Age-related Changes in Parathyroid Hormone and 25 Hydroxycholecalciferol Levels

Chapuy, M. C.; Durr, F; Chapuy, P

doi:10.1093/geronj/38.1.19

Cited by 122 publications

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“…Further, the lack of correlation between age and mid-molecule PTH in the present study suggests that there was no age-related change in renal clearance of PTH fragments in these subjects. Chapuy et al 26 suggested that age-related decreases in intestinal absorption of calcium results in increased secretion of PTH and that the decreased absorption is due to reduced synthesis of 1,25-dihydroxyvitamin D in older people as reported by Gallagher et al 27 We could not confirm this hypothesis with our results since we observed no decrease of serum calcium with age.…”

Section: Scontrasting

confidence: 75%

Parathyroid hormone, platelet calcium, and blood pressure in normotensive subjects.

Brickman¹,

Nyby²,

Hungen³

et al. 1991

Hypertension

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Relations between platelet cytosolic calcium, parathyroid hormone, and blood pressure were investigated in 91 normotensive subjects: 47 men and 44 women ranging in age from 24 to 70 years. The men had higher mean arterial blood pressure, serum creatinine, and body mass index than the women. Serum total calcium, plasma ionized calcium, and parathyroid hormone (measured as both intact hormone and mid-molecule fragment) were not different between men and women; however, serum phosphate was higher in women than in men. Basal platelet cytosolic calcium was higher in men than in women (113.7±1.9 versus 105.9±1.7, respectively; p<0.0l), but there was no difference in the peak platelet cytosolic calcium responses to thrombin between the two groups. In the combined group of male and female subjects, platelet cytosolic calcium correlated with diastolic blood pressure and mean arterial pressure (r=0J7, p<0.001 and r=032,p<0.01, respectively). Intact parathyroid hormone correlated with systolic and mean arterial blood pressure (r=0.41,p<0.001 for both). Age correlated with both systolic blood pressure (r=0.40, p<0.001) and intact parathyroid hormone (r=0.51, p<0.001). When multiple regression analysis was performed using mean arterial pressure as the dependent variable, platelet cytosolic calcium and intact parathyroid hormone maintained significant correlations with mean arterial pressure. Platelet cytosolic calcium did not correlate with intact parathyroid hormone. These results suggest that both platelet cytosolic calcium and intact parathyroid hormone are associated with blood pressure regulation in normotensive subjects. However, the influences of these two factors on blood pressure are not interrelated. (

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Section: Scontrasting

confidence: 75%

Parathyroid hormone, platelet calcium, and blood pressure in normotensive subjects.

Brickman¹,

Nyby²,

Hungen³

et al. 1991

Hypertension

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“…The expression of osteocalcin is stimulated by 1 ,25-dihydroxyvitamin D3 [1,25-(OH )2D3] and further modulated by other local factors such as TGF-# (38)(39)(40)(41). While some studies report decreased circulating levels of 1,25(OH)2D3 with age (42)(43)(44), similar findings were not observed by others (45)(46)(47). Nevertheless, an impaired ability ofthe aging kidneys to convert 25-hydroxyvitamin D3 to 1,25-(OH)2 D3 may contribute to lower circulating levels with age (44,46,48).…”

Section: Discussionmentioning

confidence: 53%

Age- and gender-related changes in the distribution of osteocalcin in the extracellular matrix of normal male and female bone. Possible involvement of osteocalcin in bone remodeling.

Ingram¹,

Park²,

Clarke³

et al. 1994

J. Clin. Invest.

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IntroductionWith increasing age, bone undergoes changes in remodeling that ultimately compromise the structural integrity ofthe skeleton. The presence of osteocalcin in bone matrix may alter bone remodeling by promoting osteoclast activity. Whether ageand/or gender-related differences exist in the distribution of osteocalcin within individual bone remodeling units is not known. In this study, we determined the immunohistochemical distribution of osteocalcin in the extracellular matrix of iliac crest bone biopsies obtained from normal male and female volunteers, 20-80 yr old. Normal bone metabolism is the result of a highly integrated relationship between bone resorption and formation. With age, the structural integrity of the skeleton declines along with the functional capacity of various organ systems. Although overall bone mass decreases with age in females and males, the rate of bone loss in females is greater than males ( 1-3). The mechanisms by which bone remodeling is altered with age and gender are poorly understood. The organic phase of normal bone consists of 90% type I collagen and the remaining 10% is composed of noncollagenous proteins (NCPs).' NCPs are synthesized and secreted by bone cells, and their expression is regulated, in part, by local growth factors and hormones (4-7). Accumulating evidence suggests that the extracellular matrix of bone exerts profound effects on cellular activity by retaining NCPs and growth factors that influence both immediate and long-term cell-matrix interactions (8-13). Reduced recruitment of osteoclasts to devitalized particles of bone from human donors of increasing age suggests that bone matrix components may be partially responsible for impaired skeletal remodeling associated with aging (9).Osteocalcin is a 6.5-kD vitamin K-dependent, gamma-carboxyglutamic acid-containing NCP secreted by osteoblasts and odontoblasts. Due to its high affinity for calcium and hydroxyapatite, osteocalcin is incorporated into the extracellular matrix of bone ( 14-16). A growing body of evidence suggests that this matrix protein is involved in bone remodeling. Significant differences in the concentration ofextractable osteocalcin between cortical and trabecular bone in humans provides evidence of distinct regulatory mechanisms among these areas (10). Osteocalcin-deficient bone particles obtained from warfarn-treated rats recruit fewer osteoclasts and are resorbed less than normal particles using in vivo assays ( 1 1, 17, 18). Osteopetrotic rat bone contains low concentrations of osteocalcin, and osteoclast activity in these animals is reduced ( 19).The possibility that NCPs are involved in regulating sitespecific cell-matrix interactions is supported by studies that have immunolocalized NCPs within the extracellular matrix of bone from several species (13,(20)(21)(22). Presently, it is not known whether age or gender differences exist in the microanatomical distribution of NCPs within bone remodeling units. In this study, the immunohistochemical distribution of osteocalcin in ...

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“…The differences in both parameters over the age range were equivalent to reductions of −0.41% and −0.65%, respectively, consistent with a continuing loss of skeletal integrity throughout life at the cortical and trabecular level. It has been postulated that enhanced PTH secretion, secondary to compromised vitamin D status or metabolism, may induce or exacerbate bone loss in older individuals [27][28][29]. Moreover, interventional data have confirmed the role of vitamin D deficiency in the pathogenesis of agerelated osteoporosis and indicated the need to maintain serum cholecalciferol levels within the normal range in elderly people [30].…”

Section: Discussionmentioning

confidence: 99%

Factors Associated with Cortical and Trabecular Bone Loss as Quantified by Peripheral Computed Tomography (pQCT) at the Ultradistal Radius in Aging Women

et al. 1997

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Abstract. Peripheral quantitative computed tomography (pQCT) allows the separate determination of cortical and trabecular bone mineral density in the peripheral skeleton. This cross-sectional study was designed to examine the effects of healthy aging on pQCT measurements at the ultradistal radius. In a well-defined sample of 129 community-based women, aged 70-87 years, the differences in cortical and trabecular density over the age range were equivalent to losses of −0.41% and −0.65% per year, respectively. To investigate the mechanism of this agerelated decline, we assessed relationships between both parameters and height, weight, body mass index, dietary calcium intake, grip strength, and serum concentrations of insulin-like growth factor-I (IGF-I), calcidiol (25(OH)D 3 ), calcitriol (1,25(OH) 2 D 3 ), parathyroid hormone (PTH), and sex hormone binding globulin (SHBG). Multiple regression was used to adjust for potential confounders. Age was not significant after controlling for other covariables. Body mass index, grip strength, serum IGF-I, 25(OH)D 3 , and PTH (1-84) were found to be independent predictors of total bone density. Including (total or free) 1,25(OH) 2 D 3 did not improve the model precision. These findings provide evidence that, among other factors, the activity of the growth hormone-IGF-I-axis is of importance for skeletal integrity. Grip strength, serum IGF-I, and PTH (1-84) were discovered to be significantly related to cortical but not to trabecular density, suggesting that different mechanisms may be involved in compact and cancellous bone loss.Key words: Peripheral quantitative computed tomography (pQCT) -Age-related bone loss -Growth hormone -IGF-I.Low bone mass, as estimated by decreased bone mineral density (BMD), is an established predictor of osteoporotic fractures. Although fracture prediction by bone density is partially site-dependent [1], numerous reports have shown that fractures at all skeletal sites are significantly related to low bone mass at the distal forearm [2][3][4][5]. In all of these studies, BMD was assessed with single-photon absorptiometry. Peripheral quantitative computed tomography (pQCT) has been proposed as an adjunct to conventional densitometry [6,7]. BMD determination with pQCT at the site of the distal radius is a method of high precision and low radiation [8]. In addition, pQCT is the only noninvasive assessment of bone mineral to measure a true-dimensional density (as opposed to an areal density by standard methods) and to allow separate determination of cortical and trabecular bone density [9].Studies have indicated that bone loss in elderly women shows no evidence for an age-related leveling off [10][11][12][13]. Even at advanced ages, interventions to preserve or to enhance bone mass may therefore be an effective approach to prevention of fractures. However, the mechanisms leading to age-related bone loss remain poorly defined. Moreover, whether cortical and trabecular bone losses are mediated by differential mechanisms is virtually unknown. In the pres...

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Age-related Changes in Parathyroid Hormone and 25 Hydroxycholecalciferol Levels

Cited by 122 publications

References 0 publications

Parathyroid hormone, platelet calcium, and blood pressure in normotensive subjects.

Parathyroid hormone, platelet calcium, and blood pressure in normotensive subjects.

Age- and gender-related changes in the distribution of osteocalcin in the extracellular matrix of normal male and female bone. Possible involvement of osteocalcin in bone remodeling.

Factors Associated with Cortical and Trabecular Bone Loss as Quantified by Peripheral Computed Tomography (pQCT) at the Ultradistal Radius in Aging Women

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