Level of serum undercarboxylated osteocalcin correlates with bone quality assessed by calcaneal quantitative ultrasound sonometry in young Japanese females

Serum 25(OH)D and vitamin K1 levels in patients with severe motor and intellectual disability: A Japanese single-center experience

PURPOSE

To investigate whether patients with severe motor and intellectual disability (SMID) have nutritional vitamin D and K insufficiencies and clarify the required vitamin supplementation.

METHODS

This prospective observational study enrolled Japanese adults with SMID receiving institutionalized care who underwent blood sampling between February 2020 and February 2022 during annual medical checkups. Serum vitamin K1 and 25-hydroxy vitamin D (25(OH)D) levels were measured to determine their relationship with serum uncarboxylated osteocalcin (ucOC) levels. Vitamin D and K intake was compared among tube-fed and oral-intake patients with SMID and control participants using corresponding serum levels.

RESULTS

The study included 124 patients with SMID (56 men and 68 women; mean age: 53.0 years) and 20 control participants. Serum 25(OH)D levels were significantly higher in the SMID group than in the control group and the oral intake SMID group than in the tube-fed SMID group. In the tube-fed SMID group, vitamin D intake was lower than the daily recommended intake and correlated with serum 25(OH)D levels. Daily vitamin K intake in the tube-fed group was lower than recommended but not correlated with serum vitamin K levels. Serum ucOC levels were significantly higher in the SMID group than in the control group. Tube feeding was significantly and positively correlated with serum 25(OH)D levels. Serum 25(OH)D levels were not correlated with serum vitamin K1 levels.

CONCLUSIONS

The SMID group had higher ucOC levels than the control group, possibly owing to daily vitamin K and D deficiencies. Vitamin D supplementation is recommended to decrease ucOC levels.

Role of Vitamin K in Bone and Muscle Metabolism

Vitamin K, a cofactor for the γ-glutamyl carboxylase enzyme, is required for the post-translational activation of osteocalcin and matrix Gla protein, which play a key role in bone and muscle homeostasis. In vivo and in vitro models for osteoporosis and sarcopenia suggest the vitamin K could exert a positive effect in both conditions. In bone, it increases osteoblastogenesis, whilst decreases osteoclast formation and function. In muscle, it is associated with increased satellite cell proliferation and migration and might play a role in energy metabolism. Observational trials suggest that high levels of vitamin K are associated with increased bone mineral density and reduced fracture risk. However, interventional studies for vitamin K supplementation yielded conflicting results. Clinical trials in sarcopenia suggest that vitamin K supplementation could improve muscle mass and function. One of the main limitations on the vitamin K studies are the technical challenges to measure its levels in serum. Thus, they are obtained from indirect sources like food questionnaires, or levels of undercarboxylated proteins, which can be affected by other environmental or biological processes. Although current research appoints to a beneficial effect of vitamin K in bone and muscle, further studies overcoming the current limitations are required in order to incorporate this supplementation in the clinical management of patients with osteosarcopenia.

Bone Strength of the Calcaneus Is Associated with Dietary Calcium Intake in Older Japanese Men, but Not Women

The relationship between calcium intake and bone strength in older Asian individuals, including Japanese, is controversial; therefore, we herein investigated this relationship in older Japanese populations. We performed a cross-sectional analysis of 314 participants older than 65 years who voluntarily participated in a medical examination and responded to questionnaires. The osteo-sono assessment index (OSI) measured at the right calcaneus using a quantitative ultrasonic device was used as an indicator of bone strength. The daily dietary intake of calcium was assessed using a brief-type self-administered diet history questionnaire. A two-way analysis of covariance revealed a significant interaction between sex and calcium intake on the OSI (p < 0.01). A multiple regression analysis showed a positive correlation between calcium intake and the OSI in males (p < 0.01), but not females (p = 0.27). In females, grip strength divided by body weight positively correlated with the OSI (p = 0.04). The present results suggest that a higher calcium intake contributes to bone strength in older Japanese males. Although a higher grip strength may contribute to bone strength in females, the potential of estrogen as a confounding factor needs to be considered.

Exclusively breastmilk-fed preterm infants are at high risk of developing subclinical vitamin K deficiency despite intramuscular prophylaxis at birth

BACKGROUND

There is near-global consensus that all newborns be given parenteral vitamin K1 (VK1 ) at birth as prophylaxis against VK deficiency bleeding (VKDB). Breastmilk has a low VK content and cases of late VKDB are reported in exclusively breastmilk-fed preterm infants despite VK prophylaxis at birth.

OBJECTIVES

To assess the prevalence of functional VK insufficiency in preterm infants based on elevated under-γ-carboxylated (Glu) species of Gla proteins, factor II (PIVKA-II), and osteocalcin (GluOC), synthesized by liver and bone, respectively.

PATIENTS/METHODS

Prospective, multicenter, observational study in preterm infants born <33 weeks' gestation. Blood samples and dietary history were collected before hospital discharge, and after discharge at 2-3 months' corrected age. Outcome measures were serum VK1 , PIVKA-II, and %GluOC (GluOC as a percentage of the sum of GluOC plus GlaOC) compared between exclusively breastmilk-fed and formula/mixed-fed infants after discharge.

RESULTS

After discharge, breastmilk-fed babies had significantly lower serum VK1 (0.15 vs. 1.81 μg/L), higher PIVKA-II (0.10 vs. 0.02 AU/ml) and higher %GluOC (63.6% vs. 8.1%) than those receiving a formula/mixed-feed diet. Pre-discharge (based on elevated PIVKA-II), only one (2%) of 45 breastmilk-fed infants was VK insufficient. After discharge, eight (67%) of 12 exclusively breastmilk-fed babies were VK insufficient versus only one (4%) of 25 formula/mixed-fed babies.

CONCLUSIONS

Preterm infants who remain exclusively or predominantly human breastmilk-fed after neonatal unit discharge are at high risk of developing subclinical VK deficiency in early infancy. Routine postdischarge VK1 supplementation of breastfed infants to provide intakes comparable to those from formula milks should prevent this deficiency.

The Role of Gut Dysbiosis in the Bone-Vascular Axis in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) are at increased risk of bone mineral density loss and vascular calcification. Bone demineralization and vascular mineralization often concur in CKD, similar to what observed in the general population. This contradictory association is commonly referred to as the 'calcification paradox' or the bone-vascular axis. Mounting evidence indicates that CKD-associated gut dysbiosis may be involved in the pathogenesis of the bone-vascular axis. A disrupted intestinal barrier function, a metabolic shift from a predominant saccharolytic to a proteolytic fermentation pattern, and a decreased generation of vitamin K may, alone or in concert, drive a vascular and skeletal pathobiology in CKD patients. A better understanding of the role of gut dysbiosis in the bone-vascular axis may open avenues for novel therapeutics, including nutriceuticals.

Vitamin K deficiency, evaluated with higher serum ucOC, was correlated with poor bone status in women

BACKGROUND

An increase in serum undercarboxylated osteocalcin concentrations suggests vitamin K deficiency. Clinical intervention studies suggested that the vitamin K supplementation might contribute to preventing bone loss in postmenopausal women. Evidence on the relationship between serum undercarboxylated osteocalcin (ucOC) levels and bone parameters of quantitative ultrasound (QUS) is limited. We examined the correlation between serum ucOC concentrations and bone status as measured by QUS among middle-aged and older Japanese men and women.

METHODS

The subjects were community-dwelling men (n = 358) and women (n = 503) aged ≥ 40 years in Japan. Heel QUS parameters, including the stiffness index, speed of sound, and broadband ultrasound attenuation, were measured. Serum ucOC concentrations were measured by electrochemiluminescence immunoassay. Grip strength was measured in the dominant hand. Information on alcohol drinking, current smoking, exercise, and menopause in women was collected.

RESULTS

Serum ucOC concentrations were significantly associated with age in both sexes. Serum ucOC concentrations in men were higher at ≥ 80 years than those in the age groups of 40-49, 50-59, and 60-69 years. Serum ucOC concentrations in women were higher in the age groups of 50-59 and 60-69 years than those at 40-49 years. Partial correlation analysis adjusting for covariates (age, body mass index, grip strength, alcohol drinking, current smoking, and exercise in men; age, body mass index, grip strength, alcohol drinking, current smoking, exercise, and menopause in women) showed that serum ucOC concentrations were negatively significantly correlated with all QUS parameters in women. Serum ucOC concentrations were not correlated with them in men.

CONCLUSIONS

Vitamin K deficiency, evaluated with higher serum ucOC, was correlated with poor bone status in women.

Bone health and hyperglycemia in pediatric populations

The impact of prediabetes and diabetes on skeletal health in the context of increased risk of fragility fractures in adults has been studied recently. However, the prevalence of diabetes, overweight, and obesity have also increased in younger subjects. Current data concerning bone metabolism based on assessment of markers for bone turnover and of bone quality in diabetes patients in diverse age groups appears to be inconsistent. This review synthesizes the current data on the assessment of bone turnover based on the use of circulating bone markers recommended by international organizations; the effects of age, gender, and other factors on the interpretation of the data; and the effects of type 1 and type 2 diabetes as well as hyperglycemia on bone quality and turnover with particular emphasis on the pediatric population. Early intervention in the pediatric population is necessary to prevent the progression of metabolic disturbances that accompany prediabetes and diabetes in the context of common low vitamin D status that may interfere with bone growth.

A meta-analysis of serum osteocalcin level in postmenopausal osteoporotic women compared to controls

Background

Circulatory osteocalcin (OC) has been widely used as a biomarker to indicate bone turnover status in postmenopausal osteoporosis (PMO). However, the change of serum OC (sOC) level in PMO cases compared to postmenopausal controls remains controversial.

Methods

We searched the online database of PubMed and Cochrane Library. A meta-analysis of case-control studies was performed to compare the pooled sOC level between PMO patients and postmenopausal controls. Subgroup analysis according to potential confounding factors (different OC molecules and regions of the study population) was also performed.

Results

Ten case-control studies with 1577 postmenopausal women were included in this meta analysis. We found no significant difference in the pooled sOC level [mean difference (MD) = 1.84, 95% confidence interval (CI): (− 1.49, 5.16), p = 0.28] between PMO patients and controls. Subgroup analysis also revealed no significant difference in intact OC [MD = 1.76, 95%CI: (− 1.71, 5.23), p = 0.32] or N-terminal mid-fragment of the OC molecule [MD = 0.67, 95%(− 5.83, 7.18), p = 0.84] between groups. For different regions, no significant difference in sOC was found in Asian population between cases and controls [MD = -0.06, 95%(− 6.02, 5.89), p = 0.98], while the pooled sOC level was significantly higher in European PMO cases than controls [MD = 3.15, 95%(0.90, 5.39), p = 0.006].

Conclusions

Our analysis revealed no significant difference in sOC level between PMO cases and controls according to all the current eligible studies. OC molecules are quite heterogeneous in the circulation and can be influenced by glucose metabolism. Therefore, sOC is currently not a good indicator for the high bone turnover status in PMO. More trials with standardized methodologies for the evaluation of circulatory OC are awaited to update our current findings.

Bone-Vascular Axis in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) are at increased risk of osteoporosis and vascular calcification. Bone demineralization and vascular mineralization go often hand in hand in CKD, similar to as in the general population. This contradictory association is independent of aging and is commonly referred to as the "calcification paradox" or the bone-vascular axis. Various common risk factors and mechanisms have been identified. Alternatively, calcifying vessels may release circulating factors that affect bone metabolism, while bone disease may infer conditions that favor vascular calcification. The present review focuses on emerging concepts and major mechanisms involved in the bone-vascular axis in the setting of CKD. A better understanding of these concepts and mechanisms may identify therapeutics able to target and exert beneficial effects on bone and vasculature simultaneously.

Short-term impact of androgen deprivation therapy on bone strength in castration-sensitive prostate cancer

OBJECTIVES

To prospectively evaluate changes in bone quality and bone mineral density after androgen deprivation therapy in castration-sensitive prostate cancer.

METHODS

A total of 32 patients with castration-sensitive prostate cancer who were scheduled for androgen deprivation therapy for >12 months were included. The bone mineral density of the femoral neck and lumbar spine was evaluated before, and 6 and 12 months after androgen deprivation therapy. Bone metabolic (serum undercarboxylated osteocalcin, tartrate-resistant acid phosphatase 5b and procollagen type I propeptides) and bone quality markers (plasma pentosidine and homocysteine) were measured before, and 3, 6 and 12 months after androgen deprivation therapy.

RESULTS

The median patient age was 71 years. A total of 17 patients were treated primarily with androgen deprivation therapy, and 15 were treated with androgen deprivation therapy in combination with definitive radiotherapy. Bone quality markers did not change substantially after androgen deprivation therapy. Bone mineral density decreased significantly after 12 months of androgen deprivation therapy. Serum undercarboxylated osteocalcin and tartrate-resistant acid phosphatase 5b levels increased significantly 3 months after androgen deprivation therapy, but procollagen type I propeptides levels stayed unchanged.

CONCLUSIONS

Bone quality markers do not change substantially after androgen deprivation therapy, whereas bone mineral density decreases significantly. Bone turnover markers might play an important role in monitoring bone health during androgen deprivation therapy.

Poor Vitamin K Status Is Associated With Low Bone Mineral Density and Increased Fracture Risk in End-Stage Renal Disease

Chronic kidney disease and osteoporosis are major public health problems associated with an aging population. Vitamin K insufficiency is prevalent among patients with end-stage renal disease (ESRD). Preliminary data indicate that poor vitamin K status may compromise bone health and that increased inflammation may be in the causal pathway. We performed an ancillary analysis of data collected in the frame of prospective observational cohort studies exploring various aspects of bone health in de novo renal transplant recipients to investigate the association between vitamin K status, inflammation, bone mineral density, and incident clinical fractures. Parameters of mineral metabolism (including biointact PTH and FGF23, sclerostin, calcidiol, calcitriol) and inflammation (CRP and IL-6), osteoprotegerin, bone turnover markers (P1NP, BsAP, and TRAP5B), and dephosphorylated-uncarboxylated Matrix Gla Protein (dp-ucMGP) were assessed on blood samples collected immediately prior to kidney transplantation in 468 patients. Areal bone mineral density (aBMD) was measured at the lumbar spine and femoral neck by dual-energy X-ray absorptiometry within 14 days posttransplant. Poor vitamin K status, defined by dp-ucMGP >500 nmol/L, was highly prevalent (90%). High dp-ucMGP levels independently associated with elevated inflammatory markers and low aBMD. No associations were observed between vitamin K status and bone turnover markers. During a median follow-up of 5.1 years, 33 patients sustained a fragility fracture. In Cox-proportional hazards analysis, a dp-ucMGP above median associated with incident fractures, independent of classical determinants, including age, gender, history of fracture, and aBMD (HR 2.21; 95% CI, 1.00 to 4.91; p < 0.05). In conclusion, poor vitamin K status associates with inflammation and low aBMD in patients with ESRD and confers an increased risk of incident fractures in de novo renal transplant recipients. © 2018 American Society for Bone and Mineral Research.