Theocharis Koufakis

The combined effect of vitamin D and parathyroid hormone concentrations on glucose homeostasis in older patients with prediabetes: A cross-sectional study

Background: The combined effect of vitamin D and parathyroid hormone on glucose homeostasis has not been adequately investigated. The aim of this study was to examine the role of parathyroid hormone/vitamin D axis on glucose homeostasis in elderly persons with prediabetes. Methods: Patients with prediabetes (nu2009=u2009144) and healthy age-matched controls (nu2009=u200981) were included in this cross-sectional study. Study parameters included anthropometric characteristics, morning fasting glucose (fasting plasma glucose), insulin (fasting plasma insulin), parathyroid hormone, 25-hydroxyvitamin D, homeostasis model assessment of insulin resistance and homeostasis model assessment of β-cell function. Both groups were stratified into subgroups according to vitamin D status and tertiles of parathyroid hormone. Results: Both groups were comparable in terms of body mass index, 25-hydroxyvitamin D and parathyroid hormone status. In the prediabetes group, fasting plasma glucose differed significantly across parathyroid hormone tertiles, increasing from the first to the third tertile (pu2009=u20090.011). There were higher fasting plasma glucose values in participants with vitamin D deficiency/parathyroid hormone third tertile compared to all other groups (pu2009=u20090.031, 0.027 and 0.039, respectively). Conclusion: Parathyroid hormone status is associated with impaired glucose homeostasis; hypovitaminosis D combined with high parathyroid hormone concentrations are associated with glycaemic dysregulation in elderly patients with prediabetes.

Effects of Orthodox religious fasting on human health: a systematic review

PurposeDifferent studies have pointed towards a positive effect of religious fasting on human health. Orthodox fasting (OF) regime could be characterized as a periodical vegetarian diet, demonstrating several common characteristics with the typical Mediterranean diet. The present systematic review aimed to synthesize available results regarding the potential impact of OF on human health.MethodsKey biomedical databases were searched to identify studies examining the effects of OF on humans. Following implementation of specific criteria, ten studies were included in the analysis and their results were systematically reported and critically appraised in this review.ResultsAccording to the available limited results, OF periods are characterized by a restriction in total energy and fat intake, an increase in carbohydrate and fiber consumption, while in terms of protein intake, results are contradictive. The overall effect of OF on lipids profile seems to be optimal, with the reduction of total cholesterol and LDL-C levels, being a consistent finding across studies (up to 17.8 and 31.4%, respectively). However, the effect on HDL-C is still unclear. Conclusions regarding the impact on body weight and glucose homeostasis cannot be drawn, given that relevant data are limited with conflicting results. Any potential negative aspects of OF, mainly attributed to reduced dietary intake of vitamin D and B12 and minerals (mainly calcium), require further investigation.ConclusionsGiven the limitations of available evidence, more studies are required before reaching definite conclusions about the effects of OF on human health.

Deconvoluting the Biological Roles of Vitamin D-Binding Protein During Pregnancy: A Both Clinical and Theoretical Challenge

The teleological purpose of an ongoing pregnancy is to fulfill its fundamental role of a successful, uncomplicated delivery, in conjunction with an optimal intrauterine environment for the developing fetus. Vitamin D metabolism is adapted to meet both these demands during pregnancy; first by stimulation of calcium absorption for adequate intrauterine bone mineral accrual of the fetus, and second, by enhancing systemic and local maternal tolerance to paternal and fetal alloantigens. Vitamin D-binding protein (VDBP) is one of the key biomolecules that optimize vitamin D homeostasis and also contributes as an immune regulator for a healthy, ongoing pregnancy. In this regard, recent results indicate that dysregulation of VDBP equilibrium could be a risk factor for adverse fetal, maternal, and neonatal outcomes, including preeclampsia, preterm birth, and gestational diabetes. Moreover, it has been hypothesized to be also implicated in the interpretation of vitamin D status in the pregnant state. The aim of this review is to assess available literature regarding the association of VDBP with clinical outcomes during pregnancy, as a potential biomarker for future clinical practice, with a discourse on current knowledge gaps and future research agenda.

Christian Orthodox fasting in practice: a comparative evaluation between Greek Orthodox general population fasters and Athonian monks

OBJECTIVESnChristian Orthodox fasting (COF), a periodical vegetarian subset of the Mediterranean diet, has been proven to exert beneficial effects on human health. Athonian fasting is a pescetarian COF variation, where red meat is strictly restricted throughout the year. Previous studies have examined the COF nutritional synthesis and health effects in general population fasters (GF) and Athonian monks (AM), separately. The aim of this study is to comparatively evaluate the characteristics and effects of this nutritional advocacy between the two populations.nnnMETHODSnThe study included 43 male GFs (20-45 y of age) and 57 age-matched male AMs following COF. Dietary intake data were collected in both groups during a restrictive (RD) and a nonrestrictive (NRD) day. Nutritional, cardiometabolic, and anthropometric parameters were compared between the two cohorts.nnnRESULTSnAM presented lower daily total caloric intake for both RD (1362.42 ± 84.52 versus 1575.47 ± 285.96 kcal, P < 0.001) and NRD (1571.55 ± 81.07 versus 2137.80 ± 470.84 kcal, P < 0.001) than GF.They also demonstrated lower body mass index (23.77 ± 3.91 versus 28.92 ± 4.50 kg/m2, P <0.001), body fat mass (14.57 ± 8.98 versus 24.61 ± 11.18 kg, Pu202f=u202f0.001), and homeostatic model assessment for insulin resistance values (0.98 ± 0.72 versus 2.67 ± 2.19 mmol/L, P < .001) than GF. Secondary hyperparathyroidism (parathyroid hormone concentrations: 116.08 ± 49.74 pg/mL), as a result of profound hypovitaminosis D [25(OH)D: 9.27 ± 5.81 ng/mL], was evident in the AM group.nnnCONCLUSIONSnThe results of the present study highlight the unique characteristics of Athonian fasting and its value as a health-promoting diet. The effects of limitation of specific vitamins and minerals during fasting warrants further investigation.

The Effects of High Altitude on Glucose Homeostasis, Metabolic Control, and Other Diabetes-Related Parameters: From Animal Studies to Real Life

Exposure to high altitude activates several complex and adaptive mechanisms aiming to protect human homeostasis from extreme environmental conditions, such as hypoxia and low temperatures. Short-term exposure is followed by transient hyperglycemia, mainly triggered by the activation of the sympathetic system, whereas long-term exposure results in lower plasma glucose concentrations, mediated by improved insulin sensitivity and augmented peripheral glucose disposal. An inverse relationship between altitude, diabetes, and obesity has been well documented. This is the result of genetic and physiological adaptations principally to hypoxia that favorably affect glucose metabolism; however, the contribution of financial, dietary, and other life-style parameters may also be important. According to existing evidence, people with diabetes are capable of undertaking demanding physical challenges even at extreme altitudes. Still, a number of issues should be taken into account, including the increased physical activity leading to changes in insulin demands and resistance, the performance of measurement systems under extreme weather conditions and the potential deterioration of metabolic control during climbing expeditions. The aim of this review is to present available evidence in the field in a comprehensive way, beginning from the physiology of glucose homeostasis adaptation mechanisms to high altitudes and ending to what real life experience has taught us.

Should the last be first? Questions and dilemmas regarding early short-term insulin treatment in Type 2 Diabetes Mellitus

ABSTRACT Introduction: Early short-term insulin treatment (STIT), defined as insulin administration shortly after diabetes diagnosis for only a brief period of time, is an alternative concept, aiming to entirely revise the perspective of type 2 diabetes (T2DM) management. Areas covered: The present review intends to summarize what is already known regarding early STIT in T2DM and highlight questions and dilemmas from the clinician’s point of view, with a discourse on future research agenda. Expert opinion: STIT has the potential to modify the natural history of T2DM, resulting in improved drug-free remission rates by favorably affecting the underlying pathophysiology of the disease. Existing data in the field manifest significant weaknesses, mainly being the small number of trials and patients included, the lack of control groups in most studies and the wide heterogeneity between study designs and explored outcomes, which limit definitive conclusions. Therefore, before such a therapeutic strategy is incorporated into daily practice, important issues require further clarification by future trials. These issues include the optimal time point for the intervention, the ideal insulin type, the identification of patients being most likely to benefit, the STIT effects on cardiovascular and other clinical outcomes and the cost-effectiveness evaluation of this therapeutic strategy. Abbreviations: T2DM: Type 2 Diabetes Mellitus; HbA1C: Hemoglobin A1c; OHA: Oral Hypoglycemic Agents; STIT: Short-term Insulin Treatment; CSII: Continuous Subcutaneous Insulin Infusion; MDI: Multiple Daily Injections; PPG: Postprandial Plasma Glucose; FPG: Fasting Plasma Glucose; HOMA-b: Homeostasis Model Assessment of beta-cell function; TDD: Total Daily Insulin Dose; DI: Disposition Index; HOMA-IR: Homeostasis Model Assessment of Insulin Resistance; ROS: Reactive Oxygen Species; TNF: Tumor Necrosis Factor; GLP-1: Glucagon-like peptide-1; GIP: Glucose-dependent Insulinotropic Polypeptide; BMI: Body Mass Index; CV: Cardiovascular; DR: Diabetic Retinopathy; SU: Sulfonylurea; IGI: Insulinogenic Index

Orthodox religious fasting as a medical nutrition therapy for dyslipidemia: where do we stand and how far can we go?

Previous studies have reported inconclusive results regarding the effects of Orthodox religious fasting (OF) on common cardiovascular risk factors, including arterial hypertension and diabetes. Contrariwise, an optimal effect on dyslipidemia has been demonstrated and significant reductions in total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) concentrations, in Orthodox populations without comorbidities, have been consistently reported. This favorable effect on lipid homeostasis is probably facilitated by a broad lifestyle modification related to OF, extended beyond dietary habits. However, several clinical issues require further clarification by future trials including the efficacy and safety of OF in specific groups of patients with dyslipidemia, mainly those with cardiovascular disease and diabetes, the effects of OF on high-density lipoprotein-cholesterol (HDL-C), the dietary limitations of specific vitamins and minerals during fasting, as well as the optimal duration of this dietary intervention. The present article aims to discuss, whether there is a strong enough theoretical background, to currently support the implementation of OF as a medical nutrition therapy for dyslipidemia in the daily clinical setting, with a discourse on available evidence and future research agenda.

Pharmacogenetics of Glucagon-like Peptide-1 Agonists for the Treatment of Type 2 Diabetes Mellitus

BACKGROUNDnPharmacogenetics is a promising area of medical research, providing methods to identify the appropriate pharmaceutical agent and dosing for each unique patient. Glucagon- like peptide-1 (GLP-1) agonists are a novel therapeutic choice used in the treatment of type 2 diabetes mellitus (T2DM), demonstrating efficacy regarding glycemic control and weight loss. Therapeutic response to GLP-1 agonist treatment is a complex biophenomenon, dependent on a plethora of modifiable (diet, exercise, adherence) and non-modifiable (genetic individual variants, ethnic characteristics) parameters. Ιn this context, it has been hypothesized that genetic polymorphisms of GLP-1 related genes may be associated with the therapeutic response to GLP-1 agonist treatment. This review focuses on the most important polymorphisms of the GLP-1 biological network that could affect clinical response to GLP-1 agonist treatment.nnnMETHODSnBiomedical databases were searched to identify key articles in the field and their results are critically presented in this review.nnnRESULTnRecent pharmacological and clinical studies demonstrated a significant variation in GLP-1 agonist treatment, in cohorts with homogeneous adherence to diet, exercise and antidiabetic treatment. These studies identified several cases of non-responders to GLP-1 agonist therapy, in association with specific allelic patterns of GLP-1 receptor or other biomolecules implicated in glucose homeostasis.nnnCONCLUSIONnAlthough the exact DNA sequences that cause the molecular changes leading to a variable response to GLP-1 agonists have not been yet fully identified, these findings underline the importance of an individualized approach in anti-diabetic treatment.