2 research outputs found
Gluconeogenesis, liver energy metabolism and weight loss in lung cancer : dynamic studies using stable isotope tracers and 31P magnetic resonance spectroscopy
Weight loss is a major problem in many types of cancer and is associated with reduced
quality of life and a poor prognosis. Weight loss can also interfere with potentially
curable treatment [41,561. Many uncertainties remain about the mechanisms underlying
weight loss in patients with cancer. This thesis describes a series of studies aimed at
defining alterations in metabolic processes that are potentially related with weight loss in
lung cancer patients. Although in literature the terms 'cachexia' (~ a syndrome of weight
loss and rnalnutrition) and 'weight loss' are often used interchangeably, in this thesis
weight loss will be preferentially used.
In this chapter, current knowledge on weight loss in cancer and its relation with
metabolic alterations are reviewed and the aim of this thesis is presented
Weight loss and elevated gluconeogenesis from alanine in lung cancer patients
BACKGROUND: The role of gluconeogenesis from protein in the pathogenesis
of weight loss in lung cancer is unclear. OBJECTIVE: Our aim was to study
gluconeogenesis from alanine in lung cancer patients and to analyze its
relation to the degree of weight loss. DESIGN: In this cross-sectional
study, we used primed-constant infusions of [6,6-(2)H(2)]-D-glucose and
[3-(13)C]-L-alanine to assess whole-body glucose and alanine turnover and
gluconeogenesis from alanine in weight-losing (WL, n = 9) and
weight-stable (WS, n = 10) lung cancer patients and healthy control (n =
15) subjects. RESULTS: Energy intake and plasma alanine concentrations did
not differ significantly among the subject groups. Mean (+/-SEM)
whole-body glucose production was significantly higher in WL than in WS
and control subjects (0.74 +/- 0.06 compared with 0.55 +/- 0.04 and 0.51
+/- 0.04 mmol*kg(-)(1)*h(-)(1), respectively, P < 0.01). Alanine turnover
was significantly elevated in WL compared with WS and control subjects
(0.57 +/- 0.04 compared with 0.42 +/- 0.05 and 0.40 +/- 0.03
mmol*kg(-)(1)*h(-)(1), respectively, P < 0.01). Gluconeogenesis from
alanine was significantly higher in WL than in WS and control subjects
(0.47 +/- 0.04 compared with 0.31 +/- 0.04 and 0.29 +/- 0.04
mmol*kg(-)(1)*h(-)(1), respectively, P < 0.01). The degree of weight loss
was positively correlated with glucose and alanine turnover and with
gluconeogenesis from alanine (r = 0.45 for all, P < 0.01). CONCLUSIONS:
Aberrant glucose and alanine metabolism occurred in WL lung cancer
patients. These changes were related to the degree of weight loss and not
to the presence of lung cancer per se