30.9 kg/m² in type 2 diabetes, P < 0.001). In the comparison of type 2 diabetic patients with and without insulin, insulin-treated subjects were more obese and had higher A1C and lower C-peptide levels (P < 0.001).CONCLUSIONS—Our conclusions are that 1) the need for insulin treatment in LADA is linked to the degree of autoimmunity and β-cell failure, 2) subjects with LADA and type 2 diabetes without the need for insulin treatment are phenotypically similar, and 3) insulin treatment in type 2 diabetic patients is associated with both insulin resistance and β-cell insufficiency.Autoimmunity is the major cause of type 1 diabetes. Autoimmunity is also assumed to be the major cause of latent autoimmune diabetes in adults (LADA) because this category of diabetes shares biochemical markers of β-cell–directed autoimmunity with “classic” type 1 diabetes. In clinical practice, autoimmunity in classic type 1 diabetes as well as in LADA is usually documented by antibodies against GAD.LADA is considered a “mild” form of type 1 diabetes. Mild indicates the fact that patients with LADA do not by clinical judgment need insulin from the time of diagnosis. However, within the first few years after the diagnosis of diabetes a need for insulin treatment develops in many patients with LADA. This distinguishes patients with LADA from those with nonautoimmune type 2 diabetes in whom a need for insulin treatment develops later than in those with LADA (1). An early need for insulin treatment in patients with LADA points to ongoing autoimmune-mediated destruction of β-cells in these patients.Risk factors for type 2 diabetes, such as age, obesity, and lack of physical activity, are associated with the development of LADA (2). In fact, odds ratios in terms of risk for diabetes for these factors of insulin resistance were the same for LADA and type 2 diabetes. This raises the question of the relative importance of autoimmunity vis-à-vis insulin resistance for the etiology of LADA and whether etiology differs among patients with LADA. Support for etiological heterogeneity comes from the large UK Prospective Diabetes Study (UKPDS), in which only a minority of patients with the diagnosis of LADA, when defined solely as GAD antibody positivity, developed the need for insulin treatment during 6 years of follow-up (1). The heterogeneity of LADA is also evident when one compares phenotypes of patients with LADA in different studies (3–6).Heterogeneity of patients with LADA could be further elucidated by comparing phenotypes of insulin-treated patients with LADA with those not treated with insulin. However, several conditions have to be met for such comparisons to be valid. First, groups of diabetic subjects to be compared must be drawn from the same geographically defined population. A population-based study is necessary to avoid the possible biases incurred by studying referral patients or patients selected for inclusion in clinical intervention studies. Second, the perceived need for insulin treatment has to be unbiased by LADA classification, because it has been shown that insulin treatment is initiated earlier when prior knowledge of autoimmunity, measured as GAD antibodies, is available (7). Third, valid comparison groups of insulin-treated and non–insulin-treated type 2 diabetic patients from the same population must be at hand.We had the opportunity to study patients with LADA and type 2 diabetes fulfilling the above-mentioned conditions, who were identified and characterized in the Nord-Trøndelag (HUNT) study. The HUNT study was performed between 1995 and 1997. The study was open to all adult subjects (∼90,000) living in a geographically defined area and had a high attendance rate (70%). To our knowledge, the patients with LADA and type 2 diabetes defined in the HUNT study did not participate in any study at the time of diagnosis and initiation of treatment, thereby minimizing any deviation from standard clinical practice and obviating increased attentiveness for signs of insufficient metabolic control and insulin requirement. Further, autoantibodies, such as GAD antibodies, were not measured by doctors (general practitioners) responsible for treatment in the region as part of the diabetes workup before and at the time of assembling data in 1995–1997. Thus, patients with autoimmune diabetes not requiring insulin at time of diagnosis were regarded and treated as type 2 diabetic patients. This assumption provided a unique opportunity to use the need for insulin as clinically perceived as a parameter for subclassifying patients with LADA and to compare phenotypes of insulin-treated and non–insulin-treated patients with LADA with respective groups of type 2 diabetic patients. Specifically, we wished to assess the influence of autoimmunity and β-cell insufficiency vis-à-vis insulin resistance factors for the perceived need for insulin treatment in patients with LADA.     

Predicting Early Mortality Among Implantable Defibrillator Patients Treated With Cardiac Resynchronization Therapy

BackgroundThe beneficial effects of a cardiac resynchronization defibrillator (CRT-D) in patients with heart failure, low left ventricular ejection fraction (LVEF), and wide QRS have clearly been established. Nevertheless, mortality remains high in some patients. The aim of this study was to develop and validate a risk score to identify patients at high risk for early mortality who are implanted with a CRT-D.Methods and ResultsFor predictive modelling, 1282 consecutive patients from 5 centers (74% male; median age 66 years; median LVEF 25%; New York Heart Association class III–IV 60%; median QRS-width 160 ms) were randomly divided into a derivation and validation cohort. The primary endpoint is mortality at 3 years. Model development was performed using multivariate logistic regression by checking log likelihood, Akaike information criterion, and Bayesian information criterion. Model performance was validated using C statistics and calibration plots. The risk score included 7 independent mortality predictors, including myocardial infarction, LVEF, QRS duration, chronic obstructive pulmonary disease, chronic kidney disease, hyponatremia, and anemia. Calibration-in-the-large was suboptimal, reflected by a lower observed mortality (44%) than predicted (50%). The validated C statistic was 0.71 indicating modest performance.ConclusionA risk score based on routine, readily available clinical variables can assist in identifying patients at high risk for early mortality within 3 years after CRT-D implantation.     

Germline succinate dehydrogenase subunit D mutation segregating with familial non-RET C cell hyperplasia

C cell hyperplasia is associated with medullary carcinoma of the thyroid in the inherited MEN2 syndromes, in which the great majority of cases have been shown to be due to a mutation in the RET oncogene. We report a study of a family with C cell hyperplasia and hypercalcitoninemia in which no cases of medullary carcinoma have yet occurred and which lacked an identifiable causative RET mutation. Four of the family members showed hypercalcitoninemia, and marked C cell hyperplasia was present in each of the three in whom thyroidectomy has been performed. We investigated the possible involvement of the SDHD gene, because somatic and germline mutations in this gene have been found in a variety of tumors of neural crest-derived tissue. A germline mutation in exon 2 of the SDHD gene (c149 A-G, His 50 Arg) was found in six members of the family; all the four available members with hypercalcitoninemia possessed the mutation. One of the five available members without hypercalcitoninemia, an 18-yr-old female, also showed the mutation. We conclude that we have identified a new syndrome, characterized by familial non-RET C cell hyperplasia. Our studies suggest that a mutation in SDHD may be causative. These observations have implications for apparently incidental cases of hypercalcitoninemia or C cell hyperplasia.     

Culture at low glucose up-regulates mitochondrial function in pancreatic β cells with accompanying effects on viability

We tested whether exposure of β cells at reduced glucose leads to mitochondrial adaptions and whether such adaptions modulate effects of hypoxia. Rat islets, human islets and INS-1 832/13 cells were pre-cultured short term at half standard glucose concentrations (5.5 mM for rat islets and cells, 2.75 mM for human islets) without overtly negative effects on subsequently measured function (insulin secretion and cellular insulin contents) or on viability. Culture at half standard glucose upregulated complex I and tended to upregulate complex II in islets and INS-1 cells alike. An increased release of lactate dehydrogenase that followed exposure to hypoxia was attenuated in rat islets which had been pre-cultured at half standard glucose. In INS-1 cells exposure to half standard glucose attenuated hypoxia-induced effects on several viability parameters (MTT, cell number and incremental apoptotic DNA). Thus culture at reduced glucose of pancreatic islets and clonal β cells leads to mitochondrial adaptions which possibly lessen the negative impact of hypoxia on β cell viability. These findings appear relevant in the search for optimization of pre-transplant conditions in a clinical setting.     

Overweight,obesity and the risk of LADA: results from a Swedish case–control study and the Norwegian HUNT Study

Aims/hypothesis

Excessive weight is a risk factor for type 2 diabetes, but its role in the promotion of autoimmune diabetes is not clear. We investigated the risk of latent autoimmune diabetes in adults (LADA) in relation to overweight/obesity in two large population-based studies.

Methods

Analyses were based on incident cases of LADA (n?=?425) and type 2 diabetes (n?=?1420), and 1704 randomly selected control participants from a Swedish case–control study and prospective data from the Norwegian HUNT Study including 147 people with LADA and 1,012,957 person-years of follow-up (1984–2008). We present adjusted ORs and HRs with 95% CI.

Results

In the Swedish data, obesity was associated with an increased risk of LADA (OR 2.93, 95% CI 2.17, 3.97), which was even stronger for type 2 diabetes (OR 18.88, 95% CI 14.29, 24.94). The association was stronger in LADA with low GAD antibody (GADA; <median) (OR 4.25; 95% CI 2.76, 6.52) but present also in LADA with high GADA (OR 2.14; 95% CI 1.42, 3.24). In the Swedish data, obese vs normal weight LADA patients had lower GADA levels, better beta cell function, and were more likely to have low-risk HLA-genotypes. The combination of overweight and family history of diabetes (FHD) conferred an OR of 4.57 (95% CI 3.27, 6.39) for LADA and 24.51 (95% CI 17.82, 33.71) for type 2 diabetes. Prospective data from HUNT indicated even stronger associations; HR for LADA was 6.07 (95% CI 3.76, 9.78) for obesity and 7.45 (95% CI 4.02, 13.82) for overweight and FHD.

Conclusions/interpretation

Overweight/obesity is associated with increased risk of LADA, particularly when in combination with FHD. These findings support the hypothesis that, even in the presence of autoimmunity, factors linked to insulin resistance, such as excessive weight, could promote onset of diabetes.