During our review of literature on the effects of prolonged (unintended) caloric restriction, we came across an interesting article on protein-energy wasting (PEW) by Lodebo et al., 2018 (1). The authors focus mainly on PEW in chronic kidney disease (CKD) but the description of PEW that the give is interesting in a broader context.
Below, there is an interesting diagram that shows possible causes and mechanisms of PEW. Note that the authors list parathyroid hormone (PTH) as “catabolic”. This is interesting.
We may question, however, classification of corticosteroids as “anabolic”.
Of interest also, the definition of PEW and its clinical presentation.
From Lodebo et al., 2018 (1):
According to the International Society for Renal Nutrition and Metabolism, PEW is most readily diagnosed by the presence of at least 3 of the following four signs: (1) low serum albumin, transthyretin (prealbumin), or cholesterol; (2) decreased body mass (low body mass index [BMI], unintentional weight loss, or decreased body fat); (3) reduced muscle mass (low mid-arm muscle circumference or area, decreased creatinine appearance or recent history of loss of muscle mass); (4) unintentional low energy or protein intake.6 Other measures which may be used to help detect or confirm PEW include reduced skeletal muscle strength or function (e.g., low handgrip strength or gait speed).7,8 Inflammatory cytokines can predispose to PEW (see below). However, it is the authors’ view that increased levels of inflammatory cytokines are not part of the diagnostic criteria for PEW, which is determined by the presence of decreased body protein and fuel mass. Future research will probably demonstrate more relevant and helpful ways of monitoring PEW; for example, the propensity of PEW to arterial inflammation or atherogenesis, antibody responses, lymphocyte or neutrophil function, or the activities of subcellular structures.
References:
1. Lodebo et al., Journal of Renal Nutrition, Vol 28, No 6 (November), 2018: pp 369-379.