Vitamin D is associated with metabotropic but not neurotrophic effects of exercise in ovariectomized rats

Aerobic training with moderate or high doses of vitamin D improve liver enzymes, LXRα and PGC-1α levels in rats with T2DM

Dysregulation of key transcription factors involved in hepatic energy metabolism, such as peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and liver X receptor alpha (LXRα), has been observed in T2DM. The present study aims to investigate the effects of aerobic training and vitamin D supplementation on liver enzyme levels and the levels of PGC-1α and LXRα proteins in hepatocytes, in a rat model of T2DM. The study involved 56 male Wistar rats, divided into two groups: one was non-diabetic and acted as a control group (n = 8), and the other had induced diabetes (n = 48). The diabetic rats were then split into six subgroups: two groups received high or moderate doses of vitamin D and aerobic training (D + AT + HD and D + AT + MD); two groups received high or moderate doses of vitamin D alone (D + HD and D + MD); one group underwent aerobic training with vehicle (sesame oil; D + AT + oil), and one group was a diabetic control receiving only sesame oil (oil-receiving). The D + AT + HD and D + HD groups received 10,000 IU of vitamin D, while the D + AT + MD and D + MD groups received 5000 IU of vitamin D once a week by injection. The D + AT + oil group and the sham group received sesame oil. After eight weeks of treatment, body weight, BMI, food intake, serum insulin, glucose, 25-hydroxyvitamin D, ALT, AST, and visceral fat were measured. The levels of PGC-1α and LXRα proteins in the liver was assessed by western blotting. Statistical analysis was performed using the paired t-test, one-way analysis of variance (ANOVA), and the Tukey post hoc test at a significance level of P < 0.05. Body weight, food intake, and BMI decreased significantly in the D + AT + HD, D + AT + MD, D + AT + oil, D + HD, and D + MD groups with the highest reduction being observed in body weight and BMI in the D + AT + HD group. The D + AT + HD group exhibited the lowest levels of insulin, glucose, and HOMA-IR while the D + C group exhibited the highest levels among the diabetic groups. The D + AT + HD and D + AT + MD groups had lower levels of ALT and AST enzymes compared to the other groups with no significant difference between D + AT + HD and D + AT + MD. D + AT + HD (p = 0.001), D + AT + MD (p = 0.001), D + HD (p = 0.023), D + MD (p = 0.029), and D + AT + oil (p = 0.011) upregulated LXRα compared to D + C. Among these groups, D + AT + HD exhibited a more profound upregulation of LXRα than D + AT + MD, D + AT + oil, D + HD, and D + MD (p = 0.005; p = 0.002, p = 0.001, and p = 0.001, respectively). Similarly, D + AT + HD showed a more notable upregulation of PGC-1α compared to D + AT + oil, D + HD, and D + MD (p = 0.002; p = 0.001, and p = 0.001, respectively). Pearson correlation tests showed significant and negative correlations between serum 25-hydroxyvitamin levels and both visceral fat (r = - 0.365; p = 0.005) and HOMA-IR (r = - 0.118; p = 0.009); while positive and significant correlations between the liver-to-bodyweight ratio with both ALT and AST enzymes and also between QUICKI levels with LXRα (r = 0.578; p = 0.001) and PGC-1α (r = 0.628; p = 0.001). Combined administration of aerobic training and vitamin D supplementation potentially improves liver enzymes in type-2 diabetic rats that were simultaneous with upregulating the levels of PGC-1α and LXRα proteins in hepatocytes. These improvements were more significant when combining exercise with high-dose vitamin D supplementation. This study highlights the potential of this combination therapy as a new diabetes treatment strategy.

Therapeutic Effects Of Combined and Chronic Treatment of Tat-GluA23y and D-Serine on Cognitive Dysfunction in Postmenopausal Rats

BACKGROUND

The incidence of Alzheimer's disease (AD) in female gender compared with male has been addressed as a health concern, particularly in menopausal age. We here hypothesized that co-administration of NMDARs agonist (D-serine) and AMPARs endocytosis inhibitor (Tat-GluA23y) might be a potential target for alleviating memory impairment in sporadic Alzheimer model of rats.

METHODS

Forty-eight female Wistar rats weighing 200-220 randomly divided into six groups. One month later, ovariectomized rats underwent stereotaxic surgery and were cannulated into the brain lateral ventricles. Streptozotocin was injected (3 mg/kg), then animals received the related treatments until the day 51, which experienced acquisition of spatial memory in Morris Water Maze test. Finally, the level of phosphorylated cAMP response element binding protein (CREB) in the hippocampus was measured by Western blotting.

RESULTS

Co-administration of D-serine and GluA23y significantly enhanced the acquisition and retrieval of impaired spatial memory in ovariectomized rats with AD (p < .001). Compared to Glu-A 23, D-serine caused more improvement in the mentioned parameters above, however, these values for both groups were still significantly different from the control group (P < .05).

CONCLUSION

Simultaneous treatment with D-serine and GluA23y synergistically improved STZ induced spatial memory impairment in OVX rat, probably partly via increase in phosphorylated CREB protein.

Concurrent high-intensity interval training and probiotic supplementation improve associative memory via increase in insulin sensitivity in ovariectomized rats

OBJECTIVES

Metabolic syndrome (MetS) is a serious concern among postmenopausal women which predisposes them to cardiovascular and cognitive disorders. Healthful diet and exercise training have been essential strategies to prevent the progress of MetS. The aim of this study was to evaluate the effect of supplementation with a native potential probiotic and high-intensity interval training (HIIT) for 8 weeks on retention of associative memory in rats with ovariectomy- induced metabolic syndrome.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into four groups (n = 8/group): Control (OVX + Veh), exercise (OVX + Exe), probiotic (OVX + Pro), exercise with probiotic (OVX + Exe + Pro). One sham surgery group was included as a control group. Animals received 8 weeks interventions, and then were tested in a step through passive avoidance learning and memory paradigm, to assess long term memory. Then serum levels of adiponectin, insulin and glucose were measured by ELISA and colorimetry respectively. Data were analyzed by Kruskal-Wallis, Mann-Whitney and also One-way analysis of variance (ANOVA).

RESULTS

Eight weeks of HIIT and probiotic supplementation caused an increase in step through latency and shortening of total time spent in the dark compartment in OVX + Exe + Pro group compared with OVX + Veh group. Also significant increase in serum adiponectin levels, in parallel with a reduction in glucose, insulin and HOMA-IR were achieved by the group of OVX + Exe + Pro.

CONCLUSION

The present study indicates that HIIT combined with probiotics supplementation for 8 weeks effectively improves associative memory in MetS model of rats partly via improving insulin sensitivity and adiponectin level.

Effects of aerobic training and vitamin D supplementation on glycemic indices and adipose tissue gene expression in type 2 diabetic rats

Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder mainly caused by overweight and obesity that accumulates pro-inflammatory factors in adipose tissue. Studies have confirmed the efficacy of exercise and vitamin D supplementation in preventing, controlling, and treating diabetes. While, reduced physical activity and vitamin D deficiency are related to increased adiposity, blood glucose level, insulin concentration, and insulin resistance. This study purposed to investigate the effect of 8-week aerobic training with vitamin D supplementation on the expression of AMPK, PGC-1α, and UCP-1 genes expression in the visceral adipose tissue of obese rats with T2DM. In this experimental study, fifty male Wistar rats were divided into 5 groups (n = 10): aerobic training and vitamin D supplementation (AT + Vit D), aerobic training (5 days/week for 8 weeks; AT), vitamin D supplementation (Vit D), diabetic control (C) and NC (Non-Diabetic Control). AT + Vit D and AT groups practiced an 8-week aerobic training, 5 days a week. Vit D and AT + Vit D groups receive 5000 IU of vitamin D by injection once a week while AT and C received sesame oil. After blood sampling, visceral fat was taken to measure AMPK, PGC-1α, and UCP1 gene expression. Data were statistically analyzed by One-way ANOVA and paired sample t-test at a significance level of p < 0.05. Based on our results BW, BMI, WC, visceral fat, insulin, glucose, and HOMA-IR were significantly lower in the AT + Vit D, AT, and Vit D groups compared with the C group (p < 0.01). Furthermore, AT + Vit D, AT, and Vit D upregulated AMPK, PGC-1α, and UCP1 gene expression compared to the C. Based on the results compared to AT and Vit D, AT + Vit D significantly upregulated AMPK (p = 0.004; p = 0.001), PGC-1α (p = 0.010; p = 0.001), and UCP1 (p = 0.032; p = 0.001) gene expression, respectively. Also, AT induced more significant upregulations in the AMPK (p = 0.001), PGC-1α (p = 0.001), and UCP1 gene expression (p = 0.001) than Vit D. Vitamin D supplementation enhanced the beneficial effects of aerobic training on BW, BMI, WC, visceral fat, insulin, glucose, and HOMA-IR in diabetic rats. We also observed that separate AT or Vit D upregulated the gene expression of AMPK, PGC-1α, and UCP1 however, combined AT + Vit D upregulated AMPK, PGC-1α, and UCP1 more significantly. These results suggested that combining aerobic training and vitamin D supplementation exerted incremental effects on the gene expressions related to adipose tissue in animal models of diabetes.

Profiling inflammatory mechanisms, hyperphosphorylated tau of hippocampal tissue and spatial memory following vitamin D3 treatment in the mice model of vascular dementia

BACKGROUND

The aim of this study was to investigate the effect of vitamin D3 (VitD3) on inflammatory mechanisms, hyperphosphorylated tau (p-tau) in the hippocampus, and cognitive impairment of the mouse model of vascular dementia (VaD).

METHODS

In this study, 32 male mice were randomly assigned to the control, VaD, VitD3 (300 IU/Kg/day), and VitD3 (500 IU/Kg/day) groups. VaD and VitD3 groups were gavaged daily for 4 weeks with a gastric needle. For biochemical assessments, blood samples and the hippocampus were isolated. IL-1β and TNF-α were analyzed by ELISA, and p-tau and other inflammatory molecules were measured by western blot.

RESULTS

VitD3 supplements significantly (P < 0.05) decreased the level of inflammatory factors in the hippocampus and prevented apoptosis. However, regarding p-tau in hippocampal tissue, this decrease was not statistically significant (P > 0.05). The results of behavioral assessments showed that VitD3 significantly improved the spatial memory of treated mice.

CONCLUSION

These results suggest that the neuroprotective effects of VitD3 are mainly associated with their anti-inflammatory effects.

Metabotropic Effect of Probiotic Supplementation and High-Intensity Interval Training in Menopause-Induced Metabolic Syndrome in Rats

OBJECTIVES

This study aimed to investigate the interactive effect of supplementation with a native potential probiotic lactobacillus and 8-week high-intensity interval training (HIIT) on insulin resistance and dyslipidemia in a menopause-induced metabolic syndrome.

METHODS

A total of 40 ovariectomized (OVX) Wistar rats were divided into five groups: control (OVX + Vehicle), exercise (EXE) (OVX + Exe), probiotic (Prob) (OVX + Prob), exercise and probiotic (OVX + Exe + Prob), and sham surgery. After the end of the treatment interventions, body weight, body mass index (BMI), waist circumference (WC), visceral fat, and serum concentrations of glucose, insulin, lipid profile, and adiponectin were measured using colorimetric analysis and enzyme-linked immunosorbent assay, respectively.

RESULTS

Data revealed a significant decrease in weight, waist circumference , visceral fat, BMI, and levels of glucose, insulin, homeostasis model assessment of insulin resistance, triacylglyceride, total cholesterol, and low-density lipoprotein (LDL), but an increase in high-density lipoprotein and adiponectin levels (P = 0.001), in OVX + Exe + Prob compared with the OVX + Vehicle group.

CONCLUSIONS

The present study indicates that native probiotic lactobacillus combined with HIIT effectively reduces body weight, visceral fat, and levels of LDL, glucose, and insulin and increases adiponectin level, although exercise contributes more to fat reduction and probiotics to insulin resistance.

Irisin is an Effector Molecule in Exercise Rehabilitation Following Myocardial Infarction (Review)

Background: Regular exercise is an effective non-pharmacological therapy for treatment and prevention of cardiovascular disease (CVD). The therapeutic benefits of exercise are mediated partly through improved vascular and increase in metabolic health. Release of exercise-responsive myokines, including irisin, is associated with beneficial effects of exercise in CVD patients.

Observations: The present review provides an overview of the role of exercise in cardiac rehabilitation of patients with myocardial infarction (MI). Further, the role of irisin as a motion-responsive molecule in improving vascular and metabolic health is explored. Possible mechanism of cardioprotective effect of irisin-mediated exercise on myocardial infarction are also summarized in this review.

Conclusion and significance of the review: Irisin is associated with reduced inflammation, antioxidant properties, and anti-apoptotic effect, implying that it is a potential key mediator of the beneficial effects of exercise on vascular and metabolic health. The findings show that irisin is a promising therapeutic target for treatment of patients with cardiovascular disease, particularly post-MI. Further research should be conducted to elucidate the potential mechanisms of cardioprotective effects of irisin and explored whether irisin induced by exercise exerts rehabilitation effects post-MI.

Correlation between vitamin D and serum brain derived neurotropic factor levels in type 2 diabetes mellitus patients

Diabetes Mellitus (DM) currently ranks as the most common endocrine disorder worldwide. Current opinion views DM as a group of heterogeneous metabolic diseases characterized by hyperglycemia triggered by defects in the ability of the body to produce or use insulin in type 1 and 2 DM, respectively. Brain-derived neurotrophic factor (BDNF), one of the neurotrophin family of growth factors, has been linked to the pathogenesis of DM and insulin resistance. Moreover, vitamin D has been associated with insulin resistance and DM. Recently, the interactions between vitamin D and BDNF have been investigated in diabetic rats. However, this correlation has never been investigated in humans. Thus, the aim of the present study was to assess the alterations in serum BDNF and vitamin D levels in T2DM patients in Jordan, prior to and following vitamin D supplementation. A combination of non-experimental case-control and experimental designed studies were utilized to assess the relationship between serum BDNF and vitamin D levels in T2DM patients. The levels of BDNF and vitamin D were measured using commercially available ELISA kits, and fasting blood glucose (FBG) and HbA1c levels were measured in medical labs. The results showed that diabetic patients had lower levels of serum vitamin D and higher levels of BDNF compared with the healthy controls. Moreover, linear regression analysis indicated that BDNF levels were inversely correlated with serum vitamin D levels. Furthermore, vitamin D supplementation significantly increased vitamin D serum levels and decreased BDNF serum levels in diabetic patients. Intriguingly, FBG and HbA1c levels were significantly improved post vitamin D supplementation. These data demonstrate a positive effect of vitamin D supplementation in diabetic patients suggesting the implementation of vitamin D as part of future T2DM treatment plans. However, additional studies are needed to investigate the direct link between vitamin D, BDNF, and T2DM.

Effects of inhibiting astrocytes and BET/BRD4 chromatin reader on spatial memory and synaptic proteins in rats with Alzheimer's disease

Communication between astrocytes and neurons has a profound effect on the pathophysiology of Alzheimer's disease (AD). Astrocytes regulate homeostasis and increase synaptic plasticity in physiological situations, however, they become activated during the progression of AD. Whether or not these reactions are supportive or detrimental for the central nervous system have not been understood yet. Considering epigenetic regulation of neuroinflammatory genes by chromatin readers, particularly bromodomain and extraterminal domain (BET) family, here we examined the effect of chronic co-inhibition of astrocytes metabolism (with fluorocitrate) and also BRD4 (with JQ1) on cognition deficit at early stages of AD. Forty adult male Wistar rats underwent stereotaxic cannulation for inducing AD by intrahippocampal injection of Aβ1-42 (4 μg/8 μl/rat). Then animals were divided into five groups of Saline+DMSO, Aβ + saline+DMSO, Aβ + JQ1, Aβ + FC (fluorocitrate), and Aβ + JQ1 + FC and received the related treatments. Two weeks later, spatial memory was recorded by Morris Water Maze (MWM), and the levels of phosphorylated cyclic-AMP response element binding protein (CREB), postsynaptic density 95 (PSD95), synaptophysin (SYP), and tumor necrosis factor-alpha (TNF-α) were measured in the hippocampus by western blotting and RT-qPCR. Administration of JQ1 significantly improved both acquisition and retrieval of spatial memory, which were evident by decreased escape latency and increased total time spent (TTS) in target quadrant, and significant rise in p-CREB, PSD95, and synaptophysin compared with Aβ + saline+DMSO group. In contrast, both groups receiving FC demonstrated memory decline, and reduction in p-CREB, PSD95 and synaptophysin in parallel with increase in TNF-α. Our data indicate that chronic inhibition of BRD4 significantly restores memory impaired by amyloid β partly via CREB signaling and upregulating synaptic proteins of PSD95 and synaptophysin. However, inhibition of astrocytes nullifies the memory-boosting effects of JQ1 and reduces CREB/PSD95/synaptophysin levels in hippocampus.

Exercise Training Improves Memory Performance in Older Adults: A Narrative Review of Evidence and Possible Mechanisms

Exercise, neurotransmitters, growth factors, myokines, and potential effects on the brain.

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Sex-Independent Cognition Improvement in Response to Kaempferol in the Model of Sporadic Alzheimer's Disease

Alzheimer's disease (AD) is associated with neural oxidative stress and inflammation, and it is assumed to affect more women than men with unknown mechanisms. Kaempferol (KMP) as a potent natural antioxidant has been known to exhibit various biological and pharmacological functions, including antioxidant and anti-inflammatory. We aimed here to evaluate the role of gender difference in response to KMP on the rat model of sporadic AD. Forty-six female and male Wistar rats were divided into six groups of sham, streptozotocin (STZ) + saline (SAL), STZ + KMP. Female rats were ovariectomized, and then all animals received an intracerebroventricular bilateral injection of STZ (3 mg/kg) to induce the AD model. KMP (10 mg/kg) was intraperitoneally administered for 21 consecutive days. Afterward, spatial learning and memory were assessed via the Morris water maze task (MWM). Finally, the hippocampus level of superoxide dismutase (SOD), glutathione, and malondialdehyde were measured using calorimetric kits. Data showed a significant cognition deficit in STZ + SAL compared with the sham. To sum up, we reported that chronic KMP treatment increase significantly improved acquisition and retrieval of spatial memory as evident by longer TTS (total time spent) and short-latency to the platform in MWM. In addition, KMP increased the levels of SOD and glutathione in the hippocampus of rats. Also, KMP decreased hippocampal levels of malondialdehyde in both genders. In conclusion, KMP successfully restores spatial memory impairment independent of gender difference. This memory restoration may at least in part be mediated through boosting the hippocampal level of SOD and glutathione.

Synergistic enhancing-memory effect of D-serine and RU360, a mitochondrial calcium uniporter blocker in rat model of Alzheimer's disease

BACKGROUND

Although Amyloid beta (Aβ) and N - methyl d- aspartate receptors (NMDARs are involved in Ca²⁺ neurotoxicity, the function of mitochondrial calcium uniporter in cognition deficit remain uncertain. Here, we examined the effect of mitochondrial calcium uniporter (MCU) blocker, together with NMDA receptor agonist d-cycloserine (DCS) on memory impairment in a rat model of AD.

METHODS

Forty adult male Wistar rats underwent stereotaxic cannulation for inducing AD by intracerebroventricular (ICV) injection of Aβ_1-42 (5 μg /8 μl/rat). Then animals were divided into 5 groups of: Saline + Saline, Aβ + Saline, Aβ + RU360, Aβ + DCS, Aβ + RU360 + DCS. Two weeks after the treatments, Morris Water Maze (MWM) and step through passive avoidance learning (SPL) were undertaken for evaluating of spatial and associative memories, respectively. Hippocampal level of cyclic-AMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were measured by western blot and ELISA.

RESULTS

Co - administration of RU360 and DCS significantly improved both acquisition and retrieval of spatial memory as evident by decreased escape latency and increased time spent in the target quadrant (TTS) in MWM, together with increase in step-through latency, but reduced time spent in the dark compartment in SPL. Furthermore, there was a significant rise in the hippocampal level of CREB and BDNF in comparison with Aβ + Saline.

CONCLUSION

The present study supports the idea that co- administration of RU360 and DCS ameliorate memory impairment induced by Aβ _1-42 probably via CREB / BDNF signaling.

Neuregulin1β improves both spatial and associative learning and memory in Alzheimer model of rats possibly through signaling pathways other than Erk1/2

BACKGROUND

Neuregulin-1β (NRG1 β) is associated with various neurological disorders such as schizophrenia, depression and Parkinson's disease. However, its role in Alzheimer's (AD) has not been understood yet. Here, we have studied the effect of NRG1 β and extracellular-signal-regulated kinase (ERK) signaling on special and associative memories and emotional stress in AD model of rats.

METHODS

Fifty six male Wistar rats were divided into eight groups of: Saline + Saline, Aβ + Saline, Aβ + NRG1β (5 μg/5 ul), Aβ + PBS, Aβ + NRG1β + PD98059 (PD, 5 μg/2 μl), Aβ + NRG1β + Saline and Saline + PD. AD model was induced by intracerebroventricular (ICV) injection of beta-amyloid protein (Aβ1-42, 4 μg/2 μl). The cognitive performances of rats were evaluated using Morris Water Maze (MWM) and Step through passive avoidance. Also locomotors activity and emotionality of animals were considered in an Open field test. Data were analyzed by one way Anova one way, repeated measure and T-test.

RESULTS

Significant improvement was found in spatial learning and memory assessed by total time spent in target quadrant [F (4, 32) = 12.4, p = 0.001], escape latency [F (4, 32) = 15.767, p = 0.001] and distance moved [F (4, 32) = 5.55, p = 0.002], in Aβ + NRG1β compared with Aβ + Saline in MWM. Also Aβ + NRG1β showed long latencies to enter into the dark compartment [F (4, 32) = 6.43, p = 0.001], but short time spent [F (4, 32) =6.93, p = 0.001] compared with control. Administration of an ERK inhibitor (PD98059, 5 μg, 15 min before NRG1β) didn't completely block learning memory restored by NRG1β in AD model (p = 0.7). No significant between groups differences was found in emotional stress characteristics in open field, except the grooming numbers which were higher in Saline + PD compared with Saline + Saline (p = 0.02).

CONCLUSION

Our findings indicate that NRG1β restores cognitive dysfunctions induced by amyloid β through signaling pathways possibly other than Erk1/2, with no significant change in anxiety, locomotion and vegetative activities.

Co-treatment of vitamin D supplementation and aerobic training improves memory deficit in ovariectomized rat

Objective: Metabolic syndrome (MetS) and insufficient vitamin D levels are globally increasing phenomena which are correlated with cognitive impairment. This study investigated the interactive effect of aerobic training with vitamin D supplementation on memory deficit in rats with metabolic syndrome induced by ovariectomy.Methods: A total of forty Wistar rats weighing 240-255 gr were randomly matched on their body weight and divided into ovariectomy (OVX, n = 32) and sham-operated (SHAM; n = 8) groups. OV group was then divided into vitamin D supplementation (OVX + Vit D; 10000 IU/kg/week, for 8 weeks, n = 8), aerobic training (OVX + AT; n = 8), aerobic training and vitamin D supplementation (OVX + AT + Vit D; 10000 IU/kg/week, for 8 weeks, n = 8), and vehicle control group receiving sesame oil (OVX + Ses Oil; n = 8). After the end of intervention, passive avoidance learning and memory were assessed in step through passive avoidance paradigm. Obtained data were analyzed by ANOVA and post hoc Tukey test.Results: After 8 weeks of aerobic training and vitamin D supplementation, step through dark compartment latency (STL) was significantly higher and total time spent in that compartment (TSD) was lower in OVX + AT + Vit D compared to the other counterpart groups.Conclusion: Vitamin D supplementation combined with 8-week aerobic training alleviates cognitive impairment metabolic syndrome induced by ovariectomy.

Association of Circulating 25-Hydroxyvitamin D Levels with Colorectal Cancer: An Updated Meta-Analysis

A higher serum 25-hydroxyvitamin D (25(OH)D) concentration benefits colorectal cancer prevention. However, whether it can improve the prognosis among patients is still under discussion. This study aims to explore the impacts of high level 25(OH)D on the survival of colorectal cancer patients. PubMed, Embase, and Cochrane were searched from January 2000 to August 2017 for relevant articles. Only published studies focusing on the relationship between 25(OH)D levels at or near the time of diagnosis and survival were considered. Two review authors independently assessed the risk of bias for each study, and any disagreement was resolved by discussion or by involving a third assessor. Eleven studies comprising 7,367 patients were included. In these studies, there were considerable differences between the higher 25(OH)D level group and the lower group in terms of overall survival (OS), progression-free survival (PFS) and colorectal cancer-specific survival (CSS) in a random effect model (OS: HR 0.67, 95% CI 0.56-0.80, p<0.00001; CSS: HR 0.73, 95% CI 0.55-0.97, p=0.03; PFS: HR 0.74, 95% CI 0.61-0.90, p=0.003). Moreover, the combined hazard ratios of OS and CSS had considerably significant heterogeneity which may be explained by subgroup analysis. The relationship between 25(OH)D and tumor characteristics/lifestyle factors was also included in the meta-analysis. BMI (p=0.03), smoking (p=0.03) and physical activity (p=0.002) seemed to be associated with circulating 25(OH)D level. Publication bias was undetected. Colorectal cancer patients with higher circulating 25(OH)D level may have a better prognosis.

Linking the metabolic syndrome and obesity with vitamin D status: risks and opportunities for improving cardiometabolic health and well-being

The global death toll from noncommunicable diseases is exceptionally high, reported to cause 71% of global deaths worldwide. Metabolic syndrome risk factors, especially excessive adiposity and obesity, are at the heart of the problem resulting in increased co-morbidities such as cardiometabolic diseases and cancer, increased health costs, poorer quality of life, and shortened survival. Vitamin D₃ can positively reverse many of these adverse effects and outcomes through blocking signaling mechanisms that predispose to cardiometabolic and metastatic disease. As an affordable natural agent, vitamin D₃ can be used to counteract obesity-induced inflammation, block early adipogenesis, enhance glucose uptake, counteract hyperleptinemia, ameliorate insulin resistance, and reduce hypertension. This is supported by data from in vitro, in vivo and epidemiological studies and clinical trials. We propose that everyone in general and obese patients in particular consider raising 25-hydroxyvitamin D levels through UVB exposure and/or supplemental vitamin D₃ intake to reduce cardiometabolic and metastatic disease and increase longevity.

Flavonoids Fraction of Mespilus Germanica Alleviates Insulin Resistance in Metabolic Syndrome Model of Ovariectomized Rats via Reduction in Tumor Necrosis Factor-α

Objectives

The rate of metabolic syndrome (MetS) in women diagnosed as they age is one of the main concerns of health cares. Recently new strategies used to prevent progressions of MetS toward the diagnosis of diabetes have focused on plant flavonoids. This study was aimed to investigate the beneficial effects of flavonoids fraction of Mespilus germanica leaves (MGL) on MetS in ovariectomized (OVX) rats.

Methods

Twenty-four adult female Wistar rats, weighing 200 to 250 g, were divided into 3 groups: Sham surgery, OVX + Salin, or OVX + Flavonoid. Three weeks after ovariectomy, animals displayed MetS criteria received flavonoid injection (10 mg/kg, intraperitoneally) for 21 days. Then the body weight, body mass index, waist circumference, visceral fat, fasting blood glucose, serum insulin, lipid profiles and tumor necrosis factor-α (TNF-α) were measured.

Results

Treatment with flavonoids fraction of MGL significantly decreased serum level of insulin (P = 0.011), glucose (P = 0.024), TNF-α (P = 0.010), also MetS Z score (P = 0.020) and homeostasis model assessment of insulin resistance (P = 0.007). Lipid profiles and visceral fat showed insignificant reduction.

Conclusions

Flavonoids of MGL attenuates some of the MetS components possibly via reduction in TNF-α inflammatory cytokine.

Kaempferol attenuates cognitive deficit via regulating oxidative stress and neuroinflammation in an ovariectomized rat model of sporadic dementia

Alzheimer's disease (AD) is associated with oxidative stress, and ultimately results in cognitive deficit. Despite existing literature on the pathophysiology of AD, there is currently no cure for AD. The present study investigated the effects of kaempferol (Kmp) isolated from the extract of Mespilus germanica L. (medlar) leaves on cognitive impairment, hippocampal antioxidants, apoptosis, lipid peroxidation and neuro-inflammation markers in ovariectomized (OVX) rat models of sporadic AD. Kaempferol, as the main flavonoid of medlar extract has been previously known for anti-oxidative, anti-inflammatory and anti-neurotoxic effects. Thirty-two female Wistar rats were ovariectomized, and randomly divided into four groups: sham, OVX + saline, OVX + streptozotocin (STZ) + saline, OVX + STZ + Kmp. Animals received intracerebroventricular injection of STZ (3 mg/kg, twice with one day interval) to establish models of sporadic AD. Intraperitoneal injection of Kmp (10 mg/kg) for 21 days was performed in the OVX + STZ + Kmp group. Spatial learning and memory of rats were evaluated using a Morris water maze. Finally, brain homogenates were used for biochemical analysis by enzyme-linked immunosorbent assay. The results showed a significant improvement in spatial learning and memory as evidenced by shortened escape latency and searching distance in Morris water maze in the OVX + STZ + Kmp group compared with the OVX + STZ group. Kmp also exhibited significant elevations in brain levels of antioxidant enzymes of superoxide dismutase and glutathione, while reduction in tumor necrosis factor-α and malondialdehyde. Our results demonstrate that Kmp is capable of alleviating STZ-induced memory impairment in OVX rats, probably by elevating endogenous hippocampal antioxidants of superoxide dismutase and glutathione, and reducing neuroinflammation. This study suggests that Kmp may be a potential neuroprotective agent against cognitive deficit in AD.