Hepatocellular carcinoma and vitamin D: a review.
The non-classical actions of vitamin D, namely antiproliferation, pro-differentiation, pro-apoptosis, anti-inflammation, and immune regulation, have received great attention during the past decade. Increasing evidence from epidemiological studies showing the inverse association between vitamin D status and incidence of many forms of cancer as well as biochemical studies has suggested that vitamin D deficiency may play a role in the cause and progression of these types of cancer. Recently, vitamin D and its analogs have been deemed as potential regimen to treat a variety of cancers alone or in combination with other drugs. Although, the epidemiologic evidence regarding the association of vitamin D and hepatocellular carcinoma (HCC) is still inconclusive, biochemical evidence clearly indicates that HCC cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss the current status of HCC and its treatment, the source, metabolism, functions, and the mechanism of actions of vitamin D, and the biochemical studies of vitamin D analogs and their implications in the prevention and treatment of HCC.
J Gastroenterol Hepatol. 2011 Nov;26(11):1597-603
Flaxseed and cardiovascular health.
Flaxseed and its components may improve cardiovascular health because of their numerous attributes. Flaxseed contains 35% of its mass as oil, of which 55% is alpha-linolenic acid (ALA). Flax meal, which is devoid of oil, contains the lignan secoisolariciresinol diglucoside (SDG). Flaxseed, flaxseed with very low ALA, flaxseed oil, flax lignan complex (FLC), and SDG reduce the development of hypercholesterolemic atherosclerosis by 46%, 69%, 0%, 73%, and 34%, respectively, in the rabbit model. FLC and SDG slow the progression of atherosclerosis but have no effect in regression of atherosclerosis. Suppression of atherosclerosis by flaxseed is the result of its lignan content and not the result of ALA content. Suppression of atherosclerosis is associated with lowering of serum lipids and antioxidant activity. Effects of flaxseed on serum lipids in experimental animals are variable from no change to slight reduction. Flaxseed oil does not affect serum lipids, except for a slight reduction in serum triglycerides. Lignan in general reduces serum total cholesterol and low-density lipoprotein cholesterol and raises serum high-density lipoprotein cholesterol. SDG and its metabolites have antioxidant activity. Flaxseed and flaxseed oil do not have antioxidant activity except they suppress oxygen radical production by white blood cells. Flaxseed oil/ALA has variable effects on inflammatory mediators/markers (interleukin [IL]-1beta, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-alpha, interferon-gamma, C-reactive protein, and serum amyloid A). Doses of ALA less than 14 g/d do not affect inflammatory mediators/markers, but 14 g/d or greater reduce inflammatory mediators/markers. Flaxseed oil decreases soluble vascular cell adhesion molecule-1 but has no effect on soluble intracellular adhesion molecule-1, soluble E-selectin, and monocyte colony-stimulating factor. Flaxseed has variable effects on IL-6, high-sensitivity C-reactive protein, and soluble vascular cell adhesion molecule-1. FLC reduces plasma levels of C-reactive protein but has no effects on IL-6, tumor necrosis factor-alpha, soluble intracellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, or monocyte chemoattractant protein. Flaxseed has a very small hypotensive effect, but flaxseed oil does not lower blood pressure. However, SDG is a very potent hypotensive agent. Flaxseed oil decreases platelet aggregation and increases platelet activating inhibitor-1 and bleeding time. Flaxseed and FLC have no effect on the hemopoietic system. SDG is a potent angiogenic and antiapoptotic agent that may have a role in cardioprotection in ischemic heart disease. In conclusion, flaxseed, FLC, and SDG, but not flaxseed oil, suppress atherosclerosis, and FLC and SDG slow progression of atherosclerosis but have no effect on regression. Flaxseed oil suppresses oxygen radical production by white blood cells, prolongs bleeding time, and in higher doses suppresses serum levels of inflammatory mediators and does not lower serum lipids.
J Cardiovasc Pharmacol. 2009 Nov;54(5):369-77
Dose-dependent effects of omega-3-polyunsaturated fatty acids on systolic left ventricular function, endothelial function, and markers of inflammation in chronic heart failure of nonischemic origin: a double-blind, placebo-controlled, 3-arm study.
BACKGROUND: Supplemen-tation with 1 g/d omega-3-polyunsaturated fatty acids (n3-PUFAs) demonstrated a small survival advantage in patients with chronic heart failure (CHF) in the GISSI-HF trial. However, a dose-efficacy relationship was postulated for the beneficial effects of n3-PUFA before. Therefore, we evaluated dose-dependent effects of n3-PUFA in patients with severe CHF. METHODS: In a double-blind, randomized, controlled pilot trial, 43 patients with severe, nonischemic heart failure received 1 g/d n3-PUFA (n = 14), 4 g/d n3-PUFA (n = 13), or placebo (n = 16) for 3 months. Changes in left ventricular ejection fraction (LVEF), flow-mediated vasodilation, plasma high-sensitive interleukin 6 and high-sensitive tumor necrosis factor, and exercise peak oxygen consumption were assessed. RESULTS: Left ventricular ejection fraction increased in a dose-dependent manner (P = .01 for linear trend) in the 4 (baseline vs 3 months [mean ± SD]: 24% ± 7% vs 29% ± 8%, P = .005) and 1 g/d treatment groups (24% ± 8% vs 27% ± 8%, P = .02). Flow-mediated vasodilation increased significantly with high-dose 4 g/d n3-PUFA (8.4% ± 4.8% vs 11.6% ± 7.0%, P = .01) but only trendwise with low-dose 1 g/d (8.3% ± 5.3% vs 10.2% ± 4.3%, P = .07). Interleukin 6 significantly decreased with 4 g/d n3-PUFA (3.0 ± 2.9 pg/mL vs 0.7 ± 0.8 pg/mL, P = .03) but only trendwise with 1 g/d (4.5 ± 6.6 pg/mL to 1.6 ± 2.1 pg/mL, P = .1). High-sensitive tumor necrosis factor α decreased trendwise with 4 g/d n3-PUFA but remained unchanged with 1 g/d. In patients with maximal exercise effort, only 4 g/d increased the peak oxygen consumption. No changes in any investigated parameters were noted with placebo. CONCLUSION: Treatment with n3-PUFA for 3 months exerts a dose-dependent increase of LVEF in patients with CHF. In parallel, a significant improvement of endothelial function and decrease of interleukin 6 is found with high-dose n3-PUFA intervention.
Am Heart J. 2011 May;161(5):915.e1-9
Anti-inflammatory effects of different drugs/agents with antioxidant property on endothelial expression of adhesion molecules.
Atherosclerosis is a chronic inflammatory process. The adhesion of leukocytes to the vascular endothelium, mediated by endothelial cell adhesion molecules including vascular adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin, is the pivotal early event in atherogenesis. Inflammatory cytokines could activate redox-sensitive transcription factors and induce endothelial expression of adhesion molecules, which could be inhibited to various degrees by different antioxidants suggesting the potential role of endogenous reactive oxygen species (ROS) in atherogenesis. Many clinical drugs that against cardiovascular diseases have exhibited antioxidant effects; these drugs simultaneously inhibit endothelial adhesion molecule expression, such as aspirin, probucol, HMG-CoA reductase inhibitors, angiotensin receptor blockers, angiotensin converting enzyme inhibitors, peroxisome proliferator-activated receptor alpha and gamma ligands, calcium channel blockers, beta-adrenergic blockers, etc. In addition, we have previously demonstrated that Ginkgo biloba extract, a Chinese herb with antioxidant activity, could significantly suppress inflammatory cytokine-stimulated endothelial adhesiveness to human monocytic cells by attenuating intracellular ROS formation, redox-senstive transcription factor activation, and VCAM-1 as well as ICAM-1 expression in human aortic endothelial cells. The similar anti-atherosclerosis effects have been also shown in other Chinese herbs or dietary supplements with antioxidant activity such as magnolol and salvianolic acid B either in vitro or in vivo. Thus, oxidative stress is critical to endothelial adhesiveness in atherogenesis. The inhibition of endothelial adhesion molecule expression by drugs/agents with antioxidant activity may serve as a potential therapeutic strategy for clinical atherosclerosis.
Cardiovasc Hematol Disord Drug Targets. 2006 Dec;6(4):279-304
Role of lipoxins and resolvins as anti-inflammatory and proresolving mediators in colon cancer.
Recently, lipoxins (LXs) and resolvins (Rvs) have become the topic of intense interest because of expanding views of their action, particularly in chronic disorders where unresolved inflammation is a key factor leading to colon carcinogenesis. Rvs are biosynthesized from omega-3 fatty acids eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) via cyclooxygenase-2/lipoxygenase (COX-2/LOX) pathways; Rvs are shown to dramatically reduce dermal inflammation, peritonitis, dendritic cell migration, and interleukin production. This explains that dietary supplementation of omega-3 fatty acids generates potent local endogenous mediators that control inflammation. LXs are biosynthesized from COX-2/LOX pathways. Metabolites of 15-LOX-1 and 2 are anti-tumorigenic; similarly, 15-epi-LXA(4) synthesized during COX-2 acetylation by low doses of aspirin too possesses anti-tumorigenic effects. Acetylating nonsteroidal anti-inflammatory drugs (NSAIDs), like aspirin, switches COX-2 from forming PGE(2) (promoting tumorigenesis) to 15-epi-LXA(4) (antitumorigenesis). LXs and Rvs are endogenously generated during the spontaneous resolution phase. These newly identified LXs and Rvs have proved to be potent regulators of both leukocytes and cytokine productions, thereby regulating the events of interest in inflammation and resolution. In light of existing knowledge on interconnected pathways of pro-inflammatory mediators (leukotrienes, chemokines (IL8, SDF-1 alpha, MIP-1 alpha, MCP-1,2 etc), and cytokines (IL3, IL6, IL12, IL-1 beta, GM-CSF, B94, TNF-alpha etc)), the anti-inflammatory properties of pro-resolving mediators in preventing chronic inflammation which leads to carcinogenesis needs further understanding. In this review, we explore the mechanisms that trigger formation of LXs and Rvs, to highlight the relative importance of LXs and Rvs in carcinogenesis in relation to pro-inflammatory mediators.
Curr Mol Med. 2009 Jun;9(5):565-79
Neuroprotection by spice-derived nutraceuticals: you are what you eat!
Numerous lines of evidence indicate that chronic inflammation plays a major role in the development of various neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, brain tumor, and meningitis. Why these diseases are more common among people from some countries than others is not fully understood, but lifestyle factors have been linked to the development of neurodegenerative diseases. For example, the incidence of certain neurodegenerative diseases among people living in the Asian subcontinent, where people regularly consume spices, is much lower than in countries of the western world. Extensive research over the last 10 years has indicated that nutraceuticals derived from such spices as turmeric, red pepper, black pepper, licorice, clove, ginger, garlic, coriander, and cinnamon target inflammatory pathways, thereby may prevent neurodegenerative diseases. How these nutraceuticals modulate various pathways and how they exert neuroprotection are the focus of this review.
Mol Neurobiol. 2011 Oct;44(2):142-59
Aged garlic extract improves endothelial function in men with coronary artery disease.
Endothelium-dependent vasodilation is impaired and predicts the risk of a coronary event in patients with coronary artery disease (CAD). Oxidant stress and increased systemic inflammation may contribute to this endothelial dysfunction. Aged garlic extract (AGE) contains antioxidant compounds and increases nitric oxide production and decreases the output of inflammatory cytokines from cultured cells. The aim of this study was to test the effect of treatment with AGE on brachial artery flow mediated endothelium-dependent dilation (FMD) and circulating markers of oxidative stress and systemic inflammation. The trial included 15 men with angiographically proven CAD in a randomized, placebo-controlled, cross-over design with 2-week treatment and washout periods. During AGE supplementation, FMD increased (44%) significantly (p = 0.04) from the baseline and mainly in men with lower baseline FMD. Levels of FMD at the end of AGE treatment were significantly (p = 0.03) higher compared with the corresponding levels at the end of placebo treatment when the variation in baseline body weight was taken into account. Markers of oxidant stress (plasma oxidized low density lipoprotein and peroxides), systemic inflammation (plasma C-reactive protein ad interleukin-6) and endothelial activation (VCAM-1) did not change significantly during the study. These data suggest that short-term treatment with AGE may improve impaired endothelial function in men with CAD treated with aspirin and a statin. Whether improvement in endothelial function decreases the risk of future cardiovascular events remains to be determined.
Phytother Res. 2005 Apr;19(4):314-9
Melatonin as a neuroprotective agent in the rodent models of Parkinson’s disease: is it all set to irrefutable clinical translation?
Parkinson’s disease (PD), a neurodegenerative disorder, is characterized by the selective degeneration of the nigrostriatal dopaminergic neurons, continuing or permanent deficiency of dopamine, accretion of an abnormal form of alpha synuclein in the adjacent neurons, and dysregulation of ubiquitin proteasomal system, mitochondrial metabolism, permeability and integrity, and cellular apoptosis resulting in rigidity, bradykinesia, resting tremor, and postural instability. Melatonin, an indoleamine produced almost in all the organisms, has anti-inflammatory, anti-apoptotic, and anti-oxidant nature. Experimental studies employing 1-methyl 4-phenyl 1, 2, 3, 6-tetrahydropyridine (MPTP), 6-hydroxydopamine (6-OHDA), methamphetamine, rotenone, and maneb and paraquat models have shown an enormous potential of melatonin in amelioration of the symptomatic features of PD. Although a few reviews published previously have described the multifaceted efficacy of melatonin against MPTP and 6-OHDA rodent models, due to development and validation of the newer models as well as the extensive studies on the usage of melatonin in entrenched PD models, it is worthwhile to bring up to date note on the usage of melatonin as a neuroprotective agent in PD. This article presents an update on the usage and applications of melatonin in PD models along with incongruous observations. The impending implications in the clinics, success, limitations, and future prospective have also been discussed in this article.
Mol Neurobiol. 2012 Feb;45(1):186-99
Protection against cognitive deficits and markers of neurodegeneration by long-term oral administration of melatonin in a transgenic model of Alzheimer disease.
The neurohormone melatonin has been reported to exert anti-beta-amyloid aggregation, antioxidant, and anti-inflammatory actions in various in vitro and animal models. To comprehensively determine the potential for long-term melatonin treatment to protect Alzheimer’s transgenic mice against cognitive impairment and development of beta-amyloid (Abeta) neuropathology, we administered melatonin (100 mg/L drinking water) to APP + PS1 double transgenic (Tg) mice from 2-2.5 months of age to their killing at age 7.5 months. A comprehensive behavioral battery administered during the final 6 weeks of treatment revealed that Tg mice given melatonin were protected from cognitive impairment in a variety of tasks of working memory, spatial reference learning/memory, and basic mnemonic function; Tg control mice remained impaired in all of these cognitive tasks/domains. Immunoreactive Abeta deposition was significantly reduced in hippocampus (43%) and entorhinal cortex (37%) of melatonin-treated Tg mice. Although soluble and oligomeric forms of Abeta1-40 and 1-42 were unchanged in the hippocampus and cortex of the same melatonin-treated Tg mice, their plasma Abeta levels were elevated. These Abeta results, together with our concurrent demonstration that melatonin suppresses Abeta aggregation in brain homogenates, are consistent with a melatonin-facilitated removal of Abeta from the brain. Inflammatory cytokines such as tumor necrosis factor (TNF)-alpha were decreased in hippocampus (but not plasma) of Tg+ melatonin mice. Finally, the cortical mRNA expression of three antioxidant enzymes (SOD-1, glutathione peroxidase, and catalase) was significantly reduced to non-Tg levels by long-term melatonin treatment in Tg mice. Thus, melatonin’s cognitive benefits could involve its anti-Abeta aggregation, anti-inflammatory, and/or antioxidant properties. Our findings provide support for long-term melatonin therapy as a primary or complementary strategy for abating the progression of Alzheimer disease.
J Pineal Res. 2009 Aug;47(1):82-96
Melatonin treatment following stroke induction modulates L-arginine metabolism.
The efficacy of melatonin treatment in experimental stroke has been established. Some of the neuroprotective properties have been attributed to its anti-oxidant and anti-inflammatory effects. Nitric oxide synthases (NOS) and cyclooxygenases (COX) are considered to have a significant role in the inflammatory milieu occurring in acute stroke. While previous reports have shown that pretreatment with melatonin in a stroke model can modulate NOS isoforms, the effect of post-treatment with melatonin on l-arginine metabolism has not been investigated. This study initially examined the effect of melatonin (1 nm-1 mm) on l-arginine metabolism pathways in human fibrosarcoma fibroblasts (HT-1080) fibroblasts. Evidence of neuroprotection with melatonin was evaluated in rats subjected to middle cerebral artery occlusion (MCAO). Animals were treated with three daily doses of 5 mg/kg i.p., starting 1 hr after the onset of ischemia. Constitutive NOS activity but not expression was significantly increased by in vitro exposure (72 hr) to melatonin. In addition, melatonin treatment increased arginase activity by increasing arginase II expression. In vivo studies showed that melatonin treatment after MCAO significantly inhibited inducible NOS activity and attenuated expression of the inducible isoform, resulting in decreased total NOS activity and tissue nitrite levels. COX activity was significantly reduced with melatonin treatment. The neuroprotective anti-inflammatory effects of melatonin were consistent with the substantial reduction in infarct volume throughout the cortex and striatum and recovery of mitochondrial enzyme activities. The evidence presented here suggests that modulation of l-arginine metabolism by melatonin make it a valuable neuroprotective therapy for stroke.
J Pineal Res. 2011 Oct;51(3):313-23