Bone mineral metabolism status, quality of life, and muscle strength in older people

Producción CientíficaAs the relationship between vitamin D and various diseases or health conditions has become known, interest in the contribution of vitamin D to overall health-related quality of life (QoL) has increased. We examined the relationship between vitamin D status and QoL in 273 participants aged 65 years and older. Serum levels of total calcium, phosphorus, intact parathyroid hormone, albumin, and 25-hydroxyvitaminD3 were analyzed. We also recruited data for QoL, physical activity, nutritional impairment, and muscular strength. Ninety percent of the subjects were classified as vitamin D deficient or insufficient. Participants with higher serum 25(OH)D3, calcium, phosphorous, and Alb levels were significantly less likely to self-report depression or anxiety after adjustment (p = 0.009, p = 0.005, p = 0.003, and p = 0.005, respectively). Additionally, we found an association between lower levels of albumin and self-reported problems with mobility or usual activities (p = 0.01). We also found associations between better muscle strength and higher levels of vitamin D, calcium, phosphorous, and albumin (p = 0.006, p = 0.003, p = 0.004 and p = 0.002, respectively). Overall, our data provide evidence that serum vitamin D and Alb levels are negatively related to self-reported anxiety or depression, usual activities, mobility, and three dimensions of QoL in older adults. Furthermore, vitamin D levels are positively related to hand grip strength in adults over 65 years old

Study of bone mineral metabolism

The use of Sr-85 as an indicator of the skeletal location and relative amount of bone demineralization which occurs during immobilization of the body or body parts, bed-rest or space flight was studied. The bone mineral replacement which occurs after immobilization was measured rather than the bone loss which occurs during immobilization. In a study with two adult beagle dogs, the Sr-85 uptake in a leg which had been immobilized for two months was 400 percent higher than the uptake in the legs in regular use. This increased uptake probably resulted from only a few percent loss in bone mineral and indicates that losses less than one percent can be easily detected and located. The sensitivity, simplicity, and low radiation dose associated with the use of this method indicates that it should receive consideration for use on humans in bed-rest and space flight studies. Methods for measuring changes in total body nitrogen and in assisting the Johnson Space Center in calibrating a whole body counter for total body potassium measurements were also investigated

Changes in mineral metabolism with immobilization/space flight

Researchers are still unsure of the accuracy of previous bone density measurements of their significance following a period of weightlessness. Rapid technological advances in the measurement of bone density will enable us now to measure bone density accurately at multiple sites in the skeleton with doses of radiation less than that given by a spine x ray. It may not be possible to obtain this type of information before the next series of space flights take place, although the bed-rest model may provide supporting information. Extensive testing of bone density on every astronaut should be performed before and after the space flight. Prevention and treatment can only be undertaken after gathering sufficient baseline information. The use of exercise in preventing bone loss is still highly speculative, but represents a relatively easy approach to the problem in terms of study

Bioavailable Vitamin D Is More Tightly Linked to Mineral Metabolism than Total Vitamin D in Incident Hemodialysis Patients

Prior studies showed conflicting results regarding the association between 25-hydroxyvitamin D (25(OH)D) levels and mineral metabolism in end-stage renal disease. In order to determine whether the bioavailable vitamin D (that fraction not bound to vitamin D binding protein) associates more strongly with measures of mineral metabolism than total levels, we identified 94 patients with previously measured 25(OH)D and 1,25-dihydroxyvitamin D $(1,25(OH)_2D)$ from a cohort of incident hemodialysis patients. Vitamin D binding protein was measured from stored serum samples. Bioavailable 25(OH)D and $1,25(OH)_2D$ were determined using previously validated formulae. Associations with demographic factors and measures of mineral metabolism were examined. When compared with whites, black patients had lower levels of total, but not bioavailable, 25(OH)D. Bioavailable, but not total, 25(OH)D and $1,25(OH)_2D$ were each significantly correlated with serum calcium. In univariate and multivariate regression analysis, only bioavailable 25(OH)D was significantly associated with parathyroid hormone levels. Hence, bioavailable vitamin D levels are better correlated with measures of mineral metabolism than total levels in patients on hemodialysis

Continued investigation of kinetic aspects of bone mineral metabolism

The total body calcium in humans was determined by measuring expired Ar-37 after neutron irradiation. The excretion of Ar-37 from humans was found to be much slower than the excretion from rats and dogs, and to be related to the age of a person. A study of the uniformity of the Ar-37 production throughout the thickness of the body was studied using phantoms. The results indicate that it should be possible to obtain a uniformity within plus or minus 3% for the production of Ar-37 per unit of calcium by using a bilateral irradiation. New low background, large volume proportional counters were developed and constructed, for more sensitive measurement of Ar-37 in the expired air from patients. A new irradiation enclosure was developed for measuring total body calcium in rats by the Ar-37 method. With this enclosure the Ar-37 production per gram of calcium is constant with a standard deviation of plus or minus 2.8% for any size rat between 100 and 500 grams. The use of Na-22 as measure of bone replacement in the fractured femur of a dog was not successful

Kinetic measurements of bone mineral metabolism: The use of Na-22 as a tracer for long-term bone mineral turnover studies

Sodium-22 was studied as a tracer for bone mineral metabolism in rats and dogs. When incorporated into bone during growth from birth to adulthood, the bone becomes uniformly tagged with (22)Na which is released through the metabolic turnover of the bone. The (22)Na which is not incorporated in the bone matrix is rapidly excreted within a few days when animals are fed high but nontoxic levels of NaCl. The (22)Na tracer can be used to measure bone mineral loss in animals during space flight and in research on bone disease

Indicators of Mineral Metabolism in the Oral Fluid in Patients with Gastroesophageal Reflux Disease

Disruption of the digestive system in the gastrointestinal tract, namely in gastroesophageal reflux disease, leads to the development of pathological processes in the oral cavity, changing the homeostasis of the viscoelastic gel layer of the esophageal mucosa. Thus, it has been proven that there are reflex connections between the receptor apparatus of the esophageal mucosa and the efferent nerve fibers of the salivary glands, which can be disrupted in GERD. Therefore, saliva is involved in providing effective protection of the esophagus. As a result, the content of mineral components changes significantly: in particular, the level of calcium and enzyme composition. Aim to study the indicators of mineral metabolism: the content of calcium, alkaline, and acid phosphatases in mixed saliva in patients with gastroesophageal reflux disease. Methods 60 patients of various ages who underwent inpatient treatment at the IFNMU University Clinic were examined, where pH-metry was performed to determine acidity. The main group consisted of patients diagnosed with GERD, with decreased and increased acidity. The content of indicators of mineral metabolism in saliva was determined as follows: calcium (Ca) - photometric method with arsenase -111; acid phosphatase (AC) was determined by the Hillman method, alkaline phosphatase (AL) by hydrolysis of p-nitrophenyl phosphate at pH -10.4, release of p-nitrophenol and phosphate. The norm of indicators of mineral metabolism was established on 30 practically healthy volunteers. Statistical processing of data was carried out using the Microsoft Excel program by calculating the arithmetic mean. Conclusions thus, the results obtained indicate that in GERD there is a violation of mineral metabolism in the oral fluid. The oral fluid is the first to come into contact with the reflux agent. This leads to a violation of saliva neutralization, so the study of saliva mineral composition can be considered as an early diagnostic marker for gastroesophageal reflux disease

Gla-rich protein (GRP) as an early and novel marker of vascular calcification and kidney dysfunction in diabetic patients with CKD: a pilot cross-sectional study

Vascular calcification (VC) is one of the strongest predictors of cardiovascular risk in chronic kidney disease (CKD) patients. New diagnostic/prognostic tools are required for early detection of VC allowing interventional strategies. Gla-rich protein (GRP) is a cardiovascular calcification inhibitor, whose clinical utility is here highlighted. The present study explores, for the first time, correlations between levels of GRP in serum with CKD developmental stage, mineral metabolism markers, VC and pulse pressure (PP), in a cohort of 80 diabetic patients with mild to moderate CKD (stages 2-4). Spearman's correlation analysis revealed a positive association of GRP serum levels with estimated glomerular filtration rate (eGFR) and α-Klotho, while a negative correlation with phosphate (P), fibroblast growth factor 23 (FGF-23), vascular calcification score (VCS), PP, calcium (x) phosphate (CaxP) and interleukin 6 (IL-6). Serum GRP levels were found to progressively decrease from stage 2 to stage 4 CKD. Multivariate analysis identified low levels of eGFR and GRP, and high levels of FGF-23 associated with both the VCS and PP. These results indicate an association between GRP, renal dysfunction and CKD-mineral and bone disorder. The relationship between low levels of GRP and vascular calcifications suggests a future, potential utility for GRP as an early marker of vascular damage in CKD.Portuguese Society of Nephrology (SPN) ; Portuguese national funds from FCT-Foundation for Science and Technology through the transitional provision DL57/2016/CP1361/CT0006 UIDB/04326/2020info:eu-repo/semantics/publishedVersio

FGF23-klotho axis as predictive factors of fractures in type 2 diabetics with early chronic kidney disease

Background: The aim of our study was to evaluate the relevance of FGF23-klotho axis in the predisposition for bone fractures in type 2 diabetic patients with early chronic kidney disease. Methods: In a prospective study we included 126 type 2 diabetic patients with CKD stages 2-3 (from 2010 to 2017). We used descriptive statistics, ANOVA and chi-square test. Our population was divided into two groups according to the occurrence of a bone fracture event or not, and the groups were compared considering several biological and laboratorial parameters. We employed a multiple regression model to identify risk factors for bone fracture events and hazard ratios (HR) were calculated using a backward stepwise likelihood ratio (LR) Cox regression. Results: Patients with a fracture event displayed higher levels of FGF-23, Phosphorus, PTH, TNF-alpha, OxLDL, HOMA-IR, calcium x phosphorus product and ACR and lower levels of Osteocalcin, alpha-Klotho, 25(OH)D3 and eGFR compared with patients without a fracture event (p < 0.001). The number of patients with a fracture event was higher than expected within inclining CKD stages (chi 2, p = 0.06). The occurrence of fracture and the levels of TNF-alpha, klotho, 25(OH)D3 and OxLDL were found to predict patient entry into RRT (p < 0.05). Age, osteocalcin, alpha-Klotho and FGF-23 independently influenced the occurrence of bone fracture (p < 0.05). Conclusions: alpha-Klotho and FGF-23 levels may have a good clinical use as biomarkers to predict the occurrence of fracture events. (C) 2019 Elsevier Inc. All rights reserved.info:eu-repo/semantics/publishedVersio