MyMedR

Displaying publications 41 - 60 of 171 in total

Abstract:

Sort:

Fulltext The Mechanism of Honey in Reversing Metabolic Syndrome

Hashim KN, Chin KY, Ahmad F

Molecules, 2021 Feb 04;26(4).
PMID: 33557218 DOI: 10.3390/molecules26040808

Metabolic syndrome is a constellation of five risk factors comprising central obesity, hyperglycaemia, dyslipidaemia, and hypertension, which predispose a person to cardiometabolic diseases. Many studies reported the beneficial effects of honey in reversing metabolic syndrome through its antiobesity, hypoglycaemic, hypolipidaemic, and hypotensive actions. This review aims to provide an overview of the mechanism of honey in reversing metabolic syndrome. The therapeutic effects of honey largely depend on the antioxidant and anti-inflammatory properties of its polyphenol and flavonoid contents. Polyphenols, such as caffeic acid, p-coumaric acid, and gallic acid, are some of the phenolic acids known to have antiobesity and antihyperlipidaemic properties. They could inhibit the gene expression of sterol regulatory element-binding transcription factor 1 and its target lipogenic enzyme, fatty acid synthase (FAS). Meanwhile, caffeic acid and quercetin in honey are also known to reduce body weight and fat mass. In addition, fructooligosaccharides in honey are also known to alter lipid metabolism by reducing FAS activity. The fructose and phenolic acids might contribute to the hypoglycaemic properties of honey through the phosphatidylinositol 3-kinase/protein kinase B insulin signalling pathway. Honey can increase the expression of Akt and decrease the expression of nuclear factor-kappa B. Quercetin, a component of honey, can improve vasodilation by enhancing nitric oxide production via endothelial nitric oxide synthase and stimulate calcium-activated potassium channels. In conclusion, honey can be used as a functional food or adjuvant therapy to prevent and manage metabolic syndrome.
Fulltext Can telomere length predict bone health? A review of current evidence

Wong SK, Ima-Nirwana S, Chin KY

Bosn J Basic Med Sci, 2020 Nov 02;20(4):423-429.
PMID: 32156247 DOI: 10.17305/bjbms.2020.4664

Telomeres are repetitive DNA sequences located at the end of chromosomes that serve as a protective barrier against chromosomal deterioration during cell division. Approximately 50-200 base pairs of nucleotides are lost per cell division, and new repetitive nucleotides are added by the enzyme telomerase, allowing telomere maintenance. Telomere shortening has been proposed as an indicator for biological aging, but its relationship with age-related osteoporosis is ambiguous. We summarize the current evidence on the relationship between telomere length and bone health in experimental and epidemiological studies, which serve as a scientific reference for the development of novel diagnostic markers of osteoporosis or novel therapeutics targeting telomere and telomerase of bone cells to treat osteoporosis.
Fulltext Therapeutic potential of annatto tocotrienol with self-emulsifying drug delivery system in a rat model of postmenopausal bone loss

Mohamad NV, Ima-Nirwana S, Chin KY

Biomed Pharmacother, 2021 May;137:111368.
PMID: 33582449 DOI: 10.1016/j.biopha.2021.111368

Tocotrienol has been shown to prevent bone loss in animal models of postmenopausal osteoporosis, but the low oral bioavailability might limit its use. A self-emulsifying drug delivery system (SEDDS) could increase the bioavailability of tocotrienol. However, evidence of this system in improving the skeletal effects of tocotrienol is scanty. This study aims to evaluate the therapeutic efficacy of annatto tocotrienol with SEDDS in a rat model of postmenopausal bone loss. Ten-month-old female Sprague Dawley rats were randomized into six groups. The baseline group was euthanatized at the onset of the study. Four other groups underwent ovariectomy to induce estrogen deficiency. The sham underwent similar surgery procedure, but their ovaries were retained. Eight weeks after surgery, the ovariectomized rats received one of the four different regimens orally daily: (a) SEDDS, (b) annatto tocotrienol [60 mg/kg body weight (b.w.)] without SEDDS, (c) annatto-tocotrienol (60 mg/kg b.w.) with SEDDS, (d) raloxifene (1 mg/kg b.w.). After eight weeks of treatment, blood was collected for the measurement of delta-tocotrienol level and oxidative stress markers. The rats were euthanized and their bones were harvested for the evaluation of the bone microstructure, calcium content and strength. Circulating delta-tocotrienol level was significantly higher in rats receiving annatto tocotrienol with SEDDS compared to the group receiving unformulated annatto-tocotrienol (p
Fulltext A Review on the Role of Denosumab in Fracture Prevention

Pang KL, Low NY, Chin KY

Drug Des Devel Ther, 2020;14:4029-4051.
PMID: 33061307 DOI: 10.2147/DDDT.S270829

Denosumab is a receptor activator of nuclear factor kappa-Β ligand inhibitor, which suppresses the bone resorption process to preserve bone mass. It is usually recommended to postmenopausal women and men with high fracture risk. With the recent publication of the results from FREEDOM study and its extension, the long-term effect of denosumab in preventing fragility fractures has been put forward. This review aims at summarising the evidence of denosumab in reducing fracture risk and its safety derived from clinical studies. Most of the evidence are derived from FREEDOM trials up to 10 years of exposure. Denosumab is reported to prevent vertebral and non-vertebral fractures. It is also proven effective in Japanese women, patients with chronic kidney diseases and breast cancer patients receiving antineoplastic therapy. Denosumab discontinuation leads to high remodeling, loss of bone mineral density and increased fracture risk. These negative effects might be preventable by bisphosphonate treatment. The safety profile of denosumab is consistent with increased years of exposure. In conclusion, denosumab is a safe and effective option for reducing fracture risk among patients with osteoporosis.
Fulltext Are Oxidative Stress and Inflammation Mediators of Bone Loss Due to Estrogen Deficiency? A Review of Current Evidence

Mohamad NV, Ima-Nirwana S, Chin KY

Endocr Metab Immune Disord Drug Targets, 2020;20(9):1478-1487.
PMID: 32496996 DOI: 10.2174/1871530320666200604160614

Osteoporosis is one of the major health issues associated with menopause-related estrogen deficiency. Various reports suggest that the hormonal changes related to menopausal transition may lead to the derangement of redox homeostasis and ultimately oxidative stress. Estrogen deficiency and oxidative stress may enhance the expression of genes involved in inflammation. All these factors may contribute, in synergy, to the development of postmenopausal osteoporosis. Previous studies suggest that estrogen may act as an antioxidant to protect the bone against oxidative stress, and as an antiinflammatory agent in suppressing pro-inflammatory and pro-osteoclastic cytokines. Thus, the focus of the current review is to examine the relationship between estrogen deficiency, oxidative stress and inflammation, and the impacts of these phenomena on skeletal health in postmenopausal women.
A concise review of testosterone and bone health

Mohamad NV, Soelaiman IN, Chin KY

Clin Interv Aging, 2016;11:1317-1324.
PMID: 27703340

Osteoporosis is a condition causing significant morbidity and mortality in the elderly population worldwide. Age-related testosterone deficiency is the most important factor of bone loss in elderly men. Androgen can influence bone health by binding to androgen receptors directly or to estrogen receptors (ERs) indirectly via aromatization to estrogen. This review summarized the direct and indirect effects of androgens on bone derived from in vitro, in vivo, and human studies. Cellular studies showed that androgen stimulated the proliferation of preosteoblasts and differentiation of osteoblasts. The converted estrogen suppressed osteoclast formation and resorption activity by blocking the receptor activator of nuclear factor k-B ligand pathway. In animal studies, activation of androgen and ERα, but not ERβ, was shown to be important in acquisition and maintenance of bone mass. Human epidemiological studies demonstrated a significant relationship between estrogen and testosterone in bone mineral density and fracture risk, but the relative significance between the two remained debatable. Human experimental studies showed that estrogen was needed in suppressing bone resorption, but both androgen and estrogen were indispensable for bone formation. As a conclusion, maintaining optimal level of androgen is essential in preventing osteoporosis and its complications in elderly men.
Effects of tocotrienol from Bixa orellana (annatto) on bone histomorphometry in a male osteoporosis model induced by buserelin

Mohamad NV, Soelaiman IN, Chin KY

Biomed Pharmacother, 2018 Jul;103:453-462.
PMID: 29674281 DOI: 10.1016/j.biopha.2018.04.083

INTRODUCTION: Osteoporosis is a debilitating skeletal side effect of androgen deprivation therapy based on gonadotropin-releasing hormone (GnRH) agonist in men. Tocotrienol from Bixa orellana (annatto) has been demonstrated to offer protection against osteoporosis by exerting anabolic effects on bone. Thus, it may prevent osteoporosis among GnRH agonist users.
OBJECTIVE: This study aimed to determine the effectiveness of annatto-tocotrienol on the bone turnover markers and bone histomorphometry in a model of male osteoporosis induced by buserelin (a GnRH agonist).
METHODS: Forty-six three-months-old male Sprague-Dawley rats (three months old; 300-350 g) were randomly divided into six groups. The baseline control group (n = 6) was sacrificed at the onset of the study. The normal control group (n = 8) received corn oil (the vehicle of tocotrienol) orally daily and normal saline (the vehicle of buserelin) subcutaneously daily. The buserelin control (n = 8) received corn oil orally daily and subcutaneous buserelin injection 75 μg/kg/day daily. The calcium control (n = 8) received 1% calcium in drinking water and subcutaneous buserelin injection 75 μg/kg/day. The remaining rats were treated with two different treatments, i.e., (1) oral annatto tocotrienol at 60 mg/kg/day plus subcutaneous buserelin injection 75 μg/kg/day (n = 8); (2) oral annatto tocotrienol at 100 mg/kg/day plus subcutaneous buserelin injection 75 μg/kg/day (n = 8). The rats were injected with calcein twice before being sacrificed to label the bones. The rats were euthanized, and their blood and right femur were harvested at the end of the treatment for bone turnover markers and bone histomorphometry examination.
RESULTS: Both serum osteocalcin and C-telopeptide of type 1 collagen were not significantly different between treated groups and buserelin control (P > 0.05). The buserelin control group had a significantly lower bone volume and higher eroded surface compared with the normal control group (P 
Fulltext Effect of tocotrienol from Bixa orellana (annatto) on bone microstructure, calcium content, and biomechanical strength in a model of male osteoporosis induced by buserelin

Mohamad NV, Ima-Nirwana S, Chin KY

Drug Des Devel Ther, 2018;12:555-564.
PMID: 29588572 DOI: 10.2147/DDDT.S158410

Background: Patients receiving androgen deprivation therapy experience secondary hypogonadism, associated bone loss, and increased fracture risk. It has been shown that tocotrienol from Bixa orellana (annatto) prevents skeletal microstructural changes in rats experiencing primary hypogonadism. However, its potential in preventing bone loss due to androgen deprivation therapy has not been tested. This study aimed to evaluate the skeletal protective effects of annatto tocotrienol using a buserelin-induced osteoporotic rat model.
Methods: Forty-six male Sprague Dawley rats aged 3 months were randomized into six groups. The baseline control (n=6) was sacrificed at the onset of the study. The normal control (n=8) received corn oil (the vehicle of tocotrienol) orally daily and normal saline (the vehicle of buserelin) subcutaneously daily. The buserelin control (n=8) received corn oil orally daily and subcutaneous buserelin injection (75 µg/kg) daily. The calcium control (n=8) was supplemented with 1% calcium in drinking water and daily subcutaneous buserelin injection (75 µg/kg). The remaining rats were given daily oral annatto tocotrienol at 60 mg/kg (n=8) or 100 mg/kg (n=8) plus daily subcutaneous buserelin injection (75 µg/kg) (n=8). At the end of the experiment, the rats were euthanized and their blood, tibia, and femur were harvested. Structural changes of the tibial trabecular and cortical bone were examined using X-ray micro-computed tomography. Femoral bone calcium content and biomechanical strength were also evaluated.
Results: Annatto tocotrienol at 60 and 100 mg/kg significantly prevented the deterioration of trabecular bone and cortical thickness in buserelin-treated rats (P<0.05). Both doses of annatto tocotrienol also improved femoral biomechanical strength and bone calcium content in buserelin-treated rats (P<0.05). The effects of annatto tocotrienol were comparable to calcium supplementation.
Conclusion: Annatto tocotrienol supplementation is effective in preventing degeneration of the bone induced by buserelin. Therefore, it is a potential antiosteoporotic agent for men receiving androgen deprivation therapy.
Tocotrienol and Its Role in Chronic Diseases

Chin KY, Pang KL, Soelaiman IN

Adv Exp Med Biol, 2016;928:97-130.
PMID: 27671814

Tocotrienol is a member of vitamin E family and is well-known for its antioxidant and anti-inflammatory properties. It is also a suppressor of mevalonate pathway responsible for cholesterol and prenylated protein synthesis. This review aimed to discuss the health beneficial effects of tocotrienol, specifically in preventing or treating hyperlipidaemia, diabetes mellitus, osteoporosis and cancer with respect to these properties. Evidence from in vitro, in vivo and human studies has been examined. It is revealed that tocotrienol shows promising effects in preventing or treating the health conditions previously mentioned in in vivo and in vitro models. In some cases, alpha-tocopherol attenuates the biological activity of tocotrienol. Except for its cholesterol-lowering effects, data on the health-promoting effects of tocotrienol in human are limited. As a conclusion, the encouraging results on the health beneficial effects of tocotrienol should motivate researchers to explore its potential use in human.
miRNA-regulated cancer stem cells: understanding the property and the role of miRNA in carcinogenesis

Chakraborty C, Chin KY, Das S

Tumour Biol., 2016 Oct;37(10):13039-13048.
PMID: 27468722

Over the last few years, microRNAs (miRNA)-controlled cancer stem cells have drawn enormous attention. Cancer stem cells are a small population of tumor cells that possess the stem cell property of self-renewal. Recent data shows that miRNA regulates this small population of stem cells. In the present review, we explained different characteristics of cancer stem cells as well as miRNA regulation of self-renewal and differentiation in cancer stem cells. We also described the migration and tumor formation. Finally, we described the different miRNAs that regulate various types of cancer stem cells, such as prostate cancer stem cells, head and neck cancer stem cells, breast cancer stem cells, colorectal cancer stem cells, lung cancer stem cells, gastric cancer stem cells, pancreatic cancer stem cells, etc. Extensive research is needed in order to employ miRNA-based therapeutics to control cancer stem cell population in various cancers in the future.
Fulltext The Osteoprotective Effects Of Kaempferol: The Evidence From In Vivo And In Vitro Studies

Wong SK, Chin KY, Ima-Nirwana S

Drug Des Devel Ther, 2019;13:3497-3514.
PMID: 31631974 DOI: 10.2147/DDDT.S227738

Kaempferol is a dietary bioflavonoid ubiquitously found in various types of plant. It possesses a wide range of medicinal properties suggesting its potential clinical utility that requires further investigation. The present review intends to highlight the efficacy of kaempferol and its molecular mechanisms of action in regulating bone metabolism. Many reports have acknowledged the bone-protecting property of kaempferol and kaempferol-containing plants using in vitro and in vivo experimental models. Kaempferol supplementation showed bone-sparing effects in newborn rats, glucocorticoid-induced and ovariectomy-induced osteoporotic models as well as bone fracture models. It achieves the bone-protective effects by inhibiting adipogenesis, inflammation, oxidative stress, osteoclastic autophagy and osteoblastic apoptosis while activating osteoblastic autophagy. The anti-osteoporotic effects of kaempferol are mediated through regulation of estrogen receptor, bone morphogenetic protein-2 (BMP-2), nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) signaling pathways. In summary, kaempferol exhibits beneficial effects on skeleton, thus is potentially effective for the prophylaxis and treatment of osteoporosis.
Berberine and musculoskeletal disorders: The therapeutic potential and underlying molecular mechanisms

Wong SK, Chin KY, Ima-Nirwana S

Phytomedicine, 2020 Jul 15;73:152892.
PMID: 30902523 DOI: 10.1016/j.phymed.2019.152892

BACKGROUND: Musculoskeletal disorders are a group of disorders that affect the joints, bones, and muscles, causing long-term disability. Berberine, an isoquinoline alkaloid, has been previously established to exhibit beneficial properties in preventing various diseases, including musculoskeletal disorders.
PURPOSE: This review article aims to recapitulate the therapeutic potential of berberine and its mechanism of action in treating musculoskeletal disorders.
METHODS: A wide range of literature illustrating the effects of berberine in ameliorating musculoskeletal disorders was retrieved from online electronic databases (PubMed and Medline) and reviewed.
RESULTS: Berberine may potentially retard the progression of osteoporosis, osteoarthritis and rheumatoid arthritis. Limited studies reported the effects of berberine in suppressing the proliferation of osteosarcoma cells. These beneficial properties of berberine are mediated in part through its ability to target multiple signaling pathways, including PKA, p38 MAPK, Wnt/β-catenin, AMPK, RANK/RANKL/OPG, PI3K/Akt, NFAT, NF-κB, Hedgehog, and oxidative stress signaling. In addition, berberine exhibited anti-apoptotic, anti-inflammatory, and immunosuppressive properties.
CONCLUSION: The current evidence indicates that berberine may be effective in preventing musculoskeletal disorders. However, findings from in vitro and in vivo investigations await further validation from human clinical trial.
Fulltext The Skeletal-Protecting Action and Mechanisms of Action for Mood-Stabilizing Drug Lithium Chloride: Current Evidence and Future Potential Research Areas

Wong SK, Chin KY, Ima-Nirwana S

Front Pharmacol, 2020;11:430.
PMID: 32317977 DOI: 10.3389/fphar.2020.00430

Lithium, the lightest natural-occurring alkali metal with an atomic number of three, stabilizes the mood to prevent episodes of acute manic and depression. Multiple lines of evidence point to lithium as an anti-suicidal, anti-viral, anti-cancer, immunomodulatory, neuroprotective and osteoprotective agent. This review article provides a comprehensive review of studies investigating the bone-enhancing effects of lithium and its possible underlying molecular mechanisms. Most of the animal experimental studies reported the beneficial effects of lithium in defective bones but not in healthy bones. In humans, the effects of lithium on bones remain heterogeneous. Mechanistically, lithium promotes osteoblastic activities by activating canonical Wingless (Wnt)/beta (β)-catenin, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and bone morphogenetic protein-2 (BMP-2) transduction pathways but suppresses osteoclastic activities by inhibiting the receptor activator of nuclear factor-kappa B (RANK)/receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) system, nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and calcium signaling cascades. In conclusion, lithium confers protection to the skeleton but its clinical utility awaits further validation from human clinical trials.
The effects of gonadotropin-releasing hormone agonist (buserelin) and orchidectomy on bone turnover markers and histomorphometry in rats

Mohamad NV, Ima-Nirwana S, Chin KY

Aging Male, 2020 Dec;23(5):327-334.
PMID: 29495911 DOI: 10.1080/13685538.2018.1446075

This study aimed to compare the skeletal effect between GnRH agonist therapy and orchidectomy in male rats assessed using serum turnover markers and bone histomorphometry. Three-month-old male Sprague-Dawley rats (n = 46) were divided into three experimental arms, baseline, buserelin, and orchidectomy. In the buserelin arm, the rats received a daily subcutaneous injection of either normal saline or buserelin acetate at 25 µg/kg or 75 µg/kg. In the orchidectomy arm, the rats were either sham-operated or orchidectomized. The rats were euthanized after the three-month treatment. Blood was collected for the evaluation of bone turnover markers. Femurs were harvested for bone histomorphometry examination. A significant increase in serum C-telopeptide of type 1 collagen was observed in the orchidectomized group compared with the sham group (p
The Skeletal Effects of Gonadotropin-Releasing Hormone Antagonists: A Concise Review

Mohamad NV, Ima-Nirwana S, Chin KY

Endocr Metab Immune Disord Drug Targets, 2021;21(10):1713-1720.
PMID: 33327926 DOI: 10.2174/1871530321666201216164410

Prolonged treatment with Gonadotropin-Releasing Hormone (GnRH) agonists is known to induce bone loss among prostate cancer patients. However, evidence on the skeletal effects of GnRH antagonists is relatively less well-known. This review aims to examine the effects of GnRH antagonists on bone health. GnRH antagonists are an effective treatment for hormone-dependent conditions, such as advanced prostate cancer and endometriosis. They induce a competitive and reversible GnRH-receptor blockage, thereby suppressing the release of gonadotropins and sex hormones. The sex hormone ablation results in undesirable side effects, including accelerated bone loss. In animal studies, treatment with GnRH antagonists is reported to cause deterioration of bone microstructure. Human clinical trials revealed significant bone loss at the spine, hip and femur in patients treated with GnRH antagonists. Thus, osteoporosis and the resultant fragility fractures pose a significant impact on health and quality of life of GnRH antagonist users. Thus, early preventive measures of bone loss are critical in preventing fractures and its associated morbidity in these patients.
Fulltext Self-emulsified annatto tocotrienol improves bone histomorphometric parameters in a rat model of oestrogen deficiency through suppression of skeletal sclerostin level and RANKL/OPG ratio

Mohamad NV, Ima-Nirwana S, Chin KY

Int J Med Sci, 2021;18(16):3665-3673.
PMID: 34790038 DOI: 10.7150/ijms.64045

Menopause is the leading cause of osteoporosis for elderly women due to imbalanced bone remodelling in the absence of oestrogen. The ability of tocotrienol in reversing established bone loss due to oestrogen deficiency remains unclear despite the plenitude of evidence showcasing its preventive effects. This study aimed to investigate the effects of self-emulsified annatto tocotrienol (SEAT) on bone histomorphometry and remodelling in ovariectomised rats. Female Sprague Dawley rats (n=36) were randomly assigned into baseline, sham, ovariectomised (OVX) control, OVX-treated with annatto tocotrienol (AT) (60 mg/kg), SEAT (60 mg/kg) and raloxifene (1 mg/kg). Daily treatment given through oral gavage was started two months after castration. The rats were euthanised after eight weeks of treatment. Blood was collected for bone biomarkers. Femur and lumbar bones were collected for histomorphometry and remodelling markers. The results showed that AT and SEAT improved osteoblast numbers and trabecular mineralisation rate (p<0.05 vs untreated OVX). AT also decreased skeletal sclerostin expression in OVX rats (p<0.05 vs untreated OVX). Similar effects were observed in the raloxifene-treated group. Only SEAT significantly increased bone formation rate and reduced RANKL/OPG ratio (p<0.05 vs untreated OVX). However, no changes in osteoclast-related parameters were observed among the groups (p>0.05). In conclusion, SEAT exerts potential skeletal anabolic properties by increasing bone formation, suppressing sclerostin expression and reducing RANKL/OPG ratio in rats with oestrogen deficiency.
Fulltext A review on the molecular basis underlying the protective effects of Andrographis paniculata and andrographolide against myocardial injury

Wong SK, Chin KY, Ima-Nirwana S

Drug Des Devel Ther, 2021;15:4615-4632.
PMID: 34785890 DOI: 10.2147/DDDT.S331027

Andrographolide is the major compound found in the medicinal plant, Andrographis paniculata (Burm.f.) Nees, which accounts for its medicinal properties. Both the plant extract and compound have been reported to exhibit potential cardiovascular activities. This review summarises related studies describing the biological activities and target mechanisms of A. paniculata and andrographolide in vivo and in vitro. The current evidence unambiguously indicated the protective effects provided by A. paniculata and andrographolide administration against myocardial injury. The intervention ameliorates the symptoms of myocardial injury by interfering with the inductive phase of a) inflammatory response mediated by nuclear factor-kappa B (NF-κB), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signalling molecules; b) oxidative stress via activation of nuclear factor erythroid 2-related factor (Nrf-2) and reduction of enzymes responsible for generating reactive oxygen and nitrogen species; c) intrinsic and extrinsic mechanisms in apoptosis regulated by upstream insulin-like growth factor-1 receptor (IGF-1R) and peroxisome proliferator-activated receptor-alpha (PPAR-α); d) profibrotic growth factors thus reducing cardiac fibrosis, improving endothelial function and fibrinolytic function. In conclusion, A. paniculata and andrographolide possess therapeutic potential in the management of myocardial injury, which requires further validation in human clinical trials.
A Review on the Effects of Testosterone Supplementation in Hypogonadal Men with Cognitive Impairment

Mohamad NV, Ima-Nirwana S, Chin KY

Curr Drug Targets, 2018;19(8):898-906.
PMID: 28914204 DOI: 10.2174/1389450118666170913162739

Cognitive function and testosterone level of men decline concurrently with age. Low testosterone levels are associated with higher risk of Alzheimer's disease and mild cognitive impairment in men. There are continuous debates on whether this relationship is casual. This paper aims to summarize the current evidence on the association between testosterone level and cognitive function in elderly men. The presence of testosterone, androgen receptor and its responsive genes indicates that testosterone has biological functions in the central nervous system. The ability of the body to convert testosterone into estrogen suggests that part of the actions of testosterone could be mediated by estrogen. Observational studies generally showed that low endogenous testosterone levels were associated with poor cognitive performance in healthy elderly men. Testosterone substitution exerted positive effects on certain cognitive domains in normal and hypogonadal elderly men. In conclusion, testosterone may influence cognitive function in elderly men and its substitution may be considered in men with cognitive impairment and testosterone deficiency.
Vitamin D and Depression: The Evidence from an Indirect Clue to Treatment Strategy

Wong SK, Chin KY, Ima-Nirwana S

Curr Drug Targets, 2018;19(8):888-897.
PMID: 28914205 DOI: 10.2174/1389450118666170913161030

Depression is a common psychiatric disorder that decreases the quality of life and increases the mortality of patients. It incurs significant healthcare costs if left untreated. Even though intervention with antidepressants can reduce depressive symptoms, side effects are often an issue and relapse is very common. Vitamin D, commonly known as the sunshine vitamin, is an essential fat-soluble vitamin for the absorption of calcium to prevent rickets (children) and osteomalacia (adults). Evidence on a possible relationship between vitamin D deficiency and depression is growing. In this review, the authors summarized the evidence on the association between vitamin D status and depression in human observational studies, followed by clinical trials to evaluate the effects of vitamin D supplementation in treating depression. In conclusion, vitamin D deficiency may be associated with an increased risk or severity of depression. Supplementation of vitamin D may confer protection for depressed patients.
A Review on the Antinociceptive Effects of Mitragyna speciosa and Its Derivatives on Animal Model

Chin KY, Mark-Lee WF

Curr Drug Targets, 2018;19(12):1359-1365.
PMID: 28950813 DOI: 10.2174/1389450118666170925154025

Mitragyna speciosa is a tropical plant with narcotic effects. The antinociceptive effects of its crude extracts, bioactive compounds and structurally modified derivatives have been examined in rodent models. This review aims to summarize the evidence on the antinociceptive effects of M. speciosa and its derivatives and explore whether they can offer an alternative to morphine in pain management. Methanolic and alkaloid extracts of M. speciosa were shown to attenuate the nociceptive response in rodents. Mitragynine and 7-hydroxymitragynine offered better antinociceptive effects than crude extracts. Structurally modified derivatives of 7-hydroxymitragynine, such as MGM-9, MGM- 15, MGM-16, demonstrated superior antinociceptive effects compared to morphine. M. speciosa and its derivatives mainly act on the opioid receptor, but receptor subtypes specificity differs between each compound. The tolerance and adverse side effects of M. speciosa and its derivatives are similar with morphine. The affinity of MGM-9 on kappa-opioid receptor could potentially limit the effects of drug dependence. In conclusion, M speciosa derivatives can offer alternatives to morphine in controlling chronic pain. Structural modification of mitragynine and 7-hydroxymitragynine can generate compounds with higher potency and lesser side-effects. Human clinical trials are required to validate the use of these compounds in clinical setting.

Filters

Please provide feedback to Administrator ([email protected])

External Links