ESPEN 2012 - Late breaking abstract submission

Topic: Late Breaking Abstract

Abs n°:ESPEN12-1944

Abs Title: EXTENSIVE TYPE II MUSCLE FIBER ATROPHY AND REDUCED SATELLITE CELL CONTENT IN ELDERLY WOMEN UNDERGOING SURGERY FOR FALL-RELATED HIP FRACTURES

I. F. Kramer ^{1 2,*}T. Snijders ²M. Poeze ¹L. B. Verdijk ²L. J. van Loon ²

¹Surgery, ²Human Movement Sciences, MAASTRICHT UNIVERSITY, Maastricht, Netherlands

Rationale: The incidence of hip fractures is rapidly increasing worldwide. The age-related loss of muscle mass (sarcopenia) forms an important risk factor for a fall-related hip fracture. We aimed to identify muscle fiber type-specific characteristics that may be predictive for falls and fractures in the frail elderly population.

Methods: Percutaneous needle biopsies were collected from the vastus lateralis muscle of 12 frail elderly women admitted with fall-related hip fractures (85±3 y), 12 healthy elderly women (73±2 y), and 12 young women (21±2 y). Immunohistochemical analyses were performed to assess muscle fiber type-specific size and satellite cell (SC) content.

Results: In all groups, type II muscle fiber size was smaller and  SC content was lower compared with type I muscle fibers (P<0.01). Type I muscle fiber size did not differ between groups. In contrast, type II muscle fiber size was significantly smaller in the hip fracture patients (2327±163 µm²) when compared with the healthy elderly (3348±263 µm²) and young (4460±364.4 µm²) controls (P<0.05). Type II muscle fiber SC content was significantly lower in the hip fracture patients compared with the healthy elderly controls (0.024±0.003 vs 0.051±0.007 SC per fiber, respectively; P<0.01). 

Conclusion: Frail elderly with fall-related hip fractures show extensive type II muscle fiber atrophy and a reduction in type II muscle fiber SC content. These type II muscle fiber specific changes are likely responsible for reduced muscle strength and functional capacity, increasing the risk of falling and sustaining a fracture. Exercise, nutritional, and/or pharmacological intervention strategies should specifically target type II muscle fiber atrophy to reduce the prevalence of fall-related fractures in this frail population.

Disclosure of Interest: None Declared

Keywords: Hip fracture elderlymuscle atrophy