Defective regulation of adipose tissue autophagy in obesity.

OBJECTIVES: Autophagy is a highly regulated process that has an important role in the control of a wide range of cellular functions, such as organelle recycling, nutrient availability and tissue differentiation. A recent study has shown an increased autophagic activity in the adipose tissue of obese subjects, and a role for autophagy in obesity-associated insulin resistance was proposed. Body mass reduction is the most efficient approach to tackle insulin resistance in over-weight subjects; however, the impact of weight loss in adipose tissue autophagy is unknown. SUBJECTS: Adipose tissue autophagy was evaluated in mice and humans. RESULTS: First, a mouse model of diet-induced obesity and diabetes was maintained on a 15-day, 40% caloric restriction. At baseline, markers of autophagy were increased in obese mice as compared with lean controls. Upon caloric restriction, autophagy increased in the lean mice, whereas it decreased in the obese mice. The reintroduction of ad libitum feeding was sufficient to rapidly reduce autophagy in the lean mice and increase autophagy in the obese mice. In the second part of the study, autophagy was evaluated in the subcutaneous adipose tissue of nine obese-non-diabetic and six obese-diabetic subjects undergoing bariatric surgery for body mass reduction. Specimens were collected during the surgery and approximately 1 year later. Markers of systemic inflammation, such as tumor necrosis factor-1α, interleukin (IL)-6 and IL-1ß were evaluated. As in the mouse model, human obesity was associated with increased autophagy, and body mass reduction led to an attenuation of autophagy in the adipose tissue. CONCLUSION: Obesity and caloric overfeeding are associated with the defective regulation of autophagy in the adipose tissue. The studies in obese-diabetic subjects undergoing improved metabolic control following calorie restriction suggest that autophagy and inflammation are regulated independently.

Serum levels and mesenteric fat tissue expression of adiponectin and leptin in patients with Crohn's disease.

Crohn's disease (CD) is characterized by inflammation and an aetiology that is still unknown. Hypertrophy of mesenteric fat is a reflection of disease activity, as this fat covers the entire length of the affected area. Adipocytes synthesize leptin and adiponectin, adipocytokines responsible for pro- and anti-inflammatory effects. Therefore, we evaluated serum levels of adiponectin and leptin, as well as mesenteral expression of adiponectin in active CD and those in remission. Sixteen patients with ileocaecal CD followed at the Outpatient Clinic, Coloproctology Unit of University of Campinas Clinical Hospital, participated in the study. Analysis of serum adiponectin and leptin by enzyme-linked immunosorbent assay was performed in patients with active CD (ACD group), remission CD (RCD group) and in six healthy controls. Ten patients with active ileocaecal CD (FCD group) and eight patients with non-inflammatory disease selected for surgery were also studied. The specimens were snap-frozen and the expression of adiponectin was determined by immunoblot of protein extracts. Serum C-reactive protein levels were higher in the ACD group when compared to the others and no difference of body mass index was observed between the groups. Serum adiponectin was lower in the ACD group when compared to control, but no differences were seen when comparing the ACD and RCD groups. Mesenteric adiponectin expression was lower in the FCD group when compared to the FC group. Serum leptin was similar in all groups. The lower levels of serum and mesenteric adiponectin in active CD suggest a defective regulation of anti-inflammatory pathways in CD pathogenesis.

Identification of the myotoxic site of the Lys49 phospholipase A(2) from Agkistrodon piscivorus piscivorus snake venom: synthetic C-terminal peptides from Lys49, but not from Asp49 myotoxins, exert membrane-damaging activities.

Group II phospholipase A(2) (PLA(2)) myotoxins found in the venoms of Crotalidae snakes can be divided into 'Asp49' and 'Lys49' isoforms, the latter being considered catalytically-inactive variants. Previous studies on one Lys49 isoform, myotoxin II from Bothrops asper, indicated that its myotoxic activity is due to the presence of a short cationic/hydrophobic sequence (115-129) near its C-terminus, which displays membrane-damaging properties. Since the C-terminal region of different group II PLA(2) myotoxins presents considerable sequence variability, synthetic peptides homologous to region 115-129 of myotoxin II, but corresponding to B. asper myotoxin III (Asp49), Agkistrodon piscivorus piscivorus Asp49 PLA(2) and Lys49 PLA(2), were studied to determine the possible functional relevance of such region for the toxic activities of these proteins. Results showed that both Lys49-derived peptides (p-BaK49 and p-AppK49) were able to lyse skeletal muscle C2C12 cells in culture, and to induce edema in the mouse footpad assay. Moreover, p-AppK49, which showed a markedly stronger cytotoxic potency than p-BaK49, additionally induced skeletal muscle necrosis when injected into mice. These observations unequivocally identify the sequence 115-129 (KKYKAYFKLKCKK) of the Lys49 PLA(2) of A. p. piscivorus as containing the key structural determinants needed for myotoxicity, and represent the first report of an unmodified, PLA(2)-derived short synthetic peptide with the ability to reproduce this effect of a parent toxin in vivo. On the other hand, the two Asp49-derived peptides did not show any toxic effects in vitro or in vivo, even at high concentrations. These findings suggests that Lys49 and Asp49 group II PLA(2)s might exert their myotoxic actions through different molecular mechanisms, by implying that the latter may not utilize their C-terminal regions as main membrane-destabilizing elements.

Immunochemical properties of the N-terminal helix of myotoxin II, a lysine-49 phospholipase A(2) from Bothrops asper snake venom.

Myotoxic class II phospholipases A(2) from snake venoms can be divided into Asp49 and Lys49 types. The latter, including Bothrops asper myotoxin II, exert membrane damage despite lacking catalytic activity. A heparin-binding, hydrophobic/cationic region, near the C-terminus of myotoxin II (115-129) has been shown to be relevant in its membrane-damaging actions. However, some observations suggest also a potential participation of its N-terminal region. An immunochemical approach was utilized to examine the properties and possible role in toxicity of the N-terminal helix of myotoxin II. Rabbit antibodies raised to a synthetic peptide comprising residues 1-15 recognized the native protein. These antibodies were utilized to compare the antigenic characteristics of the N-terminal helix of several myotoxic phospholipases A(2), showing generally stronger binding to Lys49 myotoxins, in comparison to Asp49 counterparts. However, three Lys49 myotoxins (Cerrophidion godmani myotoxin II, Atropoides nummifer myotoxin II, and Trimeresurus flavoviridis basic protein I) were not recognized by the antibodies, revealing a significant antigenic variability of the N-terminal region within this group of toxins. In neutralization experiments, pre-incubation of myotoxin II with affinity-purified antibodies to the N-terminal helix did not inhibit its myotoxic activity in mice, nor its cytotoxic effect upon cultured muscle cells. These findings argue against a critical role of the N-terminal region of this protein in toxicity. Thus, the precise role of the N-terminal helix of myotoxin II and related Lys49 phospholipases A(2), regarding their toxic mechanisms, remains controversial, and requires further experimental study to be clarified.

The treatment of mentally disordered offenders: a national survey of psychiatrists.

A nationwide (U.S.) survey of major public mental hospitals treating patients who are incompetent for trial, not guilty by reason of insanity, mentally disordered sex offenders, or mentally ill inmates was conducted. Responses were received from 71 percent of the 115 facilities surveyed. Respondents were the directors of psychiatry from the respective facilities. The pattern of treatments delivered generally appeared clinically appropriate. However, behavioral and cognitive-behavioral treatments were reported infrequently, even in areas in which they would be particularly useful.