The role of tocotrienol in protecting against metabolic diseases

Obesity is a major risk factor for diabetes, and these two metabolic conditions cause significant healthcare burden worldwide. Chronic inflammation and increased oxidative stress due to exposure of cells to excess nutrients in obesity may trigger insulin resistance and pancreatic β- cell dysfunction. Tocotrienol, as a functional food component with anti-inflammatory, antioxidant, and cell signaling-mediating effects, may be a potential agent to complement the current management of obesity and diabetes. The review aimed to summarize the current evidence on the anti-obesity and antidiabetic effects of tocotrienol. Previous studies showed that tocotrienol could suppress adipogenesis and, subsequently, reduce body weight and fat mass in animals. This was achieved by regulating pathways of lipid metabolism and fatty acid biosynthesis. It could also reduce the expression of transcription factors regulating adipogenesis and increase apoptosis of adipocytes. In diabetic models, tocotrienol was shown to improve glucose homeostasis. Activation of peroxisome proliferator-activated receptors was suggested to be responsible for these effects. Tocotrienol also prevented multiple systemic complications due to obesity and diabetes in animal models through suppression of inflammation and oxidative stress. Several clinical trials have been conducted to validate the antidiabetic of tocotrienol, but the results were heterogeneous. There is no evidence showing the anti-obesity effects of tocotrienol in humans. Considering the limitations of the current studies, tocotrienol has the potential to be a functional food component to aid in the management of patients with obesity and diabetes. Keywords: adipose; diabetes; insulin resistance; metabolic syndrome; obesity; overweight; vitamin

A Review on the Relationship between Aspirin and Bone Health

Aspirin is a cyclooxygenase inhibitor commonly used in primary prevention of cardiovascular diseases and cancers. Its users are elderly population susceptible to osteoporosis. It also inhibits the synthesis of prostaglandin E2 essential in bone remodeling. This prompts the question whether it can influence bone health among users. This review aimed to summarize the current literature on the use of aspirin on bone health. A literature search on experimental and clinical evidence on the effects of aspirin on bone health was performed using major scientific databases. In vitro studies showed that aspirin could enhance the survival of bone marrow mesenchymal stem cells, the progenitors of osteoblasts, and stimulate the differentiation of preosteoblasts. Aspirin also inhibited the nuclear factor kappa-B (NFκB) pathway and decreased the expression of receptor activator of NFκB ligand, thus suppressing the formation of osteoclast. Aspirin could prevent bone loss in animal models of osteoporosis. Despite a positive effect on bone mineral density, the limited human epidemiological studies revealed that aspirin could not reduce fracture risk. A study even suggested that the use of aspirin increased fracture risk. As a conclusion, aspirin may increase bone mineral density but its effect on fracture prevention is inconclusive. More data are needed to determine the effects of aspirin and bone health in human

Leptin, adiponectin and insulin as regulators for energy metabolism in a rat model of metabolic syndrome

Leptin, adiponectin, and insulin are pivotal regulators for lipid and glucose metabolism. This study aimed to investigate the changes in these hormones in a rat model of metabolic syndrome (MetS) induced by high-carbohydrate high-fat (HCHF) diet. Twelve-week-old male Wistar rats were divided into two experimental groups. The normal group was given standard rat chow with tap water. The HCHF group was given HCHF diet with 25% fructose-supplemented drinking water to induce MetS. Body composition of the animals was measured using dual-energy X-ray absorptiometry. Blood was collected at week 0, 8, 12, and 16 for the measurement of blood glucose and hormone levels. Our findings demonstrated that HCHF diet significantly increased fat mass, percentage of fat, and decreased lean mass in the animals starting from week 8. The levels of blood glucose, leptin, and insulin were significantly higher but the level of adiponectin was significantly lower in the HCHF rats compared to the normal rats. In conclusion, hormones play a key underlying role in regulating lipid and glucose metabolism in MetS

The Role of Vitamin E in Preventing and Treating Osteoarthritis – A Review of the Current Evidence

Osteoarthritis is a debilitating disease of the joint involving cartilage degeneration and chondrocytes apoptosis. Oxidative stress is one of the many proposed mechanisms underpinning joint degeneration in osteoarthritis. The current pharmacotherapies emphasize pain and symptomatic management of the patients but do not alter the biological processes underlying the cartilage degeneration. Vitamin E is a potential agent to prevent or treat osteoarthritis due to its antioxidant and anti-inflammatory effects. This review aims to summarize the current evidence on the relationship between vitamin E and osteoarthritis derived from preclinical and human studies. Cellular studies showed that vitamin E mitigated oxidative stress in cartilage explants or chondrocyte culture invoked by mechanical stress or free radicals. Animal studies suggested that vitamin E treatment prevented cartilage degeneration and improve oxidative status in animal models of osteoarthritis. Low circulating or synovial vitamin E was observed in human osteoarthritic patients compared to healthy controls. Observational studies also demonstrated that vitamin E was related to induction or progression of osteoarthritis in the general population. Vitamin E supplementation might improve the outcomes in patients with osteoarthritis, but negative results were also reported. Different isomers of vitamin E might possess distinct anti-osteoarthritic effects. As a conclusion, vitamin E may retard the progression of osteoarthritis by ameliorating oxidative stress and inflammation of the joint. Further studies are warranted to develop vitamin E as an anti-osteoarthritis agent to reduce the global burden of this disease

The influence of age, ethnicity and body anthropometry on the level of serum osteocalcin and terminal-c telopeptides of type I collagen in men

Bone turnover markers (BTMs) are useful in the assessment of bone health status. However, the infl uence of age, ethnicity and body anthropometry on the level of BTMs in men remains understudied. This study aimed to determine the influence of these factors on the level of BTM, namely osteoclacin (OC) and C-terminal telopeptides of type 1 collagen (CTX-1) among Malay and Chinese men (N = 407) aged 20 years and above in Klang Valley. The subjects were recruited using purposive sampling method. Their height, body weight and body mass index were measured. Their blood was collected in the morning for serum OC and CTX-1 analysis using enzyme-linked immunoasorbent assays. Results showed that OC and CTX-1 levels were significantly higher in Malay compared to Chinese men (p 0.005). There were significant and negative correlations between OC and body mass index and weight, which were significant for men aged 20-39 years only (p 0.05). As a conclusion, levels of BTMs in Malaysian men could be infl uenced by age, ethnicity and body anthropometry. Thus, these factors should be taken into consideration in the evaluation of bone health status of men using BTMs

Changes of grip strength, articular cartilage and subchondral bone in monoiodoacetate-induced osteoarthritis in rats

Osteoarthritis is a degenerative disease affecting articular cartilage among the elderly. The intra-articular monoiodoacetate injection is one of the most widely used methods to induce osteoarthritis in animals. While the effects of monoiodoacetate on cartilage are well-characterized, its effects on subchondral bone remodeling are less studied. The purpose of this study was to determine the changes of the grip strength, articular cartilage structure and subchondral bone remodeling in monoiodoacetate-induced osteoarthritis in rats. Three-month-old male Wistar rats were assigned to normal control (n=6) and osteoarthritis group (n=6), which received intra-articular injection of 4 mg/50 μL monoiodoacetate solution once at the left knee of hindlimb. The rats were monitored for four weeks. The grip strength test was performed before injection and every week after injection. After four weeks, the femurs with intact cartilage were harvested for histomorphological analysis. Grip strength was reduced significantly in the osteoarthritic rats compared to the normal rats (p0.05). As a conclusion, monoiodoacetate-induced osteoarthritis affects the cartilage and increases osteoclast formation in the subchondral bone of rats

Serum testosterone, sex hormone-binding globulin and total calcium levels predict the calcaneal speed of sound in men

OBJECTIVES: Variations in sex hormones and the calcium balance can influence bone health in men. The present study aimed to examine the relationship between the calcaneal speed of sound and biochemical determinants of bone mass, such as sex hormones, parathyroid hormones and serum calcium. METHODS: Data from 549 subjects from the Malaysian Aging Male Study, which included Malay and Chinese men aged 20 years and older residing in the Klang Valley, were used for analysis. The subjects' calcaneal speed of sound was measured, and their blood was collected for biochemical analysis. Two sets of multiple regression models were generated for the total/bioavailable testosterone and estradiol to avoid multicollinearity. RESULTS: The multiple regression results revealed that bioavailable testosterone and serum total calcium were significant predictors of the calcaneal speed of sound in the adjusted model. After adjustment for ethnicity and body mass index, only bioavailable testosterone remained significant; the total serum calcium was marginally insignificant. In a separate model, the total testosterone and sex hormone-binding globulin were significant predictors, whereas the total serum calcium was marginally insignificant. After adjustment for ethnicity and body mass index (BMI), the significance persisted for total testosterone and SHBG. After further adjustment for age, none of the serum biochemical determinants was a significant predictor of the calcaneal speed of sound. CONCLUSION: There is a significant age-dependent relationship between the calcaneal speed of sound and total testosterone, bioavailable testosterone and sex hormone-binding globulin in Chinese and Malay men in Malaysia. The relationship between total serum calcium and calcaneal speed of sound is ethnicity-dependent

Effect of Kelulut honey supplementation on bone health in male rats on high-carbohydrate high-fat diet

Purpose: To determine the effects of Kelulut honey (KH) on the bone health of rats with metabolic syndrome. Methods: Male Wistar rats were randomised into normal control and metabolic syndrome is fed with a diet enriched with carbohydrate and fat. The rats in the metabolic syndrome arm were further assigned into the negative control group and honey group supplemented orally with Kelulut honey (1g/kg) daily for eight weeks. After the rats were sacrificed, the trabecular and cortical micro-architecture of the harvested femur was analysed using X-ray micro-computed tomography, while histomorphometric method was used to determine bone cell indices. Femoral biomechanical properties were analysed using a universal mechanical tester. Results: Total cross-sectional area, osteoid surface and volume, displacement and strain reduced significantly, while eroded surface increased significantly in the rats with metabolic syndrome than the normal rats (p < 0.05). The honey group showed a significant reduction in osteoclast surface than the normal healthy control (p < 0.05). Other skeletal parameters did not show a significant intergroup difference. Conclusion: Metabolic syndrome is harmful to bone health and honey has limited effects in reversing these negative effects