Maurizio Bossola

Muscle loss during aging and disuse is a highly prevalent and disabling condition, but knowledge about cellular pathways mediating muscle atrophy is still limited. Given the postmitotic nature of skeletal myocytes, the maintenance of cellular homeostasis relies on the efficiency of cellular quality control mechanisms. In this scenario, alterations in mitochondrial function are considered a major factor underlying sarcopenia and muscle atrophy. Damaged mitochondria are not only less bioenergetically efficient, but also generate increased amounts of reactive oxygen species, interfere with cellular quality control mechanisms, and display a greater propensity to trigger apoptosis. Thus, mitochondria stand at the crossroad of signaling pathways that regulate skeletal myocyte function and viability. Studies on these pathways have sometimes provided unexpected and counterintuitive results, which suggests that they are organized into a complex, heterarchical network that is currently insufficiently understood. Untangling the complexity of such a network will likely provide clinicians with novel and highly effective therapeutics to counter the muscle loss associated with aging and disuse. In this review, we summarize the current knowledge on the mechanisms whereby mitochondrial dysfunction intervenes in the pathogenesis of sarcopenia and disuse atrophy, and highlight the prospect of targeting specific processes to treat these conditions.

PURPOSE: Lymph-node involvement is the most important prognostic factor in colorectal cancers. Many staging systems adopted node status as a parameter of tumor classification. However, the number of identified and positive glands varies across articles, depending on specimen examination. There is a consistent risk of substaging tumors and undertreating patients. Aim of this study was to investigate the prognostic significance of different pathologic methods. METHODS: Eight hundred one patients who underwent curative resection of colorectal cancer entered the study and were divided into two groups. In Group 1 the specimen was "en bloc" fixed, and nodes were identified by sight and palpation. In Group 2 the mesentery of the excised specimen was dissected away from the bowel, stretched, and pinned to cork board. The mesenteric segment surrounding the origin of principal vessels was divided from the segment surrounding the colic vessels. All specimen segments were fixed, node identification being performed by sight and palpation. Examined and positive nodes were recorded, and metastatic rate and incidence was calculated in the two groups. Patients were classified with use of different staging systems. Survival rates were calculated, related to tumor stage, and compared statistically. Pathologic procedures were included in a multivariate analysis. RESULTS: A significantly higher number of detected and positive nodes and metastatic rate (37.5 vs. 30.2 percent; P < 0.05) were observed in Group 2; 45.2 percent of Group 2 and 25.3 percent of Group 1 cases had more than three positive nodes (P < 0.05). In Group 2 several patients shifted from earlier to more advanced stages compared with Group 1 cases. Five-year and ten-year survival rates were significantly higher (P = 0.04) in Group 2 (81.5 and 77.2 percent) than in Group 1 (76.7 and 61.5 percent), mostly in patients with TNM Stage N0. Survival analysis related to Astler and Coller's and Tang's classifications confirmed such features. Higher rates of local recurrences and distant metastases were found in Group 1, particularly if related to node status (P < 0.05). Multivariate analysis demonstrated the pathologic method is an independent prognostic factor. CONCLUSIONS: This study demonstrates the prognostic impact of specimen examination. Inaccurate methods could down-stage the tumor and exclude the patient from adjuvant therapies, with detrimental effects on the outcome of the case.

Total thyroidectomy is not frequently performed in cases of benign disease because of the associated risk of postoperative hypoparathyroidism and recurrent laryngeal nerve (RLN) damage. We chose a series of patients who had undergone total thyroidectomy (TT) for benign thyroid tumors to evaluate the safety of this approach and its role in the treatment of nonmalignant lesions of the thyroid. We considered only patients with a minimum follow-up of 24 months. Records of 526 patients who underwent TT were carefully reviewed, assessing for perioperative complications and late sequelae. The mean age was 44 +/- 15.7 years; 109 patients (20.7%) were male and 417 (79.3%) were female. Altogether, 65 patients (12.3%) were operated on for toxic goiter, 429 (81.6%) for bilateral nodular goiter, and 32 (6.1%) for thyroiditis. Postoperative hemorrhage requiring reoperation occurred in 8 cases (1.5%). The incidences of permanent RLN palsy (considered as a percentage of the nerves at risk) and permanent hypocalcemia were 0.4% and 3.4%, respectively. A trend toward a decrease in the complication rate was observed during the last 5 years. There were no disease recurrences during a mean follow-up of 44 months. The results of our series show that TT can be performed safely in patients, with a low incidence of lifetime disabilities. TT has the advantage of reducing/avoiding the risk of disease recurrence and reoperation and should therefore be considered a valuable option for treating benign thyroid diseases.

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.