Bone mineral density in emphysema and chronic bronchitis phenotypes in hospitalized male chronic obstructive pulmonary disease patients

Extracellular acidification stimulates OGR1 to modify osteoclast differentiation and activity through the Ca2+‑calcineurin‑NFATc1 pathway

The aim of the present study was to explore the role of ovarian cancer G protein-coupled receptor 1 (OGR1) in osteoclast differentiation and activity induced by extracellular acid. The impact of extracellular acidification on osteoclasts was investigated. Briefly, osteoclasts were generated from RAW 264.7 cells using 100 ng/ml receptor activator of nuclear factor-κB ligand in cell culture media at pH 6.8 or 7.4. Tartrate-resistant acid phosphatase (TRAP) staining and the bone resorption pit assay were used to detect the effects of extracellular acid on the number and absorptive capacity of osteoclasts. Intracellular Ca2+ levels were analyzed using laser scanning confocal microscopy. Reverse transcription-quantitative PCR was used to detect the expression levels of genes associated with osteoclast formation and bone erosion. The role of OGR1 in the acid-stimulated formation and bone resorption of osteoclasts was also investigated. The results showed that in the pH 6.8 medium group the number of osteoclasts was 511.2±54.72 and the area of bone absorption was 4,184.88±277.14 µm2; both were significantly higher than those in the pH 7.4 medium group (all P<0.01). Inhibition of OGR1 using copper ion (Cu2+) reduced the number of osteoclasts and the area of bone resorption in the pH 6.8 medium group (all P<0.05). Furthermore, extracellular acid (pH 6.8) was able to induce a transient increase of Ca2+ levels in osteoclasts; however, inhibition of OGR1 using Cu2+ effectively attenuated the acid-induced increase of Ca2+ in osteoclasts. In addition, the elevation in Ca2+ levels was inhibited when BAPTA, a cytoplasmic Ca2+ chelator with cellular permeability, was added to the cells; however, the extracellular Ca2+-chelating agent ethylene glycol tetraacetic acid did not inhibit the acid-stimulated increase in Ca2+. Treatment with the phospholipase C inhibitor U73122 also inhibited the acid-stimulated increase of Ca2+ in osteoclasts. Furthermore, the mRNA expression levels of TRAP, matrix metalloproteinase-9, osteoclast-related receptor, nuclear factor-activated T cell 1 (NFATc1), cathepsin K and integrin β3 were elevated in the pH 6.8 medium group compared with those in the pH 7.4 medium group (all P<0.05). By contrast, the inhibition of OGR1 using Cu2+ partially reduced the effects of the acidic environment on osteoclast differentiation and activity-related gene expression (all P<0.05). In addition, the mRNA and protein expression levels of calcineurin were increased in osteoclasts in the pH 6.8 group compared with those in the pH 7.4 group (P<0.05), whereas blocking OGR1 suppressed the expression of acid-induced calcineurin. The mRNA expression levels of NFATc1 in osteoclasts were also increased in the pH 6.8 medium group compared with those in the pH 7.4 medium group (P<0.05). By contrast, the specific calcineurin inhibitor cyclosporine A significantly inhibited the acid-induced expression of NFATc1 in osteoclasts. In conclusion, the present study revealed that extracellular acidification may increase osteoclast differentiation and bone resorption activity. Furthermore, OGR1-mediated Ca2+ elevation could have a crucial role in osteoclasts by regulating the Ca2+-calcineurin-NFATc1 signaling pathway and downstream signaling.

Risk factors and prognostic value of osteoporosis in hospitalized patients with bronchiectasis

BACKGROUND

The risk factors for osteoporosis and its prognostic value in patients with bronchiectasis is not well characterized. We explored the risk factors for osteoporosis and its prognostic impact in hospitalized non-cystic fibrosis bronchiectasis (NCFB) patients in Southeast China.

METHODS

This observational cohort study consecutively enrolled 179 hospitalized patients with NCFB bronchiectasis between 2017 and 2021. The risk factors and the impact of osteoporosis on all-cause mortality were assessed.

RESULTS

21.2% (38/179) of hospitalized NCFB patients were diagnosed with osteoporosis. Patients with osteoporosis had more severe symptoms (assessed by chronic airway assessment test, CAT, median 22 vs. 17, P = 0.017), poorer quality of life (assessed by St. George Respiratory Questionnaires, SQRC, median 42 vs. 27, P = 0.007), more severe disease stage (assessed by bronchiectasis severity index, BSI, median 14 vs. 11, P = 0.02), more comorbidities (assessed by Bronchiectasis Aetiology Comorbidity Index, BACI, median 5 vs. 4, P = 0.021) than patients without. Age, female sex, anemia, post-infection, and history of regular inhaled corticosteroid treatment were independent risk factors for osteoporosis in those patients. 21 patients (11.7%) died over a median follow-up period of 32 months. The all-cause mortality in NCFB patients with osteoporosis [28.94% (11/38)] was significantly higher than those without osteoporosis [7.09% (10/141)] [hazard ratio (HR) 5.34, 95% confidence interval (CI) 2.26-12.67, P < 0.001]. After adjusting for BSI and other confounding factors, osteoporosis was still independently associated with all-cause mortality in hospitalized NCFB patients (HR 4.29, 95% CI 1.75-10.49, P < 0.001).

CONCLUSIONS

Osteoporosis had an independent effect on all-cause mortality in hospitalized NCFB patients. Management of comorbidities, including bone health, is a critical aspect of treating NCFB patients.

Development of a Sandwich Chemiluminescence Immunoassay for the Detection of Intact Procollagen Type I N Propeptide with Magnetic Nanosphere Carrier Technology

The metabolic product of type I collagen synthesis, intact procollagen type I N propeptide (intact PINP), is a potential marker of bone formation and osteoporosis, which is not affected by kidney function. We sought to establish a chemiluminescent immunoassay method for the detection of serum intact PINP with previously prepared paired monoclonal antibodies and to evaluate the diagnostic value of the assay in osteoporosis. Using the capture molecule and monoclonal antibody as detection molecule, a diagnostic reagent was developed to detect intact PINP in serum with magnetic nanosphere carriers by the chemiluminescence method, and its analytical performance in the laboratory was evaluated. Serum intact PINP was measured in 142 healthy people and 115 osteoporosis patients. Results were matched with results of a similar test kit, Roche total PINP Elecsys Chemiluminescent Immunoassay Assay. Compared with the performance of the Roche PINP assay product, our method had higher sensitivity (0.02 ng/mL), wider linear range (0.02-1500 ng/mL), and anti-interference. Serum intact PINP values in osteoporosis patients were significantly higher than in healthy subjects (p < 0.001). Our method had good consistency compared with the Roche PINP assay (r = 0.9794). This chemiluminescence method for detecting serum intact PINP (CLIA-intact PINP) with magnetic nanosphere carrier technology meets the requirements of a clinical testing reagent and is expected to have clinical application after further evaluation and can compete with expensive imported kits on the market.

Analytic Morphomics Are Related to Outcomes After Lung Volume Reduction Surgery

:Lung volume reduction surgery continues to have a high morbidity despite National Emphysema Treatment Trial selection criteria. This study evaluated the association between analytic morphomics on chest computed tomography scans and outcomes after lung volume reduction surgery. In a retrospective review of 85 lung volume reduction surgery patients from 1998-2013, dorsal muscle group area, subcutaneous and visceral fat area, and bone mineral density were assessed using analytic morphomics. Lung density was divided into five levels of increasing density (Lung density 1, emphysema; 2, normal lung; 4-5, scarring). Outcomes including survival, hospital length of stay, readmission at 30 days, and pulmonary complications were analyzed using univariate and multivariable techniques. Pulmonary complications developed in 27.1% (23/85). Mortality at 90 days was 9.4% (8/85). On multivariable analysis, lower bone mineral density (Odds ratio 0.61; 95% confidence interval 0.39-0.95) was associated with decreased survival, longer length of stay (0.83; 0.77-0.89), and readmissions (0.39; 0.15-1.00). Higher lung density 5:lung density 2 volume (1.84; 1.05-3.23), possibly due to scarring, was associated with pulmonary complications and longer length of stay (1.32; 1.23-1.41) while lower subcutaneous fat area:height was associated with readmissions which may reflect decreased metabolic reserve (0.35; 0.13-0.93). Patients with signs of frailty including lower bone mineral density may be at increased risk of adverse outcomes including decreased survival after lung volume reduction surgery. The results of this hypothesis-generating study will need to be confirmed in larger, multicenter trials to determine whether analytic morphomics can improve risk stratification and patient selection.

Prevalence of, and risk factors for underweight or excess weight in patients with chronic obstructive emphysema from a multiethnic region of Xinjiang, China

BACKGROUND

The purpose of this study is to assess the basic nutritional status (body metabolic index, BMI) and its risk factors in the patients suffering from chronic obstructive emphysema.

METHODS

We described their demographic characteristics and comorbidity distribution of 2812 obstructive emphysema participants. Comparative analyzes were conducted on BMI with different demographic characteristics and comorbidities status, and comprehensive analysis on risk factors of excess weight and underweight in patients with different characters.

RESULTS

The prevalence of underweight and excess weight was 17.57% and 31.54% respectively. There were differences in the distribution of three types of body mass index among patients with different demographic characteristics and different comorbidities. The study found that age of 50 ~ 64 (odds ratio, OR: 2.99), tuberculosis (OR: 2.41), and low TG (OR: 2.32) were the risk factors about underweight. Low HDL-C (OR: 4.15), nonalcoholic fatter liver (NAFLD) (OR: 3.96), and age of 50 ~ 64 (OR: 2.72) were closely related to the excess weight of participants.

CONCLUSIONS

This study highlighted the prevalence of underweight and excess weight in patients among emphysema. Comorbidities were important risk factors of underweight or excess weight among chronic emphysema patients. These findings were important for the prevention and treatment of chronic obstructive emphysema in the future.