The micro-structural analysis of lumbar vertebrae in alcoholic liver cirrhosis

Bone quality analysis of the mandible in alcoholic liver cirrhosis: Anatomical, microstructural, and microhardness evaluation

OBJECTIVES

Alcoholic bone disease has been recognized in contemporary literature as a systemic effect of chronic ethanol consumption. However, evidence about the specific influence of alcoholic liver cirrhosis (ALC) on mandible bone quality is scarce. The aim of this study was to explore microstructural, compositional, cellular, and mechanical properties of the mandible in ALC individuals compared with a healthy control group.

MATERIALS AND METHODS

Mandible bone cores of mаle individuаls with ALC (n = 6; age: 70.8 ± 2.5 yeаrs) and age-matched healthy controls (n = 11; age: 71.5 ± 3.8 yeаrs) were obtаined postmortem during аutopsy from the edentulous аlveolаr bone in the mandibular first molаr region аnd the mаndibulаr аngulus region of each individual. Micro-computed tomogrаphy wаs used to аssess bone microstructure. Analyses based on quаntitаtive bаckscаttered electron microscopy included the characterization of osteon morphology, osteocyte lаcunаr properties, and bone mаtrix minerаlizаtion. Composition of bone minerаl аnd collаgen phаses was assessed by Rаmаn spectroscopy. Histomorphometry wаs used to determine cellulаr аnd tissue chаrаcteristics of bone specimens. Vickers microhardness test was used to evaluate cortical bone mechanical properties.

RESULTS

The ALC group showed higher closed cortical porosity (volume of pores thаt do not communicаte with the sаmple surfаce) (p = 0.003) and smaller lacunar area in the trabecular bone of the molar region (p = 0.002) compared with the Control group. The trabecular bone of the angulus region showed lower osteoclast number (p = 0.032) in the ALC group. There were higher carbonate content in the buccal cortex of the molar region (p = 0.008) and lower calcium content in the trabecular bone of the angulus region (p = 0.042) in the ALC group. The cortical bone showed inferior mechanical properties in the ALC cortical bony sites (p < 0.001), except for the buccal cortex of the molar region (p = 0.063). There was no significant difference in cortical thickness between the groups.

CONCLUSIONS

Bone quality is differentially altered in ALC in two bony sites and compartments of the mandible, which leads to impaired mechanical properties.

CLINICAL RELEVANCE

Altered mandible bone tissue characteristics in patients with ALC should be considered by dental medicine professionals prior to oral interventions in these patients. Knowledge about mandible bone quality alterations in ALC is valuable for determining diagnosis, treatment plan, indications for oral rehabilitation procedures, and follow-up procedures for this group of patients.

Fabrication of hierarchically porous trabecular bone replicas via 3D printing with high internal phase emulsions (HIPEs)

Combining emulsion templating with additive manufacturing enables the production of inherently porous scaffolds with multiscale porosity. This approach incorporates interconnected porous materials, providing a structure that supports cell ingrowth. However, 3D printing hierarchical porous structures that combine semi-micropores and micropores remains a challenging task. Previous studies have demonstrated that using a carefully adjusted combination of light absorbers and photoinitiators in the resin can produce open surface porosity, sponge-like internal structures, and a printing resolution of about 150µm. In this study, we explored how varying concentrations of tartrazine (0, 0.02, 0.04, and 0.08 wt%) as a light absorber affect the porous structure of acrylate-based polymerized medium internal phase emulsions fabricated via vat photopolymerization. Given the importance of a porous and interconnected structure for tissue engineering and regenerative medicine, we tested cell behavior on these 3D-printed disk samples using MG-63 cells, examining metabolic activity, adhesion, and morphology. The 0.08 wt% tartrazine-containing 3D-printed sample (008 T) demonstrated the best cell proliferation and adhesion. To show that this high internal phase emulsion (HIPE) resin can be used to create complex structures for biomedical applications, we 3D-printed trabecular bone structures based on microCT imaging. These structures were further evaluated for cell behavior and migration, followed by microCT analysis after 60 days of cell culture. This research demonstrates that HIPEs can be used as a resin to print trabecular bone mimics using additive manufacturing, which could be further developed for lab-on-a-chip models of healthy and diseased bone.

Bone loss in chronic liver diseases: Could healthy liver be a requirement for good bone health?

Given that the liver is involved in many metabolic mechanisms, it is not surprising that chronic liver disease (CLD) could have numerous complications. Secondary osteoporosis and increased bone fragility are frequently overlooked complications in CLD patients. Previous studies implied that up to one-third of these individuals meet diagnostic criteria for osteopenia or osteoporosis. Recent publications indicated that CLD-induced bone fragility depends on the etiology, duration, and stage of liver disease. Therefore, the increased fracture risk in CLD patients puts a severe socioeconomic burden on the health system and urgently requires more effective prevention, diagnosis, and treatment measures. The pathogenesis of CLD-induced bone loss is multifactorial and still insufficiently understood, especially considering the relative impact of increased bone resorption and reduced bone formation in these individuals. It is essential to note that inconsistent findings regarding bone mineral density measurement were previously reported in these individuals. Bone mineral density is widely used as the “golden standard” in the clinical assessment of bone fragility although it is not adequate to predict individual fracture risk. Therefore, microscale bone alterations (bone microstructure, mechanical properties, and cellular indices) were analyzed in CLD individuals. These studies further support the thesis that bone strength could be compromised in CLD individuals, implying that an individualized approach to fracture risk assessment and subsequent therapy is necessary for CLD patients. However, more well-designed studies are required to solve the bone fragility puzzle in CLD patients.

The altered osteocytic expression of connexin 43 and sclerostin in human cadaveric donors with alcoholic liver cirrhosis: Potential treatment targets

Previous studies suggested that osteocyte lacunar network disruption could play a role in the complex pathophysiology of bone changes in aging and disease. Considering that particular research interest is lacking, we aimed to assess alcoholic liver cirrhosis (ALC)-induced changes in osteocyte lacunar network and bone marrow adiposity. Immunohistochemistry was conducted to assess changes in the micro-morphology of osteocyte lacunar network and bone marrow adiposity, and expression of connexin 43 and sclerostin in vertebral and femoral samples collected from 40 cadaveric men (age range between 44 and 70 years) divided into ALC group (n = 20) and control group (n = 20). Furthermore, the assessment of the potential association between bone changes and the severity of the hepatic disorder (given by Knodell's pathohistologic scoring) was conducted. Our data revealed fewer connexin 43-positive osteocytes per vertebral and femoral bone area (p < 0.01), suggesting defective signal transduction among osteocytes in ALC individuals. Moreover, we found an ALC-induced increase in the number of adipocytes in the vertebral bone marrow (p = 0.038). Considering significant associations between the severity of liver tissue disturbances and impaired functionality of osteocyte lacunar network (Pearson's correlation analyses, p < 0.05), we may assume that timely treatment of the liver disease may delay bone impairment. ALC induced an increase in osteocytic sclerostin expression (p < 0.001), suggesting its role in mediating low bone formation among ALC individuals. Hence, medicaments targeting low bone formation may be beneficial to attenuate the bone changes among ALC patients. However, future clinical studies are required to verify the therapeutic utility of these findings.

Bone Mineral Density, Bone Microarchitecture and Vertebral Fractures in Male Patients with Alcohol Use Disorders

AIM

To investigate abnormalities in bone mineral density, trabecular bone score and vertebral fractures in male patients with alcohol use disorder to understand the impact on bone health.

METHODS

The study subjects included 134 male patients. Controls were 134 age matched healthy males. Assessments were made of the bone mineral density (BMD), trabecular bone score (TBS) and vertebral morphometry (VFA) for vertebral fractures. Biochemical measurements included serum total T4, thyroid stimulating hormone (TSH), parathyroid hormone (PTH) and 25- Hydroxyvitamin D 25(OH) D.

RESULTS

The mean BMD at total forearm, proximal forearm (or distal 1/3) and mid forearm was significantly higher in the alcohol use disorders (AUD) group than the controls (P < 0.01). Around 15% of patients with AUD had VFs compared with 9.0% of the healthy controls (P = 0.19). For each kg/m2 gain in body mass index (BMI), lumbar spine and total hip BMD increased by 0.009 and 0.014 g/cm2, respectively. Lumbar and hip BMD decreased by 0.002 and 0.003 g/cm2 per year increase in duration of alcohol used. For every 5 years increase in age of the patients the odds of having VFs increased by 39% (odds ratio 1.393 [95% confidence interval = 1.031-1.881, P = 0.03]).

CONCLUSION

The findings of the current study suggest that persons with AUD in third and fourth decades of life, with BMI in normal range and with alcohol use disorder duration of around one decade might have no major alteration in BMD and TBS. Impact of alcohol use in this population was manifest by marginal increase in the prevalence of mild grade of vertebral fractures, mostly in the thoracic region.

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.

The comparison of age- and sex-specific alteration in pubic bone microstructure: A cross-sectional cadaveric study

BACKGROUND

The burden of age-associated fragility fracture of the pelvis has gradually amplified over the years. Commonly used clinical tools cannot fully explain age-associated fracture risk increase, and microstructural analysis could be required to elucidate pubic bone strength decline in elderly.

MATERIAL AND METHODS

The study sample encompassed 46 pubic bones obtained from cadaveric donors divided into a young women (<45 years, n = 11), aged women (>60 years, n = 11), young men (<45 years, n = 12) and aged men group (>60 years, n = 12). Micro-computed tomography was used to evaluate the cortical and trabecular microstructure of pubic bone samples.

RESULTS

Apart from age-associated loss in quantitative trabecular parameters, significant alteration of micro-CT parameters that more closely reflect internal trabecular microarchitectural complexity may contribute to pubic bone strength decline in men and women of advanced age (p < 0.05). Additionally, decreased cortical thickness and increased Ct.Po, Po.Dm and Po.N were found in the anterior and posterior cortical surface of pubic bone samples from the aged individuals (p < 0.05). The more pronounced alteration was noted in aged female donors, illustrated in a significant deterioration trend of the Tb.N, Tb.Sp, and thinner posterior cortical surface with decreased pore spacing (p < 0.05).

CONCLUSION

Our data suggest that age-associated deterioration in trabecular and cortical pubic bone micro-architecture could unravel a morphological basis for decreased pubic bone strength and increased pubic bone fragility, which leads to fracture predilection in the elderly women. Thus, the individual fracture risk assessment should be advised in the elderly, with a particular accent on aged women.

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.

Compromised bone strength in patients with alcoholic liver cirrhosis

Osteoporosis and/or osteopenia are frequently observed complications in alcoholic liver disease patients, especially in its irreversible stage (alcoholic liver cirrhosis - ALC). Current literature review regarding osteoporosis incidence increased fracture risk, bone mineral density changes, micro-structural alteration and pathogenetic mechanisms leading to ALC - induced decrease in bone quality is presented. It has been reported that osteoporosis is influenceing significant number of ALC patients, with particular accent on lumbar spine, as most commonly affected skeletal site. Several risk factors and ethio-pathogenic mechanisms have been associated with the loss of bone mineral density, in patients with ALC and other cirrhosis. Certain authors claim that dominant mechanism in ALC-induced bone loss is decrease in bone formation and osteoblastic function, while other results suggest increased bone remodeling as underlying cause of increased bone fragility in ALC patients. Increased bone fragility and susceptibility to osteoporotic fractures significantly affect life expectancy and quality of life in patients with ALC. Thus, osteological screening and individual fracture risk assessment are highly recommended for all patients with alcoholic liver cirrhosis.