Effects of growth hormone and insulin-like growth factor-1 on postoperative muscle and substrate metabolism

Signals for Muscular Protein Turnover and Insulin Resistance in Critically Ill Patients: A Narrative Review

Sarcopenia in critically ill patients is a highly prevalent comorbidity. It is associated with a higher mortality rate, length of mechanical ventilation, and probability of being sent to a nursing home after the Intensive Care Unit (ICU). Despite the number of calories and proteins delivered, there is a complex network of signals of hormones and cytokines that affect muscle metabolism and its protein synthesis and breakdown in critically ill and chronic patients. To date, it is known that a higher number of proteins decreases mortality, but the exact amount needs to be clarified. This complex network of signals affects protein synthesis and breakdown. Some hormones regulate metabolism, such as insulin, insulin growth factor glucocorticoids, and growth hormone, whose secretion is affected by feeding states and inflammation. In addition, cytokines are involved, such as TNF-alpha and HIF-1. These hormones and cytokines have common pathways that activate muscle breakdown effectors, such as the ubiquitin-proteasome system, calpain, and caspase-3. These effectors are responsible for protein breakdown in muscles. Many trials have been conducted with hormones with different results but not with nutritional outcomes. This review examines the effect of hormones and cytokines on muscles. Knowing all the signals and pathways that affect protein synthesis and breakdown can be considered for future therapeutics.

Theory: Treatments for Prolonged ICU Patients May Provide New Therapeutic Avenues for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

We here provide an overview of treatment trials for prolonged intensive care unit (ICU) patients and theorize about their relevance for potential treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Specifically, these treatment trials generally target: (a) the correction of suppressed endocrine axes, notably through a "reactivation" of the pituitary gland's pulsatile secretion of tropic hormones, or (b) the interruption of the "vicious circle" between inflammation, oxidative and nitrosative stress (O&NS), and low thyroid hormone function. There are significant parallels in the treatment trials for prolonged critical illness and ME/CFS; this is consistent with the hypothesis of an overlap in the mechanisms that prevent recovery in both conditions. Early successes in the simultaneous reactivation of pulsatile pituitary secretions in ICU patients-and the resulting positive metabolic effects-could indicate an avenue for treating ME/CFS. The therapeutic effects of thyroid hormones-including in mitigating O&NS and inflammation and in stimulating the adreno-cortical axis-also merit further studies. Collaborative research projects should further investigate the lessons from treatment trials for prolonged critical illness for solving ME/CFS.

Neuromuscular Blockade Correlates with Hormones and Body Composition in Acromegaly

Tumor resection is the first-line therapy for acromegaly patients. In some cases, unsatisfactory intraoperative neuromuscular blockades (NMBs) lead to failed operations. The purpose of this study was to investigate and quantify the NMB status of acromegaly patients and explore the relationship between NMB status and hormone levels and body composition. Twenty patients with untreated acromegaly and seventeen patients with nonfunctioning pituitary adenomas as controls were enrolled in this study. NMB was assessed using the train-of-four (TOF) technique with TOF-Watch® SX. The onset time of NMB, deep neuromuscular blockade duration (DNMBD), and clinical neuromuscular blockade duration (CNMBD) were monitored. We found a significantly longer onset time (110.25 ± 54.90 vs. 75.00 ± 27.56, s, p=0.017), shorter DNMBD (21.99 ± 5.67 vs. 34.96 ± 11.04, min, p < 0.001), and shorter CNMBD (33.26 ± 8.09 vs. 46.21 ± 10.89, min, p < 0.001) in acromegaly patients compared with the controls. DNMBD and CNMBD decreased in patients with decreasing body fat percentage and increasing growth hormone (GH) level, insulin-like growth factor 1 (IGF-1) level, and GH and IGF-1 burden. The onset time increased with increasing IGF-1 level and GH and IGF-1 burden. Taken together, a unique NMB status was identified in acromegaly patients with the following characteristics: prolonged onset time and shortened DNMBD and CNMBD. Changes in the levels and burdens of GH and IGF-1 and body composition were linearly correlated with intraoperative NMB in acromegaly patients.