Adrenalectomy Improves Body Weight, Glucose, and Blood Pressure Control in Patients With Mild Autonomous Cortisol Secretion: Results of an Randomized Controlled Trial by the Co-work of Adrenal Research (COAR) Study

OBJECTIVE

To assess the metabolic effects of adrenalectomy in patients with mild autonomous cortisol secretion (MACS).

BACKGROUND

Despite retrospective studies showing the association of adrenalectomy for MACS with beneficial metabolic effects, there have been only 2 randomized prospective studies with some limitations to date.

METHODS

A prospective, multicenter study randomized 132 patients with adrenal incidentaloma without any features of Cushing syndrome but with serum cortisol >50 nmol/L after a 1 mg overnight dexamethasone suppression test into an adrenalectomy group (n = 66) or control group (n = 66). The primary outcomes were changes in body weight, glucose, and blood pressure (BP).

RESULTS

Among the 118 participants who completed the study with a median follow-up duration of 48 months (range: 3-66), the adrenalectomy group (n = 46) exhibited a significantly higher frequency of improved weight control, glucose control, and BP control (32.6%, 45.7%, and 45.7%, respectively) compared with the control group (n = 46; 6.5%, P = 0.002; 15.2%, P = 0.002; and 23.9%, P = 0.029, respectively) after matching for age and sex. Adrenalectomy [odds ratio (OR) = 10.38, 95% CI = 2.09-51.52, P = 0.004], body mass index (OR = 1.39, 95% CI = 1.08-1.79, P = 0.010), and cortisol after a 1 mg overnight dexamethasone suppression test levels (OR = 92.21, 95% CI = 5.30-1604.07, P = 0.002) were identified as independent factors associated with improved weight control. Adrenalectomy (OR = 5.30, 95% CI = 1.63-17.25, P = 0.006) and diabetes (OR = 8.05, 95% CI = 2.34-27.65, P = 0.001) were independently associated with improved glucose control. Adrenalectomy (OR = 2.27, 95% CI = 0.87-5.94, P = 0.095) and hypertension (OR = 10.77, 95% CI = 3.65-31.81, P < 0.001) demonstrated associations with improved BP control.

CONCLUSIONS

adrenalectomy improved weight, glucose, and BP control in patients with MACS.

Temporal trends in clinical features of patients with primary aldosteronism over 20 years

Primary aldosteronism (PA) accounts for approximately 5-10% of hypertension cases. Over the past 20 years, the reported incidence of PA has increased due to widespread screening for secondary hypertension and imaging studies. We aimed to evaluate the temporal trends in the clinical characteristics and subtypes of PA. A total of 1064 patients with PA in two tertiary hospitals between 2000 and 2021 were categorized into three groups according to the year of diagnosis: 2000-2009, 2010-2015, and 2016-2021. The clinical characteristics of the patients over the three time periods were compared using a trend analysis. The age at diagnosis and sex of patients with PA did not change over 20 years. The proportion of patients with bilateral hyperaldosteronism (BHA) increased (11%, 25%, and 40%, P for trend <0.001). The proportion of hypokalemia (87%, 61%, and 40%) and plasma aldosterone concentration (36.0, 30.8, and 26.6 ng/dL) decreased (all P for trend <0.001). There was a trend toward an increased proportion of incidentally detected patients compared to clinically symptomatic patients (36%, 55%, and 61%, P for trend <0.001). The concordance rate of imaging and adrenal venous sampling results decreased (91%, 70%, and 57% P for trend <0.001). However, the proportion of patients with resistant hypertension and comorbidities did not differ. In conclusion, among patients with PA, patients with BHA and incidental detection have increased over 20 years, and more patients are likely to present with milder clinical symptoms and biochemical profiles.

Free fatty acid receptor 4 (FFA4) activation attenuates obese asthma by suppressing adiposity and resolving metaflammation

Obese asthma is recognized to have different asthma phenotypes. N-3 polyunsaturated fatty acids (PUFAs) have shown beneficial effects in obesity and metabolic syndrome. Free fatty acid receptor 4 (FFA4, also known as GPR120) is a receptor for n-3 PUFAs. In the present study, we investigated whether FFA4 activation ameliorates high-fat diet (HFD)-induced obese asthma. We investigated whether FFA4 activation ameliorates obese asthma using an FFA4 agonist, compound A (CpdA), in combination with FFA4 wild-type (WT) and knock-out (KO) mice. Administration of an FFA4 agonist, compound A (CpdA, 30 mg/kg), suppressed HFD-induced weight gain, adiposity, and airway hypersensitivity (AHR), and increased immune cell infiltration in an FFA4-dependent manner. Histological analysis revealed that CpdA treatment suppressed HFD-induced mucus hypersecretion, inflammation, and fibrosis in an FFA4-dependent manner. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed an HFD-induced increase in the mRNA levels of pro-inflammatory cytokines in the lungs and gonadal white adipose tissue, whereas CpdA inhibited this increase in an FFA4-dependent manner. In the fluorescence-activated cell sorting (FACS) analysis, HFD induced an increase in the lung innate lymphoid cells (ILC) ILC1, ILC2, and ILC3; however, CpdA reversed this increase. In addition, HFD induced an increase in the pro-inflammatory M1 macrophage population and a decrease in the anti-inflammatory M2 macrophage population in the lungs, whereas CpdA treatment reversed these changes. The present study suggests that FFA4 activation may have therapeutic potential in obese asthma.

Preoperative prediction of metastatic pheochromocytoma and paraganglioma using clinical, genetic, and biochemical markers: A cohort study

BACKGROUND

The prevalence of metastatic pheochromocytoma and paraganglioma (PPGL) is approximately 15%-20%. Although there are indicators to assess metastatic risks, none of them predict metastasis reliably. Therefore, we aimed to develop and validate a scoring system using clinical, genetic, and biochemical risk factors to preoperatively predict the metastatic risk of PPGL.

METHODS

In the cross-sectional cohort (n = 180), clinical, genetic, and biochemical risk factors for metastasis were identified using multivariate logistic regression analysis, and a novel scoring system was developed. The scoring system was validated and compared with the age, size of tumor, extra-adrenal location, and secretory type (ASES) score in the longitudinal cohort (n = 114).

RESULTS

In the cross-sectional cohort, pseudohypoxia group-related gene variants (SDHB, SDHD, or VHL), methoxytyramine >0.16 nmol/L, and tumor size >6.0 cm were independently associated with metastasis after multivariate logistic regression. Using them, the gene variant, methoxytyramine, and size of tumor (GMS) score were developed. In the longitudinal cohort, Harrell's concordance index of the GMS score (0.873, 95% confidence interval [CI]: 0.738-0.941) was higher than that of the ASES score (0.713, 95% CI: 0.567-0.814, p = 0.007). In the longitudinal cohort, a GMS score ≥2 was significantly associated with a higher risk of metastasis (hazard ratio = 25.07, 95% CI: 5.65-111.20). A GMS score ≥2 (p < 0.001), but not ASES score ≥2 (p = 0.090), was associated with shorter progression-free survival.

CONCLUSION

The GMS scoring system, which integrates gene variant, methoxytyramine level, and tumor size, provides a valuable preoperative approach to assess metastatic risk in PPGL.

Exploring the Benefits of a Reduced-Port Approach in Robotic Posterior Retroperitoneoscopic Adrenalectomy: A Comparative Study of the Two-Port and Three-Port Techniques

Background: Robotic adrenalectomy has become a surgical treatment option for benign and selected malignant adrenal diseases. We aimed to evaluate the eligibility of two-port robotic posterior retroperitoneoscopic adrenalectomy (PRA) as an alternative to the conventional three-port technique by comparing their surgical outcomes. Materials and Methods: This retrospective cohort study compared the clinicopathological factors and surgical outcomes among 197 patients who underwent two-port or three-port robotic adrenalectomy between 2016 and 2020 in a single tertiary center. For further evaluation, propensity score matching was performed to reduce the selection bias in population characteristics. Results: Patients were categorized by the number of ports (two-port group, 87; and three-port group, 110). The two-port group compared with the three-port group was significantly older (P = .006) and had a smaller mean tumor size (P = .003) and shorter mean operation time (P = .001). Upon comparing clinicopathologic characteristics according to adrenal disorders, for pheochromocytoma, the three-port group had a larger tumor size and a longer operation time. For Cushing's syndrome, the operation time was short and numeric rating scale pain score was significantly low in the two-port group. After propensity score matching, the two-port group had a short operation time and a significantly low postoperative pain score (P < .05). Predictive factors associated with prolonged operation time included male gender, an increased number of ports, and large tumor size. Conclusions: The two-port technique resulted in a shorter operation time and lower pain score compared with the three-port technique. The two-port technique may be a safe alternative to the conventional three-port technique for robotic PRA.

Diagnostic consistency between computed tomography and adrenal vein sampling of primary aldosteronism: leading to successful curative outcome after adrenalectomy; a retrospective study

BACKGROUND

Adrenal computed tomography (CT) is a useful tool for locating adrenal lesion in primary aldosteronism (PA) patients. However, adrenal vein sampling (AVS) is considered as a gold standard for subtype diagnosis of PA. The aim of this study was to investigate the consistency of CT and AVS for the diagnosis of PA subtypes and evaluate the concordance of surgical outcomes.

MATERIALS AND METHODS

This retrospective study included 264 PA patients having both CT and AVS. Diagnostic consistency between CT and AVS was accessed, and clinical and biochemical outcomes were evaluated at 6 months after adrenalectomy.

RESULTS

Of all, 207 (78%) had a CT unilateral lesion, 31 (12%) CT bilateral lesion, and 26 (10%) CT bilateral normal findings. Among the CT unilateral lesion group, 138 (67%) had ipsilateral AVS lateralization. For CT bilateral lesion and bilateral normal, AVS unilateral lateralization was found in 17 (55%) and 2 (8%), respectively. The consistency between CT lesion and AVS lateralization including CT unilateral with AVS ipsilateral, and CT bilateral lesion with AVS bilateral patients was 63.8% (152/238). Of 77 patients with available data out of 138 patients who underwent adrenalectomy with consistency between CT and AVS, the clinical success rate was 96%, for 17 inconsistency patients out of 22 patients who underwent adrenalectomy, the clinical success rate was 94% after adrenalectomy following the lateralization result of AVS.

CONCLUSION

CT is a useful tool to diagnose the adrenal lesion in PA patients. However, AVS is more sufficient to detect the unilateral PA subtype, which could provide curable treatment to surgical candidates of PA such that AVS can identify patients with contralateral PA in CT unilateral lesion and unilateral PA in CT bilateral lesion. The surgical outcome was successful when an adrenalectomy was performed according to the AVS lateralization result.

A Prospective Comparative Study of 18 F-FDOPA PET/CT Versus 123 I-MIBG Scintigraphy With SPECT/CT for the Diagnosis of Pheochromocytoma and Paraganglioma

PURPOSE

This study aimed to compare the diagnostic performances of 18 F-FDOPA PET/CT and 123 I-MIBG scintigraphy with SPECT/CT for detection of pheochromocytoma and paraganglioma (PPGL).

PATIENTS AND METHODS

We conducted a prospective, single-institution comparative study. Patients suspected of having PPGL or those showing recurrence and/or distant metastasis of PPGL were enrolled. The primary objective was to affirm the noninferiority of 18 F-FDOPA PET/CT for diagnostic sensitivity. Both 123 I-MIBG scintigraphy with SPECT/CT (at 4 and 24 hours) and 18 F-FDOPA PET/CT (at 5 and 60 minutes after radiotracer administration) were performed. The final diagnosis was established either pathologically or via clinical follow-up. Nuclear physicians, unaware of the clinical data, undertook image analysis.

RESULTS

Thirty-two patients were evaluated: 14 of 21 with an initial diagnosis and 9 of 11 with recurrence/metastasis had PPGLs in their final diagnoses. In patient-based analyses, 18 F-FDOPA PET/CT (95.7%) exhibited noninferior sensitivity compared with 123 I-MIBG SPECT/CT (91.3%), within the predetermined noninferiority margin of -12% by a 95% confidence interval lower limit of -10%. Both modalities showed no significant difference in specificity (88.9% vs 88.9%). In the region-based analysis for the recurrence/metastasis group, 18 F-FDOPA PET/CT demonstrated significantly higher sensitivity compared with 123 I-MIBG SPECT/CT (86.2% vs 65.5%, P = 0.031) and superior interobserver agreement (κ = 0.94 vs 0.85). The inclusion of an early phase in dual-phase 18 F-FDOPA PET/CT slightly improved diagnostic performance, albeit not to a statistically significant degree.

CONCLUSIONS

18 F-FDOPA PET/CT demonstrated noninferior sensitivity and comparable specificity to 123 I-MIBG SPECT/CT in the diagnosing PPGL. Notably, in the assessment of PPGL recurrence and metastasis, 18 F-FDOPA PET/CT outperformed 123 I-MIBG SPECT/CT in terms of both sensitivity and interobserver agreement.

The Fracture Risk Assessment Tool Probability and Trabecular Bone Score Mediate the Relationship between Sphingosine 1-phosphate Levels and Fracture Risk

BACKGROUND

The sphingosine 1-phosphate (S1P) concentration is a potential biomarker of osteoporotic fracture and is associated with both the fracture risk assessment tool (FRAX) probability and trabecular bone score (TBS), which are well-known predictors of fracture. We sought to estimate the effect of the S1P concentration on fracture risk using the FRAX probability and TBS as mediators.

METHODS

Plasma S1P concentrations, FRAX variables, and TBSs were measured in 66 postmenopausal women with fractures and 273 postmenopausal women without fractures. Associations between S1P concentration, FRAX probability, TBS, and fracture risk were analyzed using correlation, logistic regression, and mediation analyses.

RESULTS

Subjects in the highest S1P concentration tertile had a higher fracture risk (odds ratio [OR], 5.09; 95% confidence interval [CI], 2.22-11.67) than those in the lowest S1P concentration tertile before adjustment. Subjects in the highest FRAX probability tertile had a higher fracture risk (OR, 14.59; 95% CI, 5.01-42.53) than those in the lowest FRAX probability tertile before adjustment. Subjects in the lowest TBS tertile had a higher fracture risk (OR, 4.76; 95% CI, 2.28-9.93) than those in the highest TBS tertile before adjustment. After adjustment for FRAX probability and TBS, the highest S1P concentration tertile was still associated with a higher fracture risk (OR, 3.13; 95% CI, 1.28-7.66). The FRAX probability and TBS accounted for 32.6% and 21.7%, respectively, of the relationship between the S1P concentration and fracture risk.

CONCLUSIONS

The relationship between the circulating S1P concentration and fracture risk was partly mediated by the FRAX probability, bone microarchitecture, and other factors.

Aortic carboxypeptidase-like protein, a putative myokine, stimulates the differentiation and survival of bone-forming osteoblasts

A new target that stimulates bone formation is needed to overcome limitations of current anti-osteoporotic drugs. Myokines, factors secreted from muscles, may modulate it. In this study, we investigated the role of aortic carboxypeptidase-like protein (ACLP), which is highly expressed in skeletal muscles, on bone formation. MC3T3-E1 cells and/or calvaria osteoblasts were treated with recombinant N-terminal mouse ACLP containing a signal peptide [rmACLP (N)]. The expression and secretion of ACLP were higher in skeletal muscle and differentiated myotube than in other tissues and undifferentiated myoblasts, respectively. rmACLP (N) increased bone formation, ALP activity, and phosphorylated p38 mitogen-activated protein (MAP) kinase in osteoblasts; reversal was achieved by pre-treatment with a TGF-β receptor inhibitor. Under H2 O2 treatment, rmACLP (N) increased osteoblast survival, phosphorylated p38 MAP kinase, and the nuclear translocation of FoxO3a in osteoblasts. H2 O2 treatment caused rmACLP (N) to suppress its apoptotic, oxidative, and caspase-9 activities. rmACLP (N)-stimulated osteoblast survival was reversed by pre-treatment with a p38 inhibitor, a TGF-β-receptor II blocking antibody, and a FoxO3a shRNA. Conditioned media (CM) from muscle cells stimulated osteoblast survival under H2 O2 treatment, in contrast to CM from ACLP knockdown muscle cells. rmACLP (N) increased the expressions of FoxO3a target anti-oxidant genes such as Sod2, Trx2, and Prx5. In conclusion, ACLP stimulated the differentiation and survival of osteoblasts. This led to the stimulation of bone formation by the activation of p38 MAP kinase and/or FoxO3a via TGF-β receptors. These findings suggest a novel role for ACLP in bone metabolism as a putative myokine.

Diagnosis of osteoporotic vertebral compression fractures and fracture level detection using multitask learning with U-Net in lumbar spine lateral radiographs

Recent studies of automatic diagnosis of vertebral compression fractures (VCFs) using deep learning mainly focus on segmentation and vertebral level detection in lumbar spine lateral radiographs (LSLRs). Herein, we developed a model for simultaneous VCF diagnosis and vertebral level detection without using adjacent vertebral bodies. In total, 1102 patients with VCF, 1171 controls were enrolled. The 1865, 208, and 198 LSLRS were divided into training, validation, and test dataset. A ground truth label with a 4-point trapezoidal shape was made based on radiological reports showing normal or VCF at some vertebral level. We applied a modified U-Net architecture, in which decoders were trained to detect VCF and vertebral levels, sharing the same encoder. The multi-task model was significantly better than the single-task model in sensitivity and area under the receiver operating characteristic curve. In the internal dataset, the accuracy, sensitivity, and specificity of fracture detection per patient or vertebral body were 0.929, 0.944, and 0.917 or 0.947, 0.628, and 0.977, respectively. In external validation, those of fracture detection per patient or vertebral body were 0.713, 0.979, and 0.447 or 0.828, 0.936, and 0.820, respectively. The success rates were 96 % and 94 % for vertebral level detection in internal and external validation, respectively. The multi-task-shared encoder was significantly better than the single-task encoder. Furthermore, both fracture and vertebral level detection was good in internal and external validation. Our deep learning model may help radiologists perform real-life medical examinations.

Fatty acid amides as potential circulating biomarkers for sarcopenia

BACKGROUND

Sarcopenia is characterized by a progressive decrease in skeletal muscle mass and function with age. Given that sarcopenia is associated with various metabolic disorders, effective metabolic biomarkers for its early detection are required. We aimed to investigate the metabolic biomarkers related to sarcopenia in elderly men and perform experimental studies using metabolomics.

METHODS

Plasma metabolites from 142 elderly men, comprising a sarcopenia group and an age-matched control group, were measured using global metabolome profiling. Muscle and plasma samples from an aging mouse model of sarcopenia, as well as cell media and cell lysates during myoblast differentiation, were analysed based on targeted metabolome profiling. Based on these experimental results, fatty acid amides were quantified from human plasma as well as human muscle tissues. The association of fatty acid amide levels with sarcopenia parameters was evaluated.

RESULTS

Global metabolome profiling showed that fatty acid amide levels were significantly different in the plasma of elderly men with sarcopenia (all Ps < 0.01). Consistent with these results in human plasma, targeted metabolome profiling in an aging mouse model of sarcopenia showed decreased levels of fatty acid amides in plasma but not in muscle tissue. In addition, the levels of fatty acid amides increased in cell lysates during muscle cell differentiation. Targeted metabolome profiling in men showed decreased docosahexaenoic acid ethanolamide (DHA EA) levels in the plasma (P = 0.016) but not in the muscle of men with sarcopenia. DHA EA level was positively correlated with sarcopenia parameters such as skeletal muscle mass index (SMI) and handgrip strength (HGS) (P = 0.001, P = 0.001, respectively). The area under the receiver-operating characteristic curve (AUC) for DHA EA level ≤ 4.60 fmol/μL for sarcopenia was 0.618 (95% confidence interval [CI]: 0.532-0.698). DHA EA level ≤ 4.60 fmol/μL was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR]: 2.11, 95% CI: 1.03-4.30), independent of HGS. The addition of DHA EA level to age and HGS significantly improved the AUC from 0.620 to 0.691 (P = 0.0497).

CONCLUSIONS

Our study demonstrated that fatty acid amides are potential circulating biomarkers in elderly men with sarcopenia. DHA EA, in particular, strongly related to muscle mass and strength, can be a key metabolite to become a reliable metabolic biomarker for sarcopenia. Further research on fatty acid amides will provide insights into the metabolomic changes relevant to sarcopenia from an aging perspective.

Lumican, an Exerkine, Protects against Skeletal Muscle Loss

Exerkines are soluble factors secreted by exercised muscles, mimicking the effects of exercise in various organs, including the muscle itself. Lumican is reportedly secreted from muscles; however, its roles in skeletal muscle remain unknown. Herein, we found that lumican mRNA expression in the extensor digitorum longus was significantly higher in exercised mice than in unloading mice, and lumican stimulated myogenesis in vitro. Additionally, lumican knockdown significantly decreased muscle mass and cross-sectional area (CSA) of the muscle fiber in the gastrocnemius muscle of exercised mice. Lumican upregulated phosphorylation of p38 mitogen-activated protein kinase (MAPK) and a p38 inhibitor near completely blocked lumican-stimulated myogenesis. Inhibitors for integrin α2β1 and integrin ανβ3 also prevented lumican-stimulated myogenesis. Systemic lumican treatment, administered via the tail vein for 4 weeks, significantly increased relative muscle masses by 36.1% in ovariectomized mice. In addition, intramuscular lumican injection into unloaded muscles for 2 weeks significantly increased muscle mass by 8.5%. Both intravenous and intramuscular lumican treatment significantly increased muscle CSA. Our in vitro and in vivo experiments indicate that lumican is a muscle-secreted exerkine that affords protection against muscle loss by activating p38 MAPK via integrin receptors.

Real-World Safety and Effectiveness of Denosumab in Patients with Osteoporosis: A Prospective, Observational Study in South Korea

BACKGRUOUND

The efficacy and safety of denosumab have been established in a phase 3, randomized, placebo-controlled trial in Korean postmenopausal women with osteoporosis. This postmarketing surveillance study was aimed to investigate the safety and effectiveness of denosumab in Korean real-world clinical practice.

METHODS

Patients with osteoporosis who had received denosumab per the Korean approved indications in the postmarketing setting between September 2014 and September 2019 were enrolled. The primary endpoint was the incidence of adverse events (AEs) and adverse drug reactions (ADRs). The secondary endpoint was the percent change from baseline in bone mineral density (BMD) of the lumbar spine, total hip, and femoral neck.

RESULTS

Of the 3,221 patients enrolled, 3,185 were included in the safety analysis set; 2,973 (93.3%) were female, and the mean± standard deviation (SD) age was 68.9±9.9 years. The mean±SD study period was 350.0±71.4 days. AEs, fatal AEs, and ADRs occurred in 19.3%, 0.8%, and 1.6%, respectively. The most frequent AEs, occurring in >0.5% of patients, were dizziness (0.7%), arthralgia (0.7%), back pain (0.6%), and myalgia (0.6%). Hypocalcemia occurred in 0.3% of patients. There were no cases of osteonecrosis of the jaw and atypical femoral fracture. Mean±SD percent change from baseline in BMD of the lumbar spine, total hip, and femoral neck was 7.3%±23.6%, 3.6%±31.4%, and 3.2%±10.7%, respectively.

CONCLUSION

The safety and effectiveness of denosumab in Korean patients with osteoporosis in this study were comparable with those in the Korean randomized controlled trial, with no new safety findings.

Indices of ACTH-stimulated adrenal venous sampling as predictors of postsurgical outcomes in primary aldosteronism

OBJECTIVE

This study aimed to investigate the impact of indices of adrenal venous sampling (AVS) on postsurgical outcomes in patients with primary aldosteronism (PA).

DESIGN AND PATIENTS

This retrospective study determined biochemical and clinical outcomes based on ACTH-stimulated AVS parameters (lateralisation index [LI], contralateral ratio [CLR], and ipsilateral ratio [ILR]) in 251 patients with PA at 3 months after surgery.

RESULTS

Modified complete biochemical success was achieved in 8 of 12 (66.7%) patients with LI = 3-4, 39 of 47 (83.0%) with LI = 4-10, and 155 of 169 (91.7%) with LI ≥ 10 (p = .004 for trend). Modified complete biochemical success was achieved in 29 of 38 (76.3%) patients with CLR ≥ 1 and ILR ≤ 2, 73 of 86 (84.9%) with CLR = 0.25-1 and ILR > 2, and 100 of 104 (96.2%) with CLR < 0.25 and ILR > 2 (p = .001 for trend). After adjusting for confounders, modified complete biochemical success was associated with an LI ≥ 10 (odds ratio [OR] = 6.32; 95% confidence interval [CI] = 1.33-29.93) using LI = 3-4 as a reference and combined CLR < 0.25 and ILR > 2 (OR = 11.49; 95% confidence interval [CI] = 2.49-53.01) using combined CLR ≥ 1 and ILR ≤ 2 as a reference. Using combined CLR ≥ 1 and ILR ≤ 2 as a reference, complete clinical success was associated with combined CLR < 0.25 and ILR > 2 (OR = 3.10; 95% CI = 1.03-9.28) and combined CLR = 0.25-1 and ILR > 2 (OR = 4.92; 95% CI = 1.64-14.76).

CONCLUSION

LI ≥ 10 may be appropriate for achieving biochemical success. With ILR > 2, CLR < 0.25, and CLR < 1 may be appropriate for achieving biochemical and clinical success, respectively.

Outcome-Based Decision-Making Algorithm for Treating Patients with Primary Aldosteronism

BACKGROUND

Optimal management of primary aldosteronism (PA) is crucial due to the increased risk of cardiovascular and cerebrovascular diseases. Adrenal venous sampling (AVS) is the gold standard method for determining subtype but is technically challenging and invasive. Some PA patients do not benefit clinically from surgery. We sought to develop an algorithm to improve decision- making before engaging in AVS and surgery in clinical practice.

METHODS

We conducted the ongoing Korean Primary Aldosteronism Study at two tertiary centers. Study A involved PA patients with successful catheterization and a unilateral nodule on computed tomography and aimed to predict unilateral aldosterone-producing adenoma (n=367). Study B involved similar patients who underwent adrenalectomy and aimed to predict postoperative outcome (n=330). In study A, we implemented important feature selection using the least absolute shrinkage and selection operator regression.

RESULTS

We developed a unilateral PA prediction model using logistic regression analysis: lowest serum potassium level ≤3.4 mEq/L, aldosterone-to-renin ratio ≥150, plasma aldosterone concentration ≥30 ng/mL, and body mass index <25 kg/m2 (area under the curve, 0.819; 95% confidence interval, 0.774 to 0.865; sensitivity, 97.6%; specificity, 25.5%). In study B, we identified female, hypertension duration <5 years, anti-hypertension medication <2.5 daily defined dose, and the absence of coronary artery disease as predictors of clinical success, using stepwise logistic regression models (sensitivity, 94.2%; specificity, 49.3%). We validated our algorithm in the independent validation dataset (n=53).

CONCLUSION

We propose this new outcome-driven diagnostic algorithm, simultaneously considering unilateral aldosterone excess and clinical surgical benefits in PA patients.

Associations Between Plasma Growth and Differentiation Factor-15 with Aging Phenotypes in Muscle, Adipose Tissue, and Bone

Growth and differentiation factor 15 (GDF-15) is associated with muscle, fat, and bone metabolism; however, this association has not been well characterized. Plasma GDF-15, appendicular skeletal muscle mass (ASM), fat mass (FM), and bone mineral density (BMD) were measured in 146 postmenopausal women. GDF-15 levels were higher in subjects with low Body Mass Index (BMI)-adjusted ASM than in those without (median [interquartile range] 831.3 [635.4-1011.4] vs. 583.8 [455.8-771.1] pg/mL, p = 0.018). The GDF-15 level was inversely correlated with BMI-adjusted ASM (r =  - 0.377, p < 0.001) and BMD at femur neck (FN-BMD; r =  - 0.201, p = 0.015), and positively correlated with percent FM (pFM; r = 0.328, p < 0.001). After adjusting for confounders, the GDF-15 level was inversely associated with BMI-adjusted ASM (β = -0.250, p = 0.006) and positively associated with pFM (β = 0.272, p = 0.004), and tended to be inversely associated with FN-BMD (β = - 0.176, p = 0.076). The area under the receiver-operating characteristic curve of GDF-15 level > 618.4 pg/mL for sarcopenia was 0.706 (95% confidence interval (CI) 0.625-0.779) with a sensitivity of 83.3% and a specificity of 54.5%. Using a GDF-15 level of 618.4 pg/mL as a cut-off, the GDF-15 level was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR] 2.35; 95% CI 1.00-5.51; p = 0.049), obesity (OR 3.28; 95% CI 1.48-7.27; p = 0.001), osteopenic obesity (OR 3.10; 95% CI 1.31-7.30; p = 0.010), and sarcopenic or osteosarcopenic obesity (OR 4.84; 95% CI 0.88-26.69; p = 0.070). These findings support the potential of GDF-15 as a biomarker for age-related changes in muscle, fat, and bone.

Opportunistic Osteoporosis Screening Using Chest Radiographs With Deep Learning: Development and External Validation With a Cohort Dataset

Osteoporosis is a common, but silent disease until it is complicated by fractures that are associated with morbidity and mortality. Over the past few years, although deep learning-based disease diagnosis on chest radiographs has yielded promising results, osteoporosis screening remains unexplored. Paired data with 13,026 chest radiographs and dual-energy X-ray absorptiometry (DXA) results from the Health Screening and Promotion Center of Asan Medical Center, between 2012 and 2019, were used as the primary dataset in this study. For the external test, we additionally used the Asan osteoporosis cohort dataset (1089 chest radiographs, 2010 and 2017). Using a well-performed deep learning model, we trained the OsPor-screen model with labels defined by DXA based diagnosis of osteoporosis (lumbar spine, femoral neck, or total hip T-score ≤ -2.5) in a supervised learning manner. The OsPor-screen model was assessed in the internal and external test sets. We performed substudies for evaluating the effect of various anatomical subregions and image sizes of input images. OsPor-screen model performances including sensitivity, specificity, and area under the curve (AUC) were measured in the internal and external test sets. In addition, visual explanations of the model to predict each class were expressed in gradient-weighted class activation maps (Grad-CAMs). The OsPor-screen model showed promising performances. Osteoporosis screening with the OsPor-screen model achieved an AUC of 0.91 (95% confidence interval [CI], 0.90-0.92) and an AUC of 0.88 (95% CI, 0.85-0.90) in the internal and external test set, respectively. Even though the medical relevance of these average Grad-CAMs is unclear, these results suggest that a deep learning-based model using chest radiographs could have the potential to be used for opportunistic automated screening of patients with osteoporosis in clinical settings. © 2021 American Society for Bone and Mineral Research (ASBMR).

The association between the type of anesthesia and hemodynamic instability during pheochromocytoma surgery: a retrospective cohort study

BACKGROUND

Pheochromocytoma often carries a risk for perioperative hemodynamic instability (HDI). The aim of this study is to evaluate the risk factors of intraoperative HDI during minimally invasive posterior retroperitoneal adrenalectomy (PRA) for pheochromocytoma.

MATERIALS AND METHODS

This retrospective study analyzed the prospectively collected data of 172 patients who underwent laparoscopic PRA or robotic PRA for pheochromocytoma between January 2014 and December 2020 at a single tertiary center. The patients were divided into two groups according to the intraoperative hypertensive event of systolic blood pressure (> 160 mmHg). The clinical manifestations and perioperative hemodynamic conditions were analysed.

RESULTS

In the multivariate logistic regression analysis, the tumor size (> 3.4 cm) [OR 3.14, 95% confidence intervals (CI) (1.48-6.64), p = 0.003], type of preoperative alpha-blocker (selective type) [OR 3.9, 95% CI (1.52-10.02), p = 0.005], preoperative use of beta-blockers [OR 3.94, 95% CI (1.07-14.49), p = 0.039] and type of anesthesia [total intravenous anesthesia (TIVA) vs. balanced anesthesia (BA)] [OR 2.57, 95% CI (1.23-5.38), p = 0.012] were determined as independent risk factors of intraoperative hypertensive events during minimally invasive adrenalectomy.

CONCLUSIONS

The type of anesthesia was independently associated with intraoperative HDI along with larger tumor size, type of preoperative alpha-blocker and the use of preoperative beta-blockers. TIVA increased the risk of intraoperative hypertensive events compared with BA. Thus, the consideration of the type of anesthesia prior to adrenal surgery for pheochromocytoma along with the use of preoperative non-selective alpha-blockers may be beneficial in minimizing the risk of intraoperative HDI.

SLIT3 promotes myogenic differentiation as a novel therapeutic factor against muscle loss

BACKGROUND

Sarcopenia and osteoporosis frequently co-occur in the elderly and have common pathophysiological determinants. Slit guidance ligand 3 (SLIT3) has been recently discovered as a novel therapeutic factor against osteoporosis, and a SLIT3 fragment containing the second leucine-rich repeat domain (LRRD2) had a therapeutic efficacy against osteoporosis. However, a role of SLIT3 in the skeletal muscle is unknown.

METHODS

Skeletal muscle mass, strength, and/or physical activity were evaluated in Slit3^-/- , ovariectomized, and aged mice, based on the measurements of muscle weight and grip strength, Kondziella's inverted hanging test, and/or wheel-running test. Skeletal muscles were also histologically evaluated by haematoxylin and eosin staining and/or immunofluorescence. The ovariectomized and aged mice were intravenously injected with recombinant SLIT3 LRRD2 for 4 weeks. C2C12 cells were used to know cellular effects of SLIT3, such as in vitro myogenesis, fusion, cell viability, and proliferation, and also used to evaluate its molecular mechanisms by immunocytochemistry, immunoprecipitation, western blotting, real-time PCR, siRNA transfection, and receptor-ligand binding ELISA.

RESULTS

Slit3-deficient mice exhibited decreased skeletal muscle mass, muscle strength, and physical activity. The relative masses of gastrocnemius and soleus were lower in the Slit3^-/- mice (0.580 ± 0.039% and 0.033 ± 0.003%, respectively) than those in the WT littermates (0.622 ± 0.043% and 0.038 ± 0.003%, respectively) (all, P < 0.05). Gastrocnemius of Slit3^-/- mice showed the reduced number of Type I and Type IIa fibres (all, P < 0.05), but not of Type IIb and Type IIx fibres. SLIT3 activated β-catenin signalling by promoting its release from M-cadherin, thereby increasing myogenin expression to stimulate myoblast differentiation. In vitro experiments involving ROBO2 expression, knockdown, and interaction with SLIT3 indicated that ROBO2 functions as a SLIT3 receptor to aid myoblast differentiation. SLIT3 LRRD2 dissociated M-cadherin-bound β-catenin and up-regulated myogenin expression to increase myoblast differentiation, in a manner similar to full-length SLIT3. Systemic treatment with SLIT3 LRRD2 increased skeletal muscle mass in both ovariectomized and aged mice (all, P < 0.05). The relative masses of gastrocnemius and soleus were higher in the treated aged mice (0.548 ± 0.045% and 0.033 ± 0.005%, respectively) than in the untreated aged mice (0.508 ± 0.016% and 0.028 ± 0.003%, respectively) (all, P < 0.05). SLIT3 LRRD2 treatment increased the hanging duration of the aged mice by approximately 1.7-fold (P < 0.05).

CONCLUSIONS

SLIT3 plays a sarcoprotective role by activating β-catenin signalling. SLIT3 LRRD2 can potentially be used as a therapeutic agent against muscle loss.

Contralateral Suppression at Adrenal Venous Sampling Is Associated with Renal Impairment Following Adrenalectomy for Unilateral Primary Aldosteronism

BACKGROUND

Adrenal venous sampling (AVS) is performed to distinguish the subtype of primary aldosteronism (PA). The clinical implication of contralateral suppression (CS; aldosterone/cortisolnondominant<aldosterone/cortisolperipheral) at AVS remains unclear. We aimed to investigate the clinical significance of CS and its impact on postoperative outcomes after unilateral adrenalectomy.

METHODS

In this retrospective observational multi-center study, we analyzed PA patients who underwent both successful adrenocorticotropin hormone-stimulated AVS and unilateral adrenalectomy. Successful cannulation was defined as the selectivity index (cortisoladrenal/cortisolperipheral) ≥3. Clinical and biochemical outcomes after unilateral adrenalectomy were evaluated based on the international Primary Aldosteronism Surgical Outcome consensus.

RESULTS

Among 263 patients analyzed, 247 had CS (93.9%). Patients with CS had lower serum potassium levels, higher plasma aldosterone concentration, higher aldosterone-to-renin ratio (ARR), and larger adenoma size than those without CS. Those with CS showed significantly higher lateralization index than those without CS (P<0.001). Although postoperative blood pressure and ARR significantly decreased in those with CS, clinical and biochemical outcomes were comparable in both groups. When the cut-off value of age was determined using receiver operating characteristic (ROC) analysis, patients aged ≥50 years old with contralateral suppression index (CSI; the ratio between aldosterone/cortisolnondominant and aldosterone/cortisolperipheral) ≤0.26 had greater odds ratio (6.43; 95% confidence interval, 1.30 to 31.69) of incident chronic kidney disease than those aged <50 years with CSI >0.26 after adjusting for other factors.

CONCLUSION

CS may not predict postoperative clinical and biochemical outcomes in subjects with unilateral aldosterone excess, but it is associated with postsurgical deterioration of renal function in subjects over 50 years with CSI ≤0.26.

Associations of Circulating Levels of Sphingosine 1-Phosphate with the Trabecular Bone Score and Bone Mineral Density in Postmenopausal Women

Despite the potential roles of sphingosine 1-phosphate (S1P) as a biomarker of osteoporotic fracture (OF), independent of bone mineral density (BMD) and clinical risk factors (CRFs), its association with bone microarchitecture, a key determinant of bone quality, have not been studied yet. We here investigated the association of S1P with the trabecular bone score (TBS), an index of the bone microarchitecture. The plasma S1P concentrations, TBS, and BMD were measured in the 339 postmenopausal women. The S1P level was inversely correlated with the TBS (γ=-0.096, p=0.049) and BMD at the femur neck (FN-BMD: γ=-0.122, p=0.025) and tended to be inversely correlated the BMD at the total hip (TH-BMD: γ=-0.096, p=0.079), but not at the lumbar spine (LS-BMD). After adjusting for fracture risk assessment tool probabilities of major OF from CRFs, the S1P level was inversely associated with the TBS (β=-0.096, p=0.049) and FN-BMD (β=-0.118, p=0.025) and tended to be inversely associated with the TH-BMD (β=-0.092, p=0.083). Compared with subjects in the lowest S1P tertile, those in the highest S1P tertile had a significantly lower TBS (p=0.032) and BMD at femur (p=0.004-0.036). These findings indicated that a high S1P level in postmenopausal women was inversely associated with the both bone mass and microarchitecture, reflecting the compromised bone strength.

Diagnostic Accuracy of Computed Tomography in Predicting Primary Aldosteronism Subtype According to Age

BACKGROUND

Guidelines by the Endocrine Society Guideline on bypassing adrenal vein sampling (AVS) in patients <35 years old with marked primary aldosteronism (PA) (hypokalemia and elevated plasma aldosterone concentration [PAC]) and a unilateral lesion on computed tomography (CT) are based on limited number of studies. We aimed to determine the accuracy of CT in PA patients according to age.

METHODS

In this retrospective study, we investigated the concordance between CT and AVS in 466 PA patients from two tertiary centers who successfully underwent AVS.

RESULTS

CT had an overall accuracy of 64.4% (300/466). In the group with unilateral lesion, patients with hypokalemia had higher concordance than those without hypokalemia (85.0% vs. 43.6%, P<0.001). In the group with marked PA (hypokalemia and PAC >15.9 ng/dL) and unilateral lesion, accuracy of CT was 84.6% (11/13) in patients aged <35 years; 100.0% (20/20), aged 35 to 39 years; 89.4% (59/66), aged 40 to 49 years; and 79.8% (79/99), aged ≥50 years. Cut-off age and PAC for concordance was <50 years and >29.6 ng/dL, respectively. The significant difference in accuracy of CT in 198 patients with marked PA and a unilateral lesion between the <50-year age group and ≥50-year age group (90.9% vs. 79.8%, P=0.044) disappeared in 139 of 198 patients with PAC > 30.0 ng/dL (91.9% vs. 87.7%, P=0.590).

CONCLUSION

Patients with hypokalemia, PAC >30.0 ng/dL, and unilateral lesion were at high risk of unilateral PA regardless of age.

PDK2 Deficiency Prevents Ovariectomy-Induced Bone Loss in Mice by Regulating the RANKL-NFATc1 Pathway During Osteoclastogenesis

Estrogen deficiency leads to osteoporosis as a result of an imbalance in bone remodeling due to greater bone resorption. Estrogen deficiency increases the osteoclastic resorption of bone, and many of the FDA-approved therapies for osteoporosis are antiresorptive drugs that mainly act by reducing osteoclast activity. The mitochondrial enzyme pyruvate dehydrogenase kinase (PDK) is a critical regulator of aerobic glycolysis that exerts its effects by phosphorylating the pyruvate dehydrogenase complex (PDC), which is responsible for oxidative phosphorylation. In the present study, we found that during osteoclast differentiation, PDK2 expression increased more than that of the other PDK isoenzymes. Bone loss was delayed and the number of osteoclasts was lower in ovariectomized (OVX) Pdk2^-/- mice than in OVX wild-type mice. The differentiation of osteoclasts was suppressed in Pdk2^-/- bone marrow-derived monocyte/macrophage lineage cells, which was associated with lower phosphorylation of cAMP response element-binding protein (CREB) and c-FOS, and a consequent reduction in NFATc1 transcription. Administration of AZD7545, a specific inhibitor of PDK2, prevented the OVX-induced bone loss and reduced the phosphorylation of CREB and c-FOS, and the protein expression of NFATc1, in osteoclasts. Collectively, these results indicate that the inhibition of PDK2 prevents osteoporosis in estrogen-deficient mice by reducing aberrant osteoclast activation, probably via inhibition of the RANKL-CREB-cFOS-NFATc1 pathway. These findings imply that PDK2 inhibitors might be repurposed for the therapy of estrogen deficiency-induced osteoporosis. © 2020 American Society for Bone and Mineral Research (ASBMR).

Romosozumab in Postmenopausal Korean Women with Osteoporosis: A Randomized, Double-Blind, Placebo-Controlled Efficacy and Safety Study

BACKGROUND

This phase 3 study evaluated the efficacy and safety of 6-month treatment with romosozumab in Korean postmenopausal women with osteoporosis.

METHODS

Sixty-seven postmenopausal women with osteoporosis (bone mineral density [BMD] T-scores ≤-2.5 at the lumbar spine, total hip, or femoral neck) were randomized (1:1) to receive monthly subcutaneous injections of romosozumab (210 mg; n=34) or placebo (n=33) for 6 months.

RESULTS

At month 6, the difference in the least square (LS) mean percent change from baseline in lumbar spine BMD (primary efficacy endpoint) between the romosozumab (9.5%) and placebo (-0.1%) groups was significant (9.6%; 95% confidence interval, 7.6 to 11.5; P&lt;0.001). The difference in the LS mean percent change from baseline was also significant for total hip and femoral neck BMD (secondary efficacy endpoints). After treatment with romosozumab, the percent change from baseline in procollagen type 1 N-terminal propeptide transiently increased at months 1 and 3, while that in C-terminal telopeptide of type 1 collagen showed a sustained decrease. No events of cancer, hypocalcemia, injection site reaction, positively adjudicated atypical femoral fracture or osteonecrosis of the jaw, or positively adjudicated serious cardiovascular adverse events were observed. At month 9, 17.6% and 2.9% of patients in the romosozumab group developed binding and neutralizing antibodies, respectively.

CONCLUSION

Treatment with romosozumab for 6 months was well tolerated and significantly increased lumbar spine, total hip, and femoral neck BMD compared with placebo in Korean postmenopausal women with osteoporosis (ClinicalTrials.gov identifier NCT02791516).

Primary aldosteronism subtyping in the setting of partially successful adrenal vein sampling

BACKGROUND AND AIMS

Frequent failure of adrenal vein (AV) cannulation is a major obstacle to the universal use of adrenal vein sampling (AVS) for subtyping primary aldosteronism (PA). This study aimed to confirm and modify the value of a previously reported AVS parameter for PA subtyping in the case of cannulation failure on one side.

METHODS

Successfully catheterized AVS studies in 157 patients (121 patients as a derivation cohort and 36 patients as a validation cohort) from two tertiary hospitals were retrospectively reviewed. The AV/inferior vena cava (IVC) index was defined by dividing the aldosterone/cortisol ratio (ACR) of AV by the ACR of the IVC. Cutoff values for lateralized PA were obtained from two methods: scatterplots and the values corresponding to Youden's index in receiver operating characteristic (ROC) curves, on the assumption of catheterization failure on one side.

RESULTS

Due to multiple samplings in a single AVS procedure, 252 left AV/IVC ratios (LIRs) and 272 right AV/IVC ratios (RIRs) were calculated. Scatterplot cutoffs of LIR >5.4 or <0.5 predicted unilateral PA with a sensitivity of 42.1% and a specificity of 98.6%. Scatterplot cutoffs of RIR <0.5 or >7.0 showed a sensitivity of 55.1% and a specificity of 98.6%. ROC curve cutoffs of LIR ⩽0.8 or >3.1 predicted unilateral PA with a sensitivity of 82.5% and a specificity of 69.6%. ROC curve cutoffs of RIR ⩽0.8 or >3.9 resulted in 87.4% sensitivity and 80.7% specificity.

CONCLUSION

In the case of unilateral AVS failure, the AV/IVC index may help in diagnosing PA subtype.

Muscle-Derived Lumican Stimulates Bone Formation via Integrin α2β1 and the Downstream ERK Signal

Skeletal muscle and bone are highly interrelated, and previous proteomic analyses suggest that lumican is one of muscle-derived factors. To further understand the role of lumican as a myokine affecting adjacent bone metabolism, we investigated the effects of lumican on osteoblast biology. Lumican expression was significantly higher in the cell lysates and conditioned media (CM) of myotubes than those of undifferentiated myoblasts, and the known anabolic effects of myotube CM on osteoblasts were reduced by excluding lumican from the CM. Lumican stimulated preosteoblast viability and differentiation, resulting in increased calvaria bone formation. The expression of osteoblast differentiation markers was consistently increased by lumican. Lumican increased the phosphorylation of ERK, whereas ERK inhibitors completely reversed lumican-mediated stimulation of Runx2 and ALP activities in osteoblasts. Results of a binding ELISA experiment in osteoblasts show that transmembrane integrin α2β1 directly interacted with lumican, and an integrin α2β1 inhibitor attenuated the stimulation of ERK and ALP activities by lumican. Taken together, the results indicate that muscle-derived lumican stimulates bone formation via integrin α2β1 and the downstream ERK signal, indicating that this is a potential therapeutic target for metabolic bone diseases.

High Circulating Sphingosine 1-Phosphate is a Risk Factor for Osteoporotic Fracture Independent of Fracture Risk Assessment Tool

Circulating sphingosine 1-phosphate (S1P) levels may be a biomarker for osteoporotic fracture (OF). This study assessed whether the addition of S1P levels to the fracture risk assessment tool (FRAX) could improve predictability of OF risk. Plasma S1P concentrations and FRAX variables were measured in 81 subjects with and 341 subjects without OF. S1P levels were higher in subjects with than those without OF (3.11 ± 0.13 μmol/L vs. 2.65 ± 0.61 μmol/L, P = 0.001). Higher S1P levels were associated with a higher likelihood of OF (odds ratio [OR] = 1.33, 95% confidence interval [CI] = 1.05-1.68), even after adjusting for FRAX probabilities. Compared with the lowest S1P tertile, subjects in the middle (OR = 3.37, 95% CI = 1.58-7.22) and highest (OR = 3.65, 95% CI = 1.66-8.03) S1P tertiles had higher rates of OF after adjustment. The addition of S1P levels to FRAX probabilities improved the area under the receiver-operating characteristics curve (AUC) for OF, from 0.708 to 0.769 (P = 0.013), as well as enhancing category-free net reclassification improvement (NRI = 0.504, 95% CI = 0.271-0.737, P < 0.001) and integrated discrimination improvement (IDI = 0.044, 95% CI = 0.022-0.065, P < 0.001). Adding S1P levels to FRAX probabilities especially in 222 subjects with osteopenia having a FRAX probability of 3.66-20.0% markedly improved the AUC for OF from 0.630 to 0.741 (P = 0.012), as well as significantly enhancing category-free NRI (0.571, 95% CI = 0.221-0.922, P = 0.001) and IDI (0.060, 95% CI = 0.023-0.097, P = 0.002). S1P is a consistent and significant risk factor of OF independent of FRAX, especially in subjects with osteopenia and low FRAX probability.

Free fatty acid receptor 4 (FFA4) activation ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis by increasing regulatory T cells in mice

High dose intake of docosahexaenoic acid showed beneficial effects on atopic dermatitis in patients and was found to increase regulatory T cells in mice, but its molecular target has not been identified. Free fatty acid receptor 4 (FFA4, also known as GPR120) is a receptor sensing polyunsaturated long-chain fatty acids including docosahexaenoic acid. In the present study, we examined whether FFA4 acted as a therapeutic target of docosahexaenoic acid for treating atopic dermatitis. Experimental atopic dermatitis was induced in mice by 2,4-dinitrochlorobenzene (DNCB) sensitization on day 0, followed by repeated DNCB challenges from D7 to D48. The mice were treated with a selective agonist compound A (30 mg· kg⁻¹· d⁻¹, ip) from D19 to D48, and sacrificed on D49. We found that DNCB-induced atopic dermatitis-like skin lesions, i.e. hypertrophy and mast cell infiltration in skin tissues, as well as markedly elevated serum IgE levels. Administration of compound A significantly suppressed the atopic responses in ears and lymph nodes, such as hypertrophy and mast cell infiltration in the ears, enlarged sizes of lymph nodes, and elevated serum IgE and levels of cytokines IL-4, IL-13, IL-17, and IFN-γ in ear tissue. The therapeutic effects of compound A were abolished by FFA4 knockout. Similarly, increased CD4⁺Foxp3⁺ regulatory T-cell population in lymph nodes was observed in wide-type mice treated with compound A, but not seen in FFA4-deficient mice. In conclusion, we demonstrate that activation of FFA4 ameliorates atopic dermatitis by increasing CD4⁺Foxp3⁺ regulatory T cells, suggesting FFA4 as a therapeutic target for atopic dermatitis.

Lower hand grip strength in older adults with non-alcoholic fatty liver disease: a nationwide population-based study

Although both liver and muscle are metabolically active endocrine organs, and non-alcoholic fatty liver disease (NAFLD) and sarcopenia may share common pathogenic determinants, there have been few clinical studies of the relationship between NAFLD and muscle strength, especially in the elderly. We conducted a nationally representative population-based, cross-sectional study using data from the Korea National Health and Nutrition Examination Survey, which involved 1,897 men aged ≥50 years and 2,206 postmenopausal women. NAFLD was defined using the hepatic steatosis index (HSI) and low muscle strength was defined using the Korea-specific cut-off point of hand grip strength (HGS). Men and women with NAFLD had 7.3% and 7.9% lower HGS than controls, respectively. The odds ratios for low muscle strength in the presence of NAFLD were 2.51 in men and 2.34 in women. HSI inversely correlated with HGS in both men and women. Consistently, compared with men and women in the lowest HSI quartile, those in the highest quartile had 7.6% and 12.4% lower HGS, respectively, and were 5.63- and 3.58-times more likely to have low muscle strength, respectively. These results provide the first clinical evidence that NAFLD can be associated with muscular impairment in older adults, as demonstrated by lower muscle strength.

Association of circulating levels of total and protein-bound sphingosine 1-phosphate with osteoporotic fracture

The biological activity and effects of circulating sphingosine 1-phosphate (S1P) might be dependent on the carrier protein. Although S1P is known to be a biomarker for osteoporotic fracture (OF), its role according to its carrier protein (high-density lipoprotein (HDL), low-density lipoprotein (LDL), or albumin) has not yet been studied. We measured the protein-bound S1P levels and bone mineral density (BMD) in 58 postmenopausal women with OF and 58 age-matched and body mass index–matched postmenopausal women without OF. Albumin-bound S1P was the most abundant. Before adjustment, women with OF had higher total S1P (p=0.046) and albumin-bound S1P (p=0.026) levels than those without OF, but there was no difference in the levels of HDL-bound or LDL-bound S1P. After adjustment for confounders including BMD, women with OF had only higher levels of total S1P than those without OF (p=0.047). Before adjustment, the OR for OF was higher in subjects in the highest quartile for total S1P (OR 5.36, 95% CI 1.22 to 23.63) or albumin-bound S1P (OR 4.48, 95% CI 1.22 to 16.42). After adjustment for confounders including BMD, statistical significance persisted only for total S1P (OR 2.23, 95% CI 1.12 to 4.81). These findings suggest that the positive association of S1P with OF is mainly due to level of total plasma S1P and not due to the differing contributions from specific carrier protein-bound fractions.

Differential association of dietary fat intake with DXA-based estimates of bone strength according to sex in the KNHANES IV population

The higher the dietary fat intake is in men, the worse their bone strength. By contrast, in women, both low and high fat intakes have negative impacts on bone strength. Dietary fat intake may be a modifiable factor affecting bone health, but this needs to be reconfirmed in further studies.

PURPOSE

Despite the general belief that higher fat intake may be harmful for bone health, its impact on bone strength has not been thoroughly studied.

METHODS

We conducted a population-based cross-sectional study derived from the Korea National Health and Nutrition Examination Surveys, including 2590 participants. Composite indices of femoral neck strength, such as the compression strength index (CSI), bending strength index (BSI), and impact strength index (ISI), were generated by combining bone mineral density, weight, and height with the femoral axis length and width. Nutritional status was assessed using a 24-h dietary recall questionnaire.

RESULTS

Dietary fat intake (%: energy from fat intake/total energy intake × 100) was inversely related to CSI and ISI in men, but not in women. Men in the highest three fat intake quintiles had lower CSI, BSI, and/or ISI than those in the lowest quintile (P = 0.003-0.041). In women, compared with participants in the third fat intake quintile, those in the other four quintiles had lower CSI, BSI, and/or ISI (P = 0.004-0.049). When participants were allocated to three groups according to the dietary reference intake of fat in Koreans [low (< 15%), moderate (15-30%), or high (≥ 30%)], men with a moderate or high fat intake had significantly lower ISIs than those with a low fat intake (P = 0.045 and 0.040, respectively). By contrast, compared with women consuming a moderate amount of fat, those with a high intake had lower CSI, BSI, and ISI (P = 0.024-0.048).

CONCLUSION

Higher fat intake in men may contribute to deteriorations in bone strength. However, this finding and the observed sex differences need to be reconfirmed using established methods for assessment of dietary intake other than the 24-h dietary recall method employed in this study.

Regulation of bone metabolism by megakaryocytes in a paracrine manner

Megakaryocytes (MKs) play key roles in regulating bone metabolism. To test the roles of MK-secreted factors, we investigated whether MK and promegakaryocyte (pro-MK) conditioned media (CM) may affect bone formation and resorption. K562 cell lines were differentiated into mature MKs. Mouse bone marrow macrophages were differentiated into mature osteoclasts, and MC3T3-E1 cells were used for osteoblastic experiments. Bone formation was determined by a calvaria bone formation assay in vivo. Micro-CT analyses were performed in the femurs of ovariectomized female C57B/L6 and Balb/c nude mice after intravenous injections of MK or pro-MK CM. MK CM significantly reduced in vitro bone resorption, largely due to suppressed osteoclastic resorption activity. Compared with pro-MK CM, MK CM suppressed osteoblastic differentiation, but stimulated its proliferation, resulting in stimulation of calvaria bone formation. In ovariectomized mice, treatment with MK CM for 4 weeks significantly increased trabecular bone mass parameters, such as bone volume fraction and trabecular thickness, in nude mice, but not in C57B/L6 mice. In conclusion, MKs may secrete anti-resorptive and anabolic factors that affect bone tissue, providing a novel insight linking MKs and bone cells in a paracrine manner. New therapeutic agents against metabolic bone diseases may be developed from MK-secreted factors.

Effects of Primary Aldosteronism and Different Therapeutic Modalities on Glucose Metabolism

Despite findings that aldosterone impairs glucose metabolism, studies concerning the effect of primary aldosteronism (PA) and its treatment on glucose metabolism are controversial. We aimed to determine glucose metabolism in PA and the effect of the treatment modality. We compared glucose metabolism between PA patients (N = 286) and age-, sex-, and body mass index-matched controls (N = 816), and the changes in glucose metabolism depending on the treatment modality (adrenalectomy vs. spironolactone treatment). Hyperglycemia including diabetes mellitus (DM; 19.6% vs. 13.1%, p = 0.011) was more frequent in PA patients. Hyperglycemia was also more frequent in PA patients without subclinical hypercortisolism (SH: p < 0.001) and in those regardless of hypokalemia (p < 0.001-0.001). PA patients and PA patients without SH had higher DM risk (odds ratio (OR); 95% confidence interval (CI): 1.63; 1.11-2.39 and 1.65; 1.08-2.51, respectively) after adjusting confounders. In PA patients, there was significant decrease in the DM prevalence (21.3% to 16.7%, p = 0.004) and fasting plasma glucose (p = 0.006) after adrenalectomy. However, there was no significant change in them after spironolactone treatment. Adrenalectomy was associated with more improved glucose status than spironolactone treatment (OR; 95% CI: 2.07; 1.10-3.90). Glucose metabolism was impaired in PA, regardless of hypokalemia and SH status, and was improved by adrenalectomy, but not spironolactone treatment.

Clinical insights into the kynurenine pathway in age-related diseases

Accumulating evidence from diverse experiments, including heterochronic parabiosis-the surgical joining of two animals of different ages-has highlighted the importance of systemic factors in the progressive functional decline of various organs and tissues during aging. The major metabolic pathway of tryptophan, an essential amino acid in humans, is the kynurenine pathway (KP) in which indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) catalyze the conversion of tryptophan into kynurenine. Importantly, circulating kynurenine produced by this enzymatic breakdown, as a primary driver of the aging process, has been linked to higher mortality in humans. This review discusses the potential roles of tryptophan derivatives as biomarkers for the risk of frailty in the elderly, based on human observational studies as well as the KP as a therapeutic target for age-related diseases.

Inverse relationship between serum hsCRP concentration and hand grip strength in older adults: a nationwide population-based study

Despite the potential detrimental effects of systemic inflammation on muscle mass, which is mainly observed in patients with pathologic diseases, its role in muscle strength, especially in a healthy general population reflecting subclinical low-grade inflammation, is unclear. This is a nationally representative population-based, cross-sectional study from the Korea National Health and Nutrition Examination Survey, which enrolled 1,036 men aged ≥50 years and 1,080 postmenopausal women. After adjustment for confounders, serum high-sensitivity C-reactive protein (hsCRP) level was inversely associated with hand grip strength (HGS) in men. Consistently, compared with men in the lowest serum hsCRP quartile, those in the highest quartile showed a significant lower HGS, with a linear decrease of HGS across increasing serum hsCRP quartiles. Men with low muscle strength had 74.2% higher serum hsCRP than those without, and each standard deviation increment in serum hsCRP was associated with a multivariate-adjusted odds ratio of 1.35 for the risk of low muscle strength in men. However, these associations were not statistically significant in women. These findings provide clinical evidence that chronic subclinical low-grade inflammation may contribute to the deterioration of muscle strength seen with aging, especially in men.

The Local and Systemic Interactions Between Muscle and Bone in Postmenopausal Korean Women

Despite many studies about local and systemic interactions between bone and muscle, the more dominant interaction remains unclear. We aimed to compare the association of skeletal muscle mass with bone mineral density (BMD) at the femur, which seemed more likely affected by local interaction, and the association of skeletal muscle mass with BMD at the lumbar spine (LS-BMD) and the trabecular bone score (TBS), which seemed more likely affected by systemic interaction. In 279 women, we measured the femoral neck BMD (FN-BMD), total hip BMD (TH-BMD), LS-BMD, and TBS. Appendicular skeletal muscle mass (ASM), lean mass (LM), and other LM (OLM; remaining LM excluding ASM) were measured using bioelectrical impedance analysis. ASM (β = 0.008-0.014, p < 0.001-0.014), OLM (β = 0.006-0.011, p < 0.001-0.044), and LM (β = 0.004-0.007, p < 0.001-0.020) were positively associated with FN-BMD and TH-BMD, but not with LS-BMD or TBS. The positive association of ASM, but not of OLM, was stronger than that of LM (p = 0.023). Odd ratios (ORs) with 95% confidence intervals (95% CIs) for osteoporosis were statistically significant for ASM (OR 0.74, 95% CI 0.59-0.93) and marginally significant for OLM (OR 0.80, 95% CI 0.64-1.01) in the femur, but not in the LS. The direct and indirect (through OLM) effects of ASM on BMD were 69.1-72.2% and 27.8-30.9%, respectively. In the conclusion, ASM was more positively associated with FN-BMD, but not with LS-BMD and TBS, than OLM. This suggests stronger effects of local interaction than systemic interaction between muscle and bone.

The effects of myokines on osteoclasts and osteoblasts

Recently, muscle has received much attention as an endocrine organ regulating other biological targets, including the pancreas, liver, and adipose tissue. Although there is a possibility that muscle-secreting factors biochemically affect bone metabolism in a paracrine manner, the net effects of myokines on the biology of osteoclasts and osteoblasts, particularly on bone mass in vivo, have not yet been thoroughly investigated. Therefore, we performed in vitro as well as animal experiments using conditioned media (CM) collected from C2C12 myoblast and myotube cultures to better understand the interactions between muscle and bone. Compared with non-CM (i.e., control) and myoblast CM, myotube CM markedly inhibited in vitro bone resorption through the suppression of osteoclast differentiation and resorptive activity of individual osteoclasts. Consistently, the expressions of osteoclast differentiation markers, such as tartrate-resistant acid phosphatase (Trap) and calcitonin receptor (Ctr), decreased with myotube CM. Myotube CM significantly stimulated preosteoblast viability and migration and reduced apoptosis, thereby resulting in an increase in calvaria bone formation. Importantly, systemic treatment with myotube CM for 4 weeks increased bone per tissue volume by 30.7% and 19.6% compared with control and myoblast CM, respectively. These results support the hypothesis that muscle plays beneficial roles in bone health via secretion of anabolic factors, in addition to mechanical stimuli, and importantly indicate that muscle-derived factors can be potential therapeutic targets against metabolic bone diseases.

Change of skeletal muscle mass in patients with pheochromocytoma

The effects of catecholamine excess due to pheochromocytoma on body composition, including skeletal muscle mass, are unknown. Here, we investigated the effects of catecholamine metabolites on body composition in subjects with pheochromocytoma. After body compositions using bioelectrical impedance analysis, urinary metanephrine (UM), and urinary normetanephrine (UNM) were measured in 16 patients with pheochromocytoma and 224 patients with nonfunctioning adrenal incidentaloma (NFAI), we compared skeletal muscle mass and fat mass (FM) between the two groups. After adjustments for confounders, UM (β = - 0.171, P = 0.006) and UNM (β = - 0.249, P < 0.001) levels were correlated inversely with skeletal muscle mass index (SMI), but not FM or percentage FM (pFM), in all subjects. Patients with pheochromocytoma had lower ASM by 7.7% (P = 0.022) and SMI by 6.6% (P = 0.001) than patients with NFAI. Conversely, FM and pFM were not statistically different between the two groups. The odds ratio for low skeletal muscle mass in the presence of pheochromocytoma was 10.33 (95% confidence interval, 2.65-40.22). Our results indicate that patients with pheochromocytoma have a reduced skeletal muscle mass and suggest that catecholamine excess has adverse effects on skeletal muscle metabolism.

SLIT2 inhibits osteoclastogenesis and bone resorption by suppression of Cdc42 activity

Axon guidance molecules, originally found to mediate the positioning of axons during nerve development, have been receiving great attention due to their critical roles in regulating bone metabolism. Recently, SLITs, another group of neuronal guidance proteins, were found to be significantly expressed in bone cells. Furthermore, we had provided experimental evidence that SLIT3 is an osteoclast-secreted coupling factor playing an osteoprotective role. Therefore, we hypothesized that SLIT2, a member of the SLIT family, may also affect bone homeostasis. SLIT2 suppressed osteoclast differentiation in a dose-dependent manner and in vitro bone resorption by more than 80%. Consistently, the expression of osteoclast differentiation markers, such as tartrate-resistant acid phosphatase (Trap) and calcitonin receptor (Ctr), was decreased by SLIT2. The migration and fusion of preosteoclasts were markedly reduced in the presence of SLIT2, suggesting that SLIT2 mainly functions in the early stage of osteoclastogenesis. SLIT2 suppressed Cdc42 activity among small GTPases, whereas Cdc42 overexpression almost completely reversed the SLIT2-mediated suppression of osteoclast differentiation. Among ROBO1-4, the SLIT receptors, ROBO1 and ROBO3 were known to be predominantly expressed in osteoclast lineages. A binding ELISA experiment in mouse bone marrow-derived macrophages showed that ROBO1, rather than ROBO3, was directly associated with SLIT2, and gene silencing with Robo1 siRNA blocked the SLIT2-mediated suppression of osteoclastogenesis. Taken together, our results indicated that SLIT2 inhibits osteoclastogenesis and the resultant bone resorption by decreasing Cdc42 activity, suggesting that this was a potential therapeutic target in metabolic bone diseases related to high bone turnover states.

The Detrimental Effects of Kynurenine, a Tryptophan Metabolite, on Human Bone Metabolism

CONTEXT

Studies in aged mice support a role for kynurenine, a tryptophan metabolite, in age-induced bone loss; however, the role of kynurenine in human bone metabolism is not well understood.

OBJECTIVE

To assess whether the kynurenine level in bone marrow (BM) aspirates, directly reflecting the bone microenvironment, is associated with osteoporosis-related phenotypes and bone biochemical markers.

DESIGN AND SETTING

A case-control study conducted in a clinical unit.

PARTICIPANTS AND MAIN OUTCOME MEASURES

BM samples were collected from 72 patients at the time of hip surgery for either fragility hip fracture (HF) (n = 27) or for other causes (n = 45). In these samples, kynurenine was measured by liquid chromatography-tandem mass spectrometry, and the levels of tartrate-resistant acid phosphatase 5b (TRAP5b), bone-specific alkaline phosphatase (BSALP), receptor activator of nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG) were measured by immunoassay.

RESULTS

Age was positively correlated with BM kynurenine level. After adjustment for confounders, subjects with fragility HF had a 39.7% higher BM kynurenine level than those without, and the OR per SD increment in BM kynurenine level for fragility HF was 3.80. The BM kynurenine level was inversely associated with bone mass at the total femur. Higher kynurenine concentrations were significantly associated with higher TRAP-5b and RANKL levels, but not with BSALP and OPG levels, in BM plasma.

CONCLUSION

These results suggest that increased kynurenine levels during aging may contribute to the bone fragility seen in the elderly through increased bone resorption, with a resultant imbalance in bone remodeling.

Preventive Effects of Low Parathyroid Hormone Levels on Hip Fracture in Patients with Vitamin D Deficiency

Background

The objective of the current study is to determine the role of serum parathyroid hormone (PTH) on hip fracture development by retrospectively analyzing the relationship between vitamin D and PTH levels and hip fracture prevalence.

Methods

Among 288 patients over 50 years of age, 113 patients with hip fracture and 111 controls without fracture were analyzed after excluding patients with conditions affecting bone metabolism. Bone mineral density and serum biochemical markers were measured, while demographic data were obtained. Patients were divided into 4 groups according to serum 25-hydroxy-vitamin D (25-[OH]D) and PTH levels: LowD+LowP (low 25[OH]D and PTH); LowD+HighP, (low 25[OH]D and high PTH); HighD+LowP (high 25[OH]D and low PTH); and HighD+HighP, patients with (high 25[OH]D and PTH). Measured values and percentages of patients with hip fracture in each group were then determined and compared.

Results

The number of patients included in the LowD+LowP, LowD+HighP, HighD+LowP, and HighD+HighP groups was 116, 17, 87, and 4, while the percentages of patients with hip fracture in the same groups were 60.3%, 88.2%, 27.6%, and 100%, respectively. The percentage of hip fracture was significantly lower in the LowD+LowP than the LowD+HighP group (P=0.049).

Conclusions

Patients with low serum 25(OH)D and PTH levels showed lower hip fracture prevalence, indicating the potential protective role of low PTH levels on bone health in patients with vitamin D deficiency. Therefore, clinicians should pay more attention to the possibility of fractures in patients with vitamin D deficiency who present with high PTH levels.

GWAS of bone size yields twelve loci that also affect height, BMD, osteoarthritis or fractures

Bone area is one measure of bone size that is easily derived from dual-energy X-ray absorptiometry (DXA) scans. In a GWA study of DXA bone area of the hip and lumbar spine (N ≥ 28,954), we find thirteen independent association signals at twelve loci that replicate in samples of European and East Asian descent (N = 13,608 - 21,277). Eight DXA area loci associate with osteoarthritis, including rs143384 in GDF5 and a missense variant in COL11A1 (rs3753841). The strongest DXA area association is with rs11614913[T] in the microRNA MIR196A2 gene that associates with lumbar spine area (P = 2.3 × 10-42, β = -0.090) and confers risk of hip fracture (P = 1.0 × 10-8, OR = 1.11). We demonstrate that the risk allele is less efficient in repressing miR-196a-5p target genes. We also show that the DXA area measure contributes to the risk of hip fracture independent of bone density.

Assessment of patient-reported outcomes (PROs): treatment satisfaction, medication adherence, and quality of life (QoL) and the associated factors in postmenopausal osteoporosis (PMO) patients in Korea

Patient-reported outcomes (PROs) provide practical guides for treatment; however, studies that have evaluated PROs of women in Korea with postmenopausal osteoporosis (PMO) are lacking. This cross-sectional, multi-center (29 nationwide hospitals) study, performed from March 2013 to July 2014, aimed to assess PROs related to treatment satisfaction, medication adherence, and quality of life (QoL) in Korean PMO women using osteoporosis medication for prevention/treatment. Patient demographics, clinical characteristics, treatment patterns, PROs, and experience using medication were collected. The 14-item Treatment Satisfaction Questionnaire for Medication (TSQM) (score-range, 0-100; domains: effectiveness, side effects, convenience, global satisfaction), Osteoporosis-Specific Morisky Medication Adherence Scale (OS-MMAS) (score-range, 0-8), and EuroQol-5 dimensions questionnaire (index score range, - 0.22 to 1.0; EuroQol visual analog scale score range, 0-100) were used. To investigate factors associated with PROs, linear (treatment satisfaction/QoL) or logistic (medication adherence) regression analyses were conducted. A total of 1804 patients (age, 62 years) were investigated; 60.1% used bisphosphonate, with the majority (67.2%) using weekly medication, 27.8% used daily hormone replacement therapy, and 12.1% used daily selective estrogen receptor modulator. Several patients reported gastrointestinal (GI) events (31.6%) and dental visits due to problems (24.1%) while using medication. Factors associated with the highest OS-MMAS domain scores were convenience and global satisfaction. GI events were associated with non-adherence. TSQM scores for effectiveness, side effects, and GI risk factors were significantly associated with QoL. Our study elaborately assessed the factors associated with PROs of Korean PMO women. Based on our findings, appropriate treatment-related adjustments such as frequency/choice of medications and GI risk management may improve PROs.

Coupling factors involved in preserving bone balance

Coupling during bone remodeling refers to the spatial and temporal coordination of bone resorption with bone formation. Studies have assessed the subtle interactions between osteoclasts and osteoblasts to preserve bone balance. Traditionally, coupling research related to osteoclast function has focused on bone resorption activity causing the release of growth factors embedded in the bone matrix. However, considerable evidence from in vitro, animal, and human studies indicates the importance of the osteoclasts themselves in coupling phenomena, and many osteoclast-derived coupling factors have been identified. These include sphingosine-1-phosphate, vesicular-receptor activator of nuclear factor-κB, collagen triple helix repeat containing 1, and cardiotrophin-1. Interestingly, neuronal guidance molecules, such as slit guidance ligand 3, semaphorin (SEMA) 3A, SEMA4D, and netrin-1, originally identified as instructive cues allowing the navigation of growing axons to their targets, have been shown to be involved in the intercellular cross-talk among bone cells. This review discusses osteoclast-osteoblast coupling signals, including recent advances and the potential roles of these signals as therapeutic targets for osteoporosis and as biomarkers predicting human bone health.

High circulating follistatin-like protein 1 as a biomarker of a metabolically unhealthy state

The inflammatory biomarkers that fully characterize the metabolically unhealthy (MU) state-which is a risk factor for cardiovascular disease (CVD)-remain unclear. Recent studies suggest follistatin-like protein 1 (FSTL1) could be used as a biomarker for inflammation and CVD, however there is little information on FSTL1 levels in the MU state. We aimed to evaluate the associations between FSTL1, the presence of MU state and subclinical coronary atherosclerosis. In a cross-sectional study, we evaluated FSTL1 levels and their relationship with the presence of MU state and coronary artery plaques in 230 Korean patients. Significant increase in FSTL1 levels was observed in subjects with MU state (p = 0.020), but not those with obesity state according to body mass index criteria (p = 0.790). After adjusting for confounders, the odd ratio (OR) for the MU state among patients in the highest FSTL1 tertile (T3) was higher in comparison with the lowest tertile (T1) (OR = 3.60, 95% confidence interval [95% CI] = 1.20-10.83). In a subgroup (n = 66), FSTL1 levels were also marginally higher in patients with plaques (p = 0.098). The OR for plaque presence in patients with T3 was significantly higher in comparison with T1 after adjusting for confounders (OR = 12.51, 95% CI = 1.15-135.73). Plasma FSTL1 may be a useful biomarker for the risk of MU state and CVD.

Lack of Association Between Vitamin D and Hand Grip Strength in Asians: A Nationwide Population-Based Study

Despite the beneficial role and plausible mechanism of vitamin D on skeletal muscle in animal studies, its association in humans remains a controversial issue due to inconsistent clinical results, especially in older Asians. This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys, which enrolled 354 men aged ≥ 50 years and 328 postmenopausal women. Hand grip strength (HGS) was measured using a digital grip strength dynamometer. Low muscle strength was defined based on Korean-specific cut-off point of HGS. Serum 25-hydroxyvitamin D [25(OH)D] levels were 19.4 ± 6.7 and 17.1 ± 7.2 ng/mL in men and women, respectively. Among covariates including age, body mass index, lifestyle factors, and protein intake, age was inversely associated with HGS in both men and women, and protein intake (g/day) was positively associated with HGS only in men. However, the independent correlation between serum 25(OH)D and HGS was not observed, regardless of gender. When subjects were divided into three groups [deficient (25(OH)D < 20 ng/mL; 63.8%), insufficient (20 ≤ 25(OH)D < 30 ng/mL; 30.0%), or sufficient (25(OH)D ≥ 30 ng/mL; 6.2%)], there was no significant difference in HGS among these groups in both men and women. Consistently, serum 25(OH)D was not significantly different between subjects with and without low muscle strength, and there was no independent association of serum 25(OH)D with the risk of low muscle strength in both genders. These findings provide clinical evidence that protective role of vitamin D on human muscle metabolism may not be evident at least in older Asians.

The Differential Effect of Excess Aldosterone on Skeletal Muscle Mass by Sex

The effects of excess aldosterone on skeletal muscle in individuals with primary aldosteronism (PA) are unknown. To examine the effects of aldosterone on skeletal muscle mass in patients with PA, by sex, 309 consecutive patients were enrolled. Skeletal muscle and fat mass of 62 patients with PA were compared with those of 247 controls with non-functioning adrenal incidentaloma (NFAI). Body composition parameters were measured using bioelectrical impedance analysis, and plasma aldosterone concentration (PAC) was measured using radioimmunoassay. The PAC in all women, but not in men, showed an inverse association with both appendicular skeletal muscle mass (ASM) (β = -0.197, P = 0.016) and height-adjusted ASM (HA-ASM) (β = -0.207, P = 0.009). HA-ASM in women (but not in men) with PA was 5.0% lower than that in women with NFAI (P = 0.036). Furthermore, women with PA had a lower HA-ASM than 1:1 age- and sex-matched controls with NFAI by 5.7% (P = 0.049) and tended to have a lower HA-ASM than 1:3 age-, sex-, and menopausal status-matched controls without adrenal incidentaloma (AI) by 7.3% (P = 0.053). The odds ratio (OR), per quartile increase in PAC, of low HA-ASM in women was 1.18 [95% confidence interval (CI), 1.01-1.39; P = 0.035]. The odds of HA-ASM in subjects with PA were 10.63-fold (95% CI: 0.83-135.50) higher, with marginal significance (P = 0.069) than in those with NFAI. Skeletal muscle mass in women with PA was lower than that in women with NFAI; suggesting that excess aldosterone has adverse effects on skeletal muscle metabolism.

Higher sympathetic activity as a risk factor for skeletal deterioration in pheochromocytoma

Despite the potential biological importance of sympathetic activity in human bone metabolism, its effects on bone microarchitecture, a key determinant of bone quality, has not been thoroughly studied. In the present study, we investigated the lumbar spine trabecular bone score (TBS) as an indicator of skeletal deterioration in pheochromocytoma. Among 620 consecutive patients with newly diagnosed adrenal incidentaloma, 29 with histologically confirmed pheochromocytoma (a catecholamine-secreting neuroendocrine tumor) and 266 with nonfunctional adrenal incidentaloma were defined as cases and controls, respectively. After adjustment for confounders, subjects with pheochromocytoma had 2.9% lower lumbar spine TBS than those without pheochromocytoma (P = 0.038). Moreover, urinary normetanephrine level, but not urinary metanephrine level, was inversely correlated with lumbar spine TBS (P = 0.009). Subjects in the highest urinary normetanephrine quartile showed markedly lower lumbar spine TBS than those in the lowest quartile (P = 0.018), in a dose-response manner across increasing urinary normetanephrine quartile categories (P for trend = 0.021). Consistent with the results of previous studies, subjects with pheochromocytoma had significantly lower bone mass at the lumbar spine and higher serum level of C-terminal telopeptide of type I collagen than controls (P = 0.013 and 0.002, respectively). These findings provide clinical evidence that catecholamine excess and the resultant sympathetic overstimulation in pheochromocytoma may contribute to bone fragility, especially in the trabecular bone, through a weak microarchitecture in addition to a lower bone mass and increased bone resorption, and support the possibility of pheochromocytoma as a secondary cause of osteoporosis.