Nutraceuticals against Neurodegeneration: A Mechanistic Insight

The mechanisms underlying neurodegenerative disorders are complex and multifactorial; however, accumulating evidences suggest few common shared pathways. These common pathways include mitochondrial dysfunction, intracellular Ca²⁺ overload, oxidative stress and inflammation. Often multiple pathways co-exist, and therefore limit the benefits of therapeutic interventions. Nutraceuticals have recently gained importance owing to their multifaceted effects. These food-based approaches are believed to target multiple pathways in a slow but more physiological manner without causing severe adverse effects. Available information strongly supports the notion that apart from preventing the onset of neuronal damage, nutraceuticals can potentially attenuate the continued progression of neuronal destruction. In this article, we i) review the common pathways involved in the pathogenesis of the toxicants-induced neurotoxicity and neurodegenerative disorders with special emphasis on Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Multiple sclerosis (MS) and Amyotrophic lateral sclerosis (ALS), and ii) summarize current research advancements on the effects of nutraceuticals against these detrimental pathways.

MUC1 Vaccines, Comprised of Glycosylated or Non-Glycosylated Peptides or Tumor-Derived MUC1, Can Circumvent Immunoediting to Control Tumor Growth in MUC1 Transgenic Mice

It remains challenging to produce decisive vaccines against MUC1, a tumor-associated antigen widely expressed by pancreas, breast and other tumors. Employing clinically relevant mouse models, we ruled out such causes as irreversible T-cell tolerance, inadequate avidity, and failure of T-cells to recognize aberrantly glycosylated tumor MUC1. Instead, every tested MUC1 preparation, even non-glycosylated synthetic 9mer peptides, induced interferon gamma-producing CD4⁺ and CD8⁺ T-cells that recognized glycosylated variants including tumor-associated MUC1. Vaccination with synthetic peptides conferred protection as long as vaccination was repeated post tumor challenge. Failure to revaccinate post challenge was associated with down-regulated tumor MUC1 and MHC molecules. Surprisingly, direct admixture of MUC1-expressing tumor with MUC1-hyperimmune T-cells could not prevent tumor outgrowth or MUC1 immunoediting, whereas ex vivo activation of the hyperimmune T-cells prior to tumor admixture rendered them curative. Therefore, surrogate T-cell preactivation outside the tumor bed, either in culture or by repetitive vaccination, can overcome tumor escape.

A review of the use of melatonin in ulcerative colitis: experimental evidence and new approaches

: Ulcerative colitis (UC), an inflammatory bowel disease, affects many people across the globe, and its prevalence is increasing steadily. Inflammation and oxidative stress play a vital role in the perpetuation of inflammatory process and the subsequent DNA damage associated with the development of UC. UC induces not only local but also systemic damage, which involves the perturbation of multiple molecular pathways. Furthermore, UC leads to an increased risk of colorectal cancer, the third most common malignancy in humans. Most of the drugs used for the treatment of UC are unsatisfactory because they are generally mono-targeted, relatively ineffective and unaffordable for many people. Thus, agents that can target multiple molecular pathways and are less expensive have enormous potential to treat UC. Melatonin has beneficial effects against UC in experimental and clinical studies because of its ability to modulate several molecular pathways of inflammation, oxidative stress, fibrosis, and cellular injury. However, many novel targets are yet to be explored on which melatonin may act to exert its favorable effects in UC. It is time to explore improved intervention strategies with melatonin in UC on the basis of studies investigating different molecular targets using proteomic and genomic approaches. This review identifies various molecular targets for melatonin with the intent of providing novel strategies for combating UC and the associated extraintestinal manifestations of this debilitating disease.

Melatonin reduces ulcerative colitis-associated local and systemic damage in mice: investigation on possible mechanisms

BACKGROUND AND AIMS

Ulcerative colitis (UC) is a chronic gastrointestinal disorder. Substantial research reveals that melatonin has beneficial effects in ulcerative colitis both experimentally and clinically. We have previously reported that ulcerative colitis was associated with local and systemic damage in mice. The purpose of this study was to reveal the novel targets of melatonin in its protective mechanism against ulcerative colitis in mice. We also wished to determine whether or not melatonin protected against ulcerative colitis-induced systemic damage in mice.

METHODS

Ulcerative colitis was induced in mice by use of 3% (w/v) dextran sulfate sodium for two cycles. One cycle comprised 7 days of DSS-treated water followed by 14 days of normal drinking water. Melatonin was administered at doses of 2, 4, or 8 mg/kg bw/day, po throughout. The effect of melatonin in mice with UC was evaluated by use of biochemical data, histological evaluation, comet and micronucleus assays, immunohistochemistry, and western blot analysis.

RESULTS

The results indicated that melatonin treatment ameliorated the severity of ulcerative colitis by modulating a variety of molecular targets, for example nuclear factor kappa B, cyclooxygenase-2, interleukin 17, signal transducer and activator of transcription 3, nuclear erythroid 2-related factor 2, matrix metalloproteinase-9, and connective tissue growth factor. Further, ulcerative colitis increased gut permeability, plasma lipopolysaccharide level, systemic inflammation, and genotoxicity. Melatonin treatment led to mucosal healing and reduced ulcerative colitis-induced elevated gut permeability and reduced the plasma LPS level, systemic inflammation, and genotoxicity.

CONCLUSION

Melatonin ameliorated ulcerative colitis-associated local and systemic damage in mice.

Ulcerative colitis-induced hepatic damage in mice: studies on inflammation, fibrosis, oxidative DNA damage and GST-P expression

There exists a close relationship between ulcerative colitis and various hepatic disorders. The present study was aimed to evaluate the hepatocellular damage in experimental colitis model. Ulcerative colitis was induced in Swiss mice by cyclic treatment with 3% w/v dextran sulfate sodium in drinking water. The severity of colitis was assessed on the basis of disease activity index and colon histology. The effect of ulcerative colitis on the liver was assessed using various biochemical parameters, histological evaluation, sirius red staining, immunohistochemical staining with peroxisome proliferator-activated receptor γ, 8-oxo-7,8-dihydro-2'-deoxyguanosine and placental glutathione S-transferase, comet assay (alkaline and modified), Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling assay and western blot analysis to detect the protein expression of nuclear factor kappa B, cyclooxygenase-2, nuclear erythroid 2-related factor 2 and NADPH: quinone oxidoreductase-1. Dextran sulfate sodium induced severe colitis in mice as evident from an elevated disease activity index and histological abnormalities. Ulcerative colitis increased the permeability of colon as apparent from a significant reduction in the expression of tight junction protein, occludin. Further, the bacterial translocation assay as well as the analysis of lipopolysaccharide level revealed the existence of various bacterial species in the liver of ulcerative colitis-induced mice. There was a significant increase in the plasma alanine and aspartate transaminases and liver triglyceride levels, expression of peroxisome proliferator-activated receptor γ, inflammatory markers, oxidative stress, fibrosis, oxidative DNA damage and apoptosis in the liver of mice. Moreover, there was an increase in the expression of nuclear factor kappa B and cyclooxygenase-2 and a reduction in the expression of nuclear erythroid 2-related factor 2 and NADPH: quinone oxidoreductase-1 in the liver of severe ulcerative colitis-induced mice. The results of the present study provide evidence that ulcerative colitis is accompanied with hepatic damage in mice.

Dextran sulfate sodium-induced ulcerative colitis leads to increased hematopoiesis and induces both local as well as systemic genotoxicity in mice

Ulcerative colitis is a chronic gastrointestinal disorder eliciting the risk of colorectal cancer, the third most common malignancy in humans. The present study was aimed to characterize dextran sulfate sodium-induced ulcerative colitis and to elucidate its influence on the bone marrow cell proliferation and the subsequent stimulation of the systemic genotoxicity in mice. Experimental colitis was induced in Swiss mice using 3% (w/v) dextran sulfate sodium in drinking water. The severity of colitis was assessed on the basis of clinical signs, colon length, oxidative stress parameters, various pro-inflammatory markers, histopathological evaluation and immunohistochemical staining of 8-oxo-7,8-dihydro-2'-deoxyguanosine in the colon of dextran sulfate sodium treated mice. Further, assessment of genotoxicity was carried out using alkaline and modified comet assays in the colon and lymphocytes and micronucleus assay in the peripheral blood of mice. For the evaluation of inflammation-induced cell proliferation in the bone marrow, proliferating cell nuclear antigen immunostaining was carried out in the bone marrow of mice. Dextran sulfate sodium induced severe colitis as evident from the elevated disease activity index, reduced colon length, increased oxidative stress, histological abnormalities and oxidative DNA damage in the colon of mice. Moreover, colitis-induced elevated prostaglandin-E2 level in the plasma of dextran sulfate sodium treated mice stimulated the cell proliferation in the bone marrow, which further triggered colitis-induced DNA damage in the peripheral blood of mice.

Alkaline, Endo III and FPG modified comet assay as biomarkers for the detection of oxidative DNA damage in rats with experimentally induced diabetes

Increased production of reactive oxygen species under diabetic condition underlines the higher oxidatively damaged DNA in different tissues. However, it is practically difficult to assess the oxidatively damaged DNA in different internal organs. Therefore, the present study was aimed to evaluate the extent of oxidative stress-induced DNA damage in different organs with the progression of diabetes. Diabetic and control Sprague Dawley rats were sacrificed in time-dependent manner and the lung, liver, heart, aorta, kidney, pancreas and peripheral blood lymphocytes (PBL) were analyzed for both alkaline and modified comet assay with endonuclease-III (Endo III) and formamidopyrimidine-DNA glycosylase (FPG) (hereafter called modified comet assay) for the detection of oxidative DNA damage. The statistically significant increase in olive tail moment (OTM) was found in all the tested tissues. The extent of DNA damage was increased with the progression of diabetes as revealed by the parameter of OTM in alkaline and modified comet assay. Further, the positive correlations were observed between OTM of the lung, liver, heart, aorta, kidney and pancreas with PBL of diabetic rat in the alkaline and modified comet assay. Moreover, significant increase in the 8-oxodG positive nuclei in the lung, liver, heart, aorta, kidney and pancreas was observed in 4th and 8th week diabetic rat as compared to control. Results of the present study clearly indicated the suitability of alkaline and modified comet assay for the detection of multi-organ oxidative DNA damage in streptozotocin (STZ)-induced diabetic rat and showed that damaged DNA of PBL can be used as a suitable biomarker to assess the internal organs response to DNA damage in diabetes.