Effect of physical exercise on lipoprotein(a) and low-density lipoprotein modifications in type 1 and type 2 diabetic patients

The Role of Exercise on Cardiometabolic Profile and Body Composition in Youth with Type 1 Diabetes

Exercise has a direct positive effect on glycemic control by promoting insulin secretion from β-pancreatic islet-cells and by increasing skeletal muscle glucose uptake. The reduction in daily insulin needs and the optimization of glycemic control improves the patient's quality of life, self-esteem, mental wellness, as well as diabetes-related mobility and mortality. The aim of this study was to investigate the effect of physical activity in children and adolescents with type-1 diabetes (T1D) on diabetic control, cardiovascular, and biochemical profiles; hs-CRP; IL6; leptin; and adiponectin levels of the population under study. This is a prospective cross-sectional study that involved 80 participants (36 boys and 44 girls) with T1D, who were aged 6-21 years and who attended the Diabetes and Metabolism Clinic of the 2nd Pediatric Department, University of Athens, "P & A Kyriakou" Children's Hospital of Athens. Twenty (25%) children were above the 75th percentile regarding total levels of physical activity, while 40 (50%) and 20 (25%) were between the 25th and 75th percentile, as well as below the 25th percentile, respectively. In the group with an intermediate level of exercise, physical activity was negatively associated with the participant's family situation (traditional, single parent, grandparent, with others, or by himself/herself) (p = 0.013), ferritin (p = 0.031), lipoprotein(a) [Lp(a)] (p = 0.016), and squared leptin levels (p = 0.040). Whereas in the groups with extreme vs. no exercise there was a negative association with the number of daily glucose measurements (p = 0.047). However, in the group with non-vigorous exercise, physical activity was positively associated with high density lipoprotein-c (HDL-c) levels (p = 0.048). The findings of this study are indicative of the beneficial role of exercise on children and adolescents with T1D, which is achieved by primarily improving their cardiometabolic profile through the amelioration of lipid profile [HDL-c, Lp(a)] and leptin levels, as well as by reducing chronic systemic inflammatory response (ferritin) and ultimately decreasing the overall diabetes morbidity.

Association of HbA1c with VO2max in Individuals with Type 1 Diabetes: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to evaluate the association between glycemic control (HbA1c) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until July 2020. Randomized and observational controlled trials with a minimum number of three participants were included if cardio-pulmonary exercise tests to determine VO2max and HbA1c measurement has been performed. Pooled mean values were estimated for VO2max and HbA1c and weighted Pearson correlation and meta-regression were performed to assess the association between these parameters. We included 187 studies with a total of 3278 individuals with T1DM. The pooled mean HbA1c value was 8.1% (95%CI; 7.9−8.3%), and relative VO2max was 38.5 mL/min/kg (37.3−39.6). The pooled mean VO2max was significantly lower (36.9 vs. 40.7, p = 0.001) in studies reporting a mean HbA1c > 7.5% compared to studies with a mean HbA1c ≤ 7.5%. Weighted Pearson correlation coefficient was r = −0.19 (p < 0.001) between VO2max and HbA1c. Meta-regression adjusted for age and sex showed a significant decrease of −0.94 mL/min/kg in VO2max per HbA1c increase of 1% (p = 0.024). In conclusion, we were able to determine a statistically significant correlation between HbA1c and VO2max in individuals with T1DM. However, as the correlation was only weak, the association of HbA1c and VO2max might not be of clinical relevance in individuals with T1DM.

Physical activity to reduce PCSK9 levels

The amount of physical activity (PA) people practice everyday has been reducing in the last decades. Sedentary subjects tend to have an impaired lipid plasma profile with a higher risk of atherosclerosis and related cardio- and cerebrovascular events. Regular PA helps in both primary and secondary cardiovascular prevention because of its beneficial effect on the whole metabolism. Several studies reported lower levels of plasma lipids in trained subjects, but the precise mechanisms by which PA modulates lipoproteins remain only partially described. Thereupon, proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serin protease whose main function is to reduce the amount of low-density lipoprotein cholesterol (LDL-C) receptors, with the direct consequence of reducing LDL-C uptake by the liver and increasing its circulating pool. Accordingly, recently developed PCSK9 inhibitors improved cardiovascular prevention and are increasingly used to reach LDL-C goals in patients at high CV risk. Whether PA can modulate the levels of PCSK9 remains partially explored. Recent studies suggest PA as a negative modulator of such a deleterious CV mediator. Yet the level of evidence is limited. The aim of this review is to summarize the recent reports concerning the regulatory role of PA on PCSK9 plasma levels, highlighting the beneficial role of regular exercise on the prevention of atherosclerosis and overall CV health.

Non-genetic influences on lipoprotein(a) concentrations

An elevated level of lipoprotein(a) [Lp(a)] is a genetically regulated, independent, causal risk factor for cardiovascular disease. However, the extensive variability in Lp(a) levels between individuals and population groups cannot be fully explained by genetic factors, emphasizing a potential role for non-genetic factors. In this review, we provide an overview of current evidence on non-genetic factors influencing Lp(a) levels with a particular focus on diet, physical activity, hormones and certain pathological conditions. Findings from randomized controlled clinical trials show that diets lower in saturated fats modestly influence Lp(a) levels and often in the opposing direction to LDL cholesterol. Results from studies on physical activity/exercise have been inconsistent, ranging from no to minimal or moderate change in Lp(a) levels, potentially modulated by age and the type, intensity, and duration of exercise modality. Hormone replacement therapy (HRT) in postmenopausal women lowers Lp(a) levels with oral being more effective than transdermal estradiol; the type of HRT, dose of estrogen and addition of progestogen do not modify the Lp(a)-lowering effect of HRT. Kidney diseases result in marked elevations in Lp(a) levels, albeit dependent on disease stages, dialysis modalities and apolipoprotein(a) phenotypes. In contrast, Lp(a) levels are reduced in liver diseases in parallel with the disease progression, although population studies have yielded conflicting results on the associations between Lp(a) levels and nonalcoholic fatty liver disease. Overall, current evidence supports a role for diet, hormones and related conditions, and liver and kidney diseases in modifying Lp(a) levels.

Protective effects of physical activity against health risks associated with type 1 diabetes: "Health benefits outweigh the risks"

The magnitude of diabetes mellitus (DM) has increased in recent decades, where the number of cases and the proportion of the disease have been gradually increasing over the past few decades. The chronic complications of DM affect many organ systems and account for the majority of morbidity and mortality associated with the disease. The prevalence of type 1 DM (T1DM) is increasing globally, and it has a very significant burden on countries and at an individual level. T1DM is a chronic illness that requires ongoing medical care and patient self-management to prevent complications. This study aims to discuss the health benefits of physical activity (PA) in T1DM patients. The present review article was performed following a comprehensive literature search. The search was conducted using the following electronic databases: "Cochrane Library", Web of Science, PubMed, HINARI, EMBASE, Google for grey literature, Scopus, African journals Online, and Google Scholar for articles published up to June 21, 2021. The present review focused on the effects of PA on many outcomes such as blood glucose (BG) control, physical fitness, endothelial function, insulin sensitivity, well-being, the body defense system, blood lipid profile, insulin resistance, cardiovascular diseases (CVDs), insulin requirements, blood pressure (BP), and mortality. It was found that many studies recommended the use of PA for the effective management of T1DM. PA is a component of comprehensive lifestyle modifications, which is a significant approach for the management of T1DM. It provides several health benefits, such as improving BG control, physical fitness, endothelial function, insulin sensitivity, well-being, and the body defense system. Besides this, it reduces the blood lipid profile, insulin resistance, CVDs, insulin requirements, BP, and mortality. Overall, PA has significant and essential protective effects against the health risks associated with T1DM. Even though PA has several health benefits for patients with T1DM, these patients are not well engaged in PA due to barriers such as a fear of exercise-induced hypoglycemia in particular. However, several effective strategies have been identified to control exercise-induced hypoglycemia in these patients. Finally, the present review concludes that PA should be recommended for the management of patients with T1DM due to its significant health benefits and protective effects against associated health risks. It also provides suggestions for the future direction of research in this field.

Autoimmune Rheumatic Diseases: An Update on the Role of Atherogenic Electronegative LDL and Potential Therapeutic Strategies

Atherosclerosis has been linked with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Autoimmune rheumatic diseases (AIRDs) are associated with accelerated atherosclerosis and ASCVD. However, the mechanisms underlying the high ASCVD burden in patients with AIRDs cannot be explained only by conventional risk factors despite disease-specific factors and chronic inflammation. Nevertheless, the normal levels of plasma low-density lipoprotein (LDL) cholesterol observed in most patients with AIRDs do not exclude the possibility of increased LDL atherogenicity. By using anion-exchange chromatography, human LDL can be divided into five increasingly electronegative subfractions, L1 to L5, or into electropositive and electronegative counterparts, LDL (+) and LDL (-). Electronegative L5 and LDL (-) have similar chemical compositions and can induce adverse inflammatory reactions in vascular cells. Notably, the percentage of L5 or LDL (-) in total LDL is increased in normolipidemic patients with AIRDs. Electronegative L5 and LDL (-) are not recognized by the normal LDL receptor but instead signal through the lectin-like oxidized LDL receptor 1 (LOX-1) to activate inflammasomes involving interleukin 1β (IL-1β). Here, we describe the detailed mechanisms of AIRD-related ASCVD mediated by L5 or LDL (-) and discuss the potential targeting of LOX-1 or IL-1β signaling as new therapeutic modalities for these diseases.

The effect of prolonged intense physical exercise of special forces volunteers on their plasma protein denaturation profile examined by differential scanning calorimetry

The human blood plasma proteome profile has been an area of intensive investigation and differential scanning calorimetry (DSC) has come forward as a novel tool in analyzing plasma heat capacity changes to monitor various physiological responses in health and disease. This study used DSC to assess potential alterations in the plasma heat capacity profile of albumin and globulins during extremely demanding physical exercise. We monitored the changes in denaturation profiles of those plasma proteins for five consecutive days of an extraordinary exercise training schedule in 14 young male Special Forces volunteers, as well as after a 30-day recovery period. The major effect of the prolonged intense exercise was the continuous upward shift of the albumin peak by 2°-3 °C on the initial days of exercise, with a tendency to plateau circa the 5th day of exercise. In addition, some redistribution of the denaturational enthalpy was observed upon exercise, where the globulins peak increased relative to the albumin peak. Noteworthy, the alterations in the plasma proteome denaturational profiles were not persistent, as virtually full recovery of the initial status was observed after 30 days of recovery. Our findings indicate that 5 days of exhaustive physical exercise of highly trained individuals enhanced the thermal stability of plasma albumin shifting its denaturational transition to higher temperatures. We surmise that these effects may be a result of increased blood oxygenation during the prolonged intense exercise and, consequently, of albumin oxidation as part of the overall adaptation mechanisms of the body to extreme physical and/or oxidative stress.

Laboratory medicine: health evaluation in elite athletes

The need to evaluate the health status of an athlete represents a crucial aim in preventive and protective sports science in order to identify the best diagnostic strategy to improve performance and reduce risks related to physical exercise. In the present review we aim to define the main biochemical and haematological markers that vary significantly during and after sports training to identify risk factors, at competitive and professional levels and to highlight the set up of a specific parameter's panel for elite athletes. Moreover, we also intend to consider additional biomarkers, still under investigation, which could further contribute to laboratory sports medicine and provide reliable data that can be used by athlete's competent staff in order to establish personal attitudes and prevent sports injuries.

Association between Negatively Charged Low-Density Lipoprotein L5 and Subclinical Atherosclerosis in Rheumatoid Arthritis Patients

L5, the most negatively charged subfraction of low-density lipoprotein (LDL), is implicated in atherogenesis. We examined the relationship between plasma L5 levels and the occurrence of subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Using anion-exchange purification with fast-protein liquid chromatography, we determined the proportion of plasma L5 of LDL (L5%) in 64 RA patients and 12 healthy controls (HC). Plasma L5% and L5 levels were significantly higher in RA patients (median, 1.4% and 1.92 mg/dL) compared with HC (0.9%, p < 0.005; and 1.27 mg/dL, p < 0.05) and further increased in patients with subclinical atherosclerosis (2.0% and 2.88 mg/dL). L5% and L5 levels decreased in patients after 6-months of therapy (p < 0.01). Subclinical atherosclerosis was indicated by plaque and intima-media thickness determined by carotid ultrasonography. Using multivariate analysis, L5% and L5 levels are revealed as the predictors of subclinical atherosclerosis (odds ratio, 4.94 and 1.01; both p < 0.05). Receiver operating characteristic curves showed that cut-off values of L5% ≥ 1.45% and L5 levels ≥ 2.58 mg/dL could predict subclinical atherosclerosis in patients (both p < 0.001). Immunoblotting showed that the expression levels of lectin-like oxidized LDL receptor-1 (LOX-1) was increased in RA patients. Together, our findings suggest that plasma L5% and L5 levels may be predictors of cardiovascular risk in RA patients.

One-year unsupervised individualized exercise training intervention enhances cardiorespiratory fitness but not muscle deoxygenation or glycemic control in adults with type 1 diabetes

Adaptations to long-term exercise training in type 1 diabetes are sparsely studied. We examined the effects of a 1-year individualized training intervention on cardiorespiratory fitness, exercise-induced active muscle deoxygenation, and glycemic control in adults with and without type 1 diabetes. Eight men with type 1 diabetes (T1D) and 8 healthy men (CON) matched for age, anthropometry, and peak pulmonary O₂ uptake, completed a 1-year individualized training intervention in an unsupervised real-world setting. Before and after the intervention, the subjects performed a maximal incremental cycling test, during which alveolar gas exchange (volume turbine and mass spectrometry) and relative concentration changes in active leg muscle deoxygenated (Δ[HHb]) and total (Δ[tHb]) hemoglobin (near-infrared spectroscopy) were monitored. Peak O₂ pulse, reflecting peak stroke volume, was calculated (peak pulmonary O₂ uptake/peak heart rate). Glycemic control (glycosylated hemoglobin A_1c (HbA_1c)) was evaluated. Both T1D and CON averagely performed 1 resistance-training and 3-4 endurance-training sessions per week (∼1 h/session at ∼moderate intensity). Training increased peak pulmonary O₂ uptake in T1D (p = 0.004) and CON (p = 0.045) (group × time p = 0.677). Peak O₂ pulse also rose in T1D (p = 0.032) and CON (p = 0.018) (group × time p = 0.880). Training increased leg Δ[HHb] at peak exercise in CON (p = 0.039) but not in T1D (group × time p = 0.052), while no changes in leg Δ[tHb] at any work rate were observed in either group (p > 0.05). HbA_1c retained unchanged in T1D (from 58 ± 10 to 59 ± 11 mmol/mol, p = 0.609). In conclusion, 1-year adherence to exercise training enhanced cardiorespiratory fitness similarly in T1D and CON but had no effect on active muscle deoxygenation or glycemic control in T1D.

Effects of prolonged exercise versus multiple short exercise sessions on risk for metabolic syndrome and the atherogenic index in middle-aged obese women: a randomised controlled trial

BACKGROUND

Many people, although they may recognise the positive effects of exercise, do not exercise regularly owing to lack of time. This study aimed to investigate the effects of prolonged single-session exercise and multiple short sessions of exercise on the risk of metabolic syndrome and the atherogenic index in middle-aged obese women.

METHODS

Thirty-six participants were divided into the single-session group, multiple-session group, and control group. The single-session group engaged in one session of treadmill exercise for 30 min a day; the multiple-session group had three sessions of 10 min a day. Both groups exercised 3 days/week for 12 weeks. The control group did not perform any exercise.

RESULTS

The single-session group showed decreases in weight (0.97 kg [95% C.I. = 0.09-1.83], p < .05), body mass index (0.43 kg/m2 [95% C.I. = 0.03-0.81], p < .05), and fat mass (1.65 kg, [95% C.I. = 0.78-2.51], p < .01). Systolic blood pressure dropped in the single-session group (6.66 mmHg, [95% C.I. = 1.44-11.88], p < .05), and diastolic blood pressure dropped in the multiple-session group (3.38 mmHg, [95% C.I. = 1.44-5.88], p < .01). High-density lipoprotein cholesterol rose in the single-session group (4.08 mg/dL, [95% C.I. = -8.08-(-)0.07], p < .05) and dropped in the control group (10.75 mg/dL [95% C.I. = 1.95-19.54], p < .01). According to post hoc analysis, high-density lipoprotein cholesterol increased more in the single-session group than the control group (95% C.I. = 0.61-21.88, p < .05). Glucose levels decreased in both the single-session group (16 mg/dL [95% C.I. = 5.64-26.35], p < .01) and the multiple-session group (12.16 mg/dL, [95% C.I. = 2.18-22.14], p < .05). Waist circumference decreased in the single-session group (2.65 cm [95% C.I. = 1.46-3.83], p < .001) and multiple-session group (2.04 cm, [95% C.I. = 1.51-2.73], p < .001). Low-density lipoprotein cholesterol levels rose in both the multiple-session group (-15.79 mg/dL [95% C.I. = -34.24-(-)3.78], p < .05) and the control group (-22.94 mg/dL [95% C.I. = -44.63-(-)1.24], p < .05). The atherogenic index increased in the control group (-1.06 [95% C.I. = -1.69-(-)0.41], p < .01).

CONCLUSIONS

The findings indicate that prolonged exercise is superior to multiple short sessions for improving the risk of metabolic syndrome and the atherogenic index in middle-aged obese women. However, multiple short sessions can be recommended as an alternative to prolonged exercise when the goal is to decrease blood glucose or waist circumference.

Improving Assessment of Lipoprotein Profile in Type 1 Diabetes by 1H NMR Spectroscopy

Patients with type 1 diabetes (T1D) present increased risk of cardiovascular disease (CVD). The aim of this study is to improve the assessment of lipoprotein profile in patients with T1D by using a robust developed method 1H nuclear magnetic resonance spectroscopy (1H NMR), for further correlation with clinical factors associated to CVD. Thirty patients with T1D and 30 non-diabetes control (CT) subjects, matched for gender, age, body composition (DXA, BMI, waist/hip ratio), regular physical activity levels and cardiorespiratory capacity (VO_2peak), were analyzed. Dietary records and routine lipids were assessed. Serum lipoprotein particle subfractions, particle sizes, and cholesterol and triglycerides subfractions were analyzed by 1H NMR. It was evidenced that subjects with T1D presented lower concentrations of small LDL cholesterol, medium VLDL particles, large VLDL triglycerides, and total triglycerides as compared to CT subjects. Women with T1D presented a positive association with HDL size (p<0.005; R = 0.601) and large HDL triglycerides (p<0.005; R = 0.534) and negative (p<0.005; R = -0.586) to small HDL triglycerides. Body fat composition represented an important factor independently of normal BMI, with large LDL particles presenting a positive correlation to total body fat (p<0.005; R = 0.505), and total LDL cholesterol and small LDL cholesterol a positive correlation (p<0.005; R = 0.502 and R = 0.552, respectively) to abdominal fat in T1D subjects; meanwhile, in CT subjects, body fat composition was mainly associated to HDL subclasses. VO_2peak was negatively associated (p<0.005; R = -0.520) to large LDL-particles only in the group of patients with T1D. In conclusion, patients with T1D with adequate glycemic control and BMI and without chronic complications presented a more favourable lipoprotein profile as compared to control counterparts. In addition, slight alterations in BMI and/or body fat composition showed to be relevant to provoking alterations in lipoproteins profiles. Finally, body fat composition appears to be a determinant for cardioprotector lipoprotein profile.

Impact of Physical Activity on Glycemic Control and Prevalence of Cardiovascular Risk Factors in Adults With Type 1 Diabetes: A Cross-sectional Multicenter Study of 18,028 Patients

OBJECTIVE

Physical activity (PA) can improve cardiovascular risk in the general population and in patients with type 2 diabetes. Studies also indicate an HbA(1c)-lowering effect in patients with type 2 diabetes. Since reports in patients with type 1 diabetes are scarce, this analysis aimed to investigate whether there is an association between PA and glycemic control or cardiovascular risk in subjects with type 1 diabetes.

RESEARCH DESIGN AND METHODS

A total of 18,028 adults (≥18 to <80 years of age) from Germany and Austria with type 1 diabetes from the Diabetes-Patienten-Verlaufsdokumentation (DPV) database were included. Patients were stratified according to their self-reported frequency of PA (PA0, inactive; PA1, one to two times per week; PA2, more than two times per week). Multivariable regression models were applied for glycemic control, diabetes-related comorbidities, and cardiovascular risk factors. Data were adjusted for sex, age, and diabetes duration. P values for trend were given. SAS 9.4 was used for statistical analysis.

RESULTS

An inverse association between PA and HbA(1c), diabetic ketoacidosis, BMI, dyslipidemia (all P < 0.0001), and hypertension (P = 0.0150), as well as between PA and retinopathy or microalbuminuria (both P < 0.0001), was present. Severe hypoglycemia (assistance required) did not differ in PA groups (P = 0.8989), whereas severe hypoglycemia with coma was inversely associated with PA (P < 0.0001).

CONCLUSIONS

PA seemed to be beneficial with respect to glycemic control, diabetes-related comorbidities, and cardiovascular risk factors without an increase of adverse events. Hence, our data underscore the recommendation for subjects with type 1 diabetes to perform regular PA.

Associations of Low-Intensity Resistance Training with Body Composition and Lipid Profile in Obese Patients with Type 2 Diabetes

Resistance training to increase muscle mass and functional capacity is an integral part of diet and exercise programs for the management of obesity and type 2 diabetes. Low-intensity resistance training with slow movement and tonic force generation (LST) may be a practical and safe regimen for elderly obese individuals but the health benefits are uncertain. This study investigated the effects of LST on body composition and metabolic parameters in obese patients with type 2 diabetes. Twenty-six obese patients with type 2 diabetes engaged in LST training during hospitalization and were advised to maintain this regimen for 12 weeks after discharge. We compared lipid profile, arterial stiffness, and body composition before and after LST training. After 12 weeks of LST training, the ratio of lower extremity muscle mass to body weight increased significantly (0.176 ± 0.028 to 0.184 ± 0.023, mean ± SD), while body fat mass and body fat percentage decreased significantly (36.2 ± 10.9 kg to 34.3 ± 9.4 kg and 41.2 ± 8.6% to 40.1 ± 7.7%, respectively). Moreover, high-density lipoprotein cholesterol was significantly increased (42.2 ± 14 mg/dl to 46.3 ± 12.4 mg/dl) and both free fatty acids and lipoprotein(a) were decreased (665.2 ± 212.1 μEq/l to 525.4 ± 231.3 μEq/l and 15.4 ± 18 mg/dl to 13.8 ± 18 mg/dl, respectively). No significant change was observed in arterial stiffness. Although this study was a non-controlled investigation and some confounding factors including dietary intake, medication and compliance with training might affect the study result, a brief (12-week) LST training program may be a safe and effective strategy for the management of obesity and type 2 diabetes.

Lifestyle and cardiometabolic risk in adults with type 1 diabetes: a review

Over the past decades, there has been a major upward shift in the prevalence of cardiometabolic risk (CMR) factors (central obesity, insulin resistance, hypertension and dyslipidemia) in patients with type 1 diabetes, which could have either an additive or a synergistic effect on risk for cardiovascular disease. These metabolic changes are occurring in parallel to the worldwide obesity epidemic and the widespread use of intensive insulin therapy. Poor lifestyle habits (poor diet quality, sedentary behaviours and smoking) are known to be driving factors for increased CMR factors in the general population. The objective of this review is to explore the lifestyle habits of adults with type 1 diabetes and its potential association with CMR factors. Evidence suggests that adherence to dietary guidelines is low in subjects with type 1 diabetes with a high prevalence of patients consuming an atherogenic diet. Sedentary habits are also more prevalent than in the general population, possibly because of the additional contribution of exercise-induced hypoglycemic fear. Moreover, the prevalence of smokers is still significant in the population with type 1 diabetes. All of these behaviours could trigger a cascade of metabolic anomalies that may contribute to increased CMR factors in patients with type 1 diabetes. The intensification of insulin treatment leading to new daily challenges (e.g. carbohydrates counting, increase of hypoglycemia) could contribute to the adoption of poor lifestyle habits. Preventive measures, such as identification of patients at high risk and promotion of lifestyle changes, should be encouraged. The most appropriate therapeutic measures remain to be established.

Daily energy expenditure, cardiorespiratory fitness and glycaemic control in people with type 1 diabetes

Objective

Encouraging daily physical activity improves cardiorespiratory fitness and many cardiovascular risk factors. However, increasing physical activity often creates a challenge for people with type 1 diabetes, because of difficulties maintaining euglycemia in the face of altered food intake and adjustments to insulin doses. Our aim was to examine the triangular relationship between glucose control measured by continuous glucose monitoring system (CGMS), objective measures of total daily energy expenditure (TEE) recorded by a multi-sensory monitoring device, and cardiorespiratory fitness (CRF), in free-living subjects with type 1 diabetes.

Research Design and Methods

Twenty-three individuals (12 women) with type 1 diabetes who were free from micro- and macrovascular complications were recruited. TEE and glucose control were monitored simultaneously for up to 12 days, using a multi-sensory device and CGMS respectively. CRF was recorded as V02 max from a maximal treadmill test with the Bruce protocol.

Results

Subjects (mean±SD) were aged 37±11 years, with BMI = 26.5±5.1 kg.m⁻², HbA_1c = 7.7±1.3% (61±14 mmol/mol) and V02 max (ml.min⁻¹.kg⁻¹)  = 39.9±8.4 (range 22.4 – 58.6). TEE (36.3±5.5 kcal.kg⁻¹.day⁻¹) was strongly associated with CRF(39.9±8.4 ml.min⁻¹.kg⁻¹) independently of sex (r = 0.63, p<0.01). However, neither TEE (r = −0.20, p = 0.36) nor CRF (r = −0.20, p = 0.39; adjusted for sex), were significantly associated with mean glycaemia measured by CGMS.

Conclusion

Higher levels of energy expenditure (due to a more active lifestyle) are associated with increased cardiorespiratory fitness, but not necessarily better glycaemic control. Since increased levels of energy expenditure and good glycaemic control are both needed to protect against diabetes-related complications our data suggest they need to be achieved independently.

Influence of lifestyle on the course of type 1 diabetes mellitus

Type 1 diabetes (T1DM) is an autoimmune disease that requires insulin treatment from the time of diagnosis. Its clinical course depends on both genetic and environmental factors, and the lifestyle of a patient modulates their interaction. The evidence about the influence of lifestyle on the course of T1DM is increasing. In this paper, we present evidence on the relationship between lifestyle parameters and diabetes-related outcomes. We discuss the most commonly addressed factors associated with lifestyle, such as physical activity, nutrition and smoking, and those with sparse evidence in T1DM, such as socioeconomic status, sleep duration, psychological stress and illicit drugs intake.

Flaxseed reverses atherosclerotic lesion formation and lowers lipoprotein(a) in ovarian hormone deficiency

OBJECTIVE

The incidence of cardiovascular disease dramatically increases during menopause, and postmenopausal women seek natural alternatives to hormone therapy. Flaxseed can slow the progression of atherosclerotic lesion formation; however, it is not known whether it can reverse formation that has already occurred.

METHODS

Seventy-two female Golden Syrian hamsters were randomly divided into six groups (n = 12), sham-operated (sham) or ovariectomized (ovx), and kept on the same diet for 120 days to allow for atherosclerotic lesion development. After this 120-day period, whole flaxseed was introduced to the diets of hamsters in three of the groups: group 1 (sham + casein); group 2 (ovx + casein); group 3 (ovx + 7.5% flaxseed); group 4 (ovx + 15% flaxseed); group 5 (ovx + 22.5% flaxseed); and group 6 (ovx + 17β-estradiol). This diet was maintained for an additional 120 days. Lesion regression was examined histologically, and serum was analyzed for total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, Apo A, Apo B, and lipoprotein(a).

RESULTS

Results showed that 15% and 22.5% flaxseed, compared with ovx animals, significantly reduced lipoprotein(a) (4.4 mg/dL [ovx] vs 2.15 mg/dL [15% flaxseed] and 0.3 mg/dL [22.5% flaxseed]; P < 0.05) and Apo B (2.8 mg/dL [ovx] vs 2.4 mg/dL [15% flaxseed] and 2.5 mg/dL [22.5% flaxseed]). Flax reduced by 67% the number of animals with aortic arch lesions.

CONCLUSIONS

All three doses of flax reduce the severity of lesion formation compared with ovx controls. These results support the efficacy of flaxseed in reducing cardiovascular disease risk.

Benefits of continuous subcutaneous insulin infusion on quality of life

PURPOSE

The aim of this study was to compare the general health-related quality of life (HRQoL), the metabolic control (HbA1c), the anthropometric measurement, and the cardiorespiratory fitness (expressed by VO2max) in youths with type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) to those receiving multiple daily injections (MDI). We looked for factors influencing the HRQoL and metabolic control.

METHODS

A total of 239 patients treated with CSII (51 girls and 53 boys) or MDI (64 girls and 71 boys) between ages 8 and 18 years were assessed with the Pediatric Quality of Life Inventory, Generic Core Scales, and Diabetes Module. VO2max was evaluated using the 20-meter shuttle run test.

RESULTS

CSII group had significantly better HRQoL according to both child self-report and parent proxy-report. Youths with CSII reported better physical, emotional, and school-related functioning, and had less diabetes-related fear and symptoms than the MDI group. There were no significant differences in body mass index z-scores, insulin doses, HbA1c, and VO2max between the groups. HRQoL was predicted by the CSII therapy (β = -0.220; p = .000) and the VO2max (β = 0.386; p = .000), other clinical and anthropometric parameters had no effect; the HbA1c was predicted only by VO2max (β = -0.353; p = .000).

CONCLUSIONS

Diabetic youths treated with CSII therapy have better HRQoL than those treated with MDI. There are no differences between the investigated groups in anthropometric data, glycated hemoglobin, and physical fitness. Moreover, good physical fitness has an important role in achieving better metabolic control and HRQoL, which underlines the importance of regular aerobic exercise in the treatment and care of type 1 diabetes in childhood.

The effects of resistance training on ApoB/ApoA-I ratio, Lp(a) and inflammatory markers in patients with type 2 diabetes

The purpose of this study was to investigate the effects of resistance training (RT) on novel cardiovascular risk factors in patients with type 2 diabetes mellitus (T2DM). We enrolled 52 overweight/obese, type 2 diabetic patients, with inadequate glycemic control (HbA1c > 6.5 %), but without overt diabetic vascular complications. Participants were randomly assigned into two equivalent groups (n = 26): (1) Resistance exercise group: subjects underwent a supervised RT program (3-times/week, 60 min/session, 2-3 sets of 8 machine-weight exercises, 60-80 % of one-repetition maximum). (2) Control group (CG): at study entrance, they received a structured exercise counseling to increase daily physical activity. Clinical parameters, cardiorespiratory capacity, glycemic and lipid profile, apolipoprotein A-I (ApoA-I), apolipoprotein B (ApoB), Lipoprotein(a) [Lp(a)], insulin resistance (HOMA-IR), high-sensitivity CRP (hsCRP), fibrinogen were measured before and after 3 months. RT significantly reduced glycemic indexes, insulin resistance and systolic blood pressure, compared to CG (p < 0.05). Moreover, exercise-treated patients conferred a remarkable downregulation in ApoB levels (from 135.92 ± 30.97 mg/dL to 85.9 ± 26.46 mg/dL, p < 0.001) as compared to CG (from 126.33 ± 36.59 mg/dL to 116.23 ± 27.52 mg/dL, p = 0.872) (p < 0.001). Similarly, ApoB/ApoA-I ratio was considerably decreased in REG rather than CG (-0.32 ± 0.09 vs 0.02 ± 0.01, p < 0.001). Notably, ApoA-I, Lp(a), hsCRP, fibrinogen, the rest of lipid parameters, body weight and exercise capacity remained unaltered in both groups (p > 0.05). Among variables, HOMA-IR reduction was found to be an independent predictor of changes in ApoB/ApoA-I ratio (R (2) = 0.406, p = 0.041) in REG. Long-term RT ameliorated glycemic control, insulin sensitivity and ApoB/ApoA-I ratio in individuals with T2DM. Although we did not observe significant benefits in the rest of cardiovascular risk factors, our results indicate a merely beneficial impact of RT.

What are the health benefits of physical activity in type 1 diabetes mellitus? A literature review

Physical activity improves well-being and reduces the risk of heart disease, cancer and type 2 diabetes mellitus in the general population. In individuals with established type 2 diabetes, physical activity improves glucose and lipid levels, reduces weight and improves insulin resistance. In type 1 diabetes mellitus, however, the benefits of physical activity are less clear. There is poor evidence for a beneficial effect of physical activity on glycaemic control and microvascular complications, and significant risk of harm through hypoglycaemia. Here we review the literature relating to physical activity and health in type 1 diabetes. We examine its effect on a number of outcomes, including glycaemic control, lipids, blood pressure, diabetic complications, well-being and overall mortality. We conclude that whilst there is sufficient evidence to recommend physical activity in the management of type 1 diabetes, it is still unclear as to what form, duration and intensity should be recommended and whether there is benefit for many of the outcomes examined.

Is exercise a therapeutic tool for improvement of cardiovascular risk factors in adolescents with type 1 diabetes mellitus? A randomised controlled trial

BACKGROUND

Type 1 diabetes mellitus (T1DM) is associated with a high risk for early atherosclerotic complications especially risk of coronary heart disease.

OBJECTIVE

To evaluate the impact of six months exercise prgram on glycemic control, plasma lipids values, blood pressure, severity and frequency of hypoglycemia, anthropometric measurements and insulin dose in a sample of adolescents with T1DM.

RESEARCH DESIGN AND METHODS

A total of 196 type 1 diabetic patients participated in the study. They were classified into three groups: Group (A) did not join the exercise program(n = 48), group (B) attended the exercise sessions once/week (n = 75), group (C) attended the exercise sessions three times/week (n = 73). Studied parameters were evaluated before and six months after exercise programe.

RESULTS

Exercise improved glycemic control by reducing HbA1c values in exercise groups (P = 0.03, P = 0.01 respectively) and no change in those who were not physically active (P = 0.2). Higher levels of HbA1c were associated with higher levels of cholesterol, LDL-c, and triglycerides (P = 0.000 each). In both groups, B and C, frequent exercise improved dyslipidemia and reduced insulin requirements significantly (P = 0.00 both), as well as a reduction in BMI (P = 0.05, P = 0.00 respectively) and waist circumference(P = 0.02, P = 0.00 respectively). The frequency of hypoglycemic attacks were not statistically different between the control group and both intervention groups (4.7 +/- 3.56 and 4.82 +/- 4.23, P = 0.888 respectively). Reduction of blood pressure was statistically insignificant apart from the diastolic blood presure in group C (P = 0.04).

CONCLUSION

Exercise is an indispensable component in the medical treatment of patients with T1DM as it improves glycemic control and decreases cardiovascular risk factors among them.

A Model of Community-Based Behavioral Intervention for Depression in Diabetes: Program ACTIVE

Depression affects one in four people with diabetes and significantly affects diabetes health. Earlier studies of the treatment of depression have documented that cognitive behavioral therapy (CBT) and exercise have each been found to be effective in treating depression in people with and without diabetes in the context of medical settings. Individuals in rural areas lack regular access to medical centers and require treatment options that may be adapted for local communities. To date, no studies have combined CBT and exercise for people with diabetes. This article presents a translational behavioral depression intervention study designed for individuals with type 2 diabetes in a rural Appalachian region as a model of an interdisciplinary approach to the treatment of depression in diabetes.

An elevated level of physical activity is associated with normal lipoprotein(a) levels in individuals from Maracaibo, Venezuela

Coronary artery disease is the main cause of death worldwide. Lipoprotein(a) [Lp(a)], is an independent risk factor for coronary artery disease in which concentrations are genetically regulated. Contradictory results have been published about physical activity influence on Lp(a) concentration. This research aimed to determine associations between different physical activity levels and Lp(a) concentration. A descriptive and cross-sectional study was made in 1340 randomly selected subjects (males = 598; females = 712) to whom a complete clinical history, the International Physical Activity Questionnaire, and Lp(a) level determination were made. Statistical analysis was carried out to assess qualitative variables relationship by chi2 and differences between means by one-way analysis of variance considering a P value <0.05 as statistically significant. Results are shown as absolute frequencies, percentages, and mean +/- standard deviation according to case. Physical activity levels were ordinal classified as follows: low activity with 24.3% (n = 318), moderate activity with 35.0% (n = 458), and high physical activity with 40.8% (n = 534). Lp(a) concentration in the studied sample was 26.28 +/- 12.64 (IC: 25.59-26.96) mg/dL. Lp(a) concentration according to low, moderate, and high physical activity levels were 29.22 +/- 13.74, 26.27 +/- 12.91, and 24.53 +/- 11.35 mg/dL, respectively, observing statistically significant differences between low and moderate level (P = 0.004) and low and high level (P < 0.001). A strong association (chi2 = 9.771; P = 0.002) was observed among a high physical activity level and a normal concentration of Lp(a) (less than 30 mg/dL). A lifestyle characterized by high physical activity is associated with normal Lp(a) levels.

Effect of 6-month supervised exercise on low-density lipoprotein apolipoprotein B kinetics in patients with type 2 diabetes mellitus

Although low-density lipoprotein (LDL) cholesterol is often normal in patients with type 2 diabetes mellitus, there is evidence for a reduced fractional catabolic rate and consequently an increased mean residence time (MRT), which can increase atherogenic risk. The dyslipidemia and insulin resistance of type 2 diabetes mellitus can be improved by aerobic exercise, but effects on LDL kinetics are unknown. The effect of 6-month supervised exercise on LDL apolipoprotein B kinetics was studied in a group of 17 patients with type 2 diabetes mellitus (mean age, 56.8 years; range, 38-68 years). Patients were randomized into a supervised group, who had a weekly training session, and an unsupervised group. LDL kinetics were measured with an infusion of 1-(13)C leucine at baseline in all groups and after 6 months of exercise in the patients. Eight body mass index-matched nondiabetic controls (mean age, 50.3 years; range, 40-67 years) were also studied at baseline only. At baseline, LDL MRT was significantly longer in the diabetic patients, whereas LDL production rate and fractional clearance rates were significantly lower than in controls. Percentage of glycated hemoglobin A(1c), body mass index, insulin sensitivity measured by the homeostasis model assessment, and very low-density lipoprotein triglyceride decreased (P < .02) in the supervised group, with no change in the unsupervised group. After 6 months, LDL cholesterol did not change in either the supervised or unsupervised group; but there was a significant change in LDL MRT between groups (P < .05) that correlated positively with very low-density lipoprotein triglyceride (r = 0.51, P < .04) and negatively with maximal oxygen uptake, a measure of fitness (r = -0.51, P = .035), in all patients. The LDL production and clearance rates did not change in either group. This study suggests that a supervised exercise program can reduce deleterious changes in LDL MRT.

Interventions for being active among individuals with diabetes: a systematic review of the literature

PURPOSE

The purpose of this systematic review is to assess and summarize evidence and gaps in the literature regarding the intervention for being active (exercise) among individuals with diabetes.

METHODS

Twelve electronic databases were searched. Publications eligible for inclusion specifically studied learning, behavioral, clinical, and humanistic outcomes for exercise interventions in adult patients with type 1 and type 2 diabetes.

RESULTS

Seven reviews (2 systematic reviews, 3 meta-analyses, 2 technical reviews) and 34 individual, nonreview studies (18 randomized controlled trials, 16 nonrandomized trials) met inclusion criteria. For type 2 diabetes, findings suggested that exercise had a positive effect on glycemic control and decreased cardiovascular risk, but the impact of exercise on behavioral and humanistic outcomes was unclear; long-term outcomes and adherence to exercise interventions is unknown because most studies were of short duration. The overall impact of varied types of exercise in type 1 diabetes was unclear, especially regarding glycemic control. Potential benefits of exercise in type 1 may include improved cardiovascular health.

CONCLUSION

The review did not identify specific successful intervention details because of the heterogeneity of studies, subjects, and research gaps. General findings suggest that physical activity is better than no exercise at all; intensive regimens, if tolerated by patients, achieved better clinical outcomes than less intensive regimens. Reviewed studies using structured exercise regimens exhibited a more significant impact on outcomes. Substantial gaps in the literature include studies measuring direct effects of exercise in the US minority populations most affected by type 2 diabetes and economic evaluations of exercise interventions. Interventions must be tailored to individual patient needs to succeed.

Electronegative LDL impairs vascular endothelial cell integrity in diabetes by disrupting fibroblast growth factor 2 (FGF2) autoregulation

OBJECTIVE

L5, a circulating electronegative LDL identified in patients with hypercholesterolemia or type 2 diabetes, induces endothelial cell (EC) apoptosis by suppressing fibroblast growth factor (FGF)2 expression. FGF2 plays a pivotal role in endothelial regeneration and compensatory arteriogenesis. It is likely that vasculopathy and poor collateralization in diabetes is a result of FGF2 dysregulation.

RESEARCH DESIGN AND METHODS

To investigate this mechanism, we isolated L5 from type 2 diabetic patients. In cultured bovine aortic ECs (BAECs), L5 inhibited FGF2 transcription and induced apoptosis. Because FGF2 stimulates the phosphatidylinositol 3-kinase (PI3K)-Akt pathway, we examined whether FGF2 transcription is regulated by Akt through a feedback mechanism.

RESULTS

Diabetic L5 reduced FGF2 release to the medium but enhanced caspase-3 activity, with resultant apoptosis. Inhibition of PI3K with wortmannin or suppression of Akt activation with dominant-negative Akt inhibited FGF2 expression. Transfection of BAECs with FGF2 antisense cDNA depleted endogenous FGF2 protein. In these cells, not only was Akt phosphorylation inhibited, but FGF2 transcription was also critically impaired. In contrast, transfecting BAECs with FGF2 sense cDNA augmented Akt phosphorylation. Treatment with constitutively active Akt enhanced FGF2 expression. Augmentation of either FGF2 transcription or Akt phosphorylation rendered BAECs resistant to L5.

CONCLUSIONS

These findings suggest that FGF2 is the primary initiator of its own expression, which is autoregulated through a novel FGF2-PI3K-Akt loop. Thus, by disrupting FGF2 autoregulation in vascular ECs, L5 may impair reendothelialization and collateralization in diabetes.

Efeitos fisiológicos do treinamento físico em pacientes portadores de diabetes tipo 1

Insulinoterapia, atividade física regular e planejamento alimentar, em conjunto, consistem na abordagem mais completa no tratamento de portadores de diabetes mellitus tipo 1 (DM1). Estudos clínicos e experimentais têm evidenciado os benefícios do treinamento físico em indivíduos com DM1, tais como melhora na sensibilidade à insulina, redução das doses de insulina e atenuação das disfunções autonômicas e cardiovasculares. Essa revisão aborda as adaptações fisiológicas ao treinamento físico no indivíduo com DM1 e discute as recomendações e prescrição de atividade física para esta população.

Early and persistent increase in serum lipoprotein (a) concentrations in epileptic children treated with carbamazepine and sodium valproate monotherapy

PURPOSE

The aim of this study was to investigate by a prospective, self-controlled method, whether treatment with carbamazepine (CBZ) and sodium valproate (VPA) monotherapy may alter serum lipoprotein (a) [Lp(a)] concentrations in epileptic children.

METHODS

Serum Lp(a) concentrations have been determined in 18 epileptic children before and at 6, 12 and 24 months of treatment with CBZ monotherapy and in 30 epileptic children before and at 6, 12 and 24 months of treatment with VPA monotherapy. Serum total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoproteins A-I and B concentrations and serum concentrations of biochemical markers of liver and renal function were also measured in the study participants.

RESULTS

Serum Lp(a) concentrations were significantly increased at 6, 12 and 24 months of CBZ and VPA monotherapy. There were no significant correlations between serum Lp(a) and serum lipids, lipoproteins, apolipoproteins, concentrations of biochemical markers of liver and renal function or antiepileptic-drugs concentrations.

CONCLUSIONS

Children who receive CBZ or VPA monotherapy may have significant and persistent increase in serum lipoprotein (a) concentrations, occuring early in the course of therapy. It may be useful to measure serum Lp(a) concentrations routinely in epileptic children taking these antiepileptic drugs, especially in those that are already at higher atherosclerotic risk.

Lipids and lipoprotein(a) concentrations in Tunisian type 2 diabetic patients; Relationship to glycemic control and coronary heart disease

The aim of this study was to evaluate plasma lipoprotein(a) [Lp(a)] concentrations in Tunisian patients with type 2 diabetes mellitus (DM), to correlate the values with other lipid parameters, and to examine the relationship to glycemic control and coronary heart disease (CHD). Diabetic patients with and without CHD (n=200) had significantly higher levels of Lp(a) (327.94+/-239.93 mg/l) and a greater proportion of elevated (>300 mg/l) Lp(a) concentrations (46%) compared with 100 healthy nondiabetic controls (269.83+/-225.6 mg/l, P<.01, and 26%, P<.01), while there were no statistically significant difference between diabetics without CHD (n=100) and controls. No significant association of Lp(a) with glycemic control (HbAlc or fasting blood glucose) was noted in diabetic patients. Positive correlations were observed between Lp(a) levels and total cholesterol and LDL-C in all diabetic patients and particularly in diabetic men. Male patients with CHD showed significantly higher plasma Lp(a) levels than those without CHD (P=.023), and 57.3% of patients with CHD showed increase (>300 mg/l) Lp(a) compared with 33.3% of patients without CHD. Elevated levels of Lp (a) and abnormal lipid profile in diabetic men suggest their involvement in atherogenesis and subsequent development of CHD.

Lipids and lipoprotein(a) concentrations in Pakistani patients with type 2 diabetes mellitus

AIM

The aim of the present study was to analyze serum lipoprotein(a) [Lp(a)] levels in Pakistani patients with type 2 diabetes mellitus (DM) and to find correlations between clinical characteristics and dyslipidaemias in these patients.

METHODS

Fasting blood samples were analyzed for Lp(a), total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), glucose and glycosylated haemoglobin (HbA1c) in 68 Pakistani patients with type 2 DM and 40 non-diabetic healthy control subjects.

RESULTS

Lp(a) levels were significantly raised in diabetics as compared to the control group. No correlation of Lp(a) was seen with age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting glucose. There was a positive correlation of BMI to SBP and DBP. There was a significant positive correlation between Lp(a) and total cholesterol and LDL-c. No correlation of Lp(a) was observed with HDL-c, triglycerides and glycosylated haemoglobin (HbA1c).

CONCLUSION

The present study led us to conclude that serum Lp(a) levels are significantly raised in type 2 DM and have a positive correlation with serum total and LDL-c levels.

Efeito Benéfico do Exercício Físico no Controle Metabólico do Diabetes Mellitus Tipo 2 à Curto Prazo

O objetivo deste trabalho foi analisar o efeito do exercício físico regular no controle glicêmico em indivíduos diabéticos tipo 2, tratados e não-tratados com insulina, em pessoas da região do Vale do Itajaí, SC, com idades entre 45 e 75 anos. Foram realizados testes de glicemia jejum (GJ), hemoglobina glicosilada (HbA1) e glicemia capilar nos clientes da Unicardio/HSC e nos participantes da Associação dos Diabéticos de Blumenau (n= 33), onde estes passaram por um programa de exercício físico de 10 semanas, após as quais os participantes da amostra foram reavaliados. Foi avaliado também: perfil lipídico, pressão arterial, freqüência cardíaca de repouso e índice de massa corporal. Os instrumentos utilizados foram: o exame de sangue em jejum para avaliação laboratorial e a glicemia capilar. Para análise estatística utilizou-se o teste "t" de Student e a reta ajustada de mínimos quadrados, pela regressão linear. Obteve-se os seguintes resultados: glicemia capilar média pré-teste = 179mg/dL e pós-teste= 148mg/dL; HbA1 média pré-teste = 9,5% e pós-teste = 8,5%; GJ média pré-teste= 164,8mg/dL e pós-teste= 156,4mg/dL. Estes resultados permitem concluir que o exercício físico é de grande importância no controle glicêmico do indivíduo diabético tipo 2, tratado ou não-tratado com insulina, diminuindo a glicemia e a HbA1.

Shedding of TNF-alpha receptors, blood pressure, and insulin sensitivity in type 2 diabetes mellitus

Tumor necrosis factor-alpha (TNF-alpha) is increasingly recognized as a key component in the development of insulin resistance and increased blood pressure. In a sample of 368 individuals, the ratio of soluble TNF-alpha receptors (sTNFR2/sTNFR1) correlated positively with systolic and diastolic blood pressure (P < 0.01). This ratio was significantly greater in type 2 diabetic subjects (DM-2) than in type 1 diabetic patients and was greater than in control nondiabetic subjects (P < 0.00001). The TNF-alpha receptor 1 (TNFR1) density in peripheral blood monocytes was similar in DM-2 patients and in nondiabetic subjects. After phorbol 12-myristate 13-acetate, TNFR1 shedding was significantly decreased in DM-2 compared with control subjects, and it was directly associated with insulin sensitivity (r = 0.54, P = 0.03). Serum sTNFR1 concentration was also linked to the vasodilatory response to glyceryltrinitrate (P = 0.01). Conversely, TNF-alpha receptor 2 shedding was negatively associated with insulin sensitivity (r = -0.54, P = 0.03), whereas shedding of L-selectin showed no significant association. After exercise-induced lowering of blood pressure, a parallel decrease in sTNFR2/sTNFR1 was observed in DM-2 patients. Our findings suggest that insulin resistance and blood pressure are linked to altered shedding of TNF-alpha receptors in DM-2. The latter seems reversible and is not genetically determined.

Diabetes mellitus and cardiovascular disease

Diabetes is associated with a high incidence and poor prognosis of cardiovascular disease, and with high short- and long-term mortality. Adequate treatment of cardiovascular disorders and aggressive management of coexisting risk factors have proved to be at least as effective in diabetic as in nondiabetic patients in randomized, controlled studies. Indeed, treating diabetic patients with cardiovascular disease results in a larger absolute risk reduction than in nondiabetic subjects. Nevertheless, diabetic patients often receive inadequate therapy, which may, to a certain extent, explain their poor prognosis. Recommendations for the treatment of diabetic patients with acute myocardial infarction should include beta-blockers, aspirin, and ACE-inhibitors in all patients in whom no specific contraindications exist. Fibrinolysis should be administered when indicated, and the benefits of improving glycemic control should not be forgotten either. In patients with multi-vessel disease who need revascularization, when selecting the type of procedure, the superiority of surgical revascularization over angioplasty should be borne in mind. Even heart transplantation should be included as a therapeutic option since there are no data to support the exclusion of patients on account of their diabetes. Finally, coexisting risk factors should be intensively treated through lifestyle intervention, with or without drug therapy, in order to achieve secondary prevention goals.