Bone Microarchitecture Alterations and Inflammatory Cytokines in Chronic Hepatitis C

Overview

Chronic hepatitis C virus (HCV) infection is associated with significant reductions in trabecular and cortical bone volumetric density and cortical dimensions, alongside elevated tumor necrosis factor α (TNF-α) levels. These findings suggest that HCV-related inflammation contributes to skeletal fragility beyond traditional bone mineral density deficits.

Background

Chronic HCV infection is known to cause extrahepatic complications, including hepatic osteodystrophy characterized by low bone mineral density (BMD) and increased fracture risk. Traditional assessments using dual-energy x-ray absorptiometry (DXA) have limitations in distinguishing trabecular from cortical bone deficits. Inflammatory cytokines such as TNF-α, IL-6, and IL-18, elevated in chronic HCV, may impair bone formation and promote resorption, potentially explaining bone fragility. High-resolution peripheral quantitative computed tomography (HR-pQCT) offers detailed 3-dimensional evaluation of bone microarchitecture, enabling better understanding of HCV-associated skeletal changes.

Data Highlights

Key Findings

• Participants with chronic HCV had significantly lower trabecular volumetric BMD at the radius and tibia compared to those without HCV.
• Tibia cortical area and thickness were reduced in chronic HCV patients, indicating compromised cortical bone structure.
• Serum TNF-α levels were elevated in chronic HCV infection, whereas IL-6 and IL-18 levels showed no significant differences.
• Higher TNF-α levels correlated with lower trabecular and cortical volumetric BMD and increased cortical porosity, suggesting a role in bone degradation.
• These bone deficits were independent of age, sex, visceral fat, lean mass, and smoking status.

Clinical Implications

Clinicians should recognize that chronic HCV infection contributes to skeletal fragility through both trabecular and cortical bone deterioration, not solely via reduced BMD. Elevated TNF-α may serve as a biomarker and potential therapeutic target to mitigate bone loss in this population. Comprehensive bone health assessment using advanced imaging modalities like HR-pQCT may improve fracture risk stratification and guide management.

Conclusion

Chronic HCV infection is linked to significant alterations in bone microarchitecture and increased inflammatory cytokines, particularly TNF-α, which likely contribute to increased fracture risk. These findings highlight the importance of addressing inflammation-mediated bone loss in patients with chronic HCV.

References

1. Authors et al. 2024 -- Alterations in Trabecular and Cortical Bone Microarchitecture Linked to Chronic Hepatitis C Infection and Specific Inflammatory Cytokines