Bone histomorphometric study of young rats following oestrogen deficiency

Osteoporosis is a global problem which results in increased fractures risk. The reports from earlier studies were inconsistent with the aging factor as well as the time which is needed to induce bone loss post-ovariectomy. This study aimed to determine the short-term effects of estrogen deficiency on bone structural histomorphometric parameters in young rats. 30 Sprague-Dawley female rats weighing 250 to 300 g were assigned to baseline, sham-operated and ovariectomy groups. The baseline group (n = 10) was sacrificed immediately. Sham-operated rats (SO, n = 10) underwent sham operation while ovariectomised group (OVX, n =10) underwent bilateral ovariectomy. All the rats were sacrificed 6 weeks post-ovariectomy. Following sacrifice, the right femora were dissected and subjected to the histomorphometric analysis using modified Von Kossa method. Bone volume/tissue volume (BV/TV) and trabecular number (Tb.N) reduced significantly, while trabecular separation (Tb.Sp) increased significantly in the ovariectomized rats, compared to the baseline and sham groups 6 weeks postovariectomy (P<0.001). In the other hand, trabecular thickness (Tb.Th) was consistent among the groups (P=0.41). Estrogen deficiency resulted in marked decline in BV/TV which most probably attributed to a reduction in Tb.N. In contrast, Tb.Th was found to be preserved following estrogen loss. Hence, the period of 6 weeks post-ovariectomy was sufficient to induce osteoporosis in ovariectomized rats without affecting Tb.Th.Key words: Bone histomorphometry, menopause, estrogen deficiency, osteoporosis, ovariectomy, trabecular bone

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

A concise review of testosterone and bone health

Nur-Vaizura Mohamad, Ima-Nirwana Soelaiman, Kok-Yong Chin Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lampur, Malaysia Abstract: 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 κ-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. Keywords: androgen, men, osteopenia, osteoporosis, estrogen, skeleto

Agreement between calcaneal quantitative ultrasound and osteoporosis self-assessment tool for Asians in identifying individuals at risk of osteoporosis

Kok-Yong Chin,1 Nie Yen Low,2 Alia Annessa Ain Kamaruddin,2 Wan Ilma Dewiputri,2 Ima-Nirwana Soelaiman1 1Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Cheras, Malaysia; 2ASASIpintar Foundation Program, PERMATApintar National Gifted Centre, Universiti Kebangsaan Malaysia, Bangi, Malaysia Background: Calcaneal quantitative ultrasound (QUS) is a useful tool in osteoporosis screening. However, QUS device may not be available at all primary health care settings. Osteoporosis self-assessment tool for Asians (OSTA) is a simple algorithm for osteoporosis screening that does not require any sophisticated instruments. This study explored the possibility of replacing QUS with OSTA by determining their agreement in identifying individuals at risk of osteoporosis. Methods: A cross-sectional study was conducted to recruit Malaysian men and women aged ≥50 years. Their bone health status was measured using a calcaneal QUS device and OSTA. The association between OSTA and QUS was determined using Spearman’s correlation and their agreement was assessed using Cohen Kappa and receiver-operating curve. Results: All QUS indices correlated significantly with OSTA (p<0.05). The agreement between QUS and OSTA was minimal but statistically significant (p<0.05). The performance of OSTA in identifying subjects at risk of osteoporosis according to QUS was poor-to-fair in women (p<0.05), but not statistically significant for men (p>0.05). Changing the cut-off values improved the performance of OSTA in women but not in men. Conclusion: The agreement between QUS and OSTA is minimal in categorizing individuals at risk of osteoporosis. Therefore, they cannot be used interchangeably in osteoporosis screening. Keywords: bone, correlation, osteopenia, ROC, sensitivity, specificit

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

OBJECTIVES: Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. METHODS: A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. RESULTS: Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. CONCLUSIONS: Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia