Osteoporosis across chronic liver disease

Clinical Indicators of Bone Deterioration in Alcoholic Liver Cirrhosis and Chronic Alcohol Abuse: Looking beyond Bone Fracture Occurrence

Although previous studies indicated that chronic alcohol abuse (CAA) and alcoholic liver cirrhosis (ALC) are associated with increased bone fragility, understanding bone fragility determinants is still modest in these individuals. We used a comprehensive individualized clinical fracture risk assessment approach (vertebral osteodensitometry, femoral osteodensitometry and geometry, and serum bone turnover biomarkers) to compare adult male patients with ALC who have not previously had femoral or vertebral fractures (n = 39), patients with CAA (without liver cirrhosis, n = 78) who have not previously had femoral or vertebral fractures and healthy age- and sex-matched controls (n = 43). Our data suggested that intertrochanteric bone mineral density was significantly lower in ALC and CAA patients than in controls. Also, the trabecular bone score was considerably lower in ALC patients compared with CAA and control individuals. The most significant inter-group differences in femoral geometry were noted on the femoral shaft. Patients with ALC and CAA have a higher 10-year risk of major osteoporotic fractures compared to the controls. Analysis of bone turnover biomarkers showed increased osteoprotegerin and beta-C-terminal telopeptide serum concentrations and decreased insulin growth factor-1 concentrations in patients with ALC compared to CAA and control groups. Our data revealed that bone alterations are present in patients with ALC and CAA even if they did not sustain a nontraumatic bone fracture, but it is also indicative that current bone-assessing clinical methods are not entirely reliable. Thus, future studies should focus on developing a reliable integrative clinical tool that can be used to accurately predict and prevent bone fracture occurrences in patients with ALC and CAA.

Increased Risk of Osteoporotic Fracture in Patients With Autoimmune Hepatitis

INTRODUCTION

Few large-scale studies have been published regarding the association between autoimmune hepatitis (AIH) and risk of osteoporotic fracture. This study aimed to determine the risk of developing an osteoporotic fracture in patients with AIH.

METHODS

We used claims data from the Korean National Health Insurance Service between 2007 and 2020. Patients with AIH (n = 7,062) were matched with controls (n = 28,122) based on age, sex, and duration of follow-up using a ratio of 1:4. Osteoporotic fractures included fractures of the vertebrae, hip, distal radius, and proximal humerus. The incidence rate (IR) and IR ratio of osteoporotic fracture were compared between the 2 groups, and their associated factors were evaluated.

RESULTS

During a median follow-up period of 5.4 years, 712 osteoporotic fractures occurred in patients with AIH with an IR of 17.5 per 1,000 person-years. Patients with AIH had a significantly higher risk of osteoporotic fractures than matched controls, with an IR ratio of 1.24 (95% confidence intervals, 1.10-1.39, P < 0.01) in the multivariable analysis. Female sex, older age, history of stroke, presence of cirrhosis, and use of glucocorticoids were associated with an increased risk of osteoporotic fractures. In the 2-year landmark analysis, longer duration of glucocorticoid exposure was associated with an incremental increased risk of osteoporotic fracture.

DISCUSSION

Patients with AIH had an increased risk of osteoporotic fracture compared with controls. The presence of cirrhosis and long-term use of glucocorticoids further adversely affected osteoporotic fracture in patients with AIH.

Advancements in the pathogenesis of hepatic osteodystrophy and the potential therapeutic of mesenchymal stromal cells

Hepatic osteodystrophy (HOD) is a metabolically associated bone disease mainly manifested as osteoporosis with the characteristic of bone loss induced by chronic liver disease (CLD). Due to its high incidence in CLD patients and increased risk of fracture, the research on HOD has received considerable interest. The specific pathogenesis of HOD has not been fully revealed. While it is widely believed that disturbance of hormone level, abnormal secretion of cytokines and damage of intestinal barrier caused by CLD might jointly affect the bone metabolic balance of bone formation and bone absorption. At present, the treatment of HOD is mainly to alleviate the bone loss by drug treatment, but the efficacy and safety are not satisfactory. Mesenchymal stromal cells (MSCs) are cells with multidirectional differentiation potential, cell transplantation therapy based on MSCs is an emerging therapeutic approach. This review mainly summarized the pathogenesis and treatment of HOD, reviewed the research progress of MSCs therapy and the combination of MSCs and scaffolds in the application of osteoporotic bone defects, and discussed the potential and limitations of MSCs therapy, providing theoretical basis for subsequent studies.

SIRT2 regulates extracellular vesicle-mediated liver-bone communication

The interplay between liver and bone metabolism remains largely uncharacterized. Here, we uncover a mechanism of liver-bone crosstalk regulated by hepatocyte SIRT2. We demonstrate that hepatocyte SIRT2 expression is increased in aged mice and elderly humans. Liver-specific SIRT2 deficiency inhibits osteoclastogenesis and alleviates bone loss in mouse models of osteoporosis. We identify leucine-rich α-2-glycoprotein 1 (LRG1) as a functional cargo in hepatocyte-derived small extracellular vesicles (sEVs). In SIRT2-deficient hepatocytes, LRG1 levels in sEVs are upregulated, leading to increased transfer of LRG1 to bone-marrow-derived monocytes (BMDMs), and in turn, to inhibition of osteoclast differentiation via reduced nuclear translocation of NF-κB p65. Treatment with sEVs carrying high levels of LRG1 inhibits osteoclast differentiation in human BMDMs and in mice with osteoporosis, resulting in attenuated bone loss in mice. Furthermore, the plasma level of sEVs carrying LRG1 is positively correlated with bone mineral density in humans. Thus, drugs targeting hepatocyte-osteoclast communication may constitute a promising therapeutic strategy for primary osteoporosis.

Osteoporosis remission via an anti-inflammaging effect by icariin activated autophagy

The pace of bone formation slows down with aging, which leads to the development of osteoporosis. In addition to senescent bone marrow mesenchymal stem cells (S-BMSCs), senescent macrophages (S-MΦs) present in the bone marrow produce numerous inflammatory cytokines that contribute to the inflammaged microenvironment and are involved in the development of osteoporosis. Although autophagy activation has shown a significant anti-aging effect, its influence on inflammaging and its role in osteoporosis treatment remain unclear. Traditional Chinese herbal medicine contains bioactive components that exhibit remarkable advantages in bone regeneration. We have demonstrated that icariin (ICA), a bioactive component of traditional Chinese herbal medicine, activates autophagy, exerts a significant anti-inflammaging effect on S-MΦs, and rejuvenates osteogenesis of S-BMSCs, thereby alleviating bone loss in osteoporotic mice. The transcriptomic analysis further reveals that the TNF-α signaling pathway, which is significantly associated with the level of autophagy, regulates this effect. Moreover, the expression of senescence-associated secretory phenotype (SASP) is significantly reduced after ICA treatment. In summary, our findings suggest that bioactive components/materials targeting autophagy can effectively modulate the inflammaging of S-MΦs, offering an innovative treatment strategy for osteoporosis remission and various age-related comorbidities.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Defects in a liver-bone axis contribute to hepatic osteodystrophy disease progression

Hepatic osteodystrophy (HOD) is a metabolic bone disease that is often associated with chronic liver disease and is marked by bone loss. Here, we demonstrate that hepatic expression of the phosphatase PP2Acα is upregulated during HOD, leading to the downregulation of expression of the hepatokine lecithin-cholesterol acyltransferase (LCAT). Loss of LCAT function markedly exacerbates the bone loss phenotype of HOD in mice. In addition, we found that alterations in cholesterol levels are involved in the regulation of osteoblast and osteoclast activities. We also found that LCAT improves liver function and relieves liver fibrosis in the mouse HOD model by promoting reversal of cholesterol transport from the bone to the liver. In summary, defects in a liver-bone axis occur during HOD that can be targeted to ameliorate disease progression.

RISK FACTORS ASSOCIATED WITH FRACTURE OF THE LUMBOSACRAL SPINE AND ITS COMPROMISE IN THE QUALITY OF LIFE OF CIRRHOTICS

ABSTRACT Background Chronic hepatic disease is associated with osteoporosis, osteopenia or osteomalacia. Osteoporosis and fractures due to bone fragility present high prevalences and are more frequent in patients with liver cirrhosis than in the general population. The search for a diagnosis of osteopenia and osteoporosis in this population may allow early intervention and modify unfavorable outcomes. Objective To know the prevalence of osteopenia or osteoporosis and of fracture due to bone fragility in individuals with liver cirrhosis, the associated risk factors, and its compromise in their quality of life (QoL). Methods Observational, transversal study performed with 71 liver cirrhosis patients of the Hepatology Service of the Hospital de Base do Distrito Federal, Brasília, DF, Brazil, between July 2017 and December 2018. The patients were submitted to bone densitometry (DXA) of the lumbar spine and of the femoral neck, to x-ray of the lumbosacral spine and to the Chronic Liver Disease Questionnaire (CLDQ) for the evaluation of quality of life (QoL). The Fracture Risk Assessment (FRAX) major was calculated for patients >50 years old. The analyses were performed for the evaluation of the risk factors associated with lumbosacral spine fracture. Results The majority (62%) of the 71 evaluated patients was diagnosed with osteoporosis or osteopenia on DXA. Of the 44 patients with osteopenia or osteoporosis, 52.3% were female, with a mean age of 62.6±9.51 years old, with the majority (72.7%) being Child A, cirrhotics of alcoholic etiology (36.4%), and with an intermediate QoL according to the CLDQ (3.3). Regarding the patients with lumbosacral spine fracture, the mean age was 61.6±11.1 years old, 60% were female, most of them Child A (66.7%), of alcoholic etiology (46.7%), and with an intermediary QoL according to the CLDQ (3.5). The presence of osteopenia and/or osteoporosis was associated with lumbosacral fracture (P<0.001), without correlation with the other analyzed variables: age, body mass index, gender, presence and absence of ascites, Child-Pugh classification, vitamin D, calcium, and phosphorus serum concentration, cirrhosis etiology and FRAX major. Conclusion The prevalence of hepatic osteodystrophy was high, and the occurrence of lumbosacral spine fracture was more associated with osteoporosis and/or osteopenia among the cirrhotic patients studied. The QoL was intermediate and with no differences between cirrhotics with and without fracture.

Aging Men With Insufficient Vitamin D Have a Higher Mortality Risk: No Added Value of its Free Fractions or Active Form

CONTEXT

Low total 25-hydroxyvitamin D (25(OH)D) has been associated with mortality. Whether vitamin D in its free form or 1,25-dihydroxyvitamin D (1,25(OH)2D), provide any additional information is unclear.

OBJECTIVE

To determine what level of 25(OH)D is predictive for mortality and if free 25(OH)D or 1,25(OH) 2 D concentrations have any added value.

METHODS

This prospective cohort comprised 1915 community-dwelling men, aged 40 to 79 years. Intervention included determination of association of total and free 25(OH)D and 1,25(OH) 2 D concentrations with survival status. Vitamin D results were grouped into quintiles. For total 25(OH)D, specific cutoff values were also applied. Cox proportional hazard models were used adjusted for center, body mass index, smoking, alcohol, physical activity, season of blood sample, kidney function, and number of comorbidities.

RESULTS

A total of 469 (23.5%) men died during a mean follow-up of 12.3 ± 3.4 years. Compared to those with normal vitamin D values (> 30 µg/L), men with a total 25(OH)D of less than 20 µg/L had an increased mortality (hazard ratio [HR] 2.03 [95% CI, 1.39-2.96]; P < .001). Likewise, men in the lowest 3 free 25(OH)D quintiles (< 4.43 ng/L) had a higher mortality risk compared to the highest quintile (HR 2.09 [95% CI, 1.34-3.25]; P < .01). Mortality risks were similar across all 1,25(OH)2D and vitamin D binding protein quintiles.

CONCLUSION

Aging men with vitamin D deficiency have a 2-fold increased mortality risk. Determinations of either the free fractions of vitamin D or measurement of its active form offer no additional information on mortality risks.

Mechano-structural alteration in proximal femora of individuals with alcoholic liver disease: Implications for increased bone fragility

Although increased hip fracture risk is noted in patients with alcoholic liver disease (ALD), their femoral microstructural and mechanical properties were not investigated previously. The present study aimed to analyze the associations between subregional deteriorations in femoral mechano-structural properties and clinical imaging findings to explain increased femoral fracture risk among ALD patients. This study analyzed proximal femora of 33 male cadaveric donors, divided into ALD (n = 13, 57 ± 13 years) and age-matched control group (n = 20, 54 ± 13 years). After pathohistological verification of ALD stage, DXA and HSA measurements of the proximal femora were performed, followed by micro-CT and Vickers microindentation of the superolateral neck, inferomedial neck, and intertrochanteric region. Bone mineral density and cross sectional area of the femoral neck were deteriorated in ALD donors, compared with healthy controls (p < 0.05). Significant ALD-induced degradation of trabecular and cortical microstructure and Vickers microhardness reduction were noted in the analyzed femoral regions (p < 0.05). Still, the most prominent ALD-induced mechano-structural deterioration was noted in intertrochanteric region. Additionally, more severe bone alterations were observed in individuals with an irreversible stage of ALD, alcoholic liver cirrhosis (ALC), than in those with an initial ALD stage, fatty liver disease. Observed osteodensitometric and mechano-structural changes illuminate the basis for increased femoral fracture risk in ALD patients. Additionally, our data suggest bone strength reduction that may result in increased susceptibility to intertrochanteric femoral fracture in men with ALD. Thus, femoral fracture risk assessment should be advised for all ALD patients, especially in those with ALC.

Hepatocrinology

Hepatocrinology is defined as a bidirectional, complex relationship between hepatic physiology and endocrine function, hepatic disease and endocrine dysfunction, hepatotropic drugs and endocrine function, and endocrine drugs and hepatic health. The scope of hepatocrinology includes conditions of varied etiology (metabolic, infectious, autoimmune, and invasive) that we term as hepato-endocrine syndromes. This perspective shares the definition, concept, and scope of hepatocrinology and shares insight related to this aspect of medicine. It is hoped that this communication will encourage further attention and research in this critical field.

An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia

The prevalence of osteoporosis and sarcopenia is significantly higher in patients with liver disease than in those without liver disease and osteoporosis and sarcopenia negatively influence morbidity and mortality in liver disease, yet these musculoskeletal disorders are frequently overlooked in clinical practice for patients with chronic liver disease. The objective of this review is to provide a comprehensive understanding of the molecular mechanisms of musculoskeletal disorders accompanying the pathogenesis of liver disease. The increased bone resorption through the receptor activator of nuclear factor kappa (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) system and upregulation of inflammatory cytokines and decreased bone formation through increased bilirubin and sclerostin and lower insulin-like growth factor-1 are important mechanisms for osteoporosis in patients with liver disease. Sarcopenia is associated with insulin resistance and obesity in non-alcoholic fatty liver disease, whereas hyperammonemia, low amount of branched chain amino acids, and hypogonadism contributes to sarcopenia in liver cirrhosis. The bidirectional crosstalk between muscle and bone through myostatin, irisin, β-aminoisobutyric acid (BAIBA), osteocalcin, as well as the activation of the RANK and the Wnt/β-catenin pathways are associated with osteosarcopenia. The increased understandings for these musculoskeletal disorders would be contributes to the development of effective therapies targeting the pathophysiological mechanism involved.

The severity of hepatic disorder is related to vertebral microstructure deterioration in cadaveric donors with liver cirrhosis

Patients with liver cirrhosis (LC) commonly suffer from osteoporosis and vertebral fracture, but data about their vertebral micro-architectural changes are still limited. This study aimed to evaluate the potential differences in trabecular micro-architecture of lumbar vertebrae between male LC patients and healthy controls, in relation to etiology and pathohistological scoring of the liver disorder. After pathohistological examination of liver tissue, micro-computed tomography was performed on the vertebral samples included into: alcoholic liver cirrhosis group (ALC; n = 16; age: 59 ± 8 years), non-alcoholic liver cirrhosis group (non-ALC; n = 15; age: 69 ± 10 years) and control group (n = 16; age: 58 ± 6 years). Our data showed significant impairment of the trabecular microstructure in the lumbar vertebrae from LC donors, regardless of the alcoholic/non-alcoholic origin of liver disorder, as illustrated by lower BV/TV, Tb.Th, and Tb.N compared with controls (p < .05). Moreover, depredation in trabecular micro-architecture was inversely associated with pathohistological scores (p < .05), indicating that severity of liver disorder could be an important predictor of reduced vertebral strength in LC. We noticed significant micro-architectural deterioration in the trabecular compartment of the lumbar vertebrae of male individuals with alcoholic and non-alcoholic LC, which was associated with the severity of the liver disease. Thus, clinical assessment of fracture risk should be advised for all LC patients, regardless of the alcoholic origin of liver cirrhosis. Additionally, adequate and timely treatment of liver disorder may decelerate the progression of bone impairment in LC patients.

Bone mineral density and trabecular bone score in treatment-naïve patients with non-cirrhotic hepatitis C virus infection

We studied 112 treatment-naïve chronic HCV patients without cirrhosis, and we found that, especially HCV+ postmenopausal women, they had lower TBS and BMD values than healthy controls. This suggests that HCV infection is an independent risk factor for osteoporosis, and therefore, screening for osteoporosis in postmenopausal HCV+ women should be considered.

PURPOSE

To know whether patients in earlier stages of chronic HCV infection are at increased risk of developing low bone mass and bone microarchitectural changes and whether there is an association between bone metabolism and the severity of the liver disease.

METHODS

We studied 112 treatment-naïve chronic HCV outpatients and 233 healthy age- and sex-matched controls. Bone mineral density (BMD) and trabecular bone score (TBS) were assessed by DXA. Serum 25(OH)D, PTH, P1NP, and CTX were determined by electrochemiluminescence.

RESULTS

TBS values were significantly lower in HCV patients than in controls, both considering the population as a whole (1.337 ± 0.119 vs. 1.377 ± 0.122; p < 0.005) and after stratifying by sex (1.347 ± 0.12 vs. 1.381 ± 0.13 in men and 1.314 ± 0.10 vs. 1.369 ± 0.11 in women). The difference remained significant (p < 0.0001 in all cases) after adjusting for confounders. BMD was also lower in HCV patients (lumbar spine, 0.935 ± 0.151 vs. 0.991 ± 0.143 g/cm², p 0.001; femoral neck, 0.764 ± 0.123 vs. 0.818 ± 0.123 g/cm², p 0.0001; total hip, 0.926 ± 0.148 vs. 0.963 ± 0.132 g/cm², p 0.02), although, after adjustment, differences kept a clear trend towards statistical significance in women at the lumbar spine and femoral neck. However, in men and at the total hip in women, differences were no longer significant. We find no relationship between these parameters and the severity of the disease. No significant difference was observed in PTH and 25OHD status after adjustment. Finally, serum P1NP, but not CTX, was higher in HCV patients.

CONCLUSIONS

Our findings suggest that HCV infection is an independent risk factor for osteoporosis, especially among postmenopausal women. Therefore, the appropriateness of screening for osteoporosis in postmenopausal HCV-positive women should be considered.

Risk factors associated with hepatic osteopathy in HBV related cirrhosis measured by liver stiffness: An Observational study

To investigate the differences in bone mineral density between patients with liver cirrhosis and healthy control, and to analyze the risk factors of hepatic osteoporosis in patients with HBV related liver cirrhosis.A total of 189 patients with liver cirrhosis and 207 health controls were enrolled. The bone mineral density of lumbar spine and femoral neck was examined by dual energy X-ray absorptiometry. -2.0 <T value <-1.0 defined as osteopenia, T value ≤-2.0 defined as osteoporosis.Bone mineral density in the cirrhotic group was significantly lower than that in the control group (lumbar: 1.02 ± 0.16 vs 1.08 ± 0.13, P < .001; femoral neck: 0.86 ± 0.14 vs 0.91 ± 0.14, P < .001). Both 2 groups showed a tendency that decrease bone density correlated with age and decrease body mass index (BMI). Multivariate correlation analysis showed that women (OR = 6.931, P = .002), age (OR = 1.096, P < .001), low BMI (OR = 0.874, P = .037), and high liver stiffness value (OR = 1.125, P = .046) were independent risk factors for osteopenia and low body weight (OR = 0.934, P = .006) and high liver stiffness value (OR = 1.246, P = .034) were independent risk factors for osteoporosis.Our study shows that bone mineral density in patients with liver cirrhosis decreased significantly, especially in the elderly and low BMI patient. For HBV-related cirrhosis with risk factors, a regular bone density screening should be given, and timely intervention should be taken into consideration.

Bone microarchitecture and bone turnover in hepatic cirrhosis

Liver cirrhosis leads to bone loss. To date, information on bone quality (three-dimensional microarchitecture) and, thus, bone strength is scarce. We observed decreased bone quality at both assessed sites, independent of disease severity. Therefore, all patients should undergo early-stage screening for osteoporosis.

INTRODUCTION

Recent studies found low bone mineral density in cirrhosis, but data on bone microstructure are scarce. This study assessed weight-bearing and non-weight-bearing bones in patients with cirrhosis and healthy controls. The primary objective was to evaluate trabecular and cortical microarchitecture.

METHODS

This was a single-center study in patients with recently diagnosed hepatic cirrhosis. Thirty-two patients and 32 controls participated in this study. After determining the type of cirrhosis, the parameters of bone microarchitecture were assessed by high-resolution peripheral quantitative computed tomography.

RESULTS

Both cortical and trabecular microarchitectures showed significant alterations. At the radius, trabecular bone volume fraction was 17% lower (corrected p = 0.028), and, at the tibia, differences were slightly more pronounced. Trabecular bone volume fraction was 19% lower (p = 0.024), cortical bone mineral density 7% (p = 0.007), and cortical thickness 28% (p = 0.001), while cortical porosity was 32% higher (p = 0.023), compared to controls. Areal bone mineral density was lower (lumbar spine - 13%, total hip - 11%, total body - 9%, radius - 17%, and calcaneus - 26%). There was no correlation between disease severity and microarchitecture. Areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) correlated well with parameters of cortical and trabecular microarchitecture.

CONCLUSIONS

Hepatic cirrhosis deteriorates both trabecular and cortical microarchitecture, regardless of disease severity. Areal bone mineral density is diminished at all sites as a sign of generalized affection. In patients with hepatic cirrhosis, regardless of its origin or disease severity, aBMD measurements are an appropriate tool for osteologic screening.

Hepatic Osteodystrophy-Molecular Mechanisms Proposed to Favor Its Development

Almost all patients with chronic liver diseases (CLD) show altered bone metabolism. Depending on the etiology, this manifests in a severe osteoporosis in up to 75% of the affected patients. Due to high prevalence, the generic term hepatic osteodystrophy (HOD) evolved, describing altered bone metabolism, decreased bone mineral density, and deterioration of bone structure in patients with CLD. Once developed, HOD is difficult to treat and increases the risk of fragility fractures. Existing fractures affect the quality of life and, more importantly, long-term prognosis of these patients, which presents with increased mortality. Thus, special care is required to support the healing process. However, for early diagnosis (reduce fracture risk) and development of adequate treatment strategies (support healing of existing fractures), it is essential to understand the underlying mechanisms that link disturbed liver function with this bone phenotype. In the present review, we summarize proposed molecular mechanisms favoring the development of HOD and compromising the healing of associated fractures, including alterations in vitamin D metabolism and action, disbalances in transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signaling with histone deacetylases (HDACs) as secondary regulators, as well as alterations in the receptor activator of nuclear factor kappa B ligand (RANKL)–osteoprotegerin (OPG) system mediated by sclerostin. Based on these mechanisms, we give an overview on the limitations of early diagnosis of HOD with established serum markers.

The association between hepatitis and osteoporosis: a nested case-control study using a national sample cohort

The prevalence of hepatitis B was higher in osteoporosis patients than the control group, especially in females. However, the prevalence of hepatitis C was not different. The matching for various factors improved to have same conditions between osteoporosis patients and the control group.

PURPOSE

Although chronic liver disease, including hepatitis B and hepatitis C, has been associated with osteoporosis in previous studies, the evidence was insufficient, and some findings were inconsistent. The aim of this study was to evaluate the relationship between hepatitis B or hepatitis C and osteoporosis.

METHODS

We used the Korean National Health Insurance Service-National Sample Cohort with ≥ 50-year-old participants from 2002 to 2013. Age was determined at osteoporosis diagnosis. We extracted 68,492 osteoporosis patients (ICD-10 codes E7001-E7004, HC341-HC345) with a 68,492-member control group at a ratio of 1:1 by age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia. We analyzed previous histories of hepatitis B (ICD-10 codes B18.0-B18.1) and hepatitis C (ICD-10 code B18.2) in the osteoporosis patients and control groups. The logistic regression with the crude and adjusted model was analyzed. Additionally, subgroup analyses divided by age and sex were performed.

RESULTS

The adjusted odds ratios for hepatitis B and hepatitis C were 1.19 (95% confidence interval (CI) = 1.11-1.28, P < 0.001) and 1.04 (95% CI = 0.90-1.19, P > 0.05), respectively, in osteoporosis patients. Subgroup analyses showed that the risk of hepatitis B was higher in osteoporosis patients in female groups but not in male groups.

CONCLUSION

Hepatitis B virus infection might be a risk factor for osteoporosis.

Suboptimal Level of Bone-Forming Cells in Advanced Cirrhosis are Associated with Hepatic Osteodystrophy

Bone loss is common in advanced cirrhosis, although the precise mechanisms underlying bone loss in cirrhosis are unknown. We studied the profile and functionality of bone-forming cells and bone-building proteins in bone marrow (BM) of individuals with cirrhosis (n = 61) and individuals without cirrhosis as normal controls (n = 50). We also performed dual energy X-ray absorptiometry for clinical correlation. BM mesenchymal cells (MSCs) were analyzed for colony-forming units-fibroblasts and their osteogenic (fibronectin-1 [FN1], insulin-like growth factor binding protein 3 [IGFBP3], collagen type 1 alpha 1 chain [COL1A1], runt-related transcription factor 2 [RUNX2], and alkaline phosphatase, liver [ALPL]) and adipogenic ( adiponectin, C1Q, and collagen domain containing [ADIPOQ], peroxisome proliferator-activated receptor gamma [PPARγ], and fatty acid binding protein 4 [FABP4]) potentials. Colony-forming units-fibroblasts were lower in patients with cirrhosis (P = 0.002) than in controls. Cirrhotic BM-MSCs showed >2-fold decrease in osteogenic markers. Compared to controls, patients with cirrhosis showed fewer osteocytes (P = 0.05), osteoblasts, chondroblasts, osteocalcin-positive (osteocalcin+) area, clusters of differentiation (CD)169+ macrophages (P < 0.001, each), and nestin+ MSCs (P = 0.001); this was more apparent in Child-Turcotte-Pugh (CTP) class C than A (P < 0.001). Multivariate logistic regression showed low nestin+ MSCs (P = 0.004) as a predictor of bone loss. Bone-resolving osteoclasts were comparable among CTP groups, but >2-fold decreased anti-osteoclastic and increased pro-osteoclastic factors were noted in patients with CTP C compared to CTP A. Bone-building proteins (osteocalcin [P = 0.008], osteonectin [P < 0.001], and bone morphogenic protein 2 [P = 0.001]) were decreased while anti-bone repair factors (fibroblast growth factor 23 [P = 0.015] and dipeptidyl peptidase 4 [P < 0.001]) were increased in BM and peripheral blood; this was more apparent in advanced cirrhosis. The dual energy X-ray absorptiometry scan T score significantly correlated with the population of osteoblasts, osteocytes, MSCs, and CD169+ macrophages. Conclusion: Osteoprogenitor cells are substantially reduced in patients with cirrhosis and more so in advanced disease. Additionally, increased anti-bone repair proteins enhance the ineffective bone repair and development of osteoporosis in cirrhosis. Hepatology Communications 2018;0:0-0).

Risk factors for osteoporosis in liver cirrhosis patients measured by transient elastography

Osteoporosis or osteopenia is a common complication in patients with cirrhosis, but little is known about the risk factors for the occurrence of osteoporosis.Patients with liver cirrhosis due to chronic virus infection and alcoholic abuse were enrolled. Bone mineral density (BMD) was determined using dual-energy x-ray absorptiometry (DXA). Osteoporosis was diagnosed according to WHO criteria. The severity of liver stiffness was measured by Fibroscan. Demographic data, such as age, gender, weight, height, and body mass index (BMI), were collected. Logistic regression analysis was used to recognize the risk factors of osteoporosis in patients with cirrhosis.A total of 446 patients were included in this study: 217 had liver cirrhosis (male, 74.2%; mean age, 57.2 ± 10.27) and 229 were matched controls (male, 69%, mean age, 56.69 ± 9.37). Osteoporosis was found in 44 patients (44/217, 20.3%). The spine and hip BMD in cirrhotic patients were significantly lower than that in controls. When the cirrhotic and control subjects were stratified by age, gender, and BMI, the significant difference was also observed in women patients, patients older than 60, and patients with BMI < 18. Multivariate analysis showed that the older age [odds ratio (OR) = 1.78, P = .046], lower BMI (OR = 0.63, P = .049), greater fibroscan score (OR = 1.15, P = .009), and liver cirrhosis induced by alcohol liver disease (OR = 3.42, P < .001) were independently associated with osteoporosis in cirrhotic patients.Osteoporosis occurred in about one-fifth of patients with liver cirrhosis, which was associated with age, BMI, Fibroscan score, and alcohol liver disease related liver cirrhosis.

The epidemiology of wrist fractures in older men: the Osteoporotic Fractures in Men (MrOS) study

There is limited wrist fracture information on men. Our goal was to calculate frequency and identify risk factors for wrist fracture in the Osteoporotic Fractures in Men (MrOS) study. We confirmed that fracture history and certain medications are predictors, and identified novel predictors including markers of kidney function and physical performance.

INTRODUCTION

To calculate the incidence of wrist fractures and their risk factors in older community-dwelling men from the US Osteoporotic Fractures in Men (MrOS) study.

METHODS

Using triannual postcards, we identified incident wrist fractures (centrally confirmed by radiology) in men aged ≥ 65. Potential risk factors included the following: demographics, lifestyle, bone mineral density (BMD), selected medications, biomarkers, and physical function and performance measures. Both baseline and time-varying models were adjusted for age, race/ethnicity, MrOS geographic location, and competing mortality risks.

RESULTS

We observed 97 incident wrist fractures among 5875 men followed for an average of 10.8 years. The incidence of wrist fracture was 1.6 per 1000 person-years overall and ranged from 1.0 among men aged 65-69 to 2.4 among men age ≥ 80. Significant predictors included the following: fracture history after age 50 [hazard ratio (95% CI): 2.48 (1.65, 3.73)], high serum phosphate [1.25 (1.02, 1.53)], use of selective serotonin receptor inhibitor (SSRI) [3.60 (1.96, 6.63), decreased right arm BMD [0.49 (0.37, 0.65) per SD increase], and inability to perform the grip strength test [3.38 (1.24, 9.25)]. We did not find associations with factors commonly associated with wrist and other osteoporosis fractures like falls, diabetes, calcium and vitamin D intake, and alcohol intake.

CONCLUSIONS

Among these older, community-dwelling men, we confirmed that fracture history is a strong predictor of wrist fractures in men. Medications such as SSRIs and corticosteroids also play a role in wrist fracture risk. We identified novel risk factors including kidney function and the inability to perform the grip strength test.

The relationship between fatty liver index and bone mineral density in Koreans: KNHANES 2010-2011

Analyses using a nationally representative cohort have revealed that high fatty liver index (FLI) is associated with low bone mineral density (BMD) regardless of insulin resistance in men, thereby supporting the deteriorated bone metabolism in nonalcoholic fatty liver disease (NAFLD).

INTRODUCTION

NAFLD is linked to deteriorated bone health. We investigated the association of FLI, a scoring model for NAFLD, with BMD.

METHODS

This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys including 4264 Koreans (1908 men and 2356 women). FLI was calculated using body mass index, waist circumference, serum triglyceride, and gamma-glutamyltranspeptidase level. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index. BMD was measured using dual-energy X-ray absorptiometry at the lumbar spine, total hip, femoral neck, and whole body.

RESULTS

Men had a higher FLI than women, while the HOMA-IR index was similar between men and women. The significant association between FLI and BMD was observed only in men, but not in women. FLI was negatively correlated with total hip, femoral neck, and whole body BMD in men after adjusting for all potential confounders, including HOMA-IR (P < 0.001 to 0.010). Lumbar spine, total hip, femoral neck, and whole body BMD in men showed a decreasing trend as the FLI tertile increased after adjusting for all potential confounders, including HOMA-IR (P for trends < 0.001 to 0.034). In men aged 50 years or older, odds ratios for combined osteopenia and osteoporosis increased across increasing FLI tertiles after adjusting for confounders (P for trends < 0.011 to 0.029).

CONCLUSION

NAFLD is associated with low bone density regardless of insulin resistance in men. These findings suggest an undiscovered direct link between liver and bone that increases the risk of osteoporosis in men with NAFLD.

Current Controversies: Are Free Vitamin Metabolite Levels a More Accurate Assessment of Vitamin D Status than Total Levels?

The free hormone hypothesis postulates that only the nonbound fraction (the free fraction) of hormones that otherwise circulate in blood bound to their carrier proteins is able to enter cells and exert their biologic effects. For the vitamin D metabolites less than 1% (0.4% for 1,25(OH)₂D and 0.03% for 25(OH)D) is free, with more than 99% bound to the vitamin D binding protein (DBP) and albumin (approximately 85% and 15%, respectively). Assays to measure the free vitamin D metabolite levels have been developed, and initial studies indicated their value in subjects with altered DBP levels.

miRNAs in bone tissue correlate to bone mineral density and circulating miRNAs are gender independent in osteoporotic patients

We previously demonstrated the aberrant expression of nine specific miRNAs in serum from osteoporotic patients. In the present study, we further evaluated the expression of these miRNAs in bone tissue, osteoblasts, and osteoclasts from 28 patients. We hypothesize that miRNA expression in serum from osteoporotic patients may be gender-independent. A further hypothesis is that the miRNA expression in bone could be correlated with BMD values. Moreover, intracellular expression of these osteoporosis-related miRNAs may indicate the role of these molecules during osteoporosis. Our results indeed show that miRNA expression in serum was gender-independent except for miR125b-5p. A correlation with BMD was confirmed for miR-21-5p, miR-24-3p, miR-93-5p, miR-100-5p and miR125b-5p with linear correlation coefficients r > 0.9. Intracellular studies revealed a simultaneous up-regulation of miR-21-5p, miR-93-5p, miR-100-5p and miR125b-5p in osteoblasts and in osteoclasts. miR-148a-3p up-regulation in cells was specific for osteoporotic osteoclasts. Altogether, miR-21-5p, miR-93-5p, miR-100-5p, and miR-125b-5p showed significant upregulation in serum, tissue and bone cells of osteoporotic patients. All except miR-125b-5p showed gender independent expression and good correlation to BMD values. Our results suggest that these miRNAs may be important for an earlier diagnosis of osteoporosis.

Vitamin D metabolites in captivity? Should we measure free or total 25(OH)D to assess vitamin D status?

There is general consensus that serum 25(OH)D is the best biochemical marker for nutritional vitamin D status. Whether free 25(OH)D would be a better marker than total 25(OH)D is so far unclear. Free 25(OH)D can either be calculated based on the measurement of the serum concentrations of total 25(OH)D, vitamin D-binding protein (DBP), albumin, and the affinity between 25(OH)D and its binding proteins in physiological situations. Free 25(OH)D can also be measured directly by equilibrium dialysis, ultrafitration or immunoassays. During the vitamin D workshop held in Boston in March 2016, a debate was organized about the measurements and clinical value of free 25(OH)D, and this debate is summarized in the present manuscript. Overall there is consensus that most cells apart from the renal tubular cells are exposed to free rather than to total 25(OH)D. Therefore free 25(OH)D may be highly relevant for the local production and action of 1,25(OH)₂D. During the debate it became clear that there is a need for standardization of measurements of serum DBP and of direct measurements of free 25(OH)D. There seems to be very limited genetic or racial differences in DBP concentrations or (probably) in the affinity of DBP for its major ligands. Therefore, free 25(OH)D is strongly correlated to total 25(OH)D in most normal populations. Appropriate studies are needed to define the clinical implications of free rather than total 25(OH)D in normal subjects and in disease states. Special attention is needed for such studies in cases of abnormal DBP concentrations or when one could expect changes in its affinity for its ligands.