Gastrointestinal factors regulating lipid droplet formation in the intestine

Cytoplasmic lipid droplets (CLD) are considered as neutral lipid reservoirs, which protect cells from lipotoxicity. It became clear that these fascinating dynamic organelles play a role not only in energy storage and metabolism, but also in cellular lipid and protein handling, inter-organelle communication, and signaling among diverse functions. Their dysregulation is associated with multiple disorders, including obesity, liver steatosis and cardiovascular diseases. The central aim of this review is to highlight the link between intra-enterocyte CLD dynamics and the formation of chylomicrons, the main intestinal dietary lipid vehicle, after overviewing the morphology, molecular composition, biogenesis and functions of CLD.

Acute effects of acylated ghrelin on salbutamol-induced metabolic actions in humans

The aim of this study is to describe a potential modulatory effect of acute acylated ghrelin (AG) administration on the glucose, insulin, and free fatty acids (FFA) responses to salbutamol (SALBU). Six healthy young male volunteers underwent the following four testing sessions in random order at least 7 days apart: (a) acute AG administration (1.0 μg/kg i.v. as bolus at 0'); (b) SALBU infusion (0.06 μg/kg/min i.v. from -15' to +45'); (c) SALBU infusion+AG; and (d) isotonic saline infusion. Blood samples for glucose, insulin, and FFA levels were collected every 15 min. As expected, with respect to saline, SALBU infusion induced a remarkable increase in glucose (10.8±5.6 mmol/l×min; P<0.05), insulin (2436.8±556.9 pmol/l×min; P<0.05), and FFA (18.9±4.5 mmol/l×min; P<0.01) levels. A significant increase in glucose (7.4±3.9 mmol/l×min; P<0.05) and FFA levels (10.0±2.8 mmol/l×min; P<0.01) without significant variations in insulin levels were recorded after AG administration. Interestingly, the hyperglycemic effect of AG appeared to be significantly potentiated during SALBU infusion (26.7±4.8 mmol/l×min; P<0.05). On the other hand, the stimulatory effect of SALBU on insulin and FFA was not significantly modified by AG administration. The results of this study show that acute AG administration has a synergic effect with β2-adrenergic receptor activation by SALBU on blood glucose increase, suggesting that their pharmacological hyperglycemic action takes place via different mechanisms. On the other hand, AG has a negligible influence on the other pharmacological metabolic effects of SALBU infusion.

Does NSCLC patient-rated performance status predict survival more accurately than physician ratings?

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Background: The Eastern Cooperative Oncology Group (ECOG) score is a well known predictor of survival, which impacts on treatment decisions. Patient (pt) rated activity level, using the Patient Generated Subjective Global Assessment (PG-SGA) scale, is identical in criteria to the ECOG scale used by physicians. We compared the patient rated activity level (Pt-PS) to physician rated PS (MD-PS), at baseline, and evaluated survival with respect to the 2 PS ratings. Methods: Pts with newly diagnosed advanced NSCLC (stages 3–4) completed a PG-SGA self rated questionnaire, which was then compared to the physician-generated ECOG score recorded prior to any treatment using a Wilcoxon signed rank test. Pts were treated with standard chemotherapy. Survival analysis was performed using a Kaplan Meier analysis and Cox regression. Results: 92 pts (M: F-48:44) with a mean age of 65 years (39–83) were included. 67 (73%) presented with stage 4 disease. 62 (67%) had an MD-PS of 0–1, whereas only 51 (55%) had a Pt-PS of 0 -1. MD-PS 3–4 was seen in 9 (10%), compared to 28 (30%) by Pt-PS. Pt-PS was significantly different from MD-PS in 48% of scores (p=0.003). When scores were not congruent, 29/44 (66%) pts evaluated themselves as having a worse PS than the physician. Survival analysis demonstrated that stage and functional status irrespective of method of reporting was predictive of survival (p=0.01 for MD-PS and p=0.001 for Pt-PS). However, when comparing median survival by method of performance status evaluation, Pt-PS was associated with superior stratification of survival than MD-PS ( table 1 ). Conclusions: Pt-PS and MD-PS are not congruent almost 50% of the time. Pt-PS allows for better stratification of survival and should be further evaluated in prospective trials.

No significant financial relationships to disclose.

[Table: see text]

Physiological correlates of cancer-related fatigue in advanced non-small cell lung cancer (NSCLC) patients

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Background: Fatigue is a debilitating consequence of lung cancer and its treatments. The etiology of fatigue is unclear, and our current knowledge does not point to logical interventions. In this study, global fatigue score was assessed using the Brief Fatigue Inventory (BFI). A symptom questionnaire, as well as muscular and cardiorespiratory function, were assessed as potential contributors to the global fatigue score. Methods: Participants were evaluated by a physical therapist within the McGill Cancer Nutrition and Rehabilitation Program. Performance-based measures of physical function [upper limb strength and endurance (Jamar dynamometry), lower limb strength (30sec chair rise), cardiorespiratory function (2 minute walk -2MW)] and a symptom questionnaire [Edmonton Symptom Assessment Scale (ESAS)] were conducted at one point in time. Results: Eighty patients (43M:37F, mean age 68 ± 12 ) participated in the study. Forty-seven percent were actively receiving treatment at the time of assessment. On the BFI, 56% had moderate or severe fatigue and 88% indicated fatigue had interfered with their functioning during the past 24 hours. Global fatigue scores were unrelated to hand grip strength or endurance measurements but were significantly correlated with chair rise performance (R= -0.31, p<0.05), 2MW (R= -0.31, p<0.05), ESAS rating of pain (R=0.47, p<0.01), overall ESAS rating of breathlessness (R= 0.59, p<0.01), and ESAS rating of strength (R=0.58, p<0.01). Multivariate regression analysis suggested the best model for global fatigue scores incorporates chair rise performance, 2MW performance, ESAS rating of strength and ESAS rating of shortness of breath (adjusted R sq = 0.68, p<0.01). Conclusions: Fatigue is prevalent and impacts on the function of advanced NSCLC patients. Several key factors contribute to this fatigue, with muscular and cardiorespiratory restrictions playing an important role. Such findings may have clinical implications in the recommendations of rest and exercise to best manage fatigue.

No significant financial relationships to disclose.

Effect of "disuse" on mammalian fast-twitch muscle: joint fixation compared with neurally applied tetrodotoxin

The effect of disuse on the functional properties of fast-twitch mammalian muscle is controversial, perhaps because the various disuse models reduce activity to different degrees, and may introduce factors other than reduced activity per se. Our goal was to compare the effects of 14 days of disuse produced by neurally applied tetrodotoxin and joint fixation (knee and ankle) on several morphologic and functional characteristics of the rat gastrocnemius. Joint fixation produced a decrease in muscle wet weight and absolute tetanic tension measured in situ, and a preferential atrophy of slow-twitch fibers. The degree of atrophy was more severe with TTX-disuse and affected all fiber types to the same extent. In further contrast to joint fixation, TTX-disuse caused a preferential loss of myofibrillar protein and a decrease in tetanic tension per unit muscle wet weight. In addition, TTX-disuse resulted in an elevation of twitch:tetanic ratio, a prolonged twitch, and generated a relatively higher proportion of tetanic force at 50 Hz. The normalized maximal rate of tetanic tension development (% Po/ms) was highest in the TTX group. The fatigue index was unaffected by either intervention. The data suggest that complete disuse of mammalian fast-twitch muscle causes atrophy, prolongation of the twitch, and a loss in contractile strength per gram of tissue, and are consistent with qualitative or quantitative changes in the sarcoplasmic reticulum and a decrease in myofibrillar protein concentration with disuse.

Enzyme activities and reduced insulin need with training in streptozotocin-induced diabetic rats

Following a 12-week endurance training program, the SDH activities of gastrocnemius medialis muscle of streptozotocin-induced diabetic animals increased by 50%. On the other hand, a 14% decrease was observed in the same muscle of diabetic animals submitted to power training. No difference between groups, for soleus and gastrocnemius lateralis muscles following the two different training regimens was observed. It can be concluded that streptozotocin-induced diabetic animals controlled by daily insulin demonstrate a normal muscle enzyme adaptation to exercise. These data also demonstrate that regular power and/or endurance exercise can result in reduced exogenous insulin need in streptozotocin-induced diabetic rats (18% and 28% respectively), suggesting a more efficient membrane transport of glucose with induced exercise, and a decreased need for insulin supported transport.