The Pivotal Role of Oleuropein in the Anti-Diabetic Action of the Mediterranean Diet: A Concise Review

Type 2 diabetes currently accounts for more than 90% of all diabetic patients. Lifestyle interventions and notably dietary modifications are one of the mainstays for the prevention and treatment of type 2 diabetes. In this context, the Mediterranean diet with its elevated content of phytonutrients has been demonstrated to effectively improve glucose homeostasis. Oleuropein is the most abundant polyphenolic compound contained in extra-virgin olive oil and might account for some of the anti-diabetic actions of the Mediterranean diet. With the aim to provide an overview of the possible contributions of oleuropein to glucose metabolism, we conducted a PubMed/Medline search in order to provide an update to the available evidence regarding this interesting compound. This narrative review summarizes the data that was obtained in in vitro and animal studies and the results of clinical investigations. Preclinical studies indicate that oleuropein improves glucose transport, increases insulin sensitivity, and facilitates insulin secretion by pancreatic β-cells, thereby supporting the hypothesis of the possible benefits of the control of hyperglycemia. However, on the clinical side, the available evidence is still preliminary and requires more extensive investigations. Thus, many questions remain unanswered in regards to the potential benefits of oleuropein in diabetes prevention and treatment. These questions should be addressed in appropriately designed studies in the future

Vitamin D Deficiency Is Associated with Glycometabolic Changes in Nondiabetic Patients with Arterial Hypertension

Recent evidence indicates that mildly increased fasting and post-oral load blood glucose concentrations contribute to development of organ damage in nondiabetic patients with hypertension. In previous studies, vitamin D deficiency was associated with decreased glucose tolerance. The aim of this study was to examine the relationships between serum 25(OH)D levels and glucose tolerance and insulin sensitivity in hypertension. In 187 nondiabetic essential hypertensive patients free of cardiovascular or renal complications, we measured serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) and performed a standard oral glucose tolerance test (OGTT). Patients with 25(OH)D deficiency/insufficiency were older and had significantly higher blood pressure, fasting and post-OGTT (G-AUC) glucose levels, post-OGTT insulin (I-AUC), PTH levels, and prevalence of metabolic syndrome than patients with normal serum 25(OH)D. 25(OH)D levels were inversely correlated with age, blood pressure, fasting glucose, G-AUC, triglycerides, and serum calcium and PTH, while no significant relationships were found with body mass index (BMI), fasting insulin, I-AUC, HOMA index, and renal function. In a multivariate regression model, greater G-AUC was associated with lower 25(OH)D levels independently of BMI and seasonal vitamin D variations. Thus, in nondiabetic hypertensive patients, 25(OH)D deficiency/insufficiency could contribute to impaired glucose tolerance without directly affecting insulin sensitivity

AORTIC STIFFNESS AND INDEXES OF DISEASE SEVERITY IN SUBJECTS WITH PREVIOUS COVID-19 PNEUMONIA: A FOLLOW-UP STUDY

OBJECTIVE: Up to date the possibility of a vascular damage due to COVID-19 pneumonia is a not clarified. We searched for relationships between the carotid-femoral pulse wave velocity (cfPWV) and clinical and biochemical markers of severity of the infectious disease, after hospital discharge, in a group of patients who had been admitted in care units. DESIGN AND METHOD: In 69 subjects (age 58 ± 13 years, 36 males), previously admitted in hospital because of COVID-19 pneumonia, we evaluated at the time of hospital admission anthropometric parameters, blood pressure, history of arterial hypertension or other diseases, drugs, smoking and alcohol habit, physical activity level, and indexes of infectious disease severity, such as the SIMEU score, need for invasive oxygen delivery, PaO2, PaCo2, inflammatory markers such as white blood cells count, levels of proadrenomedulline (proADM), reactive C protein, procalcitonin, IL- 6, glomerular filtration rate (GFR), troponin, mioglobin, B natriuretic peptide. After an average 2 months follow-up the cfPWV was measured. RESULTS: At univariate analysis the cfPWV was significantly and positively related to age (r = 0.454, P < 0.001), body mass index (r = 0.436, P = 0.016), waist circumference (r = 0.345, P = 0.004), levels of plasma glucose (r = 0.430, P = 0.001), proADM (r = 0.456, P = 0.006), IL-6 (r = 0.280, P = 0.037), mioglobin (r = 0.443, P = 0.001) and inversely related to GFR (r = -0.289, P = 0.023). The cfPWV was higher in diabetics subjects than in non-diabetics (P = 0.011), and in patients who had needed invasive oxygen support (P = 0.044). There was no difference in cfPWV in patients with or without history of arterial hypertension or with different blood pressure levels at admission. At multivariate analysis the cfPWV was independently associated with invasive oxygen support (B = 0.168, P = 0.012), body mass index (B = 0.180, P = 0.001), waist circumference (B = 0.162, P = 0.002), GFR (B = 0.078, P = 0.008), and proADM levels (B = 0.161, P = 0.003). CONCLUSIONS: In patients who recovered from COVID-19 pneumonia the aortic stiffness is associated with severity of disease and levels of proADM, but not with history of hypertension. Patients with more higher proADM levels in acute phase of the infectious disease could need a longer follow-up evaluation of the CFPWV after the recovering from disease to search for long time vascular damage

RELATIONSHIPS BETWEEN NAFLD BIOCHEMICAL SCORES AND LEFT VENTRICULAR GEOMETRIC PATTERN IN NAÏVE ESSENTIAL HYPERTENSIVE PATIENTS

OBJECTIVE: The not alcoholic fatty liver disease (NAFLD) is associated with an increased cardiovascular mortality and morbidity. An hypothesis for this association could be the left ventricular (LV) geometric alteration sometime found in hypertension that is a known prognostic factor for cardiovascular events in hypertension. We searched for a relationship between biochemical scores of NAFLD and left ventricular (LV) hypertrophy (LVH) or LV geometric patterns changes in a large group of never treated essential hypertensive (EH) patients. DESIGN AND METHOD: In 434 naïve (49 ± 14 years, 234 males) we evaluated BMI, waist circumference, liver steatosis at abdominal echography, the biochemical scores of liver steatosis: Liver Fat Score (LFS), Fatty Liver Index (FLI), Hepatic Steatosis Index (NAÏVE), and the fibrosis scores: NAFLD Fibrosis Score (NFS), APRI, FIB-4, parameters of glucose and insulin homeostasis, liver blood tests, lipids, platelets count, glomerular filtration rate (GFR), reactive C protein. LV mass and relative wall thickness was calculated with echocardiography. Patients were classified in 4 groups of LV geometry: 1 = LV normal geometry, 2 = LV concentric remodeling, 3 = concentric LVH, 4 = eccentric LVH. RESULTS: A LVH was present in 17.3% of patients, and these patients had higher LFS (P < 0.001), FLI (P = 0.008), NAÏVE (P = 0.004) and NFS (P = 0.011) scores than patients without LVH. LVH was independently associated with the FLI score but not with fibrosis scores. The steatosis scores (LFS, NAÏVE, FLI) linearly increased across the four LV geometric patterns (P = 0.007, P = 0.001, P = 0.003, respectively). The fibrosis score NFS was significantly higher in subjects with concentric LVH (P = 0.041). The LFS was independently associated with BMI, GAUC, G120, and triglycerides levels. The NFS was independently associated with waist circumference, GFR and weakly with fasting glucose level. Ultrasound steatosis was not different among the four LV geometric patterns. CONCLUSIONS: In naïve EH patients the biochemical steatosis scores show a relationship with LVH and LV geometric changes, while fibrosis is associated with concentric LVH. An accurate investigation to reveal a NAFLD should be done in EH patients with altered LV geometry and to better understanding of mechanisms linking the two conditions