Outdoor artificial light at night and human health: A review of epidemiological studies.

We conducted a non-systematic review of epidemiological studies on a potential link between exposure to outdoor artificial light at night (O-ALAN) and disease occurrence in humans published since 2009. In recent years, a number of presses have been published on this issue, but the conclusions have been mixed. We therefore decided to critically analyze the available epidemiological evidence of such a correlation. After a careful search, 51 studies were identified and included in the review. They addressed the potential link between O-ALAN exposure and the incidence of breast cancer, other cancers, sleep and circadian rhythm disorders, obesity and cardiovascular diseases, mental disorders, infectious diseases, and complications during pregnancy and childbirth. The vast majority of papers revealed the existence of such a link. However, the amount of epidemiological evidence supporting the correlation across groups of disorders varied widely. In addition, we found that all papers contained at least one of the following omissions: lack of the temporal and spatial resolution in light at night measurements, measuring only light intensity without considering its wavelength, and not accounting for many important confounding factors in their statistical analyses. Therefore, we believe that the link between O-ALAN exposure and the occurrence of the disorders in question suggested by the authors of the reviewed papers may be in some cases at least to some extent, a coincidence. Further epidemiological studies, free of significant omissions highlighted in this paper, are needed.

Two-Stage Gene Therapy (VEGF, HGF and ANG1 Plasmids) as Adjunctive Therapy in the Treatment of Critical Lower Limb Ischemia in Diabetic Foot Syndrome.

One of the most serious problems in people with diabetes is diabetic foot syndrome. Due to the peripheral location of atherosclerotic lesions in the arterial system of the lower extremities, endovascular treatment plays a dominant role. However, carrying out these procedures is not always possible and does not always bring the expected results. Gene therapy, which stimulates angiogenesis, improves not only the inflow from the proximal limb but also the blood redistribution in individual angiosomes. Due to the encouraging results of sequential treatment consisting of intramuscular injections of VEGF/HGF bicistronic plasmids followed by a month of ANG1 plasmids, we decided to use the described method for the treatment of critical ischemia of the lower limbs in the course of diabetes and, more specifically, in diabetic foot syndrome. Twenty-four patients meeting the inclusion criteria were enrolled in the study. They were randomly divided into two equal groups. The first group of patients was subjected to gene therapy, where the patients received intramuscular injections of pIRES/VEGF165/HGF plasmids and 1 month of ANG-1 plasmids. The remaining patients constituted the control group. Gene therapy was well tolerated by most patients. The wounds healed significantly better in Group 1. The minimal value of ABI increased significantly in Group 1 from 0.44 ± 0.14 (± standard deviation) to 0.47 ± 0.12 (with p = 0.028) at the end of the study. There were no significant differences in the control group. In the gene treatment group, PtcO2 increased significantly (from 28.71 ± 10.89 mmHg to 33.9 ± 6.33 mmHg with p = 0.001), while in Group 2, no statistically significant changes were found. The observed resting pain decreased significantly in both groups (Group 1 decreased from 6.80 ± 1.48 to 2.10 ± 1.10; p < 0.001; the control group decreased from 7.44 ± 1.42 to 3.78 ± 1.64 with p < 0.001). In our study, we evaluated the effectiveness of gene therapy with the growth factors described above in patients with CLI in the course of complicated DM. The therapy was shown to be effective with minimal side effects. No serious complications were observed.

PPARG Hypermethylation as the First Epigenetic Modification in Newly Onset Insulin Resistance in Human Adipocytes.

Insulin acts by binding with a specific receptor called an insulin receptor (INSR), ending up with glucose transporter activation and glucose uptake. Insulin resistance (IR) is a state when the physiological amount of insulin is not sufficient to evoke proper action, i.e., glucose uptake. Epigenetic modifications associated with obesity and IR are some of the main mechanisms leading to IR pathogenesis. The mesenchymal stem cells of adipose tissue (subcutaneous (SAT) and visceral (VAT)) were collected during abdominal surgery. IR was induced ex vivo by palmitic acid. DNA methylation was determined at a global and site-specific level. We found higher global DNA methylation in IR adipocytes after 72 h following IR induction. Furthermore, numerous genes regulating insulin action (PPARG, SLC2A4, ADIPOQ) were hypermethylated in IR adipocytes; the earliest changes in site-specific DNA methylation have been detected for PPARG. Epigenetic changes appear to be mediated through DNMT1. DNA methylation is an important component of IR pathogenesis; the PPARG and its epigenetic modification appear to be the very first epigenetic modification in newly onset IR and are probably of the greatest importance.

Histone modifications influence the insulin-signaling genes and are related to insulin resistance in human adipocytes.

Insulin resistance (IR) is a state when the physiological amount of insulin is not sufficient to evoke proper action, that is, glucose uptake. Numerous conditions lead to IR, including epigenetic components. Epigenetic modifications, associated with obesity and IR are one of the main mechanisms leading to IR pathogenesis. The adipose tissue samples (subcutaneous (SAT) and visceral (VAT)) were collected during abdominal surgery from 40 patients of a wide range of BMI, age, and insulin resistance ratios (F = 9, M = 31). IR was induced in 3T3-L1 adipocytes and human adipocytes collected from SAT and VAT of healthy subjects. Global and site-specific histone modifications (H3K4me3 and H3K9/14ac) were determined. We found lower histone modifications in adipose tissue of IR patients. Furthermore, numerous genes regulating insulin action (PPARG, SLC2A4, ADIPOQ) were differently marked by histone methylation and acetylation. Moreover, we noticed that epigenetic changes appear as soon as 72 h following IR induction. The epigenetic changes appeared to be mediated through the SIRT family. Based on obtained results, the histone marks related to insulin resistance mostly concerned PPARG and SLC2A4 genes. Furthermore, our results proved a vital role of the SIRT family in insulin action and IR pathogenesis.

DNA methylation in adipocytes from visceral and subcutaneous adipose tissue influences insulin-signaling gene expression in obese individuals.

OBJECTIVE: Both obesity and insulin resistance are characterized by severe long-term changes in the expression of many genes of importance in the regulation of metabolism. Because these changes occur throughout life, as a result of external factors, the disorders of gene expression could be epigenetically regulated. MATERIALS/METHODS: We analyzed the relationship between obesity and insulin resistance in enrolled patients by means of evaluation of the expression rate of numerous genes involved in the regulation of adipocyte metabolism and energy homeostasis in subcutaneous and visceral adipose tissue depots. We also investigated global and site-specific DNA methylation as one of the main regulators of gene expression. Visceral and subcutaneous adipose tissue biopsies were collected from 45 patients during abdominal surgery in an age range of 40-60 years. RESULTS: We demonstrated hypermethylation of PPARG, INSR, SLC2A4, and ADIPOQ promoters in obese patients with insulin resistance. Moreover, the methylation rate showed a negative correlation with the expression of the investigated genes. More, we showed a correlation between the expression of PPARG and the expression of numerous genes important for proper insulin action. Given the impact of PPARγ on the regulation of the cell insulin sensitivity through modulation of insulin pathway genes expression, hypermethylation in the PPARG promoter region may constitute one of the epigenetic pathways in the development of insulin resistance in obesity. CONCLUSIONS: Our research shows that epigenetic regulation through excessive methylation may constitute a link between obesity and subsequent insulin resistance.

Double VEGF/HGF Gene Therapy in Critical Limb Ischemia Complicated by Diabetes Mellitus.

Critical leg ischemia (CLI) complicated by diabetes mellitus (DM), which is a very common and dangerous disease, represents the ultimate stage of peripheral arterial disease. Patients are treated with antiplatelet drugs, statins and limb revascularization, but a significant number of patients are not candidate for revascularization. Literature shows that in such cases, gene therapy could be a perfect therapeutic option. The aim of our study was to evaluate efficacy of double vascular endothelial growth factor/hepatocyte growth factor (VEGF/HGF) gene therapy in patients with CLI complicated by DM. We observed that 90 days after administration, serum level of VEGF and ankle-brachial index increased significantly (p < 0.001) and rest pain decreased significantly compared with the control group (p < 0.002). Moreover considerable improvement in vascularization was observed in computed tomography angiography (P = 0.04). Based on the results of this study, we suggest that the therapy with pIRES/VEGF165/HGF bicistronic plasmid administration is a safe and effective method of treatment of patients with both CLI and DM. Graphical abstract.

Metabolic Differences between Subcutaneous and Visceral Adipocytes Differentiated with an Excess of Saturated and Monounsaturated Fatty Acids.

Obesity is a major health problem in highly industrialized countries. High-fat diet (HFD) is one of the most common causes of obesity and obesity-related disorders. There are considerable differences between fat depots and the corresponding risks of metabolic disorders. We investigated the various effects of an excess of fatty acids (palmitic 16:0, stearic 18:0, and oleic acids 18:1n-9) on adipogenesis of subcutaneous- and visceral-derived mesenchymal stem cells (MSCs) and phenotypes of mature adipocytes. MSCs of white adipose tissue were acquired from adipose tissue biopsies obtained from subcutaneous and visceral fat depots from patients undergoing abdominal surgery. The MSCs were extracted and differentiated in vitro with the addition of fatty acids. Oleic acid stimulated adipogenesis, resulting in higher lipid content and larger adipocytes. Furthermore, oleic acid stimulated adipogenesis by increasing the expression of CCAAT enhancer binding protein ß (CEBPB) and peroxisome proliferator activated receptor γ (PPARG). All of the examined fatty acids attenuated the insulin-signaling pathway and radically reduced glucose uptake following insulin stimulation. Visceral adipose tissue was shown to be more prone to generate inflammatory stages. The subcutaneous adipose tissue secreted a greater quantity of adipokines. To summarize, oleic acid showed the strongest effect on adipogenesis. Furthermore, all of the examined fatty acids attenuated insulin signaling and secretion of cytokines and adipokines.

Oleic acid influences the adipogenesis of 3T3-L1 cells via DNA Methylation and may predispose to obesity and obesity-related disorders.

BACKGROUND: Adipogenesis is the process of adipocytes formation from unspecialized progenitor cells called mesenchymal stromal cells. Numerous mechanisms including epigenetic regulation modulate the correct progress of this process. Dietary exposures occurring over a specific period of time might cause long-lasting and even permanent changes in gene expression regulated by epigenetic mechanisms. For that reason, we investigated the adipogenesis of 3 T3-L1 cells with the excess of saturated and monounsaturated fatty acids and their influence on global and site-specific DNA methylation in these cells. MATERIALS AND METHODS: 3T3-L1 cells were cultured in vitro to obtain 100% of confluence, then the adipogenesis was induced by a differentiation cocktail with the addition of the excess of 0.25 mM and 0.5 mM of palmitic (16:0), stearic (18:0) and oleic (18:1n-9) acids. DNA and RNA were extracted at five-time points to assess the adipogenesis process. The phenotype of mature adipocytes (insulin sensitivity, adipokines secretion, fat content) was estimated in fully mature adipocytes. DNA methylation was investigated both during adipogenesis and in mature adipocytes. RESULTS: Oleic acids stimulated expression of C/ebpα and Pparγ, which was correlated with lower methylation levels at promoters sites. Furthermore, cells cultured with an excess of oleic acid were characterized by higher lipid accumulation rate, higher leptin, and lower adiponectin secretion. Moreover, in all experimental cells, insulin signaling and glucose utilization were impaired. CONCLUSION: Oleic acid affected the methylation of Pparγ and C/ebpα promoters, what correlated with higher expression. Furthermore, examined free fatty acids influenced the phenotype of mature adipocytes, especially insulin signaling pathway and adipokine secretion.

VDR gene single nucleotide polymorphisms and their association with risk of oral cavity carcinoma.

Vitamin D3 (1,25(OH)2D3 (1,25-dihydroxyvitamin D3)) is a hormone playing a crucial role in numerous biological processes in the human body, including induction and control of cell proliferation and differentiation. Numerous data relate the vitamin D3 level with various types of cancer. It has been suggested that SNPs in the vitamin D3 receptor (VDR) gene might influence both the risk of cancer occurrence and cancer progression. The aim of this study was to search for genetic correlations between individual SNPs in the VDR gene and the risk of oral cavity carcinoma. Two SNPs were selected based on the literature and our previous results. Seventy-three patients with squamous cell carcinoma of the head and neck and one hundred control subjects were investigated. Two SNPs in the VDR gene were genotyped in minisequencing reactions followed by capillary electrophoresis. Hardy-Weinberg equilibrium (HWE), the χ(2) test and logistic regression were used for statistical analysis. The SNP rs2238135 in the VDR gene displayed statistical differences in frequency between the tested groups (p=0,0007). Furthermore, the G/C genotype of the rs2238135 in the VDR gene was characterized by a 3.16 fold increased risk of oral cavity carcinoma. The obtained results provide evidence for a genetic association between rs2238135 in the VDR gene and the occurrence and risk of oral cavity cancer.