Association Between Radiological and Biological Features of Rectus Abdominis Muscle in  Patients with Cirrhosis who Receive a Liver Transplant
Creators: Motamedrad, Maryam
Publisher: name: University of Alberta Library
Year: 2023

<p>Sarcopenia (severe muscle depletion) and myosteatosis (pathological fat infiltration into <br>
muscle) are two common muscle abnormalities that are associated with poor prognosis in patients<br>
with cirrhosis. Sarcopenia is associated with a higher risk of mortality and morbidity in patients <br>
with cirrhosis. Myosteatosis, assessed as low muscle radiodensity on computed tomography <br>
images, is associated with an increased length of stay in the hospital and higher risk of mortality. <br>
The understanding of whether either of these features are modifiable requires an understanding of <br>
the biology of muscle that exhibit these features. This study aimed to further understand the muscle <br>
characteristics of patients with cirrhosis and find the association between muscle abnormalities <br>
(sarcopenia and myosteatosis) and muscle biological features and their impact on patients <br>
undergoing liver transplant (LT).<br>
Histological characterization of rectus abdominis muscle serial sections from 48 biopsies <br>
of patients with cirrhosis including 29 males and 19 females was performed to identify the size<br>
and distribution of the fibers in the muscle and the location of nuclei in the fibers. Triglyceride <br>
(TG) content of biopsies was quantified by gas chromatography. These muscle biological features <br>
were aligned with the muscle quantity and radiodensity assessed by secondary analysis of crosssectional CT or MRI images analysis taken as part of standard care and assessment. Muscle area <br>
measured by CT or MRI analysis was normalized by height and reported as SMI. Sarcopenia was <br>
defined as L3 SMI &lt;39 cm2<br>
/m2<br>
for women and &lt;50 cm2<br>
/m2<br>
for men. Myosteatosis defined by L3 <br>
Muscle HU&lt;28 for women and &lt;33 for men in CT images. We explored whether fiber type and <br>
size related to complications post-transplant surgery.<br>
Proportions of fiber type I was higher than hybrid and IIX fibers but there was no <br>
significant difference in this distribution based on sex. Males had significantly larger type I fibers (Median; 3625.0 vs. 2354.9 μm2<br>
, p=0.007) and more myocytes with centralized nuclei compared <br>
to females (11.0 % vs. 6.0 %, p=0.007). The prevalence of sarcopenia was almost equal in males <br>
and females (48% vs. 52%). Fiber type IIA were larger in patients with normal muscle mass<br>
compared to patients with sarcopenia (Median; 4175.1 vs. 3418.2 μm2<br>
, p&lt;0.053). TG content was <br>
higher in normal compared to sarcopenic females (39.8±20.9 vs. 21.4±8.2 µg/g, p=0.023) but was <br>
not significantly different within males. There was no significant difference in TG content of <br>
patients with low muscle radiodensity and normal radiodensity and there was no significant <br>
histological difference in patients with and without post-LT complications. These data suggest <br>
that in patients with cirrhosis, type II muscle fibers are more susceptible to atrophy and is a <br>
characteristic of muscles of patients with sarcopenia. </p>