Increased bone resorbing activity of peripheral monocyte culture supernatants in elderly women

Accelerated bone loss occurs in the years after menopause, and is an ongoing phenomenon in elderly women. The role of cytokines in bone loss after estrogen deficiency has been shown in ovariectomized rat and mice models. In humans, the involvement of bone resorbing cytokines is now well established. In the early years after menopause, monocyte activation leads to increased cytokine production. We have previously shown that the bone resorbing activity (BRA) of peripheral blood monocyte culture supernatants from postmenopausal women is higher than in premenopausal (Pre-M) women. This increased activity was related to interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha levels. We here investigate whether monocyte activation still occurs in older women and whether this relates to bone resorption. We studied 19 healthy Pre-M, and 24 early (E-Post-M, menopause < 10 yr) and 24 late (L-Post-M, menopause > 10 yr) postmenopausal women. Peripheral blood monocytes were cultured for 48 h with 20% autologous plasma. BRA of monocyte supernatants (expressed as the ratio of monocyte supernatant over control bones supernatant) was assessed using fetal long-bone resorbing assays. Bone resorption was determined by urinary total pyridinoline excretion. BRA was significantly increased in E-Post-M and L-Post-M, compared with Pre-M subjects (1.20 +/- 0.10 and 1.15 +/- 0.20 vs. 0.73 +/- 0.10, respectively, both P < 0.05). Moreover, BRA of bones cultured with the supernatant of Pre-M was lower than BRA of control bones. BRA was significantly correlated with levels of IL-1, IL-6, and tumor necrosis factor-alpha in supernatant. Supernatant IL-1 levels were increased in E-Post-M, compared with Pre-M women (506 +/- 180 vs. 122 +/- 30, P < 0.05). Similarly, pyridinoline levels were increased in E-Post-M and L-Post-M, compared with Pre-M subjects (8.8 +/- 1 and 10.5 +/- 0.9 vs. 5.8 +/- 0.5, respectively, both P < 0.05). BRA was significantly correlated to pyridinoline levels. These data indicate the presence of monocyte activation in L-Post-M, which may be responsible for the increased bone resorption and bone loss observed in this elderly population.     

Is there a means for cost reduction in intensive care fluid therapy without a loss of quality?

The objective of this study was to examine the value of NTx, a urinary cross-linked N-telopeptides of type I collagen, as a marker of bone resorption. We assessed changes in pre- and postmenopausal bone resorption by evaluating the correlation of NTx with L2-4 bone mineral density (BMD) in a total of 1100 Japanese women, aged 19-80 years [272 premenopausal (45.2 +/- 6.2 years) and 828 postmenopausal (59.5 +/- 6.2 years)]. Postmenopausal women were divided into three groups based on the range of BMD (normal, osteopenic, and osteoporotic). Within each group, subjects were further segregated according to years since menopause (YSM). NTx values were then evaluated for each group. Our results showed that BMD was significantly decreased (P < 0.05) and NTx was significantly increased (P < 0.01) after menopause in age-matched analysis. Consistent with a previous report, NTx was inversely correlated with BMD for the entire cohort of study subjects (r = -0.299), although NTx correlated better with premenopausal than postmenopausal BMD (r = -0.240 versus r = -0.086). This may have been due to the fact that elevated values of NTx were exhibited over the entire range of BMD present in the postmenopausal women, suggesting that NTx might respond faster to the estrogen withdrawal than BMD. In all postmenopausal women, regardless of the range of BMD, the increase in NTx reached a peak within 5 YSM. After 11 YSM, however, NTx remained elevated in the osteoporotic group but it decreased in the osteopenic group, and showed no significant change in the group of postmenopausal women with normal BMD. These findings suggest that bone resorption is dramatically increased within 5 years after menopause but remains increased only in osteoporotic women.     

Assessment of urinary pyridinoline excretion with a specific enzyme-linked immunosorbent assay in normal adults and in metabolic bone diseases

Pyridinoline (Pyr), a specific bone resorption marker, is usually assessed in urine by high-performance liquid chromatography (HPLC) after acid hydrolysis and a prepurification step. Immunoassays have been developed to measure urinary Pyr directly. Here we developed and evaluated an enzyme-linked immunosorbent assay (ELISA), specific for the urinary free Pyr form, in normal adults and in patients with metabolic bone diseases. Urinary Pyr excretion increased significantly with age for men (r = 0.288; p < 0.001) and for women (r = 0.362; p < 0.001). An average 55% increase was noted between premenopausal (n = 41) and early postmenopausal (n = 42) women (mean +/- 1 SD; 22.4 +/- 6.3 nmol Pyr/mmol creatinine and 34.7 +/- 16.8 nmol Pyr/mmol creatinine, respectively; p < 0.001). High Pyr levels were found in patients with hyperthyroidism (n = 29; 126.5 +/- 84.2 nmol Pyr/mmol creatinine), Paget's disease of bone (n = 30; 61.8 +/- 45.8 nmol Pyr/mmol creatinine), and primary hyperparathyroidism (n = 10; 57.4 +/- 23.9 nmol Pyr/mmol creatinine). In patients with Paget's disease, urinary free Pyr excretion was correlated with urinary hydroxyproline, the conventional bone resorption marker (r = 0.87; p < 0.001), and with total alkaline phosphatase, a marker of bone formation (r = 0.55; p < 0.005). Free Pyr measured by ELISA was highly correlated with total Pyr and with total deoxypyridinoline HPLC measurements in postmenopausal women (n = 35; r = 0.94 and 0.91, respectively) and in patients with metabolic bone diseases (n = 22; r = 0.91 and 0.88, respectively; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrasound velocity of the tibia in normal German women and hip fracture patients

One of the latest developments in quantitative ultrasound (QUS) is the measurement of the speed of sound (SOS) of cortical bone of the midtibia. To determine the diagnostic validity of this method we measured 150 healthy women aged 22-94 years. Additionally, we report on first results of patients with hip fracture. Precision in vivo of the tibial QUS expressed as the percentage coefficient of variation (CV) was 0.39% for the first day and 0.45% after repositioning the second day (mean CV = 0.42%). No significant dependency of tibial SOS was found with weight, height, and body mass index in pre- and postmenopausal women. There was a significant decline of SOS with age in postmenopausal women (SOS = 4225 - 5.3 age, r = -0.46, P < 0. 001), whereas premenopausal women showed no decline (SOS = 3906 + 1. 3 age, r = 0.13, ns) Mean SOS values of premenopausal women were significantly higher than those of postmenopausal women (3960 +/- 78.7 m/second and 3898 +/- 120 m/second, respectively, P < 0.001). Postmenopausal women on estrogen substitution had significantly higher mean tibial SOS values than age-comparable postmenopausal women without estrogen substitution (3980 +/- 99 m/second and 3869 +/- 100 m/second, respectively, P < 0.001). Significant difference between age-matched healthy women, n = 11, and hip fracture patients, n = 13, expressed as z-score of -1.4 SD was found. In conclusion, tibial QUS declines with age and detects higher values in premenopausal women and postmenopausal women on estrogen substitution and lower values in hip fracture patients. Further prospective studies are needed to clarify its role in fracture risk assessment.     

Effects of estrogen therapy of postmenopausal women on cytokines measured in peripheral blood

Estrogen replacement therapy (ERT) is known to prevent bone loss following the menopause, but the mechanism for this is unclear. Estrogen may suppress the secretion of certain bone-resorbing cytokines. The aim of this study was to assess the effect of ERT on the levels of cytokines measured in peripheral blood. We measured cytokines in 10 postmenopausal women (ages 56-59, 3-9 years since menopause) treated with ERT and 10 age-matched (54-59 years, 4-10 years since menopause) untreated women as controls. Samples of blood were taken and used for mononuclear cell cultures, whole blood (WB) cultures, and the separation of serum. The cultures were treated with lipopolysaccharide (LPS; 500 ng/ml) and hydrocortisone (10(-6) M). The conditioned medium from cultures and the serum were then assayed for interleukin-6 (IL-6), IL-1alpha IL-1beta, IL-1 IL-1ra, tumor necrosis factor alpha (TNF-alpha), and granulocyte macrophage colony stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. M-CSF and the soluble cytokine receptors soluble IL-6 receptor (sIL-6r) and soluble TNF receptor type 1 (sTNFr1) were also measured in serum and M-CSF in stimulated WB cultures. Measurements were corrected for mononuclear cell count. We also measured serum bone-specific alkaline phosphatase (ibAP) in all subjects. We found that LPS stimulated secretion of all cytokines both in WB and isolated cell cultures, and that this was attenuated by hydrocortisone. A significantly higher ratio of IL-1beta/IL-1ra (p = 0.02) in LPS stimulated WB cultures was seen in the untreated women. Levels of IL-1beta and IL-1alpha measured in WB cultures were lower and IL-1ra was higher in the ERT-treated group but these results were not significant. BAP was higher in the untreated group (p = 0.005) and correlated with IL-alpha/IL-1ra in the whole group (r = 0.49, p = 0.03). Results of other measurements showed no significant differences between groups. We conclude that estrogen may prevent bone loss following the menopause by altering the balance between IL-1beta and IL-1ra.     

Circulating levels of interleukin-6 and tumor necrosis factor-alpha are elevated in primary hyperparathyroidism and correlate with markers of bone resorption--a clinical research center study

The pathogenesis of PTH-induced bone loss is uncertain. Experimental evidence suggests that PTH induces the production by osteoblasts of the bone-resorbing cytokine, interleukin-6. We measured the circulating levels of interleukin-6, tumor necrosis factor-alpha, and interleukin-1 beta and examined their relationship to biochemical markers of bone turnover in 38 patients with primary hyperparathyroidism (7 of whom also were studied after successful parathyroid adenomectomy), 6 patients with hypoparathyroidism, and 12 subjects with normal parathyroid function. The patients with untreated primary hyperparathyroidism had mean serum levels of interleukin-6 that were 16-fold higher than control values (mean +/- SEM; primary hyperparathyroidism 18.6 +/- 2.1 pg/mL, controls 1.1 +/- 0.1; P < 0.001). Circulating levels of interleukin-6 soluble receptor (primary hyperparathyroidism 41.7 +/- 1.2 ng/ mL, controls 25.1 +/- 1.0; P < 0.001), and tumor necrosis factor-alpha (primary hyperparathyroidism 11.6 +/- 0.8 pg/mL, controls 2.5 +/- 0.2; P < 0.001) were also elevated. After successful parathyroid adenomectomy, levels of each of these cytokines fell into the normal range. The mean levels of interleukin-6, its soluble receptor, and tumor necrosis factor-alpha in the subjects with hypoparathyroidism were lower than control values (P < 0.001 for each variable). There was no difference between subjects with primary hyperparathyroidism and controls in the circulating level of interleukin-1 beta. In the subjects with untreated primary hyperparathyroidism, serum levels of interleukin-6 correlated strongly with those of intact PTH (r = 0.47, P = 0.003) and biochemical markers of bone resorption: serum deoxypyridinoline (r = 0.93, P < 0.001), serum type I collagen carboxyterminal telopeptide (r = 0.87, P < 0.001), urinary pyridinoline (r = 0.81, P < 0.001), and urinary deoxypyridinoline (r = 0.63, P = 0.005). Levels of tumor necrosis factor-alpha correlated less strongly with the same variables: PTH (r = 0.41, P = 0.01), serum deoxypyridinoline (r = 0.48, P = 0.002), serum type I collagen carboxyterminal telopeptide (r = 0.46, P = 0.004), urinary pyridinoline (r = 0.61, P = 0.008), and urinary deoxypyridinoline (r = 0.61, P = 0.007). Levels of interleukin-6 also correlated with those of tumor necrosis factor-alpha (r = 0.44, P = 0.005). Multiple regression analysis indicated that interleukin-6, but not tumor necrosis factor-alpha, was independently predictive of bone resorption. We conclude that serum levels of interleukin-6 and tumor necrosis factor-alpha are increased in patients with primary hyperparathyroidism and are normalized by successful surgical treatment. The finding that these cytokines correlate with biochemical markers of bone resorption suggests that they play a role in the pathogenesis of bone loss in primary hyperparathyroidism.     

Effects of hormone replacement therapy in bone resorption, in post-menopausal women

BACKGROUND: The effects of different therapies on bone loss rate can be measured using biochemical markers of bone resorption such as urinary hydroxyproline. AIM: To study the effects of hormone replacement therapy on urinary hydroxyproline in postmenopausal women. PATIENTS AND METHODS: Eighty three postmenopausal women without hormone replacement therapy, 54 postmenopausal women receiving hormone replacement therapy and 16 premenopausal women (considered as the control group) were studied. Hydroxyproline was measured in an early morning urine sample, after one day of diet without meat or gelatin. RESULTS: Urinary hydroxyproline in premenopausal women was 33.7 +/- 7.9 mg/g creatinine. The figure for postmenopausal women with hormonal replacement therapy was 33.7 +/- 5.9 mg/g creatinine. Postmenopausal women without replacement therapy had an urinary hydroxyproline of 47.4 +/- 8.5 mg/g creatinine, significantly higher than that of premenopausal and supplemented women. In 21 postmenopausal women, hydroxyproline was measured before and after three months of replacement therapy, values decreased 35.5 +/- 11% in this period and there was a direct correlation between initial values and the degree of reduction (r = 0.69, p < 0.001). CONCLUSIONS: Postmenopausal women receiving hormone replacement therapy have a urinary hydroxyproline excretion similar to that of premenopausal women.     

Adenosine receptor antagonism affects regional resting vascular resistance during rat peritoneal sepsis

We examined sequential changes of bone-resorbing cytokines and bone metabolic markers and the effect of ovarian hormones on bone metabolism during the menstrual cycle in 10 healthy Japanese women, aged 22-43 yr, with normal ovarian function. Serum soluble interleukin-6 receptor (sIL-6R) showed a significant variation; a rise during the early and late follicular periods followed by a fall during the early luteal period (P = 0.0423, P = 0.0334) and an increase during the mid and late luteal periods. There were significant changes in the levels of markers of bone formation: a rise in serum bone-specific alkaline phosphatase (ALP) during the mid and late follicular (P = 0.0265) periods and a fall in serum carboxyl-terminal propeptide of type I procollagen (PICP) during the midluteal period (P = 0.0161). As for the levels of bone resorption markers, urinary type I collagen C-telopeptide breakdown products (CTx) and free deoxypyridinoline (D-Pyr) decreased significantly during the early and midfollicular periods, urinary free D-Pyr and serum pyridinoline cross-linked carboxyl-terminal telopeptide of type I collagen (ICTP) (P = 0.0440) increased significantly during the early luteal period, and urinary CTx, free D-Pyr, and serum ICTP decreased significantly during the late luteal period (P = 0.0170-0.0008). The serum PTH level was significantly higher during the follicular than the luteal period (P = 0.0132). Serum sIL-6R significantly correlated with urinary CTx (r = 0.190, P < 0.05) and serum ALP (r = 0.209, P < 0.05) and serum estradiol with intact osteocalcin (r = 0.309, P < 0.0005) and serum ALP (r = 0.181, P < 0.05). These observations strongly suggest that cyclic variations in the levels of bone formation and resorption markers and of a bone-resorbing cytokine may be modulated by cyclic changes in serum steroid hormones during the menstrual period. In addition, the specific days of biochemical events in the menstrual cycle are crucial for evaluating osteoclastic and osteoblastic activities in pre- and perimenopausal women or in women starting GnRH agonist therapy.     

A prospective study of bone loss in African-American and white women--a clinical research center study

Although bone loss occurs universally with age, the incidence of age-related osteoporotic fractures varies widely among ethnic groups. In the U.S., age-adjusted hip fracture incidence is 50% lower in African-American than in white women. Adult African-American women also have higher bone mass, but it is not known whether this difference is entirely due to higher peak bone mass or also results from slower rates of bone loss. Rates of bone loss were measured prospectively in 122 white and 121 African-American healthy, nonobese, pre- and postmenopausal women. Bone density was measured at 6-month intervals over a mean of 3-4 yr using single and dual photon absorptiometry of the forearm (cortical bone) and spine (trabecular bone). Similar rates of premenopausal bone loss were documented in both white and African-American women. However, in early menopause, bone loss was faster in the white women in the forearm (-2.4%/yr in whites vs. -1.2%/yr in African-Americans; P = 0.045), with a similar trend in the spine (-2.2%/yr in whites vs. -1.3/yr in African-Americans; P = 0.27). In women more than 5 yr postmenopause, the rates of bone loss did not differ by ethnic group. Our results indicate that the higher bone mass in African-American women is largely due to the attainment of a greater peak bone mass by early adulthood. However, slower rates of bone loss in the early postmenopausal period may also contribute to the higher bone density of older African-American women. Although bone loss occurs in both groups, there are ethnic differences in bone loss rates which indicate that data derived from white women cannot be simply extrapolated to nonwhite populations. Ethnic group-specific data on the determinants of bone homeostasis are needed.     

In vitro secretion of cytokines by human bone marrow: effects of age and estrogen status

It has been proposed that cytokines mediate the acceleration of bone loss following menopause. Because of the intimate relationship between bone marrow stromal cells and bone tissue, it is possible that marrow cells and their products contribute to the bone microenvironment and influence the regulation of bone cell differentiation and activity. We examined the production of cytokines by bone marrow stromal cells from a total of 37 women and 15 men undergoing total hip replacement for noninflammatory joint disease. Low-density mononuclear cells were isolated from bone marrow and were cultured in phenol red-free alpha MEM medium supplemented with 10% FBS and antibiotics. Constitutive secretion of interleukin-6 (IL-6) was positively correlated with age in a series of 8 women and 5 men measured by bioassay (r = 0.98; P < 0.01) and in a series of 18 women and 10 men measured by immunoassay (r = 0.56; P < 0.01). The pattern of cytokine production by bone marrow stromal cells was examined in detail in 23 postmenopausal women, aged 49-88 yr. Basal secretion of immunoreactive IL-6 and IL-11, but not granulocyte-macrophage colony-stimulating factor, increased with time in culture. Exogenous IL-1 beta stimulated secretion of IL-6 and IL-11 in a saturable, dose-dependent manner. Secretion of soluble IL-6 receptor was not correlated with secretion of IL-6, either constitutively or in the presence of IL-1 beta. In 4 of 14 samples, IL-1 beta also stimulated secretion of granulocyte-macrophage colony-stimulating factor. IL-1 beta was undetectable in 7 of 9 cultures during the 2-week culture period. IL-6 did not stimulate secretion of IL-1 beta in the 7 cultures tested. Cells were dependent upon serum for viability and growth and were not sustained by a serum substitute (1% insulin-transferrin-selenium-BSA). Cells grown in medium with 10% FBS and supplemented with 1% insulin-transferrin-selenium-BSA secreted 10-fold more IL-6 than cells grown in serum alone. Marrow from 7 women receiving estrogen replacement therapy showed lower constitutive secretion of IL-6 (75%; P < 0.006) and IL-11 (43%; P < 0.05) than marrow from age-matched controls and had blunted stimulation of IL-6 and IL-11 secretion by exogenous IL-1 beta. These data indicate distinct patterns of cytokine production by human marrow stromal cultures dependent upon age and estrogen status.     

Age and sex differences in cerebral hemodynamics: a transcranial Doppler study

BACKGROUND AND PURPOSE: Hemodynamic factors seem to play an important role in the pathogenesis of cerebral ischemic events. The aim of this study was to evaluate whether changes in cerebrovascular reactivity occur in women after menopause. METHODS: Using transcranial Doppler ultrasonography, we studied the changes of flow velocity after hypercapnia in the middle cerebral arteries of 45 healthy premenopausal women (mean age, 32.3 years; range, 20 to 47 years) and 40 postmenopausal women (mean age, 54.4 years; range, 48 to 64 years). The same measurements were recorded in two groups of healthy male subjects age matched with premenopausal (45 subjects) and postmenopausal women (40 subjects). Moreover, a subgroup of postmenopausal women aged 48 to 53 years (15 subjects) were compared with a group of 15 premenopausal women of the same age. We obtained hypercapnia with breath holding and evaluated cerebrovascular reactivity with the breath-holding index (BHI). RESULTS: BHI was significantly lower in postmenopausal women (0.89+/-0.3) than in premenopausal women (1.59+/-0.3; P<0.0001) and in young (1.34+/-0.5; P<0.001) and old men (1.20+/-0.4; P<0.04). In the latter group, BHI was significantly lower than in premenopausal women (P<.0001). BHI values were also significantly lower in postmenopausal than in premenopausal women of the same age (0.81+/-0.1 versus 1.34+/-0.1; P<0.0001). CONCLUSIONS: These findings suggest that the large reduction of cerebrovascular reactivity in postmenopausal women cannot be considered a simple factor related to aging but is probably influenced by hormonal changes. The alteration in cerebrovascular regulation could be involved in the increase of cerebrovascular disease in postmenopausal women.     

The predictive value of biochemical markers of bone turnover for bone mineral density in early postmenopausal women treated with hormone replacement or calcium supplementation

To compare the relative sensitivity and specificity of bone turnover indexes for bone loss or gain in early postmenopausal women, we performed a multicenter trial in 236 menopausal women (mean age, 51 yr), who were randomized to hormone replacement therapy (HRT) or calcium supplementation (CS; 500 mg/day) for 1 yr. Two markers of bone formation, osteocalcin (OC) and bone alkaline phosphatase (BSAP), and two markers of bone resorption, urinary N-telopeptide (NTx) and urinary free deoxypyridinoline (fDpd), as well as spine and femoral neck bone mineral density (BMD) were measured at baseline and 3, 6, and 12 months after treatment. Women receiving HRT (n = 105) showed a significant increase in spine BMD (+2.5%; P < 0.0001) and hip BMD (+1.0%; P = 0.02) compared to women receiving CS, who showed a decline at both sites (-1.1%; P < 0.01). All four markers showed time-dependent decreases in women receiving HRT (P < 0.001) and no change in women receiving CS alone. When baseline indexes of turnover were stratified by quartile, there was a significantly greater increase in BMD among those with the highest NTx, OC, and BSAP levels compared to that in those with the lowest NTx, OC, and BSAP levels (P < 0.05). The highest quartile for percent change from baseline to 6 months in fDpd, BSAP, and NTx was also associated with the greatest change in spine BMD at 1 yr. Receiver operator characteristic curves for percent change from baseline to 6 months in an individual marker to 1 yr change in BMD during HRT revealed that the percent change in NTx provided the greatest discrimination between gain and loss of BMD. When subjects receiving HRT were compared by their positive or negative skeletal response at 1 yr and their baseline turnover marker, initial NTx values were significantly higher in those that gained bone than in those that lost bone (P = 0.0002). CS women in the highest quartile for NTx at baseline had significantly greater decreases in spine BMD than subjects with the lowest NTx values (P < 0.005), although this was not true for fDpd (P < 0.20). In conclusion, for early postmenopausal women there are differential responses of biochemical markers to HRT and CS. Baseline urinary NTx and serum OC were the most sensitive predictors of change in spine BMD after 1 yr of either HRT or CS. Similarly, the percent change in NTx and OC from baseline to 6 months best predicted bone gain or loss. We conclude that markers of bone formation and resorption can be used clinically to predict future BMD in early postmenopausal women.     

Evidence for leptin regulation of food intake in humans

The adipocyte hormone leptin regulates body weight in mice by decreasing food intake and increasing energy expenditure. Whether leptin is of physiological importance for these processes in humans is, however, not clear. We therefore studied the relation between leptin and habitual food intake in 64 healthy postmenopausal women. Dietary habits were assessed with a modified diet history method. Body fat content was measured using bioelectrical impedance. In the 64 women, aged 58.6+/-0.4 yr (mean+/-SD), serum leptin was 19.3+/-12.7 ng/mL, body mass index was 25.0+/-3.5 kg/m2, body fat content was 31.6+/-4.3%, fasting glucose was 4.6+/-0.5 mmol/L, and fasting insulin was 56+/-21 pmol/L. Leptin levels were negatively correlated to total energy intake (r=-0.34; P=0.006), carbohydrate intake (r=-0.36; P=0.004), and total (r=-0.27; P=0.034) as well as saturated fat intake (r=-0.31; P=0.014). Leptin was correlated to the absolute, but not to the percent, intake of these nutrients. When normalized for body fat content, the correlations remained significant. Our results suggest that plasma leptin is involved in the physiological regulation of food intake in humans, and that leptin is related to the quantity rather than the quality of habitual food intake.     

The relationship between growth hormone kinetics and sarcopenia in postmenopausal women: the role of fat mass and leptin

Sarcopenia, the decline in body cell mass (BCM) and especially in muscle mass with age, is an important age-related cause of frailty and loss of independence in the elderly. Because the decline in BCM with age parallels a decline in GH secretion from young adulthood to old age, loss of GH secretion has been considered an important contributory cause of sarcopenia in the elderly. To test this hypothesis in a group of healthy postmenopausal women (n = 15; mean +/- SD age, 66.9 +/- 7.8 yr), 24-h GH concentrations and secretory kinetics were correlated with BCM (measured by whole body counting of 40K) and percent body fat (measured by dual energy x-ray absorptiometry or neutron inelastic scattering). Serum leptin levels were determined as a measure of adipocyte mass. Contrary to prediction, GH secretion was lower in women with higher BCM (r = 0.50; P < 0.05), whereas their mean fat mass was higher (r = 0.51, P < 0.05). These data indicate that sarcopenia in postmenopausal women is not associated with reduced GH secretion and is inversely correlated with fat mass. Serum leptin levels were inversely associated with GH secretion (r = -0.67; P < 0.006). Although a causal relationship has not been demonstrated, these data suggest that leptin could modulate GH secretion through its action on the aging hypothalamic-pituitary axis, or that GH regulates leptin secretion.     

Severe manifestations in carrier females in X linked retinitis pigmentosa

The aim of this study was to assess the effect of menopause on circadian profile of blood pressure (BP) and heart rate (HR) in the normotensive pre- and postmenopausal women. Systolic BP (SBP), diagnostic BP (DBP) and HR were monitored every 30 min for 48 hrs using noninvasive ambulatory BP monitoring in 24 premenopausal and 40 postmenopausal women. Mean 48-hours, daytime (awake), and nighttime (sleeping) SBP, DBP and HR values were analyzed by reviewing the patients' diaries, and the nocturnal reduction rate (NRR) of SBP, DBP and HR were calculated according to the following formula. NRR (%9 = [(daytime mean-nighttime mean)/daytime mean] x 100. The study subjects were then divided into two groups according to the presence (dipper) or absence (nondipper) of a significant reduction in nocturnal BP (> 10%). Mean SBP, DBP and HR measured over 48 hours were similar between the premenopausal and the postmenopausal group. The NRR of DBP and HR in the postmenopausal group were significantly smaller than those in the premenopausal group (17.1 +/- 6.0% vs. 13.5 +/- 7.0%, 241.1 +/- 6.0% vs. 19.8 +/- 9.0%: p < 0.05). There tended to be higher prevalence of nondipper in the postmenopausal (37%) than in the premenopausal group (29%).     

Tumour necrosis factor alpha and interleukin 2 in normal and infected human seminal fluid

The presence of cytokines such as the tumour necrosis factor alpha (TNF alpha) and interleukin 2 (IL2) in human spermatozoa is still to be defined. The aim of this study was to measure the concentration of both soluble factors in seminal fluid. Data from normal semen samples (n = 24) confirmed the presence of IL2 (258 +/- 84 fmol/ml corresponding to 953 +/- 369 fmol/total volume of ejaculate) and TNF alpha (62.2 +/- 16.4 fmol/ml corresponding to 231.3 +/- 86 fmol/total volume of ejaculate). A significant positive correlation (r = 0.59; P < 0.01) was observed between the TNF alpha and the IL2 concentrations. The concentrations of these cytokines were not related to sperm parameters. In contrast, IL2 concentrations (196.9 +/- 60.4 fmol/ml; 686.2 +/- 236.7 fmol/total volume of ejaculate) evaluated in 16 seminal fluids with identified bacterial agents were lower than in the control group, whereas TNF alpha concentrations (68.6 +/- 12.3 fmol/ml; 241.3 +/- 78.9 fmol/total volume of ejaculate) were not significantly different from the controls. Further studies are needed to determine the potential role of these cytokines in the physiology of semen and their usefulness as indicators of reproductive pathology.     

Maintenance of bone mass in patients receiving dialytic therapy

To determine what factors contribute to and change bone mineral density (BMD) in dialysis patients, serial lumbar spine dual x-ray absorptiometry studies were analyzed by stepwise regression analysis in 67 black dialysis patients. The patients were 50.5 +/- 2.0 years of age (mean +/- SE) and 49% were men; the patients had received dialytic therapy for 3.7 +/- 0.5 years. The mean initial BMD z-score was 0.147 +/- 0.182. By cross-sectional analysis, the BMD increased in the male and premenopausal female patients but decreased in the postmenopausal female patients by 2.5% g/cm2/decade of life, less than that observed in black patients with normal renal function. Univariate analysis and stepwise regression analysis demonstrated radiographic evidence of osteopenia (beta-coefficient = -0.180 +/- 0.050; P = 0.001) and prior parathyroidectomy (beta-coefficient = 0.133 +/- 0.070; P = 0.054) as the only variables significantly correlated to the BMD. The effects of biochemical variables and different treatments on the delta BMD, calculated as the difference between each patient's first and second BMDs divided by the interval in years, were evaluated by stepwise regression analysis in 41 patients. The mean interval between the two BMDs was 18.4 +/- 1.02 months (range, 5 to 34 months) and the delta BMD was 0.025 +/- 0.018 g/cm2/yr, increasing in 65% of the patients. By univariate and stepwise regression analysis, the mean monthly serum total alkaline phosphatase concentration was the only variable that correlated with the delta BMD (beta-coefficient = 0.0001; P = 0.030).(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of reproductive hormonal dynamics in the perimenopause

Medical therapy for women in the perimenopausal period is controversial, in part due to varying degrees of ovarian hormone secretion characteristic of this time of life. To extend our understanding of the reproductive endocrine milieu of perimenopausal women, we studied 6 cycling women, aged 47 yr and older, for 6 months with daily collections of first morning voided urine. Five additional older reproductive aged (43-47 yr old) women were studied with daily urine and serum sampling for a single menstrual cycle; their urinary hormone data were combined with the former group for menstrual cycle comparisons. Urine was assayed for LH, FSH, estrone conjugates, and pregnanediol glucuronide and normalized for creatinine (Cr). Eleven midreproductive aged (19-38 yr old) normally cycling women, 5 women with well defined premature ovarian failure, and 5 women aged 54 yr and older who were at least 1 yr postmenopausal were used for comparison. Perimenopausal women had shorter follicular phases (11 +/- 2 days vs. 14 +/- 1 days; P = 0.031) and, hence, shorter menstrual cycles than midreproductive aged controls. FSH excretion in perimenopausal women was greater than that in younger women (range of means, 4-32 vs 3-7 IU/g Cr; P = 0.0005). LH secretion was overall greater than that in younger normal subjects (range of means, 1.4-6.8 vs. 1.1-4.2 IU/g Cr; P < 0.026). Overall mean estrone conjugate excretion was greater in the perimenopausal women compared to that in the younger women [76.9 ng/mg Cr (range, 13.1-135) vs. 40.7 ng/mg Cr (range, 22.8-60.3); P = 0.023] and was similarly elevated in both follicular and luteal phases. Luteal phase pregnanediol excretion was diminished in the perimenopausal women compared to that in younger normal subjects (range for integrated pregnanediol, 1.0-8.4 vs. 1.6-12.7 microg/mg Cr/luteal phase; P = 0.015). Compared to postmenopausal women, perimenopausal women had more overall estrone excretion (2.5-6.2 ng/mg Cr in postmenopausal women; P = 0.02) and lower mean FSH (range of means for postmenopause, 24-85 IU/g Cr; P = 0.017) and LH (range for postmenopause, 4.3-14.8 IU/g Cr; P = 0.041). Compared to women with premature menopause, perimenopausal women again had lower FSH (range of means for premature menopause, 36-82 IU/g Cr; P = 0.0022), lower LH (range of means for premature menopause, 5.5-23.8 IU/g Cr; P = 0.0092), borderline higher mean estrone conjugates (range of means for premature menopause, 4-44 ng/mg Cr; P = 0.064), and far longer periods of ovarian activity (one to two cycles in prematurely menopausal women vs. three to six cycles in perimenopausal women). We conclude that altered ovarian function in the perimenopause can be observed as early as age 43 yr and include hyperestrogenism, hypergonadotropism, and decreased luteal phase progesterone excretion. These hormonal alterations may well be responsible for the increased gynecological morbidity that characterizes this period of life.     

Measurement of bone degradation products in serum using antibodies reactive with an isomerized form of an 8 amino acid sequence of the C-telopeptide of type I collagen

An enzyme-linked immunosorbent assay for measuring type I collagen degradation products in serum (S-ELISA) was developed. The assay uses a high affinity polyclonal antibody which reacts with an isomerized form of an 8 amino acid sequence of the C-telopeptides of type I collagen (EKAHD-beta-GGR). Cross-reactivity to a nonisomerized synthetic peptide form of the 8 amino acid sequence is less than 0.2%. Values obtained in a group of premenopausal women (age, 33.3 +/- 3.11 years) were 69 +/- 24 ng/ml(n = 22). In a group of early postmenopausal women (age, 51.8 +/- 1.88 years) values obtained were 125 +/- 43 ng/ml (n = 46), which represents an increase of 81% (p < 0.001). Values found in untreated patients with Paget's disease were 234 +/- 95 ng/ml (n = 15), and for primary hyperparathyroidism we found 335 +/- 82 ng/ml (n = 10). Intravenous administration of a bisphosphonate (Pamidronate) to Paget's disease patients for 3 days was reflected in the S-ELISA by a decrease in the values of 55% when compared with values before treatment (n = 15). Following treatment with another bisphosphonate (Alendronate) for 6 months, values were decreased to 48 +/- 19 ng/ml (n = 12), which corresponds to a 62% decrease. Clinical results presented in this context support that the assay is a sensitive and specific index of bone resorption. It may, therefore, prove useful in the follow up of treatment of patients with metabolic bone diseases and in the clinical investigation of osteoporosis.     

Biochemical effects of calcium supplementation in postmenopausal women: influence of dietary calcium intake

We studied the biochemical effects of calcium supplementation during a 2-mo course in postmenopausal women (x +/- SD: 64 +/- 5 y of age and 14.5 +/- 6.7 y since menopause). The effects on calcium homeostasis and bone remodeling were assessed after 1 and 2 mo of daily administration of either calcium carbonate (1200 mg elemental Ca/d, n = 60) or a placebo (n = 56). The daily dietary calcium intake assessed before the beginning of calcium supplementation was 786 mg/d. We found a significant inverse relation between baseline intact parathyroid hormone (iPTH) and dietary calcium intake before supplementation (r = -0.48, P = 0.0002). A significant increase in urinary excretion of pyridinoline was observed when the dietary calcium intake was lower than the median value. Calcium supplementation resulted in a significant increase in 24-h urinary calcium (39%, P < 0.02) and a significant reduction of bone alkaline phosphatase at 2 mo and of all bone-resorption markers (hydroxyproline, pyridinoline, and deoxypyridinoline) at I and 2 mo without significant changes in 44-68 PTH fragments or iPTH concentrations. When the dietary calcium intake was low (mean +/- SD: 576 +/- 142 mg/d), calcium supplementation was responsible for a greater increase in urinary calcium excretion and a greater decrease in markers of bone turnover. The greatest variations were observed for deoxypyridinoline at 1 and 2 mo (-18.5%, P < 0.05) and for pyridinoline at 1 mo (-16.3%, P < 0.01). Two months of calcium supplementation in postmenopausal women was efficient in reducing markers of bone turnover, with a greater effect in women with a low dietary calcium intake.