Recent advances in vitamin K-dependent Gla-containing proteins and vitamin K nutrition

Masataka Shiraki,Naoko Tsugawa,Toshio Okano 대한골다공증학회 2015 Osteoporosis and Sarcopenia Vol.1 No.1

Vitamin K is a multi-functional nutrient and various tissues modify their function in response to vitamin K bioavailability mainly through post-translational modification of vitamin K-dependent (VKD) proteins. In this review, we discuss five clinical topics of vitamin K nutrition and vitamin K-dependent Gla-containing proteins. Although the physiological roles of these VKD proteins need further elucidation, study of these proteins may open new avenues for therapy in the clinical field. The topics discussed in the review are focused on des-gammacarboxyprothrombin (DCP) in relation to the pathogenesis of hepatocellular carcinoma, osteocalcin (OC) and undercarboxylated OC (ucOC) in relation to bone fractures and insulin sensitivity, matrix Gla protein (MGP) in relation to vascular calcification, and growth arrest-specific protein-6 (Gas6) in relation to inflammation and platelet aggregation. Finally, interaction among vitamins were discussed.

Antiresorptive agent-related osteonecrosis of the jaw in osteoporosis patients from Asian countries

Akira Taguchi,Masataka Shiraki,Archie Morrison,Aliya A. Khan 대한골다공증학회 2017 Osteoporosis and Sarcopenia Vol.3 No.2

Bisphosphonate (BP)-associated osteonecrosis of the jaw (ONJ) was first reported in oncology patients in 2003 and subsequently in osteoporosis patients in 2004. Since oral surgical procedures, such as tooth extraction, are also considered one of the major risk factors for ONJ, there is confusion among physicians, dentists, and patients e particularly osteoporosis patients currently taking BPs e regarding the safety of remaining on therapy surrounding these procedures. Many papers about BP-related ONJ (BRONJ) have been published to date. In addition to BRONJ, recent studies have reported an association between ONJ and the antiresorptive therapy denosumab (Dmab; a RANKL-inhibitor). BRONJ and Dmab-related ONJ are together referred to as antiresorptive agent-related ONJ (ARONJ). The pathogenesis of ARONJ still remains unknown. It is forecasted that there will be an increased incidence of patients with osteoporotic fractures and an increased number of prescriptions for antiresorptive agents in Asia in the future. However, prescriptions for antiresorptives for osteoporosis may be restricted in the Asian population as the occurrence of ARONJ may be higher as compared with those in other countries. In this review, we focused on the following topics as it pertains to the Asian osteoporotic population: the oral condition specific for osteoporosis patients; definition, staging, prevalence and incidence of ARONJ; imaging modalities for ARONJ; specific risk factors for ARONJ; prevention strategies for ARONJ, and; cooperation between physicians and dentists in the prevention of ARONJ. Ideally, the Asian Federation of Osteoporosis Societies would cooperate with one another and find more population-specific evidence for the prevention of ARONJ.

Recent nutritional trends of calcium and vitamin D in East Asia

Hiroaki Ohta,Kazuhiro Uenishi,Masataka Shiraki 대한골다공증학회 2016 Osteoporosis and Sarcopenia Vol.2 No.4

Abstract Calcium intake may play an important role on bone health. The recent national nutritional survey in Japan revealed the gradual decrease in calcium intake to around 480 mg/day. In addition, the patients with low level of vitamin D become too large in proportion. The present perspective proposes to increase calcium intake in Asian population.

Response to the Editor

Hiroaki Ohta,Kazuhiro Uenishi,Masataka Shiraki 대한골다공증학회 2017 Osteoporosis and Sarcopenia Vol.3 No.1

Thank you for your letter to our publication in Osteoporosis and Sarcopenia entitled on “Recent nutritional trend of calcium and vitamin D in East Asia”. Although the increase in calcium nutrition from food in postmenopausal women is urgent issue, Dr Yoo Kyoung Park pointed out that our claim is still premature to apply to whole population. As Dr Y-K Park pointed out that the KNHANES study had been limited the age ( 50 years of age) of the participants and the findings about calcium insufficiency should not be expanded into entire population [1]. On the other hand, the National Nutrition Survey in Japan [2] was subjected community dwelling household (n ¼ 3507) including the people aged over 1 year. Therefore, the participants of this research consisted of entire generation of Japan. The report of the National Nutritional Survey in Japan indicated that the calcium intake in younger generation (420e454 mg/ day for age 20e40 years old) was less than postmenopausal women (568e546 mg/day for sixties and seventies). In addition, total caloric intake of younger generation (1706 and 1652 kcal/day for twenties and forties, respectively) and the postmenopausal women (1766 and 1639 kcal/day for sixties and seventies, respectively) were almost same level suggesting that the calcium density in foods (Calcium in mg/day/Caloric intake in k Cal) was around 30% less in the younger generation (0.25e0.27 mg/kcal) than those in the older generation (0.32e0.33 mg/kcal). As it was written in our article, the calcium intake in older generation was still far less from the calcium requirement (788 mg/day for old women or 0.48 mg/kcal) [3]. Therefore, the postmenopausal women, who had relatively high calcium intake, took calcium around 70% of requirement. Although there was no available data regarding the effect of calcium intake on the development of peak bone mass in a prospective study design in Asian population, the low calcium intake seen in a younger generation in Japan strongly suggested that the development of proper peak bone mass may not be achieved by the recent young generation in Japan. Bone health has been reported to improve in Vietnamese postmenopausal women, who were received nutritional education [4]. Therefore, re-education regarding calcium intake will be required for the younger population. On the other hand, since the older generation in Japan had been adapted to the traditional dietary custom, it may be difficult to increase in calcium intake from the foods, further. Thus, we propose to take calcium supplement for the older generation. Since bone mineralization abnormalities in VDR knock out mice was recovered by increasing calcium and phosphate intakes [5], intestinal calcium absorption is an essential factor to promote bone calcification rather than vitamin D. Thus, the insufficient intake of calcium seen in recent Japan may be critical in not only postmenopausal women but also in the younger generation, and that is why we emphasized our concern for all Japanese generation. The intestinal calcium absorption is higher in the people with habitually low calcium intake through active transport system by calcitriol especially in younger generation [6]. On the other hand, the intestinal adaptation for low calcium intake may not properly active in elderly people because of low production of 1,25(OH)2D in kidney [7]. Therefore, passive transport of calcium, which is facilitated by high calcium intake, may have a meaningful role on the bone metabolism in the older people. In addition to high calcium intake, vitamin D nutrition also plays an important role on bone health. As Dr. Yoo Kyoung Park pointed out properly, we could not present vitamin D nutritional status in our National Nutritional survey, because the research did not measure serum level of 25(OH)D in the participants. However, the survey was reported the vitamin D intake from food in the participants. The mean intake of vitamin D in the female participants age...