8:00 am - 9:00 am
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Amber Hager. This seminar is open to the general public to attend.
Zoom Link: https://ualberta-ca.zoom.us/j/97226330461?pwd=M2IwQU1LYUtOV3dtY0lSRUJkT0ZoZz09
MSc with Dr. Diana Mager
Thesis Topic: Skeletal muscle biopsy and exercise rehabilitation in children with end-stage liver disease pre-and post-liver transplantation
Abstract:
Background: Sarcopenia, or muscle wasting (myopenia) with deficits in muscle strength/muscle function is common in children pre-and post-transplantation (LTx). Changes in skeletal muscle characteristics (fibre types, size, myocellular lipids) may be informative of the underlying physiological determinants related to sarcopenia etiology and rehabilitation. Resistance training (RT) has been shown to positively influence muscle regeneration/synthesis.
Objectives: The thesis objectives were to 1) describe skeletal muscle characteristics in children undergoing LTx and 2) to study the effect of a 12-week RT program on muscle mass and function in children after LTx.
Methods: At LTx muscle fibre types, size, location of nuclei, and triglyceride content were determined from muscle biopsies of the rectus abdominus muscle. Post-LTx and healthy children (HC) 6-18 years underwent a 12-week home-based RT program. Changes in skeletal muscle mass (SMM) and adipose tissue indices (abdomen and thigh) were determined by MRI. Muscle strength/function was assessed using handgrip (HG), sit-to-stand (STS), push-up (PU), timed-up and down stairs test (TUDS), 6-minute walk tests (6MWT).
Results: Study 1: Myopenia was present in 43% of children (N=28) pre-LTx. Children with myopenia had smaller total (median 619 vs. 844µm/m2; p=0.05) and hybrid IIA/X (525±266 vs. 993±340 µm/m2; p=0.04) muscle fibre size index, higher % of type IIA/X hybrid (median 6 vs. 0%; p=0.04) and lower % type I fibres (median 52 vs. 64%; p=0.01). Study 2: Ten children post-LTx (11.9±3.5 yrs) and 13 HC (11.7±3.9yrs) participated in the RT program. Significant increases in abdominal SMM index (+4.6% LTx vs -2.7% HC; p=0.01), 6MWT distance (463 to 540m LTx only; p=0.04), number of PU (LTx/HC; p=0.04), and greater reduction in time for the TUDS test (-9.4%LTx vs 1.2% HC; p=0.05) occurred after 12-weeks of RT. Significant reductions in visceral adipose tissue index (-18% LTx vs -0.8% HCs; p=0.04) also occurred.
Conclusion: Children at LTx had reduced skeletal muscle fibre size indices and alterations in proportions of type I and IIA/X fibres. A 12-week RT program resulted in significant improvements in SMM and function. Understanding underlying muscle physiology in children post-LTx may be informative of optimal rehabilitation approaches.
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