The Anti-Inflammatory Role of Vitamin E in Prevention of Osteoporosis

There is growing evidence that inflammation may be one of the causal factors of osteoporosis. Several cytokines such as IL-1, IL-6, RANKL, OPG, and M-CSF were implicated in the pathogenesis of osteoporosis. These cytokines are important determinants of osteoclast differentiation and its bone resorptive activity. Anticytokine therapy using cytokine antagonists such as IL-receptor antagonist and TNF-binding protein was able to suppress the activity of the respective cytokines and prevent bone loss. Several animal studies have shown that vitamin E in the forms of palm-derived tocotrienol and α-tocopherol may prevent osteoporosis in rat models by suppressing IL-1 and IL-6. Free radicals are known to activate transcription factor NFκB which leads to the production of bone resorbing cytokines. Vitamin E, a potent antioxidant, may be able to neutralise free radicals before they could activate NFκB, therefore suppressing cytokine production and osteoporosis. Vitamin E has also been shown to inhibit COX-2, the enzyme involved in inflammatory reactions. Of the two types of vitamin E studied, tocotrienol seemed to be better than tocopherol in terms of its ability to suppress bone-resorbing cytokines

Nicotine Impaired Bone Histomorphometric Parameters And Bone Remodeling Biomarkers In Sprague-Dawley Male Rats

The effects of nicotine administration on structural and cellular parameters of bone histomorphometry, cotinine, and biomarkers of bone remodeling were studied in twenty-one Sprague-Dawley male rats. Rats aged three months and weighing between 250-300 g were divided into three groups. Group 1 was the baseline group, which was sacrificed without treatment. The other 2 groups were the control group and the nicotine group. The nicotine group was treated with nicotine 7 mg/kg body weight and the C group was treated with normal saline only. Treatment was given by intraperitoneal injection, six days a week for a period of 4 months. Histomorphometric analysis was done on the metaphyseal region of the trabecular bone of the left femur by using an image analyzer. Biochemical analysis was done using ELISA-test kit to compare the serum cotinine, osteocalcin and pyridinoline (PYD) levels between pretreatment and after 4 months treatment in the control and nicotine groups. Histomorphometric analysis revealed that nicotine significantly decreased the trabecular bone volume (BV/TV) and the osteoblast surface (Ob.S/BS), and increased the osteoclast surface (Oc.S/BS) and the eroded surface (ES/BS) compared to the baseline and control groups. In addition, biochemical analysis showed that nicotine treatment for 4 months significantly decreased the osteocalcin (bone formation marker) levels while the cotinine and PYD (bone resorption marker) levels were increased as compared to pretreatment. We concluded that treatment with nicotine 7 mg/kg for 4 months exerted negative a effect on the trabecular bone histomorphometric parameters and bone remodeling biomarkers

Effects of palm tocotrienols on oxidative stress and bone strength in ovariectomised rats

Oxidative stress has been associated with postmenopausal osteoporosis which pre-disposes to risk of fracture. Palm tocotrienol is a potent antioxidant and has the poten-tial to be used for treatment of post-menopausal osteoporosis. The aim of the study is to determine if palm tocotrienol supplementation could alleviate oxidative stress in ovariectomised rat model and improve its bone strength. The rats were di-vided into four groups: (i) sham-operated group (SHAM) (ii) ovariectomised-control group (OVX) (iii) ovariectomised and given 60mg/kg α-tocopherol by oral gavage (OVX + ATF) (iv) ovariectomised and given 60mg/kg palm tocotrienols by oral gavage (OVX + PTT). After eight weeks of treatment, blood samples were taken to measure oxida-tive status (MDA, SOD and GPX) while the femurs were biomechanically tested for strength and resistance to fracture. Ovariectomy was shown to induce oxidative stress as shown by the raised MDA levels and reduced GPX activity. Palm tocotrienols seemed to offer protection against the ovariectomy-induced oxidative stress as shown by the suppression of MDA levels and raised GPX and SOD activities in the OVX+PTT group. In comparison, α-tocopherol was only able to raise the SOD but not as high as palm tocotrienols. The biomechanical tests have shown that ovariectomy has not af-fected the bone strength significantly after eight weeks. Palm tocotrienols supplemen-tation for eight weeks was effective in preventing oxidative stress in a post-meno-pausal ra

The biological effects of tocotrienol on bone: a review on evidence from rodent models

Kok-Yong Chin, Soelaiman Ima-Nirwana Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia Abstract: Osteoporosis causes significant health care and economic burden to society, leading to a relentless search for effective preventive agents. Tocotrienol, a member of the vitamin E family, has demonstrated promising potential as an osteoporosis-preventing agent. This review summarizes evidence on the effects of tocotrienol on bone in animal models. Techniques used to examine the effects of tocotrienol on bone in animals included bone histomorphometry, X-ray microtomography, dual-energy X-ray absorptiometry, bone turnover markers, bone calcium content, and biomechanical strength. Tocotrienol was shown to improve osteoblast number, bone formation, mineral deposition, and bone microarchitecture in osteopenic rats. It also decreased osteoclast number and bone erosion in the rats. Tocotrienol supplementation resulted in an improvement in bone mineral density, although biomechanical strength was not significantly altered in the rats. The beneficial effects of tocotrienol on bone can be attributed to its role as an antioxidant, anti-inflammatory agent, suppressor of the mevalonate pathway, and modulator of genes favorable to bone formation. Keywords: bone, osteoporosis, tocotrienol, vitamin

Effects of annatto-derived tocotrienol supplementation on osteoporosis induced by testosterone deficiency in rats

Kok-Yong Chin, Soelaiman Ima-Nirwana Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia Background: Previous animal models have demonstrated that tocotrienol is a potential treatment for postmenopausal osteoporosis. This study evaluated the antiosteoporotic effects of annatto-derived tocotrienol (AnTT) using a testosterone-deficient osteoporotic rat model. Methods: Forty rats were divided randomly into baseline, sham, orchidectomized, AnTT, and testosterone groups. The baseline group was euthanized without undergoing any surgical treatment or intervention. The remaining groups underwent orchidectomy, with the exception of the sham group. AnTT 60 mg/kg/day was given orally to the AnTT group, while the testosterone group received testosterone enanthate 7 mg/kg per week intramuscularly for 8 weeks. Structural changes in trabecular bone at the proximal tibia were examined using microcomputed tomography. Structural and dynamic changes at the distal femur were examined using histomorphometric methods. Serum osteocalcin and C-terminal of type 1 collagen crosslinks were measured. Bone-related gene expression in the distal femur was examined. Results: There were significant degenerative changes in structural indices in the orchidectomized group (P<0.05), but no significant changes in dynamic indices, bone remodeling markers, or gene expression (P>0.05) when compared with the sham group. The AnTT group showed significant improvement in structural indices at the femur (P<0.05) and significantly increased expression of bone formation genes (P<0.05). Testosterone was more effective than AnTT in preventing degeneration of bone structural indices in the femur and tibia (P<0.05). Conclusion: AnTT supplementation improves bone health in testosterone-deficient rats by enhancing bone formation. Its potential should be evaluated further by varying the dosage and treatment duration. Keywords: bone remodeling, osteoporosis, testosterone, tocotrieno

Effect of tocotrienol from Bixa orellana (annatto) on bone microstructure, calcium content, and biomechanical strength in a model of male osteoporosis induced by buserelin

Nur-Vaizura Mohamad, Soelaiman Ima-Nirwana, Kok-Yong Chin Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia 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. Keywords: androgen, vitamin E, fracture, gonadotropin-releasing hormone agonists, testosterone, osteopenia, osteoporosi

Research Paper - Gamma-tocotrienol is required for normal vitamin D metabolism in female rats

Objective: To study the effects of vitamin E deficiency and supplementation of vitamin D and bone metabolism in female Sprague-Dawley rats. Materials and Methods: Rats weighing between 200 and 250 g were divided into six groups, that is, rats fed on (a) normal rat chow diet (RC), (b) vitamin E-deficient diet (VED) (c) VED diet supplemented with 60 mg/kg α-tocopherol acetate (ATF), (d) VED diet supplemented with 60 mg/kg γ-tocotrienol (GTT), (e) VED diet supplemented with 60 mg/kg Tocomin ® (TOC) and (f) baseline control group which was killed without treatment (BC). Treatment was given for 2 months. Serum 1,25-dihydroxyvitamin D3, serum total calcium, urine calcium, left femur, and fourth lumbar vertebra calcium content and left femur length were measured. Results: In the VED and ATF groups, activation of vitamin D to 1,25-dihydroxyvitamin D3 was inhibited and calcium reabsorption in the kidneys were increased. Both the effects seen in ATF and GTT groups were observed in the TOC group. The GTT group was protected from the effects of the vitamin E-deficient diet. Calcium content of the fourth lumbar vertebra was also decreased by vitamin E- deficiency, which was not reversed by vitamin E supplementation. Conclusion: γ-tocotrienol and not α-tocopherol protects vitamin D metabolism and calcium homeostasis from the effects of vitamin E-deficiency

Significant association between parathyroid hormone and uric acid level in men

Kok-Yong Chin,1 Soelaiman Ima Nirwana,1 Wan Zurinah Wan Ngah21Department of Pharmacology, 2Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, MalaysiaBackground: Previous reports of patients undergoing parathyroidectomy and of patients receiving teriparatide as antiosteoporotic treatment have suggested a plausible relationship between parathyroid hormone (PTH) and uric acid. However, similar data at population level were lacking. The current study aimed to determine the relationship between PTH and uric acid in a group of apparently healthy Malaysian men.Methods: A cross-sectional study was conducted among 380 Malay and Chinese men aged 20 years and above, residing in the Klang Valley, Malaysia. Their body anthropometry was measured, and their fasting blood samples were collected for biochemical analysis. The relationship between PTH and uric acid was analyzed using regression analysis.Results: Increased serum PTH level was significantly associated with increased serum uric acid level (β=0.165; P=0.001). Increased PTH level was also significantly associated with the condition of hyperuricemia in the study population (odds ratio [OR], 1.045; 95% confidence interval [CI], 1.017–1.075; P=0.002). All analyses were adjusted for age, body mass index, vitamin D, total calcium, inorganic phosphate, blood urea nitrogen and creatinine levels.Conclusion: There is a significant positive relationship between PTH level and uric acid level in Malaysian men. This relationship and its clinical significance should be further investigated in a larger longitudinal study. Keywords: hyperuricemia, Asian, cross-sectional study, uric acid, urat

Calculating in-vivo short-term precision error of dual-energy x-ray absorptiometry in human and animal: a technical report

Bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) is important in diagnosing osteoporosis. Precision error of DXA is a useful measure to determine a true change in BMD value. This study aimed to investigate the short-term coefficient of variance of Hologic Discovery QDR Wi DXA machine. The lumbar spine and hip BMD of fifteen healthy volunteers (mean age: 30.67 + 10.41 years) and the whole body BMD of fifteen female Sprague-Dawley rats (aged three months old) were scanned using Hologic Discovery QDR Wi DXA machine. Each volunteer and rat underwent triplicate scans to assess the reproducibility of BMD values. The interval between the scans ranged within 1 to 12 weeks for human subjects. For animal samples, the scans were repeated on the same day after repositioning. The precision error was expressed as a percentage coefficient of variance (%CV). The %CV obtained for lumbar spine and hip BMD for human were 1.8% and 1.2%, respectively. The %CV for whole body BMD of rats was 1.4%. The short-term CV demonstrated for both human and animal in the present study were comparable. The precision error of DXA must be monitored to ensure optimal performance of the device