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Objective: To investigate the state of activation of the ATP-ubiquitin-dependent proteolytic system in the skeletal muscle of gastric cancer patients., Summary Background Data: Muscle wasting in experimental cancer cachexia is frequently associated with hyperactivation of the ATP-dependent ubiquitin-proteasome proteolytic system. Increased muscle ubiquitin mRNA levels have been previously shown in gastric cancer patients, suggesting that this proteolytic system might be modulated also in human cancer., Methods: Biopsies of the rectus abdominis muscle were obtained intraoperatively from 23 gastric cancer patients and 14 subjects undergoing surgery for benign abdominal diseases, and muscle ubiquitin mRNA expression and proteasome proteolytic activities were assessed., Results: Muscle ubiquitin mRNA was hyperexpressed in gastric cancer patients compared to controls. In parallel, three proteasome proteolytic activities (CTL, chymotrypsin-like; TL, trypsin-like; PGP, peptidyl-glutamyl-peptidase) significantly increased in gastric cancer patients with respect to controls. Advanced tumor stage, poor nutritional status, and age more than 50 years were associated with significantly higher CTL activity but had no influence on TL and PGP activity., Conclusions: These results confirm the involvement of the ubiquitin-proteasome proteolytic system in the pathogenesis of muscle protein hypercatabolism in cancer cachexia. The observation that perturbations of this pathway in gastric cancer patients occur even before clinical evidence of body wasting supports the thinking that specific pharmacologic and metabolic approaches aimed at counteracting the upregulation of this pathway should be undertaken as early as cancer is diagnosed.

Objective: A prospective multicenter randomized trial was designed to evaluate the clinical efficacy of postoperative protein-sparing therapy., Summary Background Data: The metabolic effect of postoperative protein-sparing therapy has been shown by several studies, but the clinical utility of this treatment has not been investigated by large prospective trials., Methods: Six hundred seventy-eight patients undergoing major elective abdominal surgery were randomly assigned to receive either protein-sparing therapy after surgery (protein-sparing therapy group) or conventional therapy (control group). The patients were monitored for postoperative complications and mortality., Results: The rate of major postoperative complications was similar in both groups (protein-sparing therapy group, 19.5%; control group, 20.9%; p=0.66) as were the overall postoperative mortality rates (4.7% and 3.5%, respectively; p=0.43)., Conclusions: The present study indicates that routine protein-sparing therapy for patients normonourished or mildly malnourished undergoing major abdominal surgery is not clinically justified.