Period Of Hypertrophy Research Articles

PP090-MON THE EFFECT OF DIFFERENT NUTRTIONAL SUPPLEMENT ON LIVER HYPERTROPHY AND BODY COMPOSITION AFTER PORTAL VEIN EMBOLISATION

Rationale: Residual liver (FLR) after liver resection should be more than 30% of the total liver (TLV). Portal vein embolisation can hypertrophise the FLR. The aim was to investigate the effects of supplementation on FLR hypertrophy, tumor volume changes (TV), body composition and nutritional status. Methods: Until now 20 patients with liver tumors, whose FLR after the planned liver resection was less than 30% of the TLV measured by CT-volumetry enrolled. In addition to the anthropometric and laboratory tests, bioimpedance analysis was performed to assess nutritional status and body composition. Patients in the arginine group received 2×200ml oral nutritional supplement (ONS), which contained 2×3 g arginine for the period of liver hypertrophy. Patients in the control group were supplemented with an ONS without arginine. Eight weeks after PVE control every measurements were performed again. Results: In the “arginine” group liver hypertrophy rate was higher (FLRArg: 15.37% vs. FLRc: 10.98%) and tumor volume growth was significantly (p < 0.05) lower in the arginine group than in the control group (TVArg: 10.38 cm3 vs. TVc: 93.91 cm3). Laboratory parameters indicating nutritional status changes became better in both groups after FLR hypertrophy. Body composition changes became better in both group after period of hypertrophy. Conclusion: Arginine supplementation may positively affect FLR hypertrophy and may reduce tumor volume growth after portal vein embolisation. Nutritional supplementation positively affects nutrition status and body composition, not only in undernourished patients.

Androgens Affect Myogenesis In Vitro and Increase Local IGF-1 Expression

The mechanism whereby anabolic androgens are associated with hypertrophy of skeletal muscle is incompletely understood but may involve an interaction with locally generated insulin-like growth factor (IGF) 1. The present investigation utilized a cell culture model of human skeletal muscle-derived cell maturation to test the hypothesis that androgens increase differentiation of human muscle precursor cells in vitro and to assess effects of androgen with or without IGF-1 on IGF-1 messenger RNA (mRNA) expression in human muscle precursor cells. Differentiation of muscle-derived cells was induced under standard low-serum conditions. Cultures were then exposed to androgen (testosterone (T)) at 50, 100, and 500 nM or IGF-1 (10-50 ng·mL⁻¹). Immunocytochemistry and real-time polymerase chain reaction (RT-PCR) were used to assess effects of androgens and IGF-1 after 3- (early) or 7-d (late) muscle differentiation, respectively; RT-PCR was used to quantify the effects on androgen receptor expression. Under low-serum conditions, 3-d exposure to androgens or IGF-1 or both resulted in no significant increase in cellular myogenic commitment. After 7-d exposure, however, T and IGF-1 were both found to increase fusion index with no observable synergistic effect. T also increased IGF-1 mRNA generation (P < 0.0001), whereas exogenous IGF-1 (P < 0.001) reduced IGF-1 mRNA transcription relative to control. The T effect was reversible after treatment with flutamide, an androgen receptor antagonist. Both T and IGF-1 increase myogenic commitment after 7-d exposure to a differentiation medium. With T causing a concomitant increase in IGF-1 mRNA underpinning IGF-1 as a central mediator in the cellular pathways associated with muscle hypertrophy, including those affected by androgens. The novel system described has the potential for elucidating the pattern of growth factor effects associated with androgens in skeletal muscle.

Testing the use/disuse hypothesis: pectoral and leg muscle changes in captive barnacle geese Branta leucopsis during wing moult

Previous studies on wild moulting waterfowl have demonstrated that flight and leg muscles experience periods of hypertrophy and atrophy. This is thought to be in response to the change in use of the locomotor muscles as described in the use/disuse hypothesis. We tested this hypothesis using captive barnacle geese. Forty geese were dissected before, during and after wing moult, to determine the changes in mass and functional capacity of the flight and leg muscles. Physiological cross sectional areas (PCSA) and mean fascicle lengths of functional muscle groups were calculated to ascertain the force-producing capabilities of the flight and leg muscles. At the onset of moult, flight muscle mass was at a minimum, having atrophied by 35% compared with pre-moult levels, but it returned to pre-moult levels by the end of wing moult. By contrast, the leg muscles hypertrophied during wing moult by 29%, and the PCSA of individual muscle groups increased substantially. Increases in mass, PCSA and fascicle length of individual leg muscle groups during moult suggest that, when flightless, the leg muscles are functionally adapted to provide greater force and/or manoeuvrability to the birds, to aid ground-based escape from predators. Through studying captive animals that are unable to fly, it has been possible to conclude that the major changes in leg and flight muscle in moulting captive geese cannot be explained through use or disuse. Instead, changes seem to be compensatory or to occur in anticipation of changes in locomotor patterns.

Differential activation of signal transduction pathways in human hearts with hypertrophy versus advanced heart failure.

Left ventricular failure is commonly preceded by a period of hypertrophy. Intriguingly, many of the signaling pathways that have been implicated in the regulation of hypertrophy, including the 3 mitogen-activated protein kinases (MAPKs: extracellular signal-regulated kinase, stress-activated protein kinase, and p38), protein phosphatase, calcineurin, and the protein kinase Akt and its target glycogen synthase kinase-3 (GSK-3), also regulate the apoptotic response. To understand the mechanisms that might regulate the progression of heart failure, we analyzed the activity of these signaling pathways in the hearts of patients with advanced heart failure, patients with compensated cardiac hypertrophy, and normal subjects. In patients with hypertrophy, neither the MAPK nor the Akt/GSK-3 pathways were activated, and the dominant signaling pathway was calcineurin. In failing hearts, calcineurin activity was increased but less so than in the hypertrophied hearts, and all 3 MAPKs and Akt were activated (and, accordingly, GSK-3ss was inhibited), irrespective of whether the underlying diagnosis was ischemic or idiopathic cardiomyopathy. In the failing heart, there is a clear prohypertrophic activity profile, likely occurring in response to increased systolic wall stress and neurohormonal mediators. However, with the activation of these hypertrophic pathways, potent proapoptotic and antiapoptotic signals may also be generated. Therapies directed at altering the balance of activity of these signaling pathways could potentially alter the progression of heart failure.

The effects of seasonal hypertrophy and atrophy on fiber morphology, metabolic substrate concentration and sound characteristics of the weakfish sonic muscle.

Male weakfish Cynoscion regalis possess highly specialized, bilateral, striated sonic muscles used in sound production associated with courtship. Androgen-driven hypertrophy of the muscles during the late spring spawning period results in a tripling of sonic muscle mass followed by post-spawning atrophy. This study examined the morphological and biochemical changes underlying seasonal changes in sonic muscle mass and the functional effects of these on contraction as measured by sound production. Sonic muscle fiber cross-sectional area (CSA) increased significantly during the period of hypertrophy and then decreased by nearly 60%. Both the CSA of the contractile cylinder and that of the peripheral sarcoplasm decreased significantly by late summer, with the peripheral ring of sarcoplasm virtually disappearing. Muscle protein content followed a similar trend, suggesting a major loss of structural elements during atrophy. Muscle glycogen and lipid content decreased precipitously in early June during the period of maximal sound production. Sound pressure level increased and sound pulse duration decreased with increasing sonic muscle mass, indicating that sonic muscle fibers contract with greater force and shorter duration during the spawning season. Neither the pulse repetition rate nor the number of pulses varied seasonally or with muscle mass, suggesting that the effects of steroids on the acoustic variables are more pronounced peripherally than in the central nervous system. Seasonal sonic muscle hypertrophy, therefore, functions as a secondary sexual characteristic that maximizes vocalization amplitude during the spawning period.

Cyclic changes in ciliation, secretion and cell height of the oviductal epithelium in women

Oviducts were obtained from women who elected to undergo sterilization either during a normal menstrual cycle, after the first trimester of pregnancy, or in the puerperium. The percent of ciliated cells, cell height and morphology of the fimbria and ampulla were determined and correlated with the stage of the reporductive cycle and plasma levels of the ovarian steroids. Mature ciliated and secretory cells were observed only at mid-cycle. Atrophy, deciliation and loss of secretory activity coincided with elevated levels of serum progesterone. These degenerative processes continued during pregnancy. Ciliation, hypertrophy, and restoration of secretory activity occurred when serum progesterone was essentially undetectable and estradiol relatively low. During each menstrual cycle the secretory cells were observed to undergo a complete cycle of dedifferentiation-differentiation, whereas 10--12% of the ciliated cells lost and regenerated their celia. Ciliogenic cells were frequently present in the epithelium obtained from women in the mid-follicular phase. Fibrous granules, deuterosomes, procentrioles and ciliary buds were observed in the apex of these cells. Plasma levels of estradiol were higher during periods of atrophy and deciliation than they were during periods of hypertrophy and reciliation. It appears that the serum levels of estradiol were adequate to maintain a mature epithelium at all the reproductive stages included in this study. However, progesterone, when present, blocked the growth-promoting effect of estradiol in the oviduct.

Lipide metabolism during cell division

1. 1. Adult male Holtzman rats were each given a single injection of P 32 as NaH 2P 32O 4 at 1, 3, and 18 days after partial hepatectomy, and were sacrificed 1 hr. later. Six hours prior to sacrifice, unoperated controls and 3-day hepatectomized rats received 0.03 mg. colchicine/100 g. body weight by subcutaneous injection. Livers were removed and the radioactivity and P in the lecithin, cephalin, and sphingomyelin fractions, as well as di-, tri-, tetra-, and pentaenoic acids were determined. 2. 2. The high P 32 uptake by the phospholipide fraction coincident with mitosis occurred in all three types of phospholipide isolated. It was not abolished by colchicine, a metaphase inhibitor, suggesting that it is associated with either interphase or prophase, but not with anaphase or telophase. 3. 3. There was an increase in the concentration of trienoic and a decrease in tetraenoic acid coincident with the period of hypertrophy (premitosis) in regenerating liver. There was an increase in dienoic acid coincident with the period of high mitotic activity. Blocking mitosis in metaphase with colchicine did not influence the level of dienoic acid.