Altered glucose metabolism rather than naive type 2 diabetes mellitus (T2DM) is related to vitamin D status in severe obesity.

CONTEXT: The last decades have provided insights into vitamin D physiology linked to glucose homeostasis. Uncertainties remain in obesity due to its intrinsic effects on vitamin D and glucose tolerance. OBJECTIVES: To assess the relationship between vitamin D and glucose abnormalities in severely obese individuals previously unknown to suffer from abnormal glucose metabolism. SETTING: Tertiary care centre. PATIENTS: 524 obese patients (50.3 ± 14.9 yrs; BMI, 47.7 ± 7.3 kg/m2) screened by OGTT, HbA1c and the lipid profile. Vitamin D status was assessed by 25(OH)D3, PTH and electrolyte levels. 25(OH)D3 deficiency/insufficiency were set at 20 and 30 ng/ml, respectively. All comparative and regression analyses were controlled for age, BMI and gender. RESULTS: The prevalence of vitamin D deficiency/insufficiency and secondary hyperparathyroidism were 95% and 50.8%, respectively. Normal glucose tolerance (NGT), impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) were found in 37.8%, 40.5% and 21.7% of cases, respectively. Large variations in metabolic parameters were seen across categories of vitamin D status, but the only significant differences were found for C-peptide, tryglicerides, LDL- and HDL-cholesterol levels (p < 0.05 for all). The prevalence of vitamin D deficiency was documented to be slightly but significantly more frequent in glucose-intolerant patients (IFG + IGT + T2DM) compared to the -normotolerant counterpart (87% vs. 80%, p < 0.05). In partial correlation analyses, there was no association between vitamin D levels and glucose-related markers but for HbA1c (r = -0.091, p < 0.05), and both basal and OGTT-stimulated insulin levels (r = 0.097 and r = 0.099; p < 0.05 for all). Vitamin D levels were also correlated to HDL-cholesterol (r = 0.13, p = 0.002). Multivariate regression analysis inclusive of vitamin D, age, BMI, gender and fat mass as independent variables, showed that vitamin D was capable of predicting HbA1c levels (ß = -0.101, p < 0.05). CONCLUSIONS: Given the inherent effect of obesity on vitamin D and glucose homeostasis, current data suggest a potential independent role for vitamin D in the regulation of glucose metabolism in a setting of obese patients previously unknown to harbour glucose metabolism abnormalities.

Evaluation of percutaneous absorption of naproxen from different liposomal formulations.

The present study concerns the percutaneous absorption of naproxen (NPX), as model anti-inflammatory drug, included in liposome formulations constituted of different lipids: stratum corneum lipids (SCL) and phosphatidylcholine/cholesterol (PC/CHOL). Liposome dispersions were produced using two different methods: reverse-phase evaporation (REV) and thin layer evaporation (TLE). Morphology and dimensions of the disperse phase were characterized by cryo-transmission electron microscopy (cryo-TEM) and photon correlation spectroscopy, respectively. X-ray diffraction was employed to determine the structural organization of the vesicles. In vitro diffusion was studied by Franz cell on liposome dispersions viscosized by carbomer. Tape stripping was performed to investigate in vivo the performance of differently composed liposomes as NPX delivery system. Cryo-TEM showed spherical vesicles and bigger irregular elongated nanoparticles for TLE SCL liposomes. REV resulted in spherical and elongated multilamellar vesicles. Also X-ray diffraction evidenced L alpha or L beta multilamellar vesicles for PC/CHOL and SCL liposome respectively. The in vitro study showed a lower NPX flux for SCL with respect to PC/CHOL liposome. Tape stripping corroborate the in vitro findings regarding SCL, suggesting that liposomes create a drug reservoir mixing with SC lipids, whilst PC/CHOL liposome promoted NPX permeation through the skin. Liposome lipid composition seems to affect NPX permeation through the skin.