Molecular and morphological alterations in uninjured skin of streptozotocin-induced diabetic mice.

Diabetes affects every tissue in the body, including the skin. The main skin problem is the increased risk of infections, which can lead to foot ulcers. Most studies evaluating the effects of diabetes on the skin are carried out in wound healing areas. There are fewer studies on uninjured skin, and some particularities of this tissue are yet to be elucidated. In general, cellular and molecular outcomes of diabetes are increased oxidative stress and lipid peroxidation. For our study, we used C57BL/6 mice that were divided into diabetic and non-diabetic groups. The diabetic group received low doses of streptozotocin on 5 consecutive days. To evaluate the effects of hyperglycemia on uninjured skin, we performed morphological analysis using hematoxylin/eosin staining, cellular analysis using Picrosirius red and Nissl staining, and immunostaining, and evaluated protein expression by polymerase chain reaction. We confirmed that mice were hyperglycemic, presenting all features related to this metabolic condition. Hyperglycemia caused a decrease in interleukin 6 (Il-6) and an increase in tumor necrosis factor alpha (Tnf-α), Il-10, F4/80, tumor growth factor beta (Tgf-ß), and insulin-like growth factor 1 (Igf-1). In addition, hyperglycemia led to a lower cellular density in the epidermis and dermis, a delay in the maturation of collagen fibers, and a decrease in the number of neurons. Furthermore, we showed a decrease in Bdnf expression and no changes in Ntrk2 expression in the skin of diabetic animals. In conclusion, chronic hyperglycemia in mice induced by streptozotocin caused disruption of homeostasis even before loss of skin continuity.

Molecular and morphological alterations in uninjured skin of streptozotocin‐induced diabetic mice

Diabetes affects every tissue in the body, including the skin. The main skin problem is the increased risk of infections, which can lead to foot ulcers. Most studies evaluating the effects of diabetes on the skin are carried out in wound healing areas. There are fewer studies on uninjured skin, and some particularities of this tissue are yet to be elucidated. In general, cellular and molecular outcomes of diabetes are increased oxidative stress and lipid peroxidation. For our study, we used C57BL/6 mice that were divided into diabetic and non-diabetic groups. The diabetic group received low doses of streptozotocin on 5 consecutive days. To evaluate the effects of hyperglycemia on uninjured skin, we performed morphological analysis using hematoxylin/eosin staining, cellular analysis using Picrosirius red and Nissl staining, and immunostaining, and evaluated protein expression by polymerase chain reaction. We confirmed that mice were hyperglycemic, presenting all features related to this metabolic condition. Hyperglycemia caused a decrease in interleukin 6 (Il-6) and an increase in tumor necrosis factor alpha (Tnf-α), Il-10, F4/80, tumor growth factor beta (Tgf-β), and insulin-like growth factor 1 (Igf-1). In addition, hyperglycemia led to a lower cellular density in the epidermis and dermis, a delay in the maturation of collagen fibers, and a decrease in the number of neurons. Furthermore, we showed a decrease in Bdnf expression and no changes in Ntrk2 expression in the skin of diabetic animals. In conclusion, chronic hyperglycemia in mice induced by streptozotocin caused disruption of homeostasis even before loss of skin continuity.

Impairment of body mass reduction-associated activation of brown/beige adipose tissue in patients with type 2 diabetes mellitus.

Backgrounds/Objectives:The activity of brown/beige adipose tissue (B/BAT) is inversely proportional to body adiposity. Studies have shown that obese subjects submitted to distinct approaches aimed at reducing body mass present an increase of B/BAT activation. However, it is unknown if this beneficial effect of body mass reduction applies to patients with type 2 diabetes mellitus. In this study, we evaluated the impact of massive body mass reduction obtained as a consequence of bariatric surgery in the cold-induced activation of B/BAT in obese non-diabetic (OND) and obese diabetic (OD) subjects. SUBJECTS/METHODS: This is an observational study. Fourteen OND, 14 OD and 11 subjects were included in the study. All obese subjects were submitted to Roux-in-Y gastric bypass and measurements were performed before and 8 months after surgery. B/BAT was evaluated by (18F)-FDG-PET/CT scan and determination of signature transcript expression in specimens obtained in biopsies. RESULTS: Before surgery, mean B/BAT activity and the expression of signature transcripts were similar between OND and OD groups. Eight months after surgery, body mass reduction was similar between the obese groups. Nevertheless, the activity of B/BAT was increased in OND and unchanged in OD subjects. This effect was correlated with a more pronounced improvement of insulin resistance, as evaluated by the hyperinsulinemic, euglycemic clamp, in OND subjects as compared with OD subjects. CONCLUSIONS: Body mass reduction has a more efficient effect to induce the activation of B/BAT in non-diabetic than in diabetic subjects. This effect is accompanied by more pronounced insulin sensitivity and serine 473 phosphorylation of Akt in B/BAT of non-diabetic than in diabetic subjects.

Hypothalamic stearoyl-CoA desaturase-2 (SCD2) controls whole-body energy expenditure.

BACKGROUND/OBJECTIVES: Stearoyl-CoA desaturase-2 (SCD2) is the main δ9 desaturase expressed in the central nervous system. Because of its potential involvement in controlling whole-body adiposity, we evaluated the expression and function of SCD2 in the hypothalami of mice. SUBJECTS/METHODS: Male mice of different strains were used in real-time PCR, immunoblot and metabolic experiments. In addition, antisense oligonucleotides and lentiviral vectors were used to reduce and increase the expression of SCD2 in the hypothalamus. RESULTS: The level of SCD2 in the hypothalamus is similar to other regions of the central nervous system and is ~10-fold higher than in any other region of the body. In the arcuate nucleus, SCD2 is expressed in proopiomelanocortin and neuropeptide-Y neurons. Upon high fat feeding, the level of hypothalamic SCD2 increases. Inhibition of hypothalamic SCD2 as accomplished by two distinct approaches, an antisense oligonucleotide or a short-hairpin RNA delivered by a lentivirus, resulted in reduced body mass gain mostly due to increased energy expenditure and increased spontaneous activity. Increasing hypothalamic SCD2 by a lentivirus approach resulted in no change in body mass and food intake. CONCLUSIONS: Thus, SCD2 is highly expressed in the hypothalami of rodents and its knockdown reduces body mass due to increased whole-body energy expenditure.

Distinct regulation of hypothalamic and brown/beige adipose tissue activities in human obesity.

BACKGROUND/OBJECTIVES: The identification of brown/beige adipose tissue in adult humans has motivated the search for methods aimed at increasing its thermogenic activity as an approach to treat obesity. In rodents, the brown adipose tissue is under the control of sympathetic signals originating in the hypothalamus. However, the putative connection between the depots of brown/beige adipocytes and the hypothalamus in humans has never been explored. The objective of this study was to evaluate the response of the hypothalamus and brown/beige adipose tissue to cold stimulus in obese subjects undergoing body mass reduction following gastric bypass. SUBJECTS/METHODS: We evaluated twelve obese, non-diabetic subjects undergoing Roux-in-Y gastric bypass and 12 lean controls. Obese subjects were evaluated before and approximately 8 months after gastric bypass. Lean subjects were evaluated only at admission. Subjects were evaluated for hypothalamic activity in response to cold by functional magnetic resonance, whereas brown/beige adipose tissue activity was evaluated using a (F 18) fluorodeoxyglucose positron emisson tomography/computed tomography scan and real-time PCR measurement of signature genes. RESULTS: Body mass reduction resulted in a significant increase in brown/beige adipose tissue activity in response to cold; however, no change in cold-induced hypothalamic activity was observed after body mass reduction. No correlation was found between brown/beige adipose tissue activation and hypothalamus activity in obese subjects or in lean controls. CONCLUSIONS: In humans, the increase in brown/beige adipose tissue activity related to body mass reduction occurs independently of changes in hypothalamic activity as determined by functional magnetic resonance.

PGC1α gene Gly482Ser polymorphism predicts improved metabolic, inflammatory and vascular outcomes following bariatric surgery.

AIMS/HYPOTHESIS: Bariatric surgery is currently employed as an effective approach to treat class III obesity and class II obesity with co-morbidities. Unfortunately, the general anthropometric and metabolic outcomes of the surgery are not homogeneous, and defining the eligibility criteria that allow for a more precise prediction of the outcomes of this invasive procedure will refine the selection of patients. Here we tested the hypothesis that the Gly482Ser polymorphism of the ppargc1a gene would predict different outcomes following bariatric surgery. METHODS: Fifty-five patients (26 Gly/Gly and 29 Gly/Ser+Ser/Ser) selected for the Roux-en-Y gastric bypass according to the National Institutes of Health Consensus Statement criteria were followed up for 1 year, monitoring their anthropometric, metabolic and inflammatory parameters. RESULTS: Patients with the Gly482Ser polymorphism had significantly improved reductions in the waist/hip ratio, fasting blood glucose, C-reactive protein, blood leukocyte count, serum interleukin-6 and intima-media thickness of the carotid artery, as compared with Gly/Gly patients. CONCLUSIONS/INTERPRETATION: Thus, the Gly482Ser polymorphism may predict a more favorable metabolic and inflammatory outcome for obese patients submitted to bariatric surgery, leading to a reduced atherosclerotic risk.

Correlation between periodontal disease, inflammatory alterations and pre-eclampsia.

BACKGROUND AND OBJECTIVE: Several studies have hypothesized that periodontal disease may increase the risk of pre-eclampsia. The correlation between the two diseases would probably be based on hypertension-related cytokine release in the local periodontal environment. The aim of this study was to evaluate the association between periodontal disease and pre-eclampsia, and the correlation of the two conditions with interleukin-6 (IL-6) and tumor necrosis factor-α(TNFα) mRNA expression. MATERIAL AND METHODS: A case-control analysis of 116 pregnant women, 58 with pre-eclampsia (cases) and 58 normotensive pregnant women (controls) was performed. In addition to collection of socio-demographic data and periodontal evaluation, peripheral blood samples were collected for laboratory analysis of IL-6 and TNFα mRNA expression by real-time PCR. RESULTS: There was an association between periodontitis and pre-eclampsia (adjusted odds ratio 3.73; 95% confidence interval 1.32-10.58). Increased TNFα mRNA expression was observed in pre-eclamptic women; however, there was no correlation between periodontitis and systemic cytokine expression. In the case group, systemic cytokine mRNA levels were similar in pregnant women with and without periodontitis (means±SD): 0.73±0.24 vs. 0.82±0.38 for TNFα and 1.31±1.49 vs. 1.09±0.74 for IL-6, respectively. CONCLUSION: Periodontitis was clinically related to pre-eclampsia; however, the supposed mechanism that correlates the two diseases, i.e. a systemic inflammatory process involving cytokines TNFα and IL-6 in the presence of periodontal disease, could not be confirmed in this study.

Interferon (IFN) beta treatment induces major histocompatibility complex (MHC) class I expression in the spinal cord and enhances axonal growth and motor function recovery following sciatic nerve crush in mice.

AIMS: Major histocompatibility complex (MHC) class I expression by neurones and glia constitutes an important pathway that regulates synaptic plasticity. The upregulation of MHC class I after treatment with interferon beta (IFN beta) accelerates the response to injury. Therefore the present work studied the regenerative outcome after peripheral nerve lesion and treatment with IFN beta, aiming at increasing MHC class I upregulation in the spinal cord. METHODS: C57BL/6J mice were subjected to unilateral sciatic nerve crush and treatment with IFN beta. The lumbar spinal cords were processed for immunohistochemistry, in situ hybridization, Western blotting and RT-PCR, while the sciatic nerves were submitted for immunohistochemistry, morphometry and counting of regenerated axons. Motor function recovery was monitored using the walking track test. RESULTS: Increased MHC class I expression in the motor nucleus of IFN beta-treated animals was detected. In the peripheral nerve, IFN beta-treated animals showed increased S100, GAP-43 and p75NTR labelling coupled with a significantly greater number of regenerated axons. No significant differences were found in neurofilament or laminin labelling. The morphological findings, indicating improvements in the regenerative process after IFN treatment were in line with the motor behaviour test applied to the animals during the recovery process. CONCLUSIONS: The present data reinforce the role of MHC class I upregulation in the response to injury, and suggest that IFN treatment may be beneficial to motor recovery after axotomy.