Protein synthesis kwashiorkor

The ratio of essential to non-essential amino acids is high in kwashiorkor but normal in marasmus. The cause of this may be low activities of the enzymes for metabolising the essential amino acids. These are required for any protein synthesis that must take place even in kwashiorkor. 

Both forms of PEM are associated with hy-percortisolemia.The level of cortisol in kwashiorkor is lower, however, than in marasmus, likely due to decreased adrenocortical function caused by low protein intake (and not adrenal failure). If a sufficiently high level of cortisol is not maintained, then adequate muscle protein is not mobilized to sustain hepatic protein synthesis. Indeed, hypoproteinemia, evident by the decreased serum albumin and transferrin levels, is more acute in kwashiorkor than marasmus. 

Kwashiorkor commonly occurs in children in third world countries where the diet, which is adequate in calories, is low in protein. A deficiency of dietary protein causes a decrease in protein synthesis that eventually affects the regeneration of intestinal epithelial cells and, thus, the problem is further compounded by malabsorption. Hepatomegaly and a distended abdomen are often observed. 

Mixedmarasmus/kwashiorkor is a form of severe protein-calorie malnutrition that develops in chronically ill, starved patients during periods of hypermetabolic stress. There is reduced visceral protein synthesis superimposed on wasting of somatic protein and energy (adipose tissue) stores. Immunocompetence is lowered, increasing the incidence of infection, and wound healing is compromised. 

One of the characteristics of critical illness is hypermetabolism. Trauma, burn injury, and sepsis are aU catalysts for the release of mediators that initiate and regulate the hypermetabohc response. The metabolic consequences of this response include altered carbohydrate metabolism, increased protein synthesis and degradation, and increased lipid oxidation, which ultimately result in loss of protein and lean body mass." In a previously well-nourished individual, critical illness can result in the onset of kwashiorkor-like malnutrition within 5 to 7 days. In a previously malnourished individual, critical illness can precipitate severe mixed marasmus-kwashiorkor in 3 to 5 days. In a prospective study of 129 patients admitted to the intensive care unit (ICU), 43% were malnourished." The malnourished patients had an increased length of stay in the ICU (a mean of 27 vs. 19 days) and a statistically significantly increased incidence of complications (55% vs. 40%) compared with well-nourished patients with a similar severity of illness. 

Kwashiorkor, a common problem of children in Third World countries, is caused by a deficiency of protein in a diet that is adequate in calories. Children with kwashiorkor suffer from muscle wasting and a decreased concentration of plasma proteins, particularly albumin. The result is an increase in interstitial fluid that causes edema and a distended abdomen that make the children appear "plump" (see Chapter 44). The muscle wasting is caused by the lack of essential amino acids in the diet existing proteins must be broken down to produce these amino acids for new protein synthesis. 

The uptake of [ C]-methionine and [ H]-histidine into the brains of the low-protein animals was accelerated in the case of methionine, this could be explained by enhanced incorporation into protein and thus by a change in protein synthesis. The raised histidine levels in the brain, on the other hand, were clearly related to the raised plasma levels. A disturbance of histidine metabolism occurs in children with kwashiorkor, resulting in the urinary excretion of urocanic acid. ... 

Marasmus is considered to be due to inadequate food intake. It is not usually the quantity but the quality of the food that is deficient, e.g. low nutritional value of bulky vegetables. Kwashiorkor is considered to be caused, more specifically, by a low-protein diet. This condition frequently develops at the time of weaning when protein-rich milk is replaced by protein-deficient solid food. It did not appear in the medical literature until 1934 when it was reported by Cicely Williams who studied the condition while she was working among tribes of Western Africa. She gave it the name kwashiorkor, which was used by the Ga tribe to describe the condition that develops when the baby is taken away from mother s breast, usually because another baby has been bom. It has generally been held that the oedema is a consequence of a low plasma albumin concentration and a reduction in the colloid osmotic pressure which reduces the movement of water from tissue fluid back into capillaries. The low albumin level results from a decreased rate of synthesis of albumin by the liver. However, if marasmus is due entirely to lack of energy... 

Fatty liver occurs in kwashiorkor, probably due to lack of protein in the diet, which reduces the synthesis of the structural protein for VLDL (apolipoprotein B). The increased triacylglycerol produced in the liver from fatty acids removed from the blood (i.e. the inter-tissue triac-... 

The higher than normal serum IgA in many children with protein calorie malnutrition may be related to increased synthesis of IgA by the intestinal lamina propria in resjionse to increased antigenic stimuli from bacteria and virus. This is probably supported by the observation that children with kwashiorkor were found to maintain their polio antibodies during malnutrition, and their immune mechanism seemed to be quite capable of inhibiting poliovirus infection, indicating that the intestinal receptor cell for poliovirus operates normally in kwashiorkor (B8). It is now known that polio antiliodies are mainly associated with IgA. 

Studies indicated that cysteine supplementation is beneficial in restoring glutathione levels in children with severe edematous malnutrition (Badaloo et al., 2002). If the reduced rate of glutathione synthesis in kwashiorkor is convincingly attributed to a shortage of protein in the... 

In cases of severe protein malnutrition (kwashiorkor), the concentration of the plasma proteins decreases, as a result of which the osmotic pressure of the blood decreases. As a result, fluid is not drawn back to the blood and instead accumulates in the interstitial space (edema). The distended bellies of famine victims are the result of fluid accumulation in the extravascular tissues because of the severely decreased concentration of plasma proteins, particularly albumin. Albumin synthesis decreases fairly early under conditions of protein malnutrition. 

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