Unaffected Arm Muscle Hypercatabolism in Dysphagic Subacute Stroke Patients: The Effects of Essential Amino Acid Supplementation

Abstract

Alterations in muscle protein turnover of the unaffected side of stroke patients could contribute to physical disability. We investigated whether hypercatabolic activity occurred in unaffected arm muscle and whether supplemented essential amino acids (EAAs) could limit muscle hypercatabolism (MH). Thirty-eight dysphagic subacute stroke subjects (<3 months after acute event) (29 males + 9 females; 69.7 ± 11.4 yrs) were enrolled and randomized to receive 8 g/day EAAs (n = 19; EAA group) or isocaloric placebo (maltodextrin; n = 19, Plac group). Before randomization, all patients had their arterial (A) and venous (V) amino acids measured and muscle (A − V) differences calculated in the unaffected arm. Eight matched and healthy subjects served as controls. When compared to healthy controls, the entire stroke population showed significant muscle release (= negative value A − V) of the amino acid phenylalanine (phenyl-) indicating a prevalence of MH. Moreover, randomized EAA and Plac groups had similar rates of MH. After 38 days from the start of the protocol, the EAA group but not the Plac group had MH converted to balanced protein turnover or anabolic activity. We concluded that muscle protein metabolism of the unaffected arm of dysphagic subacute stroke individuals could be characterized by MH which can be corrected by supplemented EAAs.

The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients

“…Secondly, the patients’ high levels of the AAs that are not metabolised by muscle, such as phenylalanine, tyrosine, lysine and methionine, are indicative of a state of muscle hypercatabolism. A previous investigation showed that the ipsilateral arm (= unaffected) in stroke patients had a net release of phenyalanine [9]. Thirdly, high serum CRP suggests increased Interleukine 6 production [44], which promotes muscle protein breakdown by several mechanisms including both inhibition of muscle protein synthesis, repair, contractility and function [45], and stimulation of the hypothalamus-pitituary-cortical axis leading to increased cortisol production.…”

“…This may contribute to explaining the inverse correlation between glycin and Hb. The high value of plasma glycin found in stroke subjects was probably due to muscle release following protein overdegradation [9].…”

“…An observational study demonstrated that spontaneous neurocognitive recovery in stroke subjects was associated with protein-calorie intakes [6]. Moreover, when stroke patients were supplemented with proteins [7], zinc [8] and Essential Amino Acids (EAAs) [9], their neurocognitive retrieval improved.…”

The Central Role of Clinical Nutrition in COVID-19 Patients During and After Hospitalization in Intensive Care Unit

“…Immunonutrients can promote patient recovery by inhibiting inflammatory responses and regulating immune function. Glutamine, which can modulate and preserve intestinal and lung function, is compromised in conditions of severe stress, reducing the production of pro-inflammatory cytokines [ 9 , 10 ]. Cytokine-mediated effects are an essential part response to infection but excessive production of pro-inflammatory cytokines increases the risk of pneumonia and death in COVID-19 patients.…”

Correlation of deglutition in subacute ischemic stroke patients with peripheral blood adaptive immunity: Essential amino acid improvement

“…This study highlights the importance in sub-acute stroke individuals of monitoring blood N/Lymph ratio over time. Strictly linked to this factor is preventing infection which may be of fundamental importance to avoid the aggravation of patient muscle hypercatabolism 24 which could also affect deglutition musculature. The N/Lymph ratio may be more useful than CRP in understanding the courses of clinical- metabolic- functional status.…”