Teriparatide Therapy Reduces Serum Phosphate and Intima-Media Thickness at the Carotid Wall Artery in Patients with Osteoporosis

An integrated multi-omics analysis reveals osteokines involved in global regulation

Bone secretory proteins, termed osteokines, regulate bone metabolism and whole-body homeostasis. However, fundamental questions as to what the bona fide osteokines and their cellular sources are and how they are regulated remain unclear. In this study, we analyzed bone and extraskeletal tissues, osteoblast (OB) conditioned media, bone marrow supernatant (BMS), and serum, for basal osteokines and those responsive to aging and mechanical loading/unloading. We identified 375 candidate osteokines and their changes in response to aging and mechanical dynamics by integrating data from RNA-seq, scRNA-seq, and proteomic approaches. Furthermore, we analyzed their cellular sources in the bone and inter-organ communication facilitated by them (bone-brain, liver, and aorta). Notably, we discovered that senescent OBs secrete fatty-acid-binding protein 3 to propagate senescence toward vascular smooth muscle cells (VSMCs). Taken together, we identified previously unknown candidate osteokines and established a dynamic regulatory network among them, thus providing valuable resources to further investigate their systemic roles.

Bazedoxifene improves renal function and increases renal phosphate excretion in patients with postmenopausal osteoporosis

INTRODUCTION

Because aging is a predictor of renal insufficiency in the general population, renal function is a concern in postmenopausal patients undergoing treatment for osteoporosis. Although high serum phosphate concentration is a predictor of renal insufficiency, the effect of selective estrogen receptor modulator (SERM) on renal function and phosphate homeostasis remains to be established.

MATERIALS AND METHODS

We administered 20 mg/day bazedoxifene to 48 postmenopausal osteoporotic women who had been taking alfacalcidol for ≥ 6 months, and assessed lumbar spine bone mineral density (LS-BMD), renal function (by calculating estimated glomerular filtration rate using serum cystatin-C levels [eGFRcys] [range 38.0-98.2 mL/min/1.73 m²]), and phosphate homeostasis.

RESULTS

LS-BMD was significantly higher 6 months after the initiation of bazedoxifene administration. eGFRcys had increased by 3 months after initiation and was stable until 12 months. Serum phosphate gradually decreased after initiation, reaching statistical significance at 6 months. The changes in serum phosphate were also significant when the maximum tubular reabsorption rate of phosphate was normalized to glomerular filtration rate (TmP/GFR), indicating that bazedoxifene treatment reduces serum phosphate by increasing the urinary excretion of phosphate. The change in eGFRcys after the initiation of bazedoxifene was significantly negatively correlated with the change in serum phosphate, suggesting that a reduction in serum phosphate improves renal function.

CONCLUSION

Bazedoxifene improves renal function, possibly by increasing renal phosphate excretion, in postmenopausal osteoporotic women without severe renal insufficiency.

Atherosclerosis and Osteoporosis. Common Targets for the Effects of Cardiovascular and Anti-Osteoporotic Drugs (Part II). The Effect of Antiosteoporotic Drugs on the Vascular Wall State

In the second part of the literature review, data are presented on the possible effect of anti-osteoporosis therapy on the vascular wall and the development of calcification. The discovery of common biological substances involved in the development of atherosclerosis, calcification of the vascular wall and osteoporosis attracts the attention of scientists in terms of targets for assessing the effects of already known drugs or developing new drugs that can simultaneously prevent or slow the progression of both atherosclerosis and osteoporosis. Currently, various groups of drugs for the treatment of osteoporosis have been studied to prevent or reduce the progression of subclinical atherosclerosis and calcification. Both antiresorptive drugs (bisphosphonates, monoclonal antibodies to RANKL, selective estrogen receptor modulators), and bone-anabolic therapy, which includes teriparatide, were studied. However, there are a few such studies and the most promising drugs that have a preventive effect in the early stages of atherosclerotic damage are bisphosphonates. Other classes of antiosteoporotic drugs did not reveal a positive effect on the vascular wall, and some of them increased the cardiovascular risk. Divergences in the results of experimental and clinical studies attract attention. If in the experiment almost all drugs for the treatment of osteoporosis had an atheroprotective effect and suppressed vascular calcification, then in clinical conditions only bisphosphonates confirmed the positive effect on the vascular wall.

Effects of 12-months treatment with zoledronate or teriparatide on intima-media thickness of carotid artery in women with postmenopausal osteoporosis: A pilot study

Atherosclerosis and osteoporosis are interrelated entities and share similar pathogenic mechanisms. Recent studies showed that key proteins of bone metabolism, such as osteoprotegerin (OPG) and osteopontin (OPN), are also involved in vascular atherosclerosis and calcifications. The carotid intima-media thickness (CA-IMT) is an early quantitative marker of generalized atherosclerosis. Aim of study was to investigate whether 12-months treatment with zoledronate (ZLN) or teriparatide (TPT) affects CA-IMT and circulating OPG and OPN levels. In this study, 11 postmenopausal osteoporotic women (aged 73, 70.5–74.5 years; median, range interquartile) treated with 5 mg/year iv ZLN; 9 postmenopausal osteoporotic women (aged 70, 62.5–73.5 years) treated with 20 µg/day sc TPT; and 10 aged-, body mass index (BMI)-, glycemic, and lipid profiles-matched, free from anti-osteoporotic and hypocholesterolemic drugs, controls were prospectively investigated at baseline and after 12 months. At baseline, median CA-IMT was similar in the three groups and increased after 12 months. CA-IMT increased significantly in TPT-treated patients (1.0, 0.8–1.2 vs 1.1, 0.9–15 mm, P = 0.04), though the change was minimal. After 12 months of treatment, CA-IMT positively correlated with alkaline phosphatase (ALP) levels (r = 0.767, P = 0.008) and negatively with high-density lipoprotein (HDL) cholesterol levels (r = −0.65, P = 0.03), suggesting interplay between active bone remodeling and lipid profile. At baseline and after 12 months, median serum OPG and OPN levels did not differ among the groups and did not correlate with changes in CA-IMT. In conclusion, ZLN and TPT treatments are safe on carotid walls in osteoporotic women with subclinical atherosclerosis; circulating OPG and OPN are not affected by long-term anti-osteoporotic treatments and do not correlate with CA-IMT.

Differential Associations for Salivary Sodium, Potassium, Calcium, and Phosphate Levels with Carotid Intima Media Thickness, Heart Rate, and Arterial Stiffness

Salivary biomarkers may offer a noninvasive and easy sampling alternative in cardiovascular risk evaluation. The aim of the present study was to establish associations of salivary potassium, sodium, calcium, and phosphate levels with the cardiovascular phenotype determined by carotid ultrasound and carotid-femoral pulse wave velocity and to identify possible covariates for these associations. N = 241 samples of nonstimulated whole buccal saliva were obtained from subjects with (n = 143; 59%) or without (n = 98; 41%) hypertension. The potassium concentrations were 10-fold higher in saliva compared with plasma, whereas sodium concentrations exhibited the reverse relation between saliva and blood. There were no significant correlations between the levels of sodium, potassium, or calcium in saliva and plasma. All salivary electrolytes, except sodium, were significantly associated with age. In age-adjusted analyses, salivary potassium was significantly associated with carotid artery intima media thickness (cIMT) and carotid-femoral pulse wave velocity, and these associations were at the limit of significance in multivariate analyses including prevalent cardiovascular disease and risk factors. Body mass index was a significant confounder for salivary potassium. Salivary phosphate was significantly associated with cIMT in the multivariate analysis. Salivary potassium, calcium, and phosphate levels were significantly associated with heart rate in the univariate age-adjusted as well as in two different multivariate models, whereas no significant associations between sodium and heart rate were observed. In conclusion, the differential association of salivary electrolytes with cardiovascular phenotypes indicates that these electrolytes should be further studied for their predictive value as noninvasive biomarkers for cardiovascular risk evaluation.

Association of Decreased Handgrip Strength with Reduced Cortical Thickness in Japanese Female Patients with Type 2 Diabetes Mellitus

LD-100, a quantitative ultrasonic device, allows us to measure cortical thickness (CoTh). Patients with type 2 diabetes mellitus (T2DM) show high prevalence of sarcopenia. This study aimed to clarify the association of handgrip strength (HGS) with cortical porosis, a major risk for fracture of DM. CoTh and trabecular bone mineral density (TrBMD) at the 5.5% distal radius were assessed in T2DM female patients (n = 122) and non-DM female controls (n = 704) by LD-100. T2DM patients aged older 40 years showed significantly lower HGS and CoTh, but not TrBMD, than non-DM counterparts. Although HGS was significantly and positively correlated with CoTh and TrBMD in T2DM patients, multivariate analysis revealed HGS as an independent factor positively associated with CoTh, but not TrBMD, in T2DM patients, suggesting the preferential association of HGS with cortical, but not trabecular, bone component in T2DM female patients. In conclusion, the present study demonstrated an early decline of HGS in T2DM female patients as compared with non-DM healthy controls after the age of 40 years, which is independently associated with thinner CoTh, but not TrBMD in T2DM patients, and thus suggested that reduced muscle strength associated with DM might be a major factor for cortical porosis development in DM patients.

Relationship between bone turnover and left ventricular function in primary hyperparathyroidism: The EPATH trial

Observational studies suggested a link between bone disease and left ventricular (LV) dysfunction that may be pronounced in hyperparathyroid conditions. We therefore aimed to test the hypothesis that circulating markers of bone turnover correlate with LV function in a cohort of patients with primary hyperparathyroidism (pHPT). Cross-sectional data of 155 subjects with pHPT were analyzed who participated in the "Eplerenone in Primary Hyperparathyroidism" (EPATH) Trial. Multivariate linear regression analyses with LV ejection fraction (LVEF, systolic function) or peak early transmitral filling velocity (e', diastolic function) as dependent variables and N-terminal propeptide of procollagen type 1 (P1NP), osteocalcin (OC), bone-specific alkaline phosphatase (BALP), or beta-crosslaps (CTX) as the respective independent variable were performed. Analyses were additionally adjusted for plasma parathyroid hormone, plasma calcium, age, sex, HbA1c, body mass index, mean 24-hours systolic blood pressure, smoking status, estimated glomerular filtration rate, antihypertensive treatment, osteoporosis treatment, 25-hydroxy vitamin D and N-terminal pro-brain B-type natriuretic peptide. Independent relationships were observed between P1NP and LVEF (adjusted β-coefficient = 0.201, P = 0.035) and e' (β = 0.188, P = 0.042), respectively. OC (β = 0.192, P = 0.039) and BALP (β = 0.198, P = 0.030) were each independently related with e'. CTX showed no correlations with LVEF or e'. In conclusion, high bone formation markers were independently and paradoxically related with better LV diastolic and, partly, better systolic function, in the setting of pHPT. Potentially cardio-protective properties of stimulated bone formation in the context of hyperparathyroidism should be explored in future studies.

Effect of teriparatide treatment on endothelial function, glucose metabolism and inflammation markers in patients with postmenopausal osteoporosis

OBJECTIVE

Teriparatide, an anabolic agent used in the treatment of postmenopausal osteoporosis, can induce effects similar to primary hyperparathyroidism. Our objective was to evaluate the effects of teriparatide on endothelial functions, glucose metabolism and inflammation markers in patients diagnosed with postmenopausal osteoporosis.

DESIGN, PATIENTS AND MEASUREMENTS

This was a single-centre, single-arm, 6-month prospective study. Twenty-three postmenopausal women over 65 years old with a lumbar spine or femoral neck T-score of -4·0 or lower and having at least two compression fractures in thoracic or lumbar spine were studied. Low-dose intermittent teriparatide (20 μg/day) was supplemented with calcium carbonate (1000 mg elemental calcium) and 880 IU cholecalciferol for 6 months. The biochemical parameters for glucose metabolism, inflammation and atherosclerosis were determined. For the assessment of vascular endothelial function, carotid intima-media thickness (CIMT), brachial artery intima-media thickness (BIMT), per cent change in flow-mediated dilation (FMD%) and nitroglycerine-induced dilations (NID%) were measured on ultrasonography.

RESULTS

The fasting plasma glucose, homoeostatic model assessment of insulin resistance, fibrinogen, homocysteine and high-density lipoprotein cholesterol increased significantly with teriparatide treatment (P < 0·05 for all). Baseline CIMT and BIMT did not change significantly with 6 months of teriparatide treatment (P > 0·05); however, FMD% and NID% showed significant decrease after treatment (P < 0·01 for both).

CONCLUSIONS

Intermittent teriparatide treatment may adversely affect some parameters of glucose metabolism, inflammation and endothelial function. On the basis of our findings, further large-scale and controlled studies are needed to clarify the exact effect of teriparatide treatment on glucose metabolism, inflammation and endothelial function.

Renal Phosphate Reabsorption is Correlated with the Increase in Lumbar Bone Mineral Density in Patients Receiving Once-Weekly Teriparatide

In order to assess the changes in serum calcium and phosphate and the changes in renal tubular phosphate reabsorption (TmP/GFR) and to evaluate the association between these indices and the increase in bone mineral density (BMD) with once-weekly intermittent administration of teriparatide (TPTD), the results from the teriparatide once-weekly efficacy research (TOWER) trial were re-analyzed. The TOWER trial studied postmenopausal women and older men with osteoporosis. Patients were randomly assigned to receive TPTD 56.5 μg or placebo for 72 weeks. Of these patients, the present study investigated those whose calcium and phosphate levels and lumbar BMD (L-BMD) were measured (TPTD group, n = 153 and Placebo group, n = 137). The TPTD group had significantly lower serum phosphate, calcium-phosphate product, and TmP/GFR at weeks 4, 24, 48, and 72 and urinary fractional calcium excretion (FECa) at weeks 12, 48, and 72 (p < 0.05). In the TPTD group, the serum phosphate and TmP/GFR during early treatment (4, and 12 weeks) showed a significant positive correlation with the percent change in L-BMD at weeks 48 and 72. Based on multivariate analysis corrected for age, BMI, and L-BMD at the start of treatment, serum phosphate and TmP/GFR at week 4 showed a significant correlation with the percent change in L-BMD. This study suggests that the L-BMD response to once-weekly long-term TPTD treatment is associated with circulating phosphate or with the status of its renal reabsorption. Preventing decrease in serum phosphate levels may be important in acquiring greater L-BMD with once-weekly TPTD.