Proanthocyanidins potentiate hypothalamic leptin/STAT3 signalling and Pomc gene expression in rats with diet-induced obesity.

OBJECTIVE: Dietary obesity is usually linked with hypothalamic leptin resistance, in which the primary impact is an interference in the homeostatic control of body weight and appetite. Notably, proanthocyanidins (PACs), which are the most abundant phenolic compounds present in human diet, modulate adiposity and food intake. The aim of this study was to assess whether PACs could re-establish appropriate leptin signalling in both the hypothalamus and peripheral tissues. DESIGN: Male Wistar rats were fed either a standard chow diet (STD group, n=7) or a cafeteria diet (CD) for 13 weeks. The CD-fed rats were treated with either grape-seed PAC extract (GSPE) at 25 mg per kg of body weight per day (CD+GSPE group, n=7) or with the vehicle (CD group, n=7) for the last 21 days of the study period. Specific markers for intracellular leptin signalling, inflammation and endoplasmic reticulum stress in the hypothalamus, liver, mesenteric white adipose tissue and skeletal muscle were analysed using immunoblotting and quantitative PCR. RESULTS: GSPE treatment significantly reduced the food intake but did not reverse the hyperleptinemia and body wt gain assessed. However, the animals treated with GSPE exhibited greater hypothalamic activation of signal transducer and activator of transcription-3, which was associated with a rise in the Pomc mRNA levels compared with the CD group. In addition, this restoration of leptin responsiveness was accompanied by lower local inflammation and increased Sirt1 gene expression. The effects of the GSPE treatment in the peripheral tissues were not as evident as those in the hypothalamus, although the GSPE treatment significantly restored the mRNA levels of Socs3 and Ptp1b in the skeletal muscle. CONCLUSIONS: The use of GSPE reduces hyperphagia and improves the central and peripheral leptin resistance associated with diet-induced obesity. Our results suggest that GSPE could exert these effects partially by increasing Sirt1 expression and preventing hypothalamic inflammation.

Effect of low molecular grape seed proanthocyanidins on blood pressure and lipid homeostasis in cafeteria diet-fed rats

Cardiovascular disease (CVD) and related pathologies are the leading cause of death worldwide. Fruits and vegetables are known to improve CVD, an effect that has been associated with flavonoid intake. The aim of this study was to simultaneously evaluate the acute effect of a low molecular grape seed proanthocyanidin extract (LM-GSPE) on two of the main risk factors of CVD, high blood pressure (BP) and dyslipidaemia, using high-fat diet-fed rats. Therefore, male Wistar rats that were cafeteria diet fed for 10 weeks were administered with 375 mg/kg of body weight of LM-GSPE, and the BP as well as plasmatic and hepatic parameters were determined at 6 h post-administration. The BP and plasmatic and hepatic lipid were decreased 6 h after the LM-GSPE administration. Moreover, the liver lipid peroxidation products decreased after the LM-GSPE treatment, indicating a reduction in oxidative stress. However, hepatic-reduced glutathione or plasma angiotensin converting enzyme activity was not altered by the LM-GSPE. In conclusion, grape proanthocyanidins is able to simultaneously reduce more than one risk factor for CVD by decreasing the BP and improving hypertriglyceridaemia at least in part due to an improvement in oxidative stress. These results open up the possibility of using grape proanthocyanidins in functional foods for CVD improvement

Effect of low molecular grape seed proanthocyanidins on blood pressure and lipid homeostasis in cafeteria diet-fed rats.

Cardiovascular disease (CVD) and related pathologies are the leading cause of death worldwide. Fruits and vegetables are known to improve CVD, an effect that has been associated with flavonoid intake. The aim of this study was to simultaneously evaluate the acute effect of a low molecular grape seed proanthocyanidin extract (LM-GSPE) on two of the main risk factors of CVD, high blood pressure (BP) and dyslipidaemia, using high-fat diet-fed rats. Therefore, male Wistar rats that were cafeteria diet fed for 10 weeks were administered with 375 mg/kg of body weight of LM-GSPE, and the BP as well as plasmatic and hepatic parameters were determined at 6 h post-administration. The BP and plasmatic and hepatic lipid were decreased 6 h after the LM-GSPE administration. Moreover, the liver lipid peroxidation products decreased after the LM-GSPE treatment, indicating a reduction in oxidative stress. However, hepatic-reduced glutathione or plasma angiotensin converting enzyme activity was not altered by the LM-GSPE. In conclusion, grape proanthocyanidins is able to simultaneously reduce more than one risk factor for CVD by decreasing the BP and improving hypertriglyceridaemia at least in part due to an improvement in oxidative stress. These results open up the possibility of using grape proanthocyanidins in functional foods for CVD improvement.

Effect of a cocoa polyphenol extract in spontaneously hypertensive rats.

In this study, we evaluated the short-term effect of a cocoa polyphenol extract (CPE), in spontaneously hypertensive rats (SHR). Male 17-22-week-old SHR were administered by intragastric gavage water, 50 mg kg(-1) Captopril or CPE at different doses (13, 26, 80 and 160 mg kg(-1)). The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded by the tail cuff method before the administration and also 2, 4, 6, 8, 24, 48 and 72 h post-administration. Highly significant decreases in the SBP and in the DBP were observed when captopril or CPE was administered to SHR. The cocoa extract produced a dose dependent effect in the SBP of the SHR up to the dose of 80 mg kg(-1). Nevertheless this dose of CPE did not decrease the arterial blood pressure in the normotensive Wistar Kyoto rats. The decrease in the SBP caused by 80 mg kg(-1) of CPE in the SHR (-39.1 ± 3.7 mm Hg) was maximum 6 h post-administration, and the initial values of SBP were recovered 72 h post-administration of this extract. Paradoxically, 160 mg kg(-1) of the cocoa extract caused a decreased antihypertensive effect than lower doses of CPE. In addition, the decrease in DBP was always more accentuated when the dose of CPE administered was lower. Our results suggest that CPE may be used as a functional food ingredient with beneficial effects for controlling arterial blood pressure.

Evidence that nitric oxide mediates the blood pressure lowering effect of a polyphenol-rich cocoa powder in spontaneously hypertensive rats.

The involvement of endothelial-relaxing factors on the antihypertensive effect of a polyphenol-rich cocoa powder named CocoanOX (CCX) was studied. Thirty 17-20-week-old male spontaneously hypertensive rats (SHR), weighing 314 ± 3g were used. They were divided into two groups of 15 animals, that were respectively administered by gastric intubation distilled water or 300 mg/kg CCX dissolved in distilled water, between 9 am and 10 am. 2h after the oral administration, 5 of the animals in each group were intraperitoneally administered 1 ml saline. The remaining rats in both groups were divided into another two groups of 5 animals that were respectively administered 30 mg/kg Nw-nitro-L-arginine methyl ester (L-NAME) dissolved in 1 ml of saline or 5 mg/kg indomethacin also dissolved in 1 ml of saline by the same procedure. Systolic blood pressure (SBP) was recorded in the rats by the tail cuff method before the initial oral administration and also 4h after this administration. CCX caused a significant decrease in SBP (-49.5 ± 4.9 mmHg; p<0.05). L-NAME caused a clear increase in SBP in the rats (+16.2 ± 4.3 mmHg; p<0.05), and the effect of CCX was not observed in the SHR that were treated with L-NAME (+4.1 ± 1.7 mmHg; p<0.05). Nevertheless, indomethacin treatment did not modify SBP in the SHR and this compound failed to modify the antihypertensive effect of CCX in these animals. In conclusion, this study proves the participation of NO in the antihypertensive effect of CCX in the SHR strain. When CCX is administered, the synthesis, or the bioavailability, of this endothelial factor could increase, but other mechanisms may also participate in the antihypertensive effect of this cocoa powder. In any case, further investigation should be carried out to characterize the signalling pathways involved in the antihypertensive effect of CCX.

Changes in arterial blood pressure of a soluble cocoa fiber product in spontaneously hypertensive rats.

The effect produced by long-term intake of a soluble cocoa fiber product (SCFP) on the development of hypertension of spontaneously hypertensive rats (SHR) was evaluated. Twenty male 3-week-old SHR were divided into two groups of 10 animals that drank either tap water (control) or a solution of SCFP (0.75 g/day SCFP) until the 20th week of life. Five 20-week-old rats of each group were sacrificed. Tap water as drinking fluid was given to all the animals from the 20th to 24th week of life. The 24-week-old rats were also sacrificed. Body weight, liquid and dry food intake, and arterial blood pressure (tail cuff) were recorded weekly. Malondialdehyde (MDA), glucose and angiotensin converting enzyme (ACE) activity in the plasma from the sacrificed rats were also obtained, and we evaluated the relaxation caused by acetylcholine in the aorta from these animals. SCFP attenuated the development of hypertension in SHR; however, the withdrawal of SCFP caused an increase in blood pressure in the rats. Body weight gain was slower in the group treated with SCFP. SCFP increased liquid intake but decreased dry food intake in the rats. SCFP decreased plasma MDA concentrations and slightly decreased plasma ACE activity, but no differences were observed in plasma glucose and in the aorta responses to acetylcholine in both groups of 20-week-old SHR. We have demonstrated the antihypertensive and antioxidant properties of SCFP. The control of body weight and the control of increased angiotensin II may be involved in the antihypertensive effect of this product.

Péptidos antihipertensivos derivados de proteínas de leche y huevo / Peptides with antihypertensive activity obtained from milk and egg proteins

Algunos fragmentos de proteínas alimentarias, una vez liberados mediante hidrólisis, pueden producir un descenso del tono arterial. Son importantes los hidrolizados y péptidos provenientes de proteínas lácteas. Destacan los hidrolizados de caseína con tripsina, y los productos antihipertensivos obtenidos por fermentación de la leche con Lactobacillus helveticus. Estos productos contienen secuencias como Val-Pro-Pro (VPP) e Ile-Pro-Pro (IPP), que inhiben la enzima convertidor a de la angiotensina (ECA). Algunas cepas de Enterococcus faecalis también producen péptidos antihipertensivos inhibidores de la ECA. Entre estos péptidos destaca la secuencia LHLPLP. Existen asimismo péptidos e hidrolizados antihipertensivos derivados de proteínas de huevo. Podemos citar las secuencias FRADHPFL (ovokinina) y RADHPF (ovokinina 2-7) con actividad vasodilatadora endotelio-dependiente, y algunos hidrolizados de clara de huevo que inhibenla ECA. Los productos mencionados podrían utilizarse como ingredientes en alimentos funcionales. Algunos han probado ya su eficacia y seguridad en pacientes hipertensos

Antihypertensive hydrolysates and peptides have been isolated from food proteins. Among them, there are of particular interest the antihypertensive casein hydrolysates, and some antihypertensive products obtained when milk was fermented by Lactobacillus helveticus. The sequences Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), with angiotensin- converting enzyme (ACE) inhibitory activity, have been isolated from these fermented products. Selected Enterococcus faecalis strains can also produce milk derived peptides with ACE inhibitory and antihypertensive activities. The main of them is the sequence LHLPLP. Some studies also describe the production of antihypertensive hydrolysates and peptides from egg proteins. The sequences FRADHPFL (ovokinin) and RADHPFL (ovokinin 2-7),that have shown endothelium-dependent vasodilator activity, were obtained at first. Some egg white hydrolysates with ACE inhibitory activity have also been described. The idea of including the abovementioned products as functional food ingredients is particularly attractive. Some of them have already proved their safety and effectiveness in hypertensive patients

[Peptides with antihypertensive activity from milk and egg proteins]. / Péptidos antihipertensivos derivados de proteínas de leche y huevo.

Antihypertensive hydrolysates and peptides have been isolated from food proteins. Among them, there are of particular interest the antihypertensive casein hydrolysates, and some antihypertensive products obtained when milk was fermented by Lactobacillus helveticus. The sequences Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), with angiotensin-converting enzyme (ACE) inhibitory activity, have been isolated from these fermented products. Selected Enterococcus faecalis strains can also produce milk derived peptides with ACE inhibitory and antihypertensive activities. The main of them is the sequence LHLPLP. Some studies also describe the production of antihypertensive hydrolysates and peptides from egg proteins. The sequences FRADHPFL (ovokinin) and RADHPFL (ovokinin 2-7), that have shown endothelium-dependent vasodilator activity, were obtained at first. Some egg white hydrolysates with ACE inhibitory activity have also been described. The idea of including the above-mentioned products as functional food ingredients is particularly attractive. Some of them have already proved their safety and effectiveness in hypertensive patients.

Highly methoxylated pectin improves insulin resistance and other cardiometabolic risk factors in Zucker fatty rats.

In this study, we evaluated the effect of a highly methoxylated apple pectin (HMAP) on cardiometabolic risk factors in Zucker fatty rats. beta-Glucan, a fiber known for its hypocholesterolemic properties, also was used. The rats fed both fiber-enriched diets exhibited a reduction in body weight and in total cholesterol and triglycerides when compared to the Zucker fatty rats fed the standard diet. The effect on the lipid profile was more remarkable in the HMAP group. A decrease in blood glucose was only noticed in this group. Moreover, a decrease in plasma insulin, HOMA-IR, and HOMA-beta was noticed in the fiber groups, and in particular in the HMAP group, these variables being similar to the lean rats. Blood pressure and endothelial function were similar in all the Zucker fatty rats. These results warrant evaluation in humans to determine if HMAP could be used as a functional ingredient to reduce lipid profile, insulin resistance, and other cardiometabolic risk factors.

Determination of the antihypertensive peptide LHLPLP in fermented milk by high-performance liquid chromatography-mass spectrometry.

Among different lactic acid bacteria isolated from raw milk, 4 Enterococcus faecalis strains have stood out as producers of fermented milk with potent antihypertensive activity. The peptide beta-casein f(133-138), LHLPLP, was identified as one of the major peptides responsible for the activity of these fermented milk products. A simple method was developed to quantify this peptide in fermented milk using high-performance liquid chromatography coupled in line with mass spectrometry. This procedure does not require any previous sample fractionation or extraction, and direct analysis of the water-soluble extract obtained from the fermented milk can be performed. Validation studies showed sufficient specificity, reproducibility, linearity, and recovery, demonstrating that this method can be used for the routine quantification of LHLPLP during the production of fermented milk products. The developed method was readily applied to quantify the peptide LHLPLP under different fermentation conditions and with different aromatized products.

Efecto producido por la ingesta crónica de leche fermentada por Enterococcus faecalis CECT 5728 en ratas hipertensas / Effect produced by chronic intake of milk fermented by Enterococcus faecalis CECT 5728 in hypertensive rats

Introducción y objetivos. La fermentación de la leche por algunas bacterias genera péptidos con actividad inhibidora de la enzima convertidora de la angiotensina. Se evalúan los cambios de la presión arterial que produce en ratas espontáneamente hipertensas la administración crónica de leche fermentada por Enterococcus faecalis CECT 5728 con actividad inhibidora de esta enzima. Material y métodos. Se utilizaron ratas macho espontáneamente hipertensas recién destetadas con 3 semanas de vida. Las ratas se dividieron en cinco grupos que ingerían los siguientes productos líquidos: agua (control negativo), leche fermentada sin actividad inhibidora de la enzima convertidora de la angiotensina (testigo), captopril (100 mg/kg) (control positivo), leche fermentada por Enterococcus faecalis CECT 5728 y leche fermentada por Enterococcus faecalis CECT 5728 que estaba enriquecida en calcio. Los tratamientos se retiraron cuando las ratas tenían 20 semanas de vida. Se midió la presión arterial sistólica y diastólica de las ratas mediante el método del maguito en la cola cuando tenían 5, 10, 15, 20 y 25 semanas de vida. Resultados. El tratamiento con captopril disminuyó significativamente la presión arterial sistólica y diastólica de las ratas. La leche fermentada por Enterococcus faecalis CECT 5728 también disminuyó significativamente estas variables, pero su efecto fue menor que el de captopril. Los valores de la presión arterial sistólica y diastólica aumentaron tras la retirada de los tratamientos antihipertensivos. Conclusiones. Podría utilizarse la cepa bacteriana Enterococcus faecalis CECT 5728 para producir leches fermentadas útiles en el tratamiento y/o la prevención de la hipertensión

Introduction and objectives. Fermentation of milk by some bacteria generates peptides with angiotensin converting enzyme inhibitor activity. The changes of blood pressure that are produced in spontaneous hypertensive rats by the chronic administration of milk fermented by Enterococcus faecalis CECT 5728 with inhibitor activity of this enzyme are evaluated. Material and methods. Recently weaned spontaneous male hypertensive rats with 3 weeks of life were used. The rats were divided into five groups that took the following liquid products: water (negative control), fermented milk without angiotensin converting enzyme inhibitor activity (control), captopril (100 mg/kg) (positive control), milk fermented by Enterococcus faecalis CECT 5728, and milk fermented by Enterococcus faecalis CECT 5728 that was enriched in calcium. The treatments were withdrawn when the rats were 20 weeks old. Systolic and diastolic blood pressure of the rats was measured with the tail cuff method, when they were 5, 10, 15, 20 and 25 weeks old. Results. Treatment with captopril significantly decreased the systolic and diastolic blood pressure of the rats. Milk fermented by Enterococcus faecalis CECT 5728 also significantly decreased these variables, but its effect was less than that of captopril. The systolic and diastolic blood pressure values increased after withdrawal of the antihypertensive treatments. Conclusions. The bacterial strain Enterococcus faecalis CECT 5728 can be used to produce fermented milks useful in the treatment and/or prevention of hypertension

Changes in arterial blood pressure in hypertensive rats caused by long-term intake of milk fermented by Enterococcus faecalis CECT 5728.

We have evaluated the changes in arterial blood pressure caused in spontaneously hypertensive rats (SHR) by long-term intake of an Enterococcus faecalis CECT 5728-fermented milk with significant angiotensin-converting enzyme (ACE)-inhibitory activity. After being weaned, male 3-week-old SHR were randomized into five groups. Until the 20th week of life, rats in each group were given one of the following drinking fluids: tap water (negative control 1), a fermented milk without ACE-inhibitory activity (negative control 2), captopril (100 mg/kg) (positive control), the E. faecalis CECT 5728-fermented milk that had significant ACE-inhibitory activity, or Ca-enriched E. faecalis CECT 5728-fermented milk. Animals in the different groups were then given tap water as drinking fluid from the 20th to 25th week of life. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly in the rats, from the 6th to 25th week of life, by the tail-cuff method. A definite decrease in SBP and DBP could be observed in the rats treated with captopril and also in the rats that received the E. faecalis CECT 5728-fermented milks. The greatest antihypertensive effect was observed when the pharmacological treatment was administered. The effect of the Ca-enriched fermented milk was slightly more accentuated and more constant than the effect of the E. faecalis CECT 5728-fermented milk that had not been enriched in Ca. SBP and DBP increased in the treated SHR when the corresponding antihypertensive treatment was removed. Fermentation of milk with E. faecalis CECT 5728 may therefore be a successful strategy to produce a functional food with antihypertensive activity.

Antifibrogenic effect in vivo of low doses of insulin-like growth factor-I in cirrhotic rats.

Insulin-like growth factor-I (IGF-I) is produced mainly in the liver and it induces beneficial effects on the nutritional status, the liver function and oxidative hepatic damage in cirrhotic rats. The aim of this work was to analyze the effect of IGF-I on mechanisms of fibrogenesis in cirrhotic rats. Liver cirrhosis was induced by CCl(4) inhalation and phenobarbital in Wistar rats. Ten days after stopping CCl(4) administration (day 0), rats received either IGF-I (2 microg/100 g bw/day) (CI+IGF) or saline (CI) subcutaneously during 14 days. Animals were sacrificed on day 15. As control groups were used: healthy rats (CO) and healthy rats treated with IGF-I (CO+IGF). Liver histopathology, hydroxyproline content, prolyl hydroxylase activity, collagen I and III mRNA expression and the evolution of transformed Ito cells into myofibroblasts were assessed. Among the two control groups (CO+IGF), no differences were found in hydroxyproline content and these levels were lower than those found in the two cirrhotic groups. Compared with untreated cirrhotic rats, the CI+IGF-I animals showed a significant reduction in hydroxyproline content, prolyl hydroxylase activity and collagen alpha 1(I) and alpha1(III) mRNA expression. A higher number of transformed Ito cells (alpha-actin +) was observed in untreated cirrhotic animals as compared to CO and CI+IGF groups. In summary, treatment with IGF-I reduced all of the studied parameters of fibrogenesis. In conclusion, low doses of IGF-I induce in vivo an antifibrogenic effect in cirrhotic rats.

Effects of IGF-I treatment on osteopenia in rats with advanced liver cirrhosis.

IGF-I is an anabolic hormone which has been reported to increase bone formation in several conditions of undernutrition. Advanced liver cirrhosis is associated with osteopenia and also with low serum levels of IGF-I. Previous results showed that low doses of IGF-I increase osteoblastic activity and decrease bone reabsorption in early liver cirrhosis. The aim of this study was to evaluate whether IGF-I-treatment also induces beneficial effect on osteopenia associated with advanced cirrhosis. Rats with ascitic cirrhosis were divided into two groups: group CI (n=10) which received saline and group CI+IGF (n=10) which were treated with IGF-I (2 microg/100 g bw x day, sc, during 21 days). Healthy controls which received saline were studied in parallel (CO n=10). On the 22nd day, the animals were sacrificed, and bone parameters were analyzed in femur. Posterior-anterior diameter was similar in all groups. No significant differences were observed in bone content of calcium, total proteins, collagen and hydroxyapatite in cirrhotic rats as compared with controls. However, CI rats showed significant reductions in total bone density (-13.5%, p<0.001) assessed by densitometry and radiological study. In CI+IGF rat bone density (assessed by densitometry) improved significantly as compared with CI animals. In summary, osteopenia characterized by loss of bone mass and preserved bone composition was found in rats with advanced cirrhosis induced by CCl4 and phenobarbital in drinking water. This bone disorder is partially restored by treatment with low doses of IGF-I during only three weeks. Thus, IGF-I could be considered as a possible therapy for osteopenia associated with advanced liver cirrhosis.

Osteopenia in rats with liver cirrhosis: beneficial effects of IGF-I treatment.

BACKGROUND/AIMS: Liver cirrhosis is associated with osteopenia and also with low levels of IGF-I. This hormone has been reported to stimulate bone formation in states of undernutrition and low bone turnover. Our aims were to evaluate whether osteopenia develops in male Wistar rats with CCl4-induced cirrhosis and whether IGF-I is effective in the restoration of bone mass in these animals. METHODS: Cirrhotic rats were distributed into two groups: group CI (n = 12) which received placebo and group CI + IGF (n = 12) which was treated with human recombinant IGF-I (2 microg/100 g bw/day, s.c., 21 days). Twelve normal animals which received placebo constituted the control group. On the 22nd day, the animals were sacrificed, and bone parameters were analyzed in femur and/or tibia. RESULTS: Posterior-anterior and latero-medial diameters were similar in all groups. Also, no significant differences were observed in bone contents of calcium, total proteins, collagen and hydroxyapatite in CI rats as compared with controls. However, CI rats showed significant reductions in bone weight (-13.5%, p < 0.001), total bone density (-9.28%, p < 0.001), and increased perimedullar bone resorption and urinary levels of deoxypyridinoline (a marker of bone resorption). In CI + IGF rats these parameters improved significantly as compared with CI animals. CONCLUSIONS: Osteopenia characterized by loss of bone mass and preserved bone composition is found in rats with CCl4-induced cirrhosis. This bone disorder is partially corrected by treatment with low doses of IGF-I. Since osteoporosis seems to be the predominant form of osteopenia in patients with cirrhosis, IGF-I should be considered as a possible therapy for this disorder.

Hepatoprotective effects of insulin-like growth factor I in rats with carbon tetrachloride-induced cirrhosis.

BACKGROUND & AIMS: Bioavailability of insulin-like growth factor (IGF-I) is reduced in liver cirrhosis. The aim of this study was to analyze the effect of IGF-I on liver histopathology and function in experimental cirrhosis. METHODS: Rats received CCl4 inhalations for 11 or 30 weeks (protocols 1 and 2, respectively) and were treated with 2 microg x 100 g body wt(-1) x day(-1) IGF-I (group CI + IGF) or saline (group CI) on weeks 13 and 14 (protocol 1) or on weeks 28-30 (protocol 2). Normal rats were studied in parallel. RESULTS: Serum albumin and total protein levels were reduced in CI but not in CI + IGF rats compared with normal rats. Clotting factors II, VII, and X were significantly greater in CI + IGF than in CI rats. Liver lipid peroxidation products were significantly increased in CI but not in CI + IGF rats, and liver fibrosis was less pronounced in CI + IGF than in CI animals. The activities of antioxidant enzymes and mitochondrial transmembrane potential were reduced compared with normal animals in CI but not in CI + IGF rats. CONCLUSIONS: IGF-I improves liver function and reduces oxidative liver damage and fibrosis in rats with compensated or advanced liver cirrhosis. Improved mitochondrial function could play a role in the hepatoprotective effect of this hormone.

Low doses of insulin-like growth factor-I improve nitrogen retention and food efficiency in rats with early cirrhosis.

BACKGROUND/AIMS: In order to ascertain whether malnutrition is an early-onset feature of liver cirrhosis and whether the anabolic hormone insulin-like growth factor I (IGF-I) could be useful in the treatment of this complication, we analyzed the nutritional alterations present in rats with early-stage liver cirrhosis and the effects of IGF-I on nutritional parameters in these animals. METHODS: After a 24 h fast, a 15N-enriched diet was administered for 5 days to normal control rats and to cirrhotic rats receiving subcutaneous injections of vehicle (Group 1) or IGF-I, 2 micrograms.100 g bw-1.day-1, (Group 2) during the 5 experimental days. 15N, a stable N isotope, was measured in biological samples by mass spectrometry. RESULTS: Compared with control rats, Group 1 animals showed significant reductions in N intake and food efficiency (p < 0.05, both). In addition, the weight of the gastrocnemius muscle, its total N content and the dietary N content of this muscle were significantly lower in Group 1 than in control animals (p < 0.05, all). In rats from Group 2, mean values of N intake, food efficiency, gastrocnemius N content and the amount of dietary N incorporated into this muscle were similar to those in control rats, and (with the exception of gastrocnemius N total content) significantly higher than those in non-treated cirrhotic rats (p < 0.05, all). CONCLUSIONS: A variety of nutritional disturbances were detected in rats from the early stages of liver cirrhosis. Low doses of IGF-I were found to reverse most of these changes. These results stimulate further studies to determine whether IGF-I might be useful in the correction of the malnutrition present in patients with liver cirrhosis.

Effect of aging on the rate of muscle protein turnover in rat.

The urinary excretion of Nt-methylhistidine (e-methylhistidine, 3-MH, an index related to myofibrillar protein breakdown), as well as the rate of L-[14C]-tyrosine incorporation into gastrocnemius muscle (ks, fractional rate of muscle protein synthesis, evaluated by the constant infusion method) have been measured to assess the effect of aging on the rate of skeletal muscle protein turnover. In addition, nucleic acids, muscle protein and serum corticosterone levels were determined. Weaning rats were fed a 10% lactalbumin diet and killed in groups of seven when they were 35, 60, 120 and 300 days old. Apart from the rate of growth, no major differences were found between 35- and 60-day old animals. However, as compared to the youngest rats, 120-day old rats showed a significant reduction in the relative weight of the four muscles excised. Plasma corticosterone levels, increased as the animals became older. Finally, in the 300-day old rats, the reduced rate of growth was accompanied by a significant reduction in the relative organ weight (with the exception of soleus), 3-MH and Ks. It is concluded that aging caused a reduction in the rates of both protein breakdown and synthesis. The reduced muscle breakdown may not be due to a relative reduced muscle mass in elder rats since urinary 3-MH remained low even when expressed per creatinine output.

A potential experimental model for the study of osteopenia in CCl4 liver cirrhotic rats.

In order to search for an experimental model to further investigate the osteopenia associated to liver cirrhosis (LC), this study has been focused on investigating the occurrence of bone disorders in male rats to which LC histologically confirmed was induced through the validated procedure of CCl4 inhalation. Length, anteroposterior and lateromedial diameters, densitometry, mechanical stress resistance, hydroxyproline (OHprol) and calcium and phosphate contents were measured in femurs from control (n = 10) and liver cirrhosis rats (n = 10). It has been found that femurs from liver cirrhosis rats showed a significant reduction (p < 0.01) in bone weight (0.254 +/- 0.003 vs 0.230 +/- 0.004 g/100 g b.w.), anteroposterior (4.08 +/- 0.06 vs 3.69 +/- 0.05 mm) and lateromedial (5.33 +/- 0.05 vs 5.08 +/- 0.04 mm, p < 0.05) diameters, resistance to mechanical stress (405.8 +/- 9.5 vs 332.5 +/- 9.1 N) and total densitometry (0.416 +/- 0.005 vs 0.381 +/- 0.004 g/cm2). However, no significant differences were observed in bone length, calcium, OHprol and phosphate (all expressed as mg/100 mg fresh bone tissue) contents. Therefore, the proteins matrix to mineral contents ratio was not altered. These results indicate that in this model of experimental liver cirrhosis there is osteopenia characterized by bone frailty and reduced thickness, and it could offer an experimental model to study bone changes associated to liver cirrhosis.