Estrogen deficiency worsens steatohepatitis in mice fed high-fat and high-cholesterol diet

Recent studies indicate an accelerated progression of nonalcoholic steatohepatitis (NASH) in postmenopausal women. Hypercholesterolemia, an important risk factor for NASH progression, is often observed after menopause. This study examined the effects of estrogen on NASH in ovariectomized (OVX) mice fed a high-fat and high-cholesterol (HFHC) diet. To investigate the effects of estrogen deficiency, OVX mice and sham-operated (SO) mice were fed normal chow or HFHC diet for 6 wk. Next, to investigate the effects of exogenous estrogen replenishment, OVX mice fed with HFHC diet were treated with implanted hormone release pellets (containing 17β-estradiol or placebo vehicle) for 6 wk. OVX mice on the HFHC diet showed enhanced liver injury with increased liver macrophage infiltration and elevated serum cholesterol levels compared with SO-HFHC mice. Hepatocyte monocyte chemoattractant protein-1 (MCP1) protein expression in OVX-HFHC mice was also enhanced compared with SO-HFHC mice. In addition, hepatic inflammatory gene expressions, including monocytes chemokine (C-C motif) receptor 2 (CCR2), were significantly elevated in OVX-HFHC mice. Estrogen treatment improved serum cholesterol levels, liver injury, macrophage infiltration, and inflammatory gene expressions in OVX-HFHC mice. Moreover, the elevated expression of liver CCR2 and MCP1 were decreased by estrogen treatment in OVX-HFHC mice, whereas low-density lipoprotein dose dependently enhanced CCR2 expression in THP1 monocytes. Our study demonstrated that estrogen deficiency accelerated NASH progression in OVX mice fed HFHC diet and that this effect was improved by estrogen therapy. Hypercholesterolemia in postmenopausal women would be a potential risk factor for NASH progression.     

TGF-beta1 increases microbial clearance but worsens lung injury during Escherichia coli pneumonia in rats

We investigated the effects of either intravenous (IV) or intrabronchial (IB) treatment with transforming growth factor beta1 (TGF-beta1) during bacterial pneumonia in rats. Immediately following IB Escherichia coli inoculation (T0), animals (n=270) were randomized to receive a single treatment with human recombinant TGF-beta1 either via IV or IB, or via both IV and IB routes, or to receive placebo (human serum albumin, HSA) only. Blood and lung analysis was done at 6 and 168 h after E. coli inoculation. Other animals (n=40) were administered IV TGF-beta1 or HSA at T0 and 6, 12 and 24 h after E. coli inoculation to investigate the effects of multiple treatments also on survival rates alone. All animals received ceftriaxone daily. Route of administration did not influence TGF-beta1 (p=ns for the effect of TGF-beta1 comparing IV vs IB routes) and we averaged over this variable in analysis. The relative risk of death (mean +/- sem) was not altered by either single treatments administered at T0 (-0.18 +/- 0.25, p=0.47) or multiple treatments (0.40 +/- 0.50, p=0.66) of TGF-beta1. Single treatment with TGF-beta1 first decreased and then increased vascular leukocytes at 6 and 168 h, respectively, but increased alveolar leukocytes at both time points (p=0.02 comparing the differing effects of TGF-beta1 on vascular and alveolar leukocytes at 6 and 168 h). Although TGF-beta1 decreased blood and lung bacteria counts at 6 and 168 h, it also increased serum tumor necrosis factor levels and lung injury scores at these time points (p<0.05 for the effects of TGF-beta1 on each parameter at 6 and 168 h together). Thus, while increases in lung leukocyte recruitment with TGF-beta1 were associated with improved microbial clearance in this rat model of pneumonia, worsened lung injury may have negated these beneficial host defense effects, and overall survival was not significantly improved. Despite these harmful effects, additional studies may be warranted to better define the influence of exogenous TGF-beta1 on host defense during acute bacterial infections.     

Ovariectomy ameliorates dextromethorphan--induced memory impairment in young female rats

We have previously found that dextromethorphan (DM), over-the-counter cough suppressant, impairs memory retention in water maze task, when it is repeatedly administrated to adolescent female rats at high doses. In this study we examined first if ovariectomy ameliorates the DM-induced memory impairment in female rats, and then whether or not the DM effect is revived by estrogen replacement in ovariectomized female rats. Female rat pups received bilateral ovariectomy or sham operation on postnatal day (PND) 21, and then intraperitoneal DM (40 mg/kg) daily during PND 28-37. Rats were subjected to the Morris water maze task from PND 38, approximately 24 h after the last DM injection. In probe trial, goal quadrant dwell time was significantly reduced by DM in the sham operated group, however, the reduction by DM did not occur in the ovariectomy group. When 17beta-estradiol was supplied to ovariectomized females during DM treatment, the goal quadrant dwell time was significantly decreased, compared to the vehicle control group. Furthermore, a major effect of estrogen replacement was found in the escape latency during the last 3 days of initial learning trials. These results suggest that ovariectomy may ameliorate the adverse effect of DM treatment on memory retention in young female rats, and that estrogen replacement may revive it, i.e. estrogen may take a major role in DM-induced memory impairment in female rats.     

Pathology of renal secondary hyperparathyroidism in mice

Typical renal secondary hyperparathyroidism was observed in 19 specific pathogen-free ICR mice. The renal lesions were severe amyloidosis and glomerulonephritis. The bone lesion, osteodystrophia fibrosa, consisted of both resorptive and reparative processes. The parathyroid glands were enlarged and there was hyperplasia of the chief cells.     

A high-fructose diet worsens eccentric left ventricular hypertrophy in experimental volume overload

The development of left ventricular (LV) hypertrophy (LVH) can be affected by diet manipulation. Concentric LVH resulting from pressure overload can be worsened by feeding rats with a high-fructose diet. Eccentric LVH is a different type of hypertrophy and is associated with volume overload (VO) diseases. The impact of an abnormal diet on the development of eccentric LVH and on ventricular function in chronic VO is unknown. This study therefore examined the effects of a fructose-rich diet on LV eccentric hypertrophy, ventricular function, and myocardial metabolic enzymes in rats with chronic VO caused by severe aortic valve regurgitation (AR). Wistar rats were divided in four groups: sham-operated on control diet (SC; n = 13) or fructose-rich diet (SF; n = 13) and severe aortic regurgitation fed with the same diets [aortic regurgitation on control diet (ARC), n = 16, and aortic regurgitation on fructose-rich diet (ARF), n = 13]. Fructose-rich diet was started 1 wk before surgery, and the animals were euthanized 9 wk later. SF and ARF had high circulating triglycerides. ARC and ARF developed significant LV eccentric hypertrophy after 8 wk as expected. However, ARF developed more LVH than ARC. LV ejection fraction was slightly lower in the ARF compared with ARC. The increased LVH and decreased ejection fraction could not be explained by differences in hemodynamic load. SF, ARC, and ARF had lower phosphorylation levels of the AMP kinase compared with SC. A fructose-rich diet worsened LV eccentric hypertrophy and decreased LV function in a model of chronic VO caused by AR in rats. Normal animals fed the same diet did not develop these abnormalities. Hypertriglyceridemia may play a central role in this phenomenon as well as AMP kinase activity.     

Sucrose-enriched diet during maturation increases ethanol preference in rats

In the present study we used a diet enriched with 10% sucrose, which was consumed by adolescent animals of the experimental group for one month. We found that consumption of sweet food during sexual maturation affected alcohol preference, anxiety, and locomotor and exploratory activity in the adult rats. Our data show that easily available tasty food during adolescence probably impairs the reward system and serves as a trigger of future alcohol preference.     

Hormone release during computer-monitored sexual behavior in mature and aged male rats

Sexual behavior and the increase in plasma hormone levels of LH, prolactin, and testosterone associated with sexual behavior were examined in three age groups of sexually naive male rats. The two younger groups (5- and 11-month-old) mated normally and their behavioral latencies decreased significantly following sexual experience. Both plasma testosterone and LH concentrations increased significantly following entrance of a receptive female into the mating arena. Plasma prolactin levels rose but not significantly. However, the 27-month-old rats neither mated nor showed an increase in the three plasma hormone concentrations during exposure to a receptive female. Only basal testosterone levels were significantly lower than those of the younger animals. Low testosterone levels possibly contributed to deficiencies in both behavior and its associated hormone release. The monitoring of sexual behavior was facilitated by a computer, programmed to record, store, and analyze behavioral events.     

Percutaneous ethanol injections in the treatment of secondary hyperparathyroidism

INTRODUCTION: Renal insufficiency is the most common etiology of secondary hyperparathyroidism. In case of resistance for conservative treatment, methods of choice are surgical intervention or percutaneous ethanol injections. AIM OF THE STUDY: The aim of the study was to evaluate usefulness of percutaneous ethanol injection therapy in the treatment of patients with secondary hyperparathyroidism. MATERIAL AND METHODS: We performed percutaneous 96% ethanol injections under USG guideance in 51 patients: 22 women (mean age 49.6 years) and 29 men (46.6 yrs). The base level of parathormone was 689.35 pg/ml. We managed to visualize one parathyroid gland in 34 patients, 2 in 12, 3 in 5 patients. The mean volume of a single gland was 0,8 cm3. All the injections were performed with the use of needle number 6. We repeated injections in case of no effects. One injection was performed in 18 patients, 2 in 18, 3 in 13, 5 in 1 and 6 in 1 patient. Before and after the treatment patients were examined with USG, scintigraphy and densitometry. Serum levels of calcium (Ca), phosphorus (P), parathormone (PTH) and alkaline phosphatase (FA) activity were also obtained. The main criteria for success was decrease in parathormone level of 50% or more in comparison with pre-injection level or to less than 200 pg/ml. RESULTS: In the whole group of patients after the first month, positive results were observed in 67%. There were no changes in 23%, and PTH level increased in 10%. After 6 months-positive results in 53%, no change in 35% and increase in 12%. We noted the best results in patients with PTH less than 800 pg/ml-72% of them had positive results after 1 as far as after the 6 month. CONCLUSIONS: Percutaneous ethanol injections are valuable method of treatment of secondary hyperparathyroidism. The best results can be obtained if PTH level is less than 800 pg/ml, one parathyroid gland dominating over the rest is visualised in USG, and if patient responds after 1 or at least 2 injections.     

Nitrogen excretion in rats on a protein-free diet and during starvation

Nitrogen balances (six days) were determined in male Wistar rats during feeding a diet with sufficient protein or a nearly protein-free diet (n = 2 x 24), and then during three days of starvation (n = 2 x 12). The objective was to evaluate the effect of protein withdrawal on minimum nitrogen excretion in urine (UN), corresponding to endogenous UN, during feeding and subsequent starvation periods. The rats fed the protein free-diet had almost the same excretion of urinary N during feeding and starvation (165 and 157 mg/kg W(0.75)), while it was 444 mg/kg W(0.75) in rats previously fed with protein, demonstrating a major influence of protein content in a diet on N excretion during starvation. Consequently, the impact of former protein supply on N losses during starvation ought to be considered when evaluating minimum N requirement necessary to sustain life.     

Nitrogen excretion in rats on a protein-free diet and during starvation

Nitrogen balances (six days) were determined in male Wistar rats during feeding a diet with sufficient protein or a nearly protein-free diet (n = 2×24), and then during three days of starvation (n = 2×12). The objective was to evaluate the effect of protein withdrawal on minimum nitrogen excretion in urine (UN), corresponding to endogenous UN, during feeding and subsequent starvation periods. The rats fed the protein free-diet had almost the same excretion of urinary N during feeding and starvation (165 and 157 mg/kg W^0.75), while it was 444 mg/kg W^0.75 in rats previously fed with protein, demonstrating a major influence of protein content in a diet on Nexcretion during starvation. Consequently, the impact of former protein supply on Nlosses during starvation ought to be considered when evaluating minimum N requirement necessary to sustain life.     

Impaired collateral development in mature rats

The effect of maturation on collateral development of resistance arteries was investigated. Three to four sequential mesenteric arteries were ligated to create collateral pathways in anesthetized young (approximately 200 g) and mature (approximately 600 g) rats. Blood flow was similarly elevated in collaterals of young and mature animals. In vivo inner arterial diameter was increased only within young collaterals (33 +/- 7%, P < 0.001). Increases in number of intimal nuclei (57 +/- 10% vs. 52 +/- 14%) and cross-sectional medial area (33 +/- 13% vs. 38 +/- 5%) were similar between young and mature collaterals. Relative to the same animal controls, collateral endothelial nitric oxide synthase mRNA was increased as much in mature as in young rats. Proteomic analysis revealed significant differences in protein expression with maturation between control arteries as well as flow-loaded collateral vessels. The results indicate that, whereas intimal and medial remodeling events were similar in collaterals of young and mature rats, luminal expansion occurred only in young rats. Alteration in arterial protein expression with maturation and altered responses to stimuli for collateral development may contribute to this impairment.     

Postnatal behavioral consequences of antenatal intermittent hypoxia experienced during early organogenesis in mature rats

This study analyses the spontaneous behavior and anxiety-phobic status of mature rats that were subjected to antenatal intermittent hypoxia during the early stages of organogenesis. Antenatal intermittent hypoxia caused a decrease of motor activity as well as an enhanced anxiety level in rats of both sexes, while males appeared to be more sensitive to hypoxic influence. The effects of single antenatal intermittent hypoxia were more expressed than those of double exposure.     

Ovariectomy has minimal effects on neuroadaptations associated with ethanol dependence in female rats

We previously found gender selective alterations in gene expression for GABA_A and NMDA receptors associated with the development of ethanol dependence. Males and females have a differing hormonal environment, including steroid hormone derivatives (neuroactive steroids) that exert effects at GABA_A and NMDA receptors. Therefore, we explored whether the removal of ovarian steroids would alter gender differences in response to chronic ethanol exposure. We found that ovariectomy reduced ethanol drinking levels by 15%, comparable to earlier observations between intact female and male rats. However, investigation of the effects of chronic ethanol exposure on intact versus ovariectomized female rats uncovered few differences in chronic ethanol-induced alterations in selected GABA_A or NMDA receptor subunit peptide levels. In general, findings for both groups of females were similar to previous observations. There was no reduction in GABA_A receptor 1 subunit levels in cerebral cortex in either intact or ovariectomized female rats, in contrast to the significant reduction observed in male rats. In addition, both intact and ovariectomized female rats had increased levels of the NMDA NR1 subunit in cerebral cortex and hypothalamus, but not in hippocampus, whereas ethanol dependent male rats displayed significant increases in the NR1 subunit only in hippocampus. Radioligand binding analysis with [³⁵S]TBPS found no differences in modulation of the GABA_A receptor by neuroactive steroids between ethanol dependent male, intact female or ovariectomized female rats. Seizure susceptibility was not different between intact or ovariectomized female rats during ethanol withdrawal. We did observe differential effects on brain allopregnanolone and plasma corticosterone levels between ethanol dependent intact and ovariectomized female rats, suggesting that ovarian steroids influence HPA axis adaptations to prolonged ethanol exposure. Overall, these data suggest that ovarian steroids do not significantly impact the gender selective alterations of GABA_A and NMDA receptors associated with ethanol dependence.     

Digestive enzyme activity is present in mature copepods despite the absence of the corresponding substrates in the diet during development

Experiments with copepods raised on diets of diatoms, dinoflagellatesand a cryptophyte demonstrate that digestive enzyme activity(laminarinase and amylase) is present regardless of the presenceof the corresponding substrate during development.     

Raspberry pomace alters cecal microbial activity and reduces secondary bile acids in rats fed a high-fat diet

The profile of bile acids (BA) largely depends on the enzymatic activity of the microbiota, but this can be modulated by the dietary addition of biologically active compounds, e.g., polyphenols and polyunsaturated fatty acids. The aim of this study was to examine the effect of dietary raspberry pomace as a rich source of biologically active compounds on microbial activity and the BA profile in the caecum of rats fed a high-fat diet. Wistar rats were fed the standard diet AIN-93, a high-fat diet or a modified high-fat diet enriched with 7% different types of processed raspberry pomaces produced by standard grinding and fine grinding, with or without seeds. Rats fed the high-fat diet for 8 weeks showed some disorders in liver function and cecal BA, as manifested by an increased concentration of cholesterol, total BA in the liver and cholic, deoxycholic, and β-muricholic acids in the cecal digesta. In general, irrespective of the type of raspberry pomace, these dietary preparations decreased liver cholesterol, hepatic fibroblast growth factor receptor 4, peroxisome proliferator-activated receptor alpha, cecal ammonia and favorable changed BA profile in the cecum. However, among all dietary pomaces, the finely ground preparation containing seeds had the greatest beneficial effect on the caecum by modulating bacterial activity and reducing the levels of secondary BA.