OBJECTIVE: This review aimed to provide an overview of the relationship between mevalonate pathway and bone metabolism, as well as agents which act through this pathway to achieve their therapeutic potential.
DISCUSSION: Mevalonate pathway produces farnesyl pyrophosphate and geranylgeranyl pyrophosphate essential in protein prenylation. An increase in protein prenylation favours bone resorption over bone formation. Non-nitrogen containing bisphosphonates inhibit farnesyl diphosphate synthase which produces farnesyl pyrophosphate. They are used as the first line therapy for osteoporosis. Statins, a well-known class of cholesterol-lowering agents, inhibit 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, the rate-determining enzyme in the mevalonate pathway. It was shown to increase bone mineral density and prevent fracture in humans. Tocotrienol is a group of vitamin E commonly found in palm oil, rice bran and annatto bean. It causes degradation of HMG-CoA reductase. Many studies demonstrated that tocotrienol prevented bone loss in animal studies but its efficacy has not been tested in humans.
CONCLUSION: Mevalonate pathway can be exploited to develop effective antiosteoporosis agents.
OBJECTIVE: To investigate the effect of administration of VCO on lipid profile, markers of hepatic and renal dysfunction, and hepatic and renal antioxidant activities of alloxan induced diabetic rats.
METHODS: Twenty-four male albino rats were used, and they were divided into four groups of six rats each. Group 1 (Normal Control, NC) received distilled water (1 mL/kg); Group 2 (VCO Control) received VCO (5 mL/kg); Group 3 (Diabetic Control, DC) received distilled water (1 mL/kg); Group 4 (Test Group, TG) received 5 ml/kg of VCO.
RESULTS: There were no significant differences in blood glucose, body weights, relative liver weights, relative kidney weights, hepatic and renal Superoxide Dismutase (SOD) activities, Malondialdehyde (MDA), albumin, aspartate Amino Transaminase (AST), alanine Amino Transaminase (ALT), Alkaline Phosphatase (ALP), urea, creatinine, uric acid, total cholesterol, triacylglycerol, Very Low Density Lipoprotein cholesterol (VLDL) and Low Density Lipoprotein cholesterol (LDL) concentrations; significant increases in renal Glutathione (GSH), hepatic catalase, Glutathione Peroxidase (GPx) and GSH but significant reduction in renal GPx and catalase activities of VCO control group compared with NC group. There were significant increases in blood glucose, relative liver and kidney weights, hepatic GPx, hepatic and renal MDA concentration, ALP, AST, ALT, urea, creatinine, uric acid, triacylglycerol, total cholesterol, LDL and VLDL concentrations; and significant decreases in body weight, hepatic SOD and GSH activities and albumin concentration but no significant difference in hepatic catalase activity of DC group compared with NC group. Administration of VCO to diabetic rats positively modulated these parameters compared with the diabetic control.
CONCLUSION: The study showed the potentials of VCO in the management of hyperlipidemia, renal and hepatic dysfunctions imposed by hyperglycemia and by oxidative stress in diabetic rats.
OBJECTIVE: The study aimed to investigate the effect of African walnuts (Tetracarpidium conophorum) on lipids storage and the regulatory enzymes of hepatic lipid metabolism in obese rats.
METHODS: Nuts were extracted in ethanol (WE) and further separated to obtain the ethyl-acetate fraction (ET) and the residue (RES). These were administered orally to 3 groups of monosodium glutamate- obese rats (n = 6), respectively, for 6 weeks. Other groups in the study were: normal (NC), obese control (OC) and standard control (SC) which received orlistat. Hepatic total lipids, total phospholipids, triacylglycerol (TG), total cholesterol (TCHOL), 3-hydroxyl-3-methylglutaryl-CoA (HMG-CoA) reductase and paraoxonase were studied.
RESULTS: Total lipids, TG and TCHOL which increased in OC compared to NC group, decreased. HMG-CoA reductase activity decreased in the 3 study groups relative to OC. Paraoxonase activity which decreased in OC was up-regulated, while the magnitude of hepatic cholesterol decreased from 94.32 % in OC to 52.19, 65.43 and 47.04 % with WE, ET and RES, respectively. Flavonoids, alkaloids, glycosides, tannins and saponins were detected in the nut. GC-MS analysis revealed 16, 18 and 10 volatile components in WE, ET and RES, respectively. Unsaturated fatty acids (linolenic acids: 33.33, 47.95 and 50.93 %, and α-linolenic acids: 25, 19.66 and 26.63 %) in WE, ET and RES, respectively, are the most abundant, and likely to be responsible for the observed activity.
CONCLUSION: African walnuts can prevent hepatic lipid accumulation through reciprocal actions on HMG-CoA reductase and paraoxonase in obesity.
OBJECTIVE: This study aimed to compare the circulating markers of osteocytes and calcium homeostasis between Malaysian postmenopausal women with and without osteoporosis.
METHODS: Postmenopausal women with (n=20) or without osteoporosis (n=20) as determined by dual- energy X-ray absorptiometry were randomly drawn from a bone health cohort. Their fasting blood was collected and assayed by a multiplex immunoassay panel.
RESULTS: The results showed that osteoprotegerin and sclerostin levels were significantly lower among postmenopausal women with osteoporosis than the normal control. No significant differences in other markers were observed between the two groups. Sclerostin level correlated positively with spine Bone Mineral Density (BMD), while 25-hydroxyvitamin D correlated negatively with hip BMD in the control group. No significant correlation was observed between other markers with spine or hip BMD.
CONCLUSION: These data provide an insight into the possible roles of osteocyte markers, especially osteoprotegerin and sclerostin, in classifying subjects with osteoporosis. However, the lack of association between these markers and BMD indicates that osteoporosis is a complex and multifactorial condition.
DISCUSSION: Several treatment options are available for different stages of prostate cancer. Hormone therapy known as androgen deprivation therapy (ADT) is the first line treatment used to treat advanced prostate cancer. Chemical castration by gonadotropin-releasing hormone agonists suppresses lutenizing hormone production, which in turn inhibits the production of testosterone and dihydrotestosterone. This will prevent the growth of prostate cancer cells. However, ADT causes deleterious effects on bone health because the androgens are essential in preserving optimal bone health in men.
CONCLUSION: Various observational studies showed that long-term ADT for advanced or metastatic prostate cancer was associated with decreased bone mineral density, as well as altered body composition that might affect bone health. Considering the potential impact of osteoporotic fracture, interventions to mitigate these skeletal adverse effects should be considered by physicians when initiating ADT on their patients.
AIMS: We conducted a study on Solena heterophylla Lour. fruits to evaluate their anti-diabetic activity in vivo, standardize their HPTLC, and profile their metabolites using LC-QTOF-MS. We aimed to explore the molecular mechanism behind their effects on oxidative stress and glycosylated hemoglobin (HbA1c).
METHODS: Firstly, the ethyl acetate fraction of Solena heterophylla Lour. fruits was standardized using Cucurbitacin B as a standard marker by conducting HPTLC evaluation. Next, we delved into analyzing metabolite profiling. In addition, the standardized fraction was utilized in an experimental study to investigate the molecular mechanism of action in an in vivo high-fat diet and a low dose of streptozotocin-induced diabetic model.
RESULTS: We have reportedly identified 52 metabolites in the ethyl acetate fraction of Solena heterophylla (EASH). In the in vitro tests, it has been observed that this extract from plants possesses notable inhibitory properties against α-amylase and α-glucosidase. Solena heterophylla fruits with high levels of Cucurbitacin B (2.29% w/w) helped lower FBG levels in animals with EASH treatment. EASH treatment reduced HbA1c levels and normalized liver lipid peroxidation and antioxidant enzyme levels. SGOT, SGPT, and SALP serum enzyme levels also returned to normal.
CONCLUSION: Based on the current evaluation, it was found that EASH exhibited encouraging hypoglycemic effects in diabetic rats induced by a low dose of STZ and high-fat diet, which warrants further investigation.
OBJECTIVE: This study aimed to compare the difference in cytokine profile between postmenopausal women with and without osteoporosis in Klang Valley, Malaysia.
METHODS: Postmenopausal women with (n = 20) and without osteoporosis (n = 20) were recruited for this study. Their bone health status was determined using dual-energy X-ray absorptiometry. Their fasting blood was collected for proteomic analysis. A protein array was performed for four subjects randomly selected from each group to screen the potential cytokines. Three cytokines at least 20% different between groups and consistently expressed by each subject were selected for validation using enzyme-linked immunosorbent assays (ELISA).
RESULTS: The protein array screening demonstrated that platelet-derived growth factor-BB, interleukin- 6 receptor (IL-6R), and tissue inhibitor of metallopeptidase-2 were higher in women with osteoporosis than women without osteoporosis (n = 4 per group), and consistently expressed by all women. Only body mass index (BMI)-adjusted logarithmically transformed IL-6R levels were lower among postmenopausal women with osteoporosis compared to women with normal bone health (p = 0.026) (n = 16 per group) in the ELISA test.
CONCLUSION: IL-6R was lower among postmenopausal women with osteoporosis compared to women with normal bone health after adjusting for BMI. However, a large-scale epidemiological study with proteomic analysis needs to confirm the findings.
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OBJECTIVE: This study aimed to investigate the immuno-modulatory effects of agarwood leaf extract (ALE) derived from Aquilaria malaccensis using RAW264.7 murine macrophages.
METHODS: In this study, RAW264.7 macrophages were incubated with ALE alone for 26 hours or ALE for 2 hours, followed by bacterial lipopolysaccharide for 24 hours. The nitrite and cytokine production (tumour necrosis factor-alpha (TNFα), interleukin (IL)-1β, IL-6, and IL-10), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) expression in the macrophages were assayed.
RESULTS: The study showed that ALE alone was immunostimulatory on the macrophages by increasing the nitrite, TNFα, and IL-6 production and COX2 expression (p<0.05 vs. untreated unstimulated cells). Pre-treatment of ALE suppressed nitrite level and iNOS expression but enhanced TNFα and IL-6 production and COX2 expression (p<0.05 vs. untreated lipopolysaccharides (LPS)-stimulated cells). ALE also increased IL-10 production regardless of LPS stimulation (p<0.05 vs. untreated cells).
CONCLUSION: ALE was able to promote the immune response of macrophages by upregulating pro-inflammatory cytokine levels and COX2 expression. It also regulated the extent of the inflammation by reducing iNOS expression and increasing IL-10 levels. Thus, ALE may have a role in enhancing the innate immune system against infection; however, its validation from in vivo studies is still pending.