Changes in weight after traumatic brain injury in adult patients: a longitudinal study

BACKGROUND & AIMS

Although changes in weight have been reported after traumatic brain injury (TBI), their frequency and underlying factors are little known. Our aim was to determine the prevalence of weight changes and the associated factors during the recovery phase after TBI.

METHODS

Longitudinal follow-up of adults with TBI. Multivariate analysis was carried out on weight change, demographic data, dysexecutive syndrome, eating behavior, physical activity, therapeutic classes and metabolic complications.

RESULTS

107 patients (81 males/26 females), age 36 ± 13 yrs, baseline BMI 23.3 ± 3.9, followed for 38 (8-66) months, were included. In intensive care, patients lost a mean 11 ± 6 kg. End of follow-up, mean BMI was not different to pre-TBI BMI, but patients could be categorized in 3 groups: stable (30%), loss (28%, -8 ± 7 kg) and gain (42%, +9 ± 6 kg). Sex, age, severity of TBI, intensive care weight loss, physical activity, therapeutic classes and the occurrence of metabolic syndrome did not differ between the groups. Factors related to weight gain were hyperphagia, OR 4.5 (IC95%, 1.6-12.1) and presence of a dysexecutive syndrome, OR 2.5 (IC95%, 1.03-6.3). Factors related to weight loss were hypophagia, OR 4.1 (IC95%, 1.5-10.9) and higher pre-TBI BMI, OR 4.9 (IC95%, 1.7-14.0).

CONCLUSIONS

Over a median period of 38 months, 42% of TBI patients gained and 28% lost weight. Factors associated with these changes were the presence of a behavioral dysexecutive syndrome for weight gain, oral food intake and initial BMI, which were inversely associated with weight at end of follow-up. These findings highlight the importance of evaluating the time course of weight changes and providing specific nutritional care.

[Circulating citrulline levels: a biomarker for intestinal functionality assessment]

Circulating citrulline is emerging as an innovating biomarker candidate for assessment of intestinal function. Amino acid synthesized by enterocytes of intestinal mucosal, citrulline is not included in proteins or nutrition products and is a precursor for production of arginine by the kidney. Plasma citrulline is, in clinical situation, an established biomarker of enterocyte functional metabolic mass (trophicity) in children and in adult patients due to its high relation to active functional small bowel remnant length in intestinal diseases (short bowel, extensive enteropathies, intestinal toxicity of chemotherapy and radiotherapy. Plasma citrulline concentration (30-50  μmol/L), independent of nutritional status, if less than 10  μmol/L can give an objective threshold for nutrition parenteral use in case of intestinal failure due to enterocyte abnormalities or lack. Its regular dosage allows the monitoring of intestinal function except in case of significant renal failure.

Effect of intestinal resections on arginine metabolism: practical implications for nutrition support

PURPOSE OF REVIEW

The present review relates recent developments in the understanding of arginine and citrulline metabolism and complementation after intestinal resection.

RECENT FINDINGS

Arginine metabolism is disturbed after significant intestinal resection, with reduced fluxes and circulating and tissue concentrations. There is also a reduction in citrulline production, a major source of endogenous arginine by enterocyte metabolism. There is evidence to suggest that arginine or citrulline supplementation may be important in this situation.

SUMMARY

In experimental intestinal resection, arginine availability decreases as intestinal citrulline synthesis decreases. In this setting, there is debate over the efficiency of arginine supplementation on intestinal adaptation, perhaps due to different doses used. In contrast, citrulline, a precursor for arginine synthesis, whether provided enterally or parenterally, is more efficient at 1 g/kg/day than complementation with arginine (at the same dose) in sustaining arginine pools. In addition, citrulline is more effective than arginine in maintaining nitrogen homeostasis. Clinical studies are vital in order to establish the value of citrulline supplementation in short bowel patients.

Citrulline as a biomarker of intestinal failure due to enterocyte mass reduction

BACKGROUND & AIMS

In human, citrulline (plasma concentration about 40 micromol/L) is an amino acid involved in intermediary metabolism and that is not incorporated in proteins. Circulating citrulline is mainly produced by enterocytes of the small bowel. For this reason plasma or serum citrulline concentration has been proposed as a biomarker of remnant small bowel mass and function. This article reviews this concept and its metabolic basis.

METHODS

Conditions in which there is a significantly reduced small bowel enterocyte mass and function and a plasma or serum citrulline were measured in adults and children. These studies included patients with a short bowel syndrome, villous atrophy states, Crohn's disease, during monitoring of digestive toxicity of chemotherapy and radiotherapy or follow-up of patients after small bowel transplantation.

RESULTS

In all these situations, with more than 500 studied patients a decreased level of plasma citrulline correlated with the reduced enterocyte mass independently of nutritional and inflammatory status. A close correlation between small bowel remnant length and citrullinemia was found. In addition, diagnosis of intestinal failure was assessed through plasma citrulline levels in severe small bowel diseases in which there is a marked enterocyte mass reduction.

DISCUSSION

The threshold for establishing a diagnosis of intestinal failure is lower in villous atrophy disease (10mumol/L) than in short bowel syndrome (20mumol/L). Compromised renal function is an important factor when considering plasma citrulline levels as a marker of intestinal failure as this potentially can increase circulating citrulline values.

CONCLUSIONS

Reduced plasma citrulline levels are an innovative quantitative biomarker of significantly reduced enterocyte mass and function in different disease states in humans.