Mechanical Properties of Single Muscle Fibers: Understanding Poor Muscle Quality in Older Adults with Diabetes

Alterations in respiratory mechanics and gas exchange in models of treated and untreated type 2 diabetes

“…However, the trends of changes of G and H in diabetes indicate a somewhat stiffened fiber network of ECM associated with reduced internal friction within chest wall tissues. The trend of increased chest wall elastance is in line with previous results demonstrating increased passive stiffness of single skeletal muscle fibers in older adults with T2DM 53 . The reduced sensitivity of our measurements to detect alterations in skeletal muscle mechanics can be explained by the involvement of the cage bones and costal cartilage in our in vivo mechanical parameters.…”

“…Skeletal muscle plays an important role in glucose homeostasis, and insulin resistance of the skeletal muscle cells is the foremost cause of T2DM development [51][52][53] . Therefore, diabetes also leads to functional and structural changes in skeletal muscle 54 , due to elevated plasma levels of dicarbonyl metabolites 55 leading to ECM remodelling and muscle loss by prolonged activation of receptor for AGEs 56 .…”

“…Because the chest wall is a major compartment of the respiratory system, the aforementioned pathologies may also affect the diaphragm and the pectoral and intercostal respiratory muscles. Indeed, the involvement of chest wall properties in T2DMrelated respiratory abnormalities can also be anticipated from AGEs accumulation in the skeletal muscles 57 , in association with the increased passive stiffness and overexpression of the skeletal muscle fibres of ECM 53 . As the total work of breathing includes the work needed to overcome the resistive losses and elastic recoil of the lungs and chest wall [58][59][60] , characterizing the individual involvement of these compartments in respiratory dysfunction related to diabetes is of major importance.…”

Levosimendan’s Effects on Length-Dependent Activation in Murine Fast-Twitch Skeletal Muscle

“…The restoration force/stress in response to stretch will therefore, consistently increase with SL up to rupture [45]. Myofibrils, single fibres, and whole EDL muscle typically produce between ∼40 to 70 kPa passive restoration stress from 3.0 µm to 4.0 µm [40,[46][47][48] which is in agreement with data from our control group; the axial Young's modulus can easily reveal values that are twice of those (E mod = stress strain = 40to70 kPa 0.4 ∼100-200 kPa). This seems plausible given the fact that the Young's modulus of soleus single muscle fibres scales between 400-600 kPa [48] and are considered twice as stiff as EDL single muscle fibres [49].…”