Maryam Motamedrad | ALES Graduate Seminar

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 Maryam Motamedrad. This seminar is open to the general public to attend.

Thesis Topic: Association Between Radiological and Biological Features of Rectus Abdominis Muscle in Patients with Cirrhosis who Receive a Liver Transplant

MSc with Dr. Vera Mazurak.

Seminar Abstract:

Sarcopenia (severe muscle depletion) and myosteatosis (pathological fat infiltration into muscle) are two common muscle abnormalities in patients with cirrhosis that are associated with their poor prognosis. Sarcopenia is associated with a higher risk of mortality and morbidity in patients with cirrhosis. Myosteatois or low muscle radiodensity is associated with an increased length of stay in the hospital and higher risk of mortality. The understanding of whether either of these features are modifiable requires an understanding of the biology of muscle that exhibits these features. This study aimed to further understand the muscle characteristics of patients with cirrhosis and find the association between muscle abnormalities (sarcopenia and myosteotosis) and muscle biological features and their impact on patients undergoing LT.

Histological characterization of rectus abdominis muscle serial sections from 48 biopsies of patients with cirrhosis including 29 males and 19 females was performed to identify the size and distribution of the fibers in the muscle and the location of nuclei in the fibers. Triglyceride (TG) content of biopsies was quantified by gas chromatography. These muscle biological features were aligned with the muscle quantity and radiodensity assessed by secondary analysis of cross-sectional CT or MRI images analysis taken as part of standard care and assessment. Muscle area measured by CT or MRI analysis was normalized by height and reported as SMI. Sarcopenia was defined as L3 SMI <39 cm²/m² for women and <50 cm²/m² for men. Myosteatosis defined by L3 Muscle HU<28 for women and <33 for men in CT images.  We explored whether fiber type and size related to complications post-transplant surgery.

Fiber type I distribution is higher than hybrid and IIX fibers but there is no significant difference in this distribution based on sex. Males had significantly larger fiber type I (Median; 3625.0 vs. 2354.9 μm², p=0.007) and more centralized nuclei compared to females (11.0 % vs. 6.0 %, p=0.007). The prevalence of sarcopenia was almost equal in males and females (48% vs. 52%). Fiber type IIA was larger in patients with normal muscle mass compared to patients with sarcopenia (Median; 4175.1 vs. 3418.2 μm², p<0.053). TG content was higher in non-sarcopenic compared to sarcopenic females (39.8±20.9 vs. 21.4±8.2 µg/g, p=0.023) but was not significantly different in male groups.

There was no significant difference in TG content of patients with low muscle radiodensity and normal radiodensity and there was no significant histological difference in patients with and without post-LT complications.  These data suggest that in patients with cirrhosis, FTII is more susceptible to atrophy and is a characteristic of muscles of patients with sarcopenia.