Differential Modulation of Autophagy Contributes to the Protective Effects of Resveratrol and Co-Enzyme Q10 in Photoaged Mice.

BACKGROUND: In photoaging, the accumulation of ultraviolet (UV)-induced oxidative damage leads to the characteristic hallmarks of aging. Here arises the importance of autophagy as a cellular degradation process that cleans the cells of defective or aged organelles and macromolecules, thus maintaining cellular homeostasis. In spite of this, the exact impact of autophagy in photoaging is still elusive. OBJECTIVE: To evaluate the protective effects of resveratrol and/or co-enzyme-Q10 against the UVA-induced alterations and to explore the role of autophagy in their proposed benefits. METHODS: Sixty female mice were randomly divided into normal control, untreated UVA-exposed, resveratrol (50mg/kg), co-enzyme-Q10 (100mg/kg), and resveratrol/co-enzyme-Q10-treated UVA-- exposed groups. Clinical signs of photoaging were evaluated using a modified grading score and the pinch test. Skin malondialdehyde and reduced glutathione were assessed as markers of oxidative stress. Tissues were examined for histopathological signs of photodamage, and autophagic changes were determined by immunohistochemical detection of LC3 and P62 in the different cells of the skin. RESULTS: UVA-exposure increased the oxidative stress with subsequent epidermal and dermal injury. This was associated with the stimulation of autophagy in the keratinocytes and inhibition of autophagic flux in the fibroblasts and infiltrating macrophages. Both drugs corrected the impaired pinch test, macro-and microscopic changes, and exhibited distinct staining patterns with anti-LC3 and P62 in the different cell types denoting autophagic modulation. CONCLUSION: Changes in autophagic flux are strongly implicated in photoaging associated skin damage and the differential modulation of autophagy by resveratrol and, to a lesser extent by Co-enzyme- Q10, is partially involved in their therapeutic benefits.

Anti-Arthritic Activity of Schistosoma mansoni and Trichinella spiralis Derived-Antigens in Adjuvant Arthritis in Rats: Role of FOXP3+ Treg Cells.

A growing body of evidence supports the concept of helminths therapy in a variety of autoimmune diseases. Here, we aimed to investigate the protective effects of autoclaved Schistosoma mansoni antigen (ASMA) and Trichinella spiralis antigen (ATSA) on the clinical and immunopathological features of rheumatoid arthritis (RA). Adjuvant arthritis was induced by subcutaneous and intradermal injections of complete Freund's adjuvant into the plantar surface of the right hind paw and the root of the tail, respectively. Rats were randomly assigned to serve as normal control, untreated arthritis, ASMA or ATSA-treated arthritis groups. Antigens were given by intradermal injection in two doses, two weeks apart. The development, progression of arthritic features, and the impact on animals' gait and body weight were followed up for 4 weeks. The associated changes in serum cytokines (IL-17, IFN-γ and IL-10), joints' histopathology and immunohistochemistry of Foxp3+ T regulatory cells (Tregs) were evaluated at the end of the study. Treatment with either ASMA or ATSA attenuated the progression of clinical features of polyarthritis, improved gait and body weight gain, reduced the elevated serum IL-17 and further increased both IFN-γ and IL-10. Histopathologically, this was associated with a remarkable regression of paws' inflammation that was limited only to the subcutaneous tissue, and a significant increase in the number of Foxp 3+ cells versus the untreated arthritis group. In conclusion, both Schistosoma mansoni and Trichinella spiralis derived antigens exerted protective effect against adjuvant arthritis with better effect achieved by ASMA treatment. This anti-arthritic activity is attributed to upregulation of the Foxp3+ Tregs, with subsequent favorable modulation of both pro- and anti-inflammatory cytokines. The use of autoclaved parasitic antigens excludes the deleterious effects of imposing helminthic infection by using live parasites, which may pave the way to a new therapeutic modality in treating RA.

Pleiotropic protective effects of Vitamin D against high fat diet-induced metabolic syndrome in rats: One for all.

Several lines of evidence point to the association of vitamin D deficiency with the different components of metabolic syndrome. Yet, the effect of vitamin D supplementation on metabolic syndrome is not clearly elucidated. Herein, we tested the hypothesis that administration of vitamin D, either alone or in combination of metformin can improve metabolic and structural derangements associated with metabolic syndrome. Fifty wistar rats were randomly assigned to serve either as normal control (10 rats) or metabolic syndrome rats, by feeding them with a standard or a high fat diet (HFD), respectively. Metabolic syndrome rats were further assigned to receive either vehicle, Metformin (100mg/Kg orally), vitamin D (6ng/Kg SC.) or both, daily for 8 weeks. Body weight, blood pressure, serum glucose, insulin, insulin resistance, lipid profile, oxidative stress, serum uric acid and Ca+2 were assessed at the end of the study. Histopathological examination of hepatic, renal and cardiac tissues were also performed. Treatment with vitamin D was associated with a significant improvement of the key features of metabolic syndrome namely obesity, hypertension and dyslipidaemia with a neutral effect on Ca+2 level. When combined with metformin, most of the other metabolic abnormalities were ameliorated. Furthermore, a significant attenuation of the associated hepatic steatosis was observed with vitamin D as well as vitamin D/metformin combination. In conclusion, vitamin D can improve hypertension, metabolic and structural abnormalities induced by HFD, and it provides additional benefits when combined with metformin. Therefore, vitamin D could represent a feasible therapeutic option for prevention of metabolic syndrome.

Nebivolol suppresses asymmetric dimethylarginine and attenuates cyclosporine-induced nephrotoxicity and endothelial dysfunction in rats.

BACKGROUND: Cyclosporine A (CsA)-induced nephrotoxicity is a challenging problem complicating its chronic use in a large array of autoimmune diseases, as well as in organ transplantation. A considerable body of evidence points to the involvement of nitric oxide (NO) and its endogenous synthesis inhibitor, asymmetric dimethylarginine (ADMA), in CsA-induced renal and cardiovascular adverse effects. In this study, the potential of the third generation ß-blocker, nebivolol, to modify the NO/ADMA system is hypothesized to play a role in protection against CsA-induced renal injury and endothelial dysfunction. METHODS: Both in vivo and in vitro studies were carried out on 36 male Wistar rats randomly divided into three groups; normal control, CsA (30mg/kg/day)-treated or CsA+nebivolol (30mg/kg and 1mg/kg daily, respectively)-treated groups. After four weeks, blood pressure, lipid profile, renal functions, renal oxidative status, NO, inducible NO synthase and ADMA were assessed. In vitro evaluation of vascular relaxant responses of norepinephrine pre-contracted aortic rings to acetylcholine (ACh) and sodium nitroprusside were evaluated. RESULTS: Concurrent nebivolol treatment significantly attenuated CsA-induced hypertension, impairment of renal functions, oxidative stress and restored the balance in renal NO system with lowering of the elevated ADMA. This was associated with favourable effects on lipid profile. Nebivolol treatment also abrogated the CsA-induced impairment of relaxant responses of aortic rings to ACh. CONCLUSIONS: Nebivolol possesses multifaceted actions that make it advantageous to combat the CsA-induced toxic effects on renal and endothelial functions.

Adalimumab ameliorates OVA-induced airway inflammation in mice: Role of CD4(+) CD25(+) FOXP3(+) regulatory T-cells.

Asthma is a chronic inflammatory heterogeneous disorder initiated by a dysregulated immune response which drives disease development in susceptible individuals. Though T helper 2 (TH2) biased responses are usually linked to eosinophilic asthma, other Th cell subsets induce neutrophilic airway inflammation which provokes the most severe asthmatic phenotypes. A growing evidence highlights the role of T regulatory (Treg) cells in damping abnormal Th responses and thus inhibiting allergy and asthma. Therefore, strategies to induce or augment Treg cells hold promise for treatment and prevention of allergic airway inflammation. Recently, the link between Tumor necrosis factor-α (TNF-α) and Treg has been uncovered, and TNF-α antagonists are increasingly used in many autoimmune diseases. Yet, their benefits in allergic airway inflammation is not clarified. We investigated the effect of Adalimumab, a TNF-α antagonist, on Ovalbumin (OVA)-induced allergic airway inflammation in CD1 mice and explored its impact on Treg cells. Our results showed that Adalimumab treatment attenuated the OVA-induced increase in serum IgE, TH2 and TH1 derived inflammatory cytokines (IL-4 and IFN-γ, respectively) in bronchoalveolar lavage (BAL) fluid, suppressed recruitment of inflammatory cells in BAL fluid and lung, and inhibited BAL fluid neutrophilia. It also ameliorated goblet cell metaplasia and bronchial fibrosis. Splenocytes flow cytometry revealed increased percentage of CD4(+) CD25(+) FOXP3(+) Treg cells by Adalimumab that was associated with increase in their suppressive activity as shown by elevated BAL fluid IL-10. We conclude that the beneficial effects of Adalimumab in this CD1 neutrophilic model of allergic airway inflammation are attributed to augmentation of Treg cell number and activity.

Differential metformin dose-dependent effects on cognition in rats: role of Akt.

RATIONAL: Epidemiological evidence suggests that individuals with diabetes mellitus are at greater risk of developing Alzheimer's disease, and controversy overwhelms the usefulness of the widely prescribed insulin-sensitizing drug, metformin, on cognition. OBJECTIVES: Through the scopolamine-induced memory deficit model, we investigated metformin influence on cognitive dysfunction and explored underlying mechanisms. METHODS: Sixty adult male Wistar rats were randomly assigned into 5 groups (12 rats each) to receive either normal saline, scopolamine 1 mg/kg intraperitoneally once daily, scopolamine + oral metformin (100 mg/kg/day), scopolamine + oral metformin (300 mg/kg/day) or scopolamine + oral rivastigmine (0.75 mg/kg/day) for 14 days. Cognitive behaviours were tested using Morris water maze and passive avoidance tasks. Biochemically, brain oxidative (malondialdehyde) and inflammatory (TNF-α) markers, nitric oxide, Akt, phospho-Akt, phospho-tau and acetyl cholinesterase activity in hippocampal and cortical tissues were assessed. RESULTS: The lower dose of metformin (100 mg/kg) ameliorated scopolamine-induced impaired performance in both Morris water maze and passive avoidance tasks, and was associated with significant reduction of inflammation and to a lesser extent oxidative stress versus rivastigmine. Given the role of total Akt in regulation of abnormal tau accumulation and degradation, our finding that metformin 100 decreased the elevated total Akt while increasing its phosphorylated form explains its beneficial modulatory effect on phosphorylated tau in both tissues, and could further clarify its protection against memory impairment. CONCLUSION: Metformin, only in the average human antidiabetic dose, offers a protective effect against scopolamine-induced cognitive impairment, while no deleterious effect was observed with the higher dose, which may support a bonus effect of metformin in type 2 diabetic patients.

The hydrogen sulfide releasing compounds ATB-346 and diallyl trisulfide attenuate streptozotocin-induced cognitive impairment, neuroinflammation, and oxidative stress in rats: involvement of asymmetric dimethylarginine.

Hydrogen sulfide (H2S) has attracted interest as a gaseous mediator involved in diverse processes in the nervous system, particularly with respect to learning and memory. However, its therapeutic potential in Alzheimer disease (AD) is not fully explored. Therefore, the effects of H2S-releasing compounds against AD-like behavioural and biochemical abnormalities were investigated. Memory deficit was induced by intracerberoventicular injection of streptozotocin (STZ, 3 mg·kg(-1)). Animals were randomly assigned into 5 groups (12 rats each): normal control, STZ treated, and 3 drug-treated groups receiving naproxen, H2S-releasing naproxen (ATB-346), and diallyl trisulfide in 20, 32, 40 mg·kg(-1)·day(-1), respectively. Memory function was assessed by passive avoidance and T-maze tasks. After 21 days, hippocampal IL-6, malondialdehyde, reduced glutathione (GSH), asymmetric dimethylarginine (ADMA), and acetylcholinestrase activity were determined. ATB-346 and diallyl trisulfide ameliorated behavioural performance and reduced malondialdehyde, ADMA, and acetylcholinestrase activity while increasing GSH. This study demonstrates the beneficial effects of H2S release in STZ-induced memory impairment by modulation of neuroinflammation, oxidative stress, and cholinergic function. It also delineates the implication of ADMA to the cognitive impairment induced by STZ. These findings draw the attention to H2S-releasing compounds as new candidates for treating neurodegenerative disorders that have prominent oxidative and inflammatory components such as AD.

Suppression of connective tissue growth factor mediates the renoprotective effect of Sitagliptin rather than Pioglitazone in type 2 diabetes mellitus.

AIM: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease, and thus, the ability of antidiabetic drugs to ameliorate renal microvascular disease may be as important as their ability to control blood glucose. Therefore, we investigated the reno-protective effect of the antidiabetic drugs, Sitagliptin and Pioglitazone, versus combined Metformin/Enalapril in a rat model of type 2 diabetes. METHOD: Male Wistar rats were randomly assigned to be either normal control or diabetic. Induction of type 2 diabetes was done by intraperitoneal injection of\ low dose streptozotocin (35mg/kg) on top of 2 weeks of high fat diet. Hyperglycemic animals were divided into 4 groups: untreated diabetic, Sitagliptin (10mg/kg), Pioglitazone (10mg/kg) and Metformin/Enalapril (500, 10mg/kg, respectively) treated. After 6 weeks, fasting blood glucose, plasma insulin, ß-cell function, insulin resistance, serum lipids, urea & creatinine, albuminurea, kidney weight, renal oxidative stress, plasma connective tissue growth factor (CTGF) and renal histopathology were assessed. KEY FINDINGS: Sitagliptin decreased microalbuminurea, urea & creatinine, renal tropism, oxidative stress and CTGF to levels similar to Metformin/Enalapril group. It also preserved near normal renal histology. Although Pioglitazone treatment reduced urea, creatinine, renal tropism and oxidative stress, it did not improve renal pathological changes or significantly alter CTCF. SIGNIFICANCE: Early Sitagliptin treatment in type 2 diabetes can equally ameliorate renal functions and structural changes as combined Metformin/Enalapril. Moreover Sitagliptin is a better renoprotective than Pioglitazone, probably due to its suppressor effect on CTGF, a key factor mediating diabetic renal injury.