Intermittent fasting induces rapid hepatocyte proliferation

Nutrient availability fluctuates in most natural populations, forcing organisms to undergo periods of fasting and re-feeding. It is unknown how dietary change influences cell proliferation in the liver. Here, we show that intermittent fasting (IF) promotes rapid hepatocyte proliferation. Mechanistically, IF elicits intestinal production of endocrine FGF15, which activates the b- KLOTHO receptor on hepatocytes to induce proliferation. Furthermore, IF-induced proliferation is locally controlled in hepatocytes by WNT signaling and the WNT target gene Tbx3. IF induces hepatocyte proliferation to re-establish a constant liver-to-body-mass ratio during periods of fasting and re-feeding and maintain the hepatostat. This study provides the first example of dietary influence on adult hepatocyte proliferation and identifies both systemic FGF and local WNT as regulators of this process.

Nicotinamide Riboside Alleviates Cardiac Dysfunction and Remodeling in Pressure Overload Cardiac Hypertrophy

Background. Cardiac hypertrophy is a compensatory response to pressure overload, which eventually leads to heart failure. The current study explored the protective effect of nicotinamide riboside (NR), a NAD+ booster that may be administered through the diet, on the occurrence of myocardial hypertrophy and revealed details of its underlying mechanism. Methods. Transverse aortic constriction (TAC) surgery was performed to establish a murine model of myocardial hypertrophy. Mice were randomly divided into four groups: sham, TAC, sham+NR, and TAC+NR. NR treatment was given daily by oral gavage. Cardiac structure and function were assessed using small animal echocardiography. Mitochondrial oxidative stress was evaluated by dihydroethidium (DHE) staining, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity. Levels of expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), IL-1β, TNF-α, and Sirtuin3 were measured by real-time PCR and ELISA. Expression levels of Caspase-1, Caspase-1 pro, cleaved Gasdermin D (GSDMD), NLRP3, ASC, Sirtuin3, ac-MnSOD, and total MnSOD were measured by Western blot. Results. Reductions in the heart/body mass ratio (HW/BW) and lung/body mass ratio (LW/BW) and in ANP, BNP, and LDH levels were observed in the TAC group on the administration of NR ( P < 0.05 ). Moreover, echocardiography data showed that cardiac dysfunction and structural changes caused by TAC were improved by NR treatment ( P < 0.05 ). NR treatment also reduced levels of the inflammatory cytokines, IL-1β and TNF-α, and attenuated activation of NLRP3 inflammasomes induced by TAC. Furthermore, changes in DHE staining, MDA content, and SOD activity indicated that NR treatment alleviated the oxidative stress caused by TAC. Data from ELISA and Western blots revealed elevated myocardial NAD+ content and Sirtuin3 activity and decreased acetylation of MnSOD after NR treatment, exposing aspects of the underlying signaling pathway. Conclusion. NR treatment alleviated TAC-induced pathological cardiac hypertrophy and dysfunction. Mechanically, these beneficial effects were attributed to the inhibition of NLRP3 inflammasome activation and myocardial inflammatory response by regulating the NAD+-Sirtuin3-MnSOD signaling pathway.

Using relative brain size to better understand trophic interactions and phenotypic plasticity of invasive lionfish (Pterois volitans)

Predator-prey dynamics provide critical insight into overall coral reef health. It has been shown that predator-prey relationships link the relative brain size of predators to their prey. Predation pressure forces prey to use decision-making skills that require higher cognition by inspecting and identifying predators and then adjusting their behavior to achieve the highest chance for survival. However, the predation pressure that prey face outweighs the pressure predators face to find prey, resulting in prey having larger relative brain sizes than their predators. There is little data on the relative brain size of fishes with few natural predators such as Pterois volitans. This study compared the brain mass to body mass ratio of Pterois volitans, which have very few natural predators and thus very little predation pressure, to the brain mass to body mass ratio of their prey, possible predators, competitors, and taxonomically similar fish. Lionfish had a significantly smaller relative brain size than their predators, prey, and competitors, but was not significantly smaller than taxonomically similar fish. These results demonstrate that the morphological anti-predator adaptation of venomous spines causes little predation pressure. Thus, lionfish do not use the same cognitive skills as other prey or predators and, in turn, have smaller relative brain sizes.

COLONY COMPOSITION AND BIOMASS OF MACROTERMES GILVUS HAGEN (BLATTODEA: TERMITIDAE) IN INDONESIA

ABSTRACT: There is no study conducted to investigate the composition and biomass of Macrotermes gilvus Hagen in natural forest ecosystem. This study aimed to analyze the colony composition and biomass of M. gilvus Hagen colony in natural forest and to evaluate the need of food of the species as well as factors affecting it. Research was conducted in Yanlappa Sanctuary, Bogor, West Java. Termites were surveyed by collecting individual M. gilvus Hagen from different colony at different size of mound, small (0 – 0.99 m), medium (1- 1.99 m), large (? 2 m) and then were measured the number of individuals, wet and dry body mass, ratio of dry or wet body mass, and the average of biomass. Results indicated that the small mount was dominated by workers, whereas the medium and the large nest was dominated by nymph. Mean of the termite biomass was 936 kg/ha2. Average of termite biomass collected from large mount was 949.8 kg/km2, medium mount was 605.2 kg/ha2 and small mount was about 537.5 kg/ha2. Factor affecting the biomass of subterranean termite M. gilvus Hagen are food source, energy efficiency, predators, and environment. The presence of termite mounds influences natural ecosystem, but that the type of mound plays a crucial role in determining the nature of the effects. ABSTRAK: Kajian tentang komposisi koloni dan biomas anai-anai tanah M. gilvus Hagen di hutan alam belum pernah dilakukan. Kajian ini bertujuan untuk menganalisis komposisi koloni dan biomas koloni anai-anai tanah M. gilvus Hagen di hutan alam dan menganalisa faktor-faktor yang mempengaruhi pemakanannya. Kajian ini dilakukan di Cagar Alam Yanlappa, Bogor, Jawa Barat. Hasil kaji selidik menunjukkan terdapat perbedaan koloni didasarkan pada ukuran tinggi sarang. Sarang kecil (0 – 0.99 m), sarang sedang (1- 1.99 m), dan sarang besar (? 2 m) dan ukuran berat basah, berat kering serta kadar berat basah atau berat kering, dan rata-rata biomas. Hasil kajian menunjukkan bahwa sarang kecil didominasi oleh koloni pekerja, sementara itu sarang serdahana dan sarang besar didominasi oleh koloni nympha. Rata-rata biomas yang ditemukan untuk sarang besar 949.8 kg/ha2, sarang serdahana 605.2 kg/ha2, dan sarang kecil 537.5 kg/ha2. Faktor-faktor yang mempengaruhi biomas anai-anai tanah M. gilvus Hagen adalah makanan, tenaga, pemangsa dan lingkungan. Kehadiran koloni anai-anai mempengaruhi ekosistem semulajadi, tetapi jenis koloni memainkan peranan penting dalam menentukan sifat kesannya.

Shorter but More Frequent Rest Periods: No Effect on Velocity and Power Compared to Traditional Sets not Performed to Failure

Performing traditional sets to failure is fatiguing, but redistributing total rest time to create short frequent sets lessens the fatigue. Since performing traditional sets to failure is not always warranted, we compared the effects of not-to-failure traditional sets and rest redistribution during free-weight back squats in twenty-six strength-trained men (28 ± 5.44 y; 84.6 ± 10.5 kg, 1RM-to-body-mass ratio of 1.82 ± 0.33). They performed three sets of ten repetitions with 4 min inter-set rest (TS) and five sets of six repetitions with 2 min inter-set rest (RR6) at 70% of one repetition maximum. Mean velocity (p > 0.05; d = 0.10 (-0.35, 0.56)) and mean power (p > 0.05; d = 0.19 (-0.27, 0.64)) were not different between protocols, but the rating of perceived exertion (RPE) was less during RR6 (p < 0.05; d = 0.93 (0.44, 1.40)). Also, mean velocity and power output decreased (RR6: 14.10% and 10.95%; TS: 17.10% and 15.85%, respectively) from the first repetition to the last, but the percentage decrease was similar (velocity: p > 0.05; d = 0.16 (0.30, 0.62); power: p > 0.05; d = 0.22 (-0.24, 0.68)). These data suggest that traditional sets and rest redistribution maintain velocity and power output to a similar degree when traditional sets are not performed to failure. However, rest redistribution might be advantageous as RR6 displayed a lower RPE.

PO-201 Aging attenuates the effect of aerobic capacity in muscle and serum metabolic profile but not in white adipose tissue

Objective Aerobic capacity is a quantitative predictor of the morbidity and mortality in many diverse patient populations. While aging is the main factor affecting aerobic capacity. The present study aimed to assess the effect of aerobic capacity and aging on metabolic profile in rats and to investigate the metabolic interactions between white adipose tissue (WAT), muscle and serum. Methods In this study, we used rat models that were selectively bred to differ in maximal running capacity (High capacity runners (HCR) and Low capacity runners (LCR)). Part of the rats were sacrificed after 9 months and the rest at 21 months. The effect of aerobic capacity on metabolic profile was assessed from 9 months old young rats (HCR-Y and LCR-Y), while the effect of aging on the metabolic profile in different capacity rats was determined comparing 9 months to 21 months old rats (HCR-O and LCR-O). Nuclear magnetic resonance (NMR) spectroscopy was performed to detect the metabolomics of WAT, muscle and serum. Partial least-squares-discriminant analysis (PLS-DA) was used for pattern recognition between HCR-Y and LCR-Y and between HCR-O and LCR-O. Metabolites with variable influence on projection (VIP) >1.0 and p<0.05 were classified as significantly different metabolites between groups. Spearman correlation was used to assess the metabolic interactions between white adipose tissue (WAT), muscle and serum. Results HCR-Y rats had significantly higher skeletal muscle mass-to-body mass ratio (p<0.001), while lower body mass (p<0.001), fat mass (p<0.001), skeletal muscle mass (p=0.035) and fat mass to body mass ratio (p=0.004) than LCR-Y rats. The running capacity of HCR-Y rats was 132.7% (best running speed) better than LCR-Y rats (p<0.001). However, with age, the difference between body compositions between the two capacity groups became insignificant. HCR-O only had significantly lower body mass than the LCR-O (p=0.02). Running capacity (p=0.06) was 86.4% (best running speed) higher in the HCR-O rats than that of the LCR-O rats. PLS-DA revealed marked effects of aerobic capacity on metabolic profile in all three tissue types between HCR-Y and LCR-Y. The metabolic profile classification and prediction was best (i.e. sharper) in muscle than in WAT and serum. In addition, muscle and serum contained more significantly different metabolites than WAT in HCR-Y than in LCR-Y. Pathway analysis of the significantly different metabolites between HCR-Y and LCR-Y revealed that all the pathways belong to the lipid metabolism and amino acid metabolism in muscle while in serum it is only amino acid metabolism. However, in the case of the old groups, the PLS-DA gave reversed results. It revealed that WAT performed best in terms of classification and prediction of metabolites between HCR-O and LCR-O and had the most significantly different metabolites out of the three tissue types. The significantly different metabolites’ pathways belong to lipid metabolism in WAT. When assessing the metabolic interaction between different tissue types, all significantly different metabolites between HCR and LCR rats in young and old groups were moderately or strongly correlated (Spearman correlation between 0.45-0.9) with one or more metabolites in any of the three tissues. Conclusions In this study, we assessed the metabolic profile and body composition of WAT, muscle and serum in young and old rats with different aerobic capacities. We found that aerobic capacity greatly impacts body composition and the metabolic profile in muscle and serum in young rats, however the impact is attenuated with age. In addition, it is aging and not aerobic capacity that had the most influence on WAT metabolites. This suggest that WAT has more important role in aging process than previously assumed.