Metabolic stress

Maintaining adequate nutritional status, especially during periods of illness and metabolic stress, is an important part of patient care. Malnutrition in hospitalized patients is associated with significant complications, including increased infection risk, poor wound healing, prolonged hospital stay, and increased mortality, especially in surgical and critically ill patients.1 Specialized nutrition support refers to the administration of nutrients via the oral, enteral, or parenteral route for therapeutic purposes.1 Parenteral nutrition (PN), also... 

Liu R, Li Z, Bai S, et al. Mechanism of cancer cell adaptation to metabolic stress proteomics identification of a novel thyroid hormone-mediated gastric carcinogenic signaling pathway. Mol. Cell. Proteomics 2009 8 70-85. 

Lemly, A.D. 1993c. Metabolic stress during winter increases the toxicity of selenium to fish. Aquat. Toxicol. 27 133-158. 

Daily energy requirements are 20 to 25 kcal/kg for healthy adults, 25 to 30 kcal/kg for malnourished or metabolically stressed adults, and 30 to 40 kcal/kg for adults with major burns. Unfortunately, this simple approach fails to consider age- and gender-related differences in energy metabolism. 

Protein requirements are based on age, nutrition status, disease state, and clinical condition. The usual recommended daily protein allowances are 0.8 g/kg for adults, 1.5 to 2 g/kg for patients with metabolic stress (e.g., infection, trauma, and surgery), and 2.5 to 3 g/kg for patients with burns. See Table 57-5 for recommendations for children. 

Modified amino acid solutions are designed for patients with altered protein requirements associated with hepatic encephalopathy, renal failure, and metabolic stress or trauma. However, these solutions are expensive and their role in disease-specific PN regimens is controversial. 

Metabolic stress, infection, corticosteroids, pancreatitis, diabetes mellitus, peritoneal dialysis, excessive dextrose administration Abrupt dextrose withdrawal, excessive insulin Excess dextrose administration... 

Metabolic stress, familial hyperlipidemia, pancreatitis, excess IVFE dose rapid IVFE infusion rate... 

Metabolic stress, infection, excess carbohydrate intake, excess caloric intake, EFAD long-term PN therapy... 

To provide fuels and bnilding materials for all these cells, in a severe infection or tranma (including surgery), requires large changes in the metabolism, which may be snch as to impose a significant metabolic stress upon the patient (see Chapter 18). 

Benign tnmonrs are nsnally only a problem when they impair the fnnction of organs or canse metabolic stress. They can be removed by snrgery or radiation therapy. Malignant tnmonrs are mnch more of a problem, since the cells can escape from the primary tnmonr to other sites in the body, where they settle and develop into secondary tumours (metastases). Then, chemotherapy is the only treatment available. The process is known as metastasis. 

If caused by maternal TSH-R Ab [stim], the disease is usually self-limited and subsides over a period of 4-12 weeks, coinciding with the fall in the infant s TSH-R Ab [stim] level. However, treatment is necessary because of the severe metabolic stress the infant experiences. Therapy includes propylthiouracil in a dose of 5-10 mg/kg/d in divided doses at 8-hour intervals Lugol s solution (8 mg of iodide per drop), 1 drop every 8 hours and propranolol, 2 mg/kg/d in divided doses. Careful supportive therapy is essential. If the infant is very ill, oral prednisone, 2 mg/kg/d in divided doses, will help block conversion of T4 to T3. These medications are gradually reduced as the clinical picture improves and can be discontinued by... 

It should be noted that there is a growing list of conditionally essential amino acids. These are amino acids that must be augmented through the diet under a variety of special circumstances. Often these circumstances include infancy (where the various enzyme systems for metabolism have not been fully expressed) or periods of metabolic stress due to injury or illness. Conditionally essential amino acids include taurine (infants) and glutamine (metabolic stress). 

Lactic acidosis is a severe and potentially fatal form of mitochondrial toxicity. Metabolic stress or vitamin deficiencies (riboflavin, carnitine) might provoke it. There is suggestive evidence of clinical benefit with riboflavin therapy (846). 

The role of the IF, and particularly the keratin filament system, in resisting the forces of mechanical stress has been well established. However, IFs also play a role in countering metabolic stress. Perhaps the best example is the cytoprotective role played by the simple epithelial keratins, K8/18. However, vimentin, desmin, peripherin, GFAP, the lens proteins phakinin, and filensin and other keratins have also been shown to associate with members of the small heat shock protein (HSP) family, including HSP27 and aB-crystallin (reviewed in Coulombe and Wong, 2004 Marceau et al., 2001 Nicholl and Quinlan, 1994). 

Fig. 21.1 Regulation of AMPK in cardiomyocyte. External metabolic stresses induce an increase in AMP/ATP ratio. Binding with AMP makes AMPK a better substrate to its upstream kinases, and a poor substrate for protein phosphatases 2C, which is known to dephosphorylate and inactivate AMPK. Moreover, insulin through activation of Akt also decreases AMPK activity in...

R., Strittmatter, W. J., Blass, J. P. Glyceraldehyde-3-phosphate dehydrogenase abnormality in metabolically stressed Huntington disease fibroblasts. Dev. Neurosci. 1998, 20 462-468. 

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