Does the autonomic nervous system play a role in the development of insulin resistance? A study on heart rate variability in first‐degree relatives of Type 2 diabetes patients and control subjects

AIMS: To investigate dysregulation of the autonomic nervous system as a potential mechanism for early insulin resistance in the development of Type 2 diabetes. METHODS: Thirteen healthy individuals with first-degree relatives with Type 2 diabetes (R) were compared with 14 control subjects without family history of diabetes (C), matched for age, body mass index and sex. An oral glucose tolerance test and a hyperinsulinaemic euglycaemic clamp were performed. Analysis of heart rate variability during rest, controlled breathing, an orthostatic manoeuvre and a standardized physical stress (cold pressor test (CPT)), were used to evaluate the activity of the autonomic nervous system. RESULTS: Fasting blood glucose, HbA1c and serum insulin were similar in the R and C groups. The M-value, reflecting insulin sensitivity, did not differ significantly between the groups. Total spectral power and high-frequency power were lower in R during controlled breathing (P = 0.05 and P = 0.07, respectively), otherwise there were no significant differences between R and C in heart rate variability. However, low-frequency (LF)/high-frequency (HF) spectral power ratio during CPT, reflecting sympathetic/parasympathetic balance, was negatively associated with insulin sensitivity (r = -0.53, P = 0.006). When all subjects were divided into two groups by the mean M-value, the low M-value group displayed an overall higher LF/HF ratio (P = 0.04). HF power was lower in the low M-value group during controlled breathing and CPT (P = 0.01 and P = 0.03, respectively). CONCLUSION: An altered balance of the parasympathetic and sympathetic nervous activity, mainly explained by an attenuated parasympathetic activity, might contribute to the development of insulin resistance and Type 2 diabetes.     

Quality of life in chronic NSAID users: a comparison of the effect of omeprazole and misoprostol

OBJECTIVE: To compare the impact on quality of life (QoL) of omeprazole and misoprostol during healing, and omeprazole, misoprostol, and placebo during maintenance treatment in chronic NSAID users with NSAID-associated gastroduodenal lesions. METHODS: Validated baseline and follow-up QoL questionnaires were completed by 610 patients (healing: after 4/8 weeks; maintenance: after 6 months). RESULTS: Patients with arthritis being treated with NSAIDs have a poor QoL. Rheumatoid arthritis causes more joint problems and physical mobility limitations than osteoarthritis. Chronic NSAID use causes heartburn and dyspepsia. QoL improved on both treatments (about equally on two general QOL scales), but omeprazole relieved gastrointestinal symptoms more than misoprostol, particularly reflux, abdominal pain and indigestion symptoms. During maintenance, both treatments maintained QoL, but misoprostol induced diarrhoea. CONCLUSION: QoL in arthritis patients on chronic NSAID treatment is destroyed. Omeprazole is superior to misoprostol for relief and prevention of NSAID-associated gastrointestinal symptoms allowing continued NSAID treatment without compromising the patients' QoL.     

A bioluminescence method for the mapping of local ATP concentrations within the arterial wall, with potential to assess the in vivo situation

According to the anoxemia theory of atherosclerosis, an imbalance between the demand for and supply of oxygen and nutrients in the arterial wall is a key factor in atherogenesis. However, the energy metabolic state of the arterial tissue in vivo is largely unknown. We applied a bioluminescence method, metabolic imaging, to study local ATP concentrations in cryosections of normal pig and atherosclerotic and normal rabbit aorta. Some vessels were subjected to energy metabolic restrictions by incubation at different oxygen and glucose concentrations and others were rapidly frozen in liquid nitrogen to reflect the in vivo situation. Local ATP concentrations and the ATP distribution at a microscale was dependent on oxygen as well as glucose concentrations during incubation. ATP depletion was seen in the mid media of pig aorta in all incubations, but only at low oxygen concentration without glucose in the media of the thinner rabbit aorta. ATP-depleted zones were seen deep in pig media (>750 microm from the lumen) and in rabbit plaques (>300 micrometer+ from the lumen) even at high oxygen (pig 75% O2 and rabbit 21% O2) and glucose concentrations (5.6 mmol/L glucose). This observation probably illustrates an insufficient diffusion of glucose, which highlights the importance of studying the conditions for diffusion not only of oxygen but also of other metabolites in the arterial wall. In rapidly frozen vessels the medial ATP concentration was shown to be 0.6 to 0.8 micromol/g wet weight (both pig and rabbit aorta) and in pig aorta a gradient could be seen indicating higher ATP concentrations at the lumenal side. We propose that metabolic imaging, as applied to snap-frozen tissue, may be used to assess the energy metabolic situation in the arterial wall in vivo. The spatial resolution allows the detection of local variations within the arterial tree. However, steep concentration gradients (eg, near the border of the tissue) will be underestimated. The method may be extended to include determinations of glucose and lactate concentrations and will be used in parallel with an established method to assess hypoxia in the arterial wall in vivo.     

Quality of life in patients with endoscopy-negative heartburn: reliability and sensitivity of disease-specific instruments

OBJECTIVES: Endoscopy-negative gastroesophageal reflux disease (GERD) lacks objective markers of disease severity. Evaluation of therapies for GERD must therefore rely on subjective measures, including patient self-report questionnaires, to measure the clinical effectiveness of therapeutic interventions. We aimed to evaluate the previously validated Gastrointestinal Symptoms Rating Scale (GSRS) and the Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaires for reliability and responsiveness to change over time. METHODS: Patients (n = 1143) with heartburn, but no esophagitis included in a randomized clinical trial assessing the effectiveness of active treatment with proton pump inhibitors over 4 wk were evaluated. RESULTS: The test-retest reliability of both questionnaires over time was good to excellent (GSRS 0.53-0.69; QOLRAD 0.65-0.76), as was the responsiveness estimated by standardized response means (GSRS reflux dimension, -1.43; QOLRAD 0.81-1.43) and effect sizes (GRSR reflux dimension, -1.74; QOLRAD 0.82-1.56). The relationship between improvement in the GSRS reflux dimension score and the amount of clinical benefit as estimated by the patients themselves (based on the Overall Treatment Evaluation) suggested a minimally clinical relevant change is 0.5 on the seven graded scales applied. The importance rating indicated that an important change in the GSRS reflux dimension and the QOLRAD dimensions is equivalent to 1.0, and a very important change to 1.5. CONCLUSIONS: The GSRS and QOLRAD are valid questionnaires that are reliable and sensitive to change. Both questionnaires should be suitable for use in clinical trials of therapeutic interventions for patients with heartburn.