Effect and the probable mechanisms of silibinin in regulating insulin resistance in the liver of rats with non-alcoholic fatty liver

Our previous study has shown that reduced insulin resistance (IR) was one of the possible mechanisms for the therapeutic effect of silibinin on non-alcoholic fatty liver disease (NAFLD) in rats. In the present study, we investigated the pathways of silibinin in regulating hepatic glucose production and IR amelioration. Forty-five 4- to 6-week-old male Sprague Dawley rats were divided into a control group, an HFD group (high-fat diet for 6 weeks) and an HFD + silibinin group (high-fat diet + 0.5 mg kg^-1·day^-1 silibinin, starting at the beginning of the protocol). Both subcutaneous and visceral fat was measured. Homeostasis model assessment-IR index (HOMA-IR), intraperitoneal glucose tolerance test and insulin tolerance test (ITT) were performed. The expression of adipose triglyceride lipase (ATGL) and of genes associated with hepatic gluconeogenesis was evaluated. Silibinin intervention significantly protected liver function, down-regulated serum fat, and improved IR, as shown by decreased HOMA-IR and increased ITT slope. Silibinin markedly prevented visceral obesity by reducing visceral fat, enhanced lipolysis by up-regulating ATGL expression and inhibited gluconeogenesis by down-regulating associated genes such as Forkhead box O1, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. Silibinin was effective in ameliorating IR in NAFLD rats. Reduction of visceral obesity, enhancement of lipolysis and inhibition of gluconeogenesis might be the underlying mechanisms.     

Stereological characterization of left ventricular cardiomyocytes, capillaries, and innervation in the nondiabetic, obese mouse

BackgroundObesity is associated with left ventricular hypertrophy and dysfunction, but little is known about the structural remodeling of cardiomyocytes, capillaries, and nerve fibers in this state. We hypothesized that all three compartments should show quantitative structural alterations.MethodsTen C57Bl6 mice were randomly assigned to a control or obesity group. Lean mice received standard chow, whereas obese mice received a high-fat Western diet. After 28 weeks, the mice were sacrificed, and the hearts were prepared for design-based stereology using light and electron microscopy.ResultsBody mass and left ventricular mass were significantly elevated in obese vs. control mice. The left ventricular hypertrophy was accompanied by a significant increase in cardiomyocyte lipid droplets and total myocyte volume. The volume fractions of myofibrils, free sarcoplasm, and mitochondria did not differ between the groups. The total length of capillaries was significantly enhanced in obese vs. control mice, whereas the total length of axons ramifying between cardiomyocytes was not different.ConclusionsObesity is associated with significant structural alterations in cardiomyocytes and capillaries, whereas no structural changes in the myocardial innervation were observed. The structural characteristics in obese mice do not provide a clear basis for functional changes observed in obesity-related cardiac hypertrophy.     

Protection of brain and pancreas from high-fat diet: effects of catechin and caffeine

To investigate the effect of a high-fat diet on brain and pancreas functions, we used SAMP10 mice that have characteristics of brain atrophy and cognitive dysfunction with aging. Simultaneously, we investigated the effect of green tea catechin consumption on high-fat diet feeding, because green tea catechin has been reported to improve brain atrophy, brain dysfunction and obesity. The body weight of mice fed a high-fat diet from 2 to 12 months was higher than that of the control, although the calorie intake was not. The high-fat diet also increased insulin secretion; however, the hypersecretion of insulin and obesity were suppressed when mice were fed a high-fat diet with green tea catechin and caffeine. Furthermore, brain atrophy was suppressed and the working memory, tested using Y-maze, improved in mice fed a high-fat diet containing green tea catechin and caffeine. The secretion of insulin might affect both obesity and brain function. A strong correlation was found between working memory and insulin release in mice fed a high-fat diet with green tea catechin and/or caffeine. The results indicate the protective effect of green tea catechin and caffeine on the functions of brain and pancreas in mice fed a high-fat diet.     

Morphoquantitative analysis of the Ileum of C57BL/6 mice (Mus musculus) fed with a high-fat diet

Due to the increase in overweight and obesity in humans, various studies have been conducted in recent years that demonstrate the detrimental effects on tissues and organs. The aim of this study was to assess the morphoquantitative changes produced in the ileum of mice, associated with high-fat diets. Fourteen male C57BL/6 mice, 5 months old, were fed two types of diets for 14 weeks. The control group (C) was fed a standard diet (10% fat, AIN-93M) and the experimental group (E) was fed a high-fat diet (42% fat, AIN-93M-AG). The assessments included: body weight, calorie consumption, food efficiency, biochemical analysis of plasma lipids, diameter, total wall thickness, thickness of the tunica mucosa and tunica muscularis, length and width of the intestinal villi, depth of the intestinal crypts and number of goblet cells per mm^-2 (N_A). For the statistical analysis the Student’s t-test was used, considering a P value less than 0.05. The mice in the E group presented greater weight gain (P = 0.028), higher levels of total and LDL cholesterol (P = 0.03 and P = 0.01, respectively), and length of the intestinal villi (P = 0.000). The width of the intestinal villi and the NA of PAS-positive goblet cells presented significantly lower values (P = 0.037 and P = 0.039, respectively) than the C group. The observed changes could be related to the higher demand for fat absorption and to possible alterations in the intestinal microflora and inflammation by action of high-fat diets.     

Resistance training improves body composition and increases matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles of diet-induced obese rats

OBJECTIVE:

We investigated the influence of resistance training on body composition and matrix metalloproteinase 2 activity in skeletal muscles of rats fed a high-fat diet.

METHODS:

Thirty-two Wistar rats were divided into four experimental groups (n = 8/each) according to diet and exercise status: Control (standard diet), Obese Control (high-fat diet), Resistance Training (standard diet) and Obese Resistance Training (high-fat diet) groups. Animals were fed a high-fat diet for 12 weeks to promote excessive weight gain. Resistance Training groups performed 12 weeks of training periods after this period in a vertical ladder three times/week. Fat percentage, fat-free mass and fat mass were assessed using dual-energy X-ray absorptiometry, and matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles was analyzed using zymography.

RESULTS:

Resistance training significantly reduced body and fat masses and fat percentages in both trained groups (p<0.05). The maximal carrying load between trained groups was not different, but relative force was higher in the Resistance Training group (p<0.05). Of note, increased matrix metalloproteinase 2 activity was noted in the tested muscles of both trained groups (p<0.05).

CONCLUSION:

In conclusion, altered body composition and muscle matrix metalloproteinase 2 activity promoted by excessive weight gain were positively modified by resistance training.     

Prognostic value of the C-reactive protein to albumin ratio in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

Background/aimThis study investigated whether baseline serum level of C-reactive protein (CRP)/albumin ratio is associated with infarct localization, number of vascular lesions, and in-hospital mortality in patients undergoing primary percutaneous coronary intervention (PCI) for acute ST elevation myocardial infarction (STEMI).MethodsThe study population consisted of 116 patients diagnosed with STEMI. The CRP/albumin ratio at first admission, cardiac troponin-I (cTnI), PCI results, and clinical outcomes were recorded. ResultsThe mean CRP/albumin ratio, cTnI level, and mean number of vascular lesions were significantly higher in non-survivors than in survivors (p = 0.006, p = 0.004, and p = 0.007, respectively). Multivariate logistic regression analysis demonstrated that the CRP/albumin ratio and number of coronary artery lesions were independent predictors of mortality in STEMI patients. According to these analyses, the presence of ≥ 2 vessel lesions was the most important predictor of mortality, with an odds ratio of 2.009 (95% confidence interval: 1.191–3.387, p = 0.009). ConclusionThis study demonstrates the potential utility of the CRP/albumin ratio for predicting the clinical outcome of patients with STEMI. In addition, the presence of ≥ 2 vascular lesions contributed to a 2-fold increase in mortality rate in STEMI patients.     

The effect of obstructive sleep apnea therapy on cardiovascular autonomic function: a systematic review and meta-analysis

Study ObjectivesAutonomic function is impaired in obstructive sleep apnea (OSA) and may mediate the association between OSA and cardiovascular risk. We investigated the effect of OSA therapy on autonomic function through a systematic review and meta-analysis of intervention studies.MethodsA systematic search using three databases (Medline, Embase, and Scopus) was performed up to December 9, 2020. Studies of OSA patients ≥ 18 years with autonomic function assessed before and after treatment with positive airway pressure, oral appliance, positional therapy, weight loss, or surgical intervention were included for review. Random effects meta-analysis was carried out for five groups of autonomic function indices. Risk of bias was assessed using the Cochrane Collaboration tool.ResultsForty-three eligible studies were reviewed with 39 included in the meta-analysis. OSA treatment led to large decreases in muscle sympathetic nerve activity (Hedges’ g = −1.08; 95% CI −1.50, −0.65, n = 8) and moderate decreases in catecholamines (−0.60; −0.94, −0.27, n = 3) and radio nucleotide imaging (−0.61; −0.99, −0.24, n = 2). OSA therapy had no significant effect on baroreflex function (Hedges’ g = 0.15; 95% CI −0.09, 0.39, n = 6) or heart rate variability (0.02; −0.32, 0.36, n = 14). There was a significant risk of bias due to studies being primarily non-randomized trials.ConclusionsOSA therapy selectively improves autonomic function measures. The strongest evidence for the effect of OSA therapy on autonomic function was seen in reduced sympathetic activity as assessed by microneurography, but without increased improvement in parasympathetic function. OSA therapy may reduce the risk of cardiovascular disease in OSA through reduced sympathetic activity.     

Obesity influence on bladder inflammation and cancer: a cystitis model

Background: Recently, the role of subclinical inflammation in obesity has gained prominence. An association between obesity and chronic inflammation has been observed in several studies that show a relationship between increased morbidity and high Body Mass Index (BMI). This study aims to compare inflammatory pathways in obese (by high-fat diet) and non-obese mice after exposure to an intravesical carcinogen in a cystitis model. Methods: We divided 16 female, 7 week old mice into two groups: 1) CONTROL: standard diet, and 2) OBESE: high fat diet for 8 weeks. Both groups underwent a protocol for N-Nitroso-N-methylurea (MNU) pro-inflammatory bladder instillation. Bladder was analyzed by histopathology and western blotting for proteins of the inflammatory pathway (JNK, NFκB, c-JUN, IKK), and immunohistochemistry (proliferation and apoptosis). Results: While mice eating standard diet showed minimal histologic alteration in 4 of 5 (80%) bladder tissues, those eating a high fat diet showed moderate (60%) and intense (40%) chronic active inflammation with dysplasia foci, increased proliferation, apoptosis and inflammatory pathway activation with increased NFκB, and also IKKβ, JNK, and c-JUN phosphorylation in the urothelium. Conclusion: A high-fat diet causes increased urothelial proliferation, apoptosis, and NFκB expression with cystitis exacerbation and dysplasia. Together, these results suggest that obesity induced by a high-fat diet increases the inflammatory pathway in the bladder with possible pre-malignant alterations.     

Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy

Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [³H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of β-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy.     

Calorie restriction decreases platelet-derived growth factor (PDGF)-A and thrombin receptor mRNA expression in autoimmune murine lupus nephritis

Calorie restriction (CR) and supplementation with fish oil (FO) are known to increase the life span and diminish histological evidence of glomerulonephritis in lupus prone (NZB×NZW)F_l (B/W) mice. Cellular proliferation is an important pathological element in the development of lupus nephritis, and we have examined the expression of thrombin receptor (TR) and the mitogenic agents PDGF-A and -B. Weanling B/W mice were fed either ad libitum or a calorie restricted (CR; 40% less calories than ad libitum) diet supplemented with either 5% (w/w) corn oil (CO) or FO. CR animals consumed 2.7–3.0 g of wet food per day versus 4.5–5.0 g for the ad libitum animals. Renal RNA was extracted from young (3.5–4.0 months of age) and old (8–10 months of age) mice. Densitometric analysis (reference gene GAPDH) of blots from Northern (PDGF-A and -B) and ribonuclease protection assays (TR) produced the following data: (i) in young mice no signal was detected for PDGF-A, -B and TR in all four groups, while the signals were readily detectable in old mice; (ii) in old mice low and similar levels of PDGF-B were detected, and neither CR nor the source of lipid altered its expression; (iii) CR significantly inhibited PDGF-A and TR expression in both CO (ad libitumversus CR; PDGF-A, 3.25-fold, P<0.025; TR, 3.7-fold, P<0.01) and FO (ad libitumversus CR; PDGF-A, 4.56-fold, P<0.01; TR, 3.6-fold, P<0.025) groups; (iv) although FO (versus CO) produced a trend towards decreased expression, results were not statistically significant. We conclude that suppression of renal disease in lupus-prone mice by CR is accompanied by decreased expression of PDGF-A and the thrombin receptor.     

Effect of trimetazidine treatment on the transient outward potassium current of the left ventricular myocytes of rats with streptozotocin-induced type 1 diabetes mellitus

Cardiovascular complications are a leading cause of mortality in patients with diabetes mellitus (DM). The present study was designed to investigate the effects of trimetazidine (TMZ), an anti-angina drug, on transient outward potassium current (I_to) remodeling in ventricular myocytes and the plasma contents of free fatty acid (FFA) and glucose in DM. Sprague-Dawley rats, 8 weeks old and weighing 200-250 g, were randomly divided into three groups of 20 animals each. The control group was injected with vehicle (1 mM citrate buffer), the DM group was injected with 65 mg/kg streptozotocin (STZ) for induction of type 1 DM, and the DM+TMZ group was injected with the same dose of STZ followed by a 4-week treatment with TMZ (60 mg·kg⁻¹·day⁻¹). All animals were then euthanized and their hearts excised and subjected to electrophysiological measurements or gene expression analyses. TMZ exposure significantly reversed the increased plasma FFA level in diabetic rats, but failed to change the plasma glucose level. The amplitude of I_to was significantly decreased in left ventricular myocytes from diabetic rats relative to control animals (6.25 ± 1.45 vs 20.72 ± 2.93 pA/pF at +40 mV). The DM-associated I_to reduction was attenuated by TMZ. Moreover, TMZ treatment reversed the increased expression of the channel-forming alpha subunit Kv1.4 and the decreased expression of Kv4.2 and Kv4.3 in diabetic rat hearts. These data demonstrate that TMZ can normalize, or partially normalize, the increased plasma FFA content, the reduced I_to of ventricular myocytes, and the altered expression Kv1.4, Kv4.2, and Kv4.3 in type 1 DM.     

The total number of Leydig and Sertoli cells in the testes of men across various age groups – a stereological study

The aim of this study was to estimate the total number of Sertoli and Leydig cells in testes from male subjects across the human lifespan, using an optimized stereological method for cell-counting. In comparison with many other organs, estimation of the total cell numbers in the testes is particularly sensitive to methodological problems. Therefore, using the optical fractionator technique and a sampling design specifically optimized for human testes, we estimated the total number of Sertoli and Leydig cells in the testes from 26 post mortem male subjects ranging in age from 16 to 80 years. The mean unilateral total number of Sertoli cells was 407 × 10⁶ [range: 86 × 10⁶ to 665 × 10⁶, coefficient of variation (CV) = 0.33], and the mean unilateral total number of Leydig cells was 99 × 10⁶ (range: 47 × 10⁶ to 245 × 10⁶, CV = 0.48). There was a significant decline in the number of Sertoli cells with age; no such decline was found for Leydig cells. Quantitative stereological analysis of post mortem tissue may help understand the influence of age or disease on the number of human testicular cells.     

The Absence of Myocardial Calcium-Independent Phospholipase A2γ Results in Impaired Prostaglandin E2 Production and Decreased Survival in Mice with Acute Trypanosoma cruzi Infection

Cardiomyopathy is a serious complication of Chagas'' disease, caused by the protozoan parasite Trypanosoma cruzi. The parasite often infects cardiac myocytes, causing the release of inflammatory mediators, including eicosanoids. A recent study from our laboratory demonstrated that calcium-independent phospholipase A₂γ (iPLA₂γ) accounts for the majority of PLA₂ activity in rabbit ventricular myocytes and is responsible for arachidonic acid (AA) and prostaglandin E₂ (PGE₂) release. Thus, we hypothesized that cardiac iPLA₂γ contributes to eicosanoid production in T. cruzi infection. Inhibition of the isoform iPLA₂γ or iPLA₂β, with the R or S enantiomer of bromoenol lactone (BEL), respectively, demonstrated that iPLA₂γ is the predominant isoform in immortalized mouse cardiac myocytes (HL-1 cells). Stimulation of HL-1 cells with thrombin, a serine protease associated with microthrombus formation in Chagas'' disease and a known activator of iPLA₂, increased AA and PGE₂ release, accompanied by platelet-activating factor (PAF) production. Similarly, T. cruzi infection resulted in increased AA and PGE₂ release over time that was inhibited by pretreatment with (R)-BEL. Further, T. cruzi-infected iPLA₂γ-knockout (KO) mice had lower survival rates and increased tissue parasitism compared to wild-type (WT) mice, suggesting that iPLA₂γ-KO mice were more susceptible to infection than WT mice. A significant increase in iPLA₂ activity was observed in WT mice following infection, whereas iPLA₂γ-KO mice showed no alteration in cardiac iPLA₂ activity and produced less PGE₂. In summary, these studies demonstrate that T. cruzi infection activates cardiac myocyte iPLA₂γ, resulting in increased AA and PGE₂ release, mediators that may be essential for host survival during acute infection. Thus, these studies suggest that iPLA₂γ plays a cardioprotective role during the acute stage of Chagas'' disease.     

Effects of terlipressin and naloxone compared with epinephrine in a rat model of asphyxia-induced cardiac arrest

OBJECTIVE:

To evaluate the hemodynamic and metabolic effects of terlipressin and naloxone in cardiac arrest.

METHODS:

Cardiac arrest in rats was induced by asphyxia and maintained for 3.5 minutes. Animals were then resuscitated and randomized into one of six groups: placebo (n = 7), epinephrine (0.02 mg/kg; n = 7), naloxone (1 mg/kg; n = 7) or terlipressin, of which three different doses were tested: 50 µg/kg (TP50; n = 7), 100 µg/kg (TP100; n = 7) and 150 µg/kg (TP150; n = 7). Hemodynamic variables were measured at baseline and at 10 (T10), 20 (T20), 30 (T30), 45 (T45) and 60 (T60) minutes after cardiac arrest. Arterial blood samples were collected at T10, T30 and T60.

RESULTS:

The mean arterial pressure values in the TP50 group were higher than those in the epinephrine group at T10 (165 vs. 112 mmHg), T20 (160 vs. 82 mmHg), T30 (143 vs. 66 mmHg), T45 (119 vs. 67 mmHg) and T60 (96 vs. 66.8 mmHg). The blood lactate level was lower in the naloxone group than in the epinephrine group at T10 (5.15 vs. 10.5 mmol/L), T30 (2.57 vs. 5.24 mmol/L) and T60 (2.1 vs. 4.1 mmol/L).

CONCLUSIONS:

In this rat model of asphyxia-induced cardiac arrest, terlipressin and naloxone were effective vasopressors in cardiopulmonary resuscitation and presented better metabolic profiles than epinephrine. Terlipressin provided better hemodynamic stability than epinephrine.     

Age-related trends in vertebral dimensions

Several studies have demonstrated age-related changes in vertebral dimensions. Vertebral size has been reported to increase among elderly adults, with periosteal apposition resulting in increased cross-sectional area (CSA) of the vertebral corpus combined with reduction in bone mineral density. These changes in CSA are observed to be sex-specific, as the pronounced increase of vertebral CSA is found only in elderly males. However, the reduction in bone mineral density in old age is apparent within both sexes. It is thus hypothesized that higher fracture risk in elderly women is a result of their incapacity to increase vertebral size and thus adapt to bone mineral reduction. In this study, our aim was to explore whether the onset of these changes could be ascribed to specific age intervals and whether the proposed differences between the sexes are as great as previously suggested. To conduct this study we utilized two large early 20th century skeletal collections known as Terry and Bass (n = 181). We also utilized data from two lumbar spine magnetic resonance imaging samples as a modern-day reference (n = 497). Age, sex and ethnicity of all individuals were known. Vertebral CSA was determined by measuring three width and length dimensions from the corpus of the fourth lumbar vertebra (L4). Our results indicate only a moderate association between age and vertebral CSA. This association was observed to be relatively similar in both sexes, and we thus conclude that there is no clear sex-specific compensatory mechanism for age-related bone loss in vertebral size.     

Whole-Body Vibration Training Effect on Physical Performance and Obesity in Mice

The purpose of this study was to verify the beneficial effects of whole-body vibration (WBV) training on exercise performance, physical fatigue and obesity in mice with obesity induced by a high-fat diet (HFD). Male C57BL/6 mice were randomly divided into two groups: normal group (n=6), fed standard diet (control), and experimental group (n=18), fed a HFD. After 4-week induction, followed by 6-week WBV of 5 days per week, the 18 obese mice were divided into 3 groups (n=6 per group): HFD with sedentary control (HFD), HFD with WBV at relatively low-intensity (5.6 Hz, 0.13 g) (HFD+VL) or high-intensity (13 Hz, 0.68 g) (HFD+VH). A trend analysis revealed that WBV increased the grip strength in mice. WBV also dose-dependently decreased serum lactate, ammonia and CK levels and increased glucose level after the swimming test. WBV slightly decreased final body weight and dose-dependently decreased weights of epididymal, retroperitoneal and perirenal fat pads and fasting serum levels of alanine aminotransferase, CK, glucose, total cholesterol and triacylglycerol. Therefore, WBV could improve exercise performance and fatigue and prevent fat accumulation and obesity-associated biochemical alterations in obese mice. It may be an effective intervention for health promotion and prevention of HFD-induced obesity.     

A study on the short-term effect of cafeteria diet and pioglitazone on insulin resistance and serum levels of adiponectin and ghrelin

The interaction between ghrelin and adiponectin is still controversial. We investigated the effect of cafeteria diet and pioglitazone on body weight, insulin resistance, and adiponectin/ghrelin levels in an experimental study on male Wistar rats. The animals were divided into four groups of 6 rats each, and received balanced chow with saline (CHOW-O) or pioglitazone (CHOW-P), or a cafeteria diet with saline (CAFE-O) or pioglitazone (CAFE-P). The chow/cafeteria diets were administered for 35 days, and saline/pioglitazone (10 mg·kg body weight⁻¹·day⁻¹) was added in the last 14 days prior to euthanasia. CAFE-O animals had a higher mean final weight (372.5 ± 21.01 g) than CHOW-O (317.66 ± 25.11 g, P = 0.017) and CHOW-P (322.66 ± 28.42 g, P = 0.035) animals. Serum adiponectin levels were significantly higher in CHOW-P (55.91 ± 20.62 ng/mL) than in CHOW-O (30.52 ± 6.97 ng/mL, P = 0.014) and CAFE-O (32.54 ± 9.03 ng/mL, P = 0.027) but not in CAFE-P. Higher total serum ghrelin levels were observed in CAFE-P compared to CHOW-P animals (1.65 ± 0.69 vs 0.65 ± 0.36 ng/mL, P = 0.006). Likewise, acylated ghrelin levels were higher in CAFE-P (471.52 ± 195.09 pg/mL) than in CHOW-P (193.01 ± 87.61 pg/mL, P = 0.009) and CAFE-O (259.44 ± 86.36 pg/mL, P = 0.047) animals. In conclusion, a cafeteria diet can lead to a significant weight gain. Although CAFE-P animals exhibited higher ghrelin levels, this was probably related to food deprivation rather than to a direct pharmacological effect, possibly attenuating the increase in adiponectin levels.     

Male but not female mice with severe osteogenesis imperfecta are partially protected from high-fat diet-induced obesity

Previously we have shown that young mice with a dominant severe form of osteogenesis imperfecta (OI), caused by mutated collagen type I, exhibit an altered glucose/insulin metabolism and energy expenditure along with elevated levels of osteocalcin, a bone-derived hormone involved in the regulation of whole-body metabolism. This study aimed to examine the long-term effects of a western diet in these OI mice. Male and female OI mice and wild type littermates (WT) were fed a high-fat diet (HFD) or a matched low-fat diet (LFD) for 26 weeks. HFD-induced obesity was observed in male and female WT and female OI mice, but not in male OI mice. HFD-fed WT and OI mice of both sexes developed hyperglycemia and glucose intolerance, but the degree of glucose intolerance was significantly lower in male and female OI mice compared to sex- and diet-matched WT mice. Indirect calorimetry revealed increased movement of male OI mice on HFD compared to LFD and, while HFD lowered energy expenditure in WT mice, energy expenditure was not changed in OI mice. Further, HFD-fed male OI mice demonstrated a diet-induced increased expression of the thermogenesis genes, Ucp1 and Pgc1α, in brown adipose tissue. On LFD, total and Gla-13 osteocalcin levels were similar in 30-week-old WT and OI mice, but on HFD, both were significantly higher in OI mice than WT. Thus, male OI mice respond to HFD with increased movement, energy expenditure, brown adipose tissue thermogenesis, and higher levels of osteocalcin, resulting in partial protection against HFD-induced obesity.     

Periostin as a modulator of chronic cardiac remodeling after myocardial infarction

OBJECTIVE:

After acute myocardial infarction, during the cardiac repair phase, periostin is released into the infarct and activates signaling pathways that are essential for the reparative process. However, the role of periostin in chronic cardiac remodeling after myocardial infarction remains to be elucidated. Therefore, the objective of this study was to investigate the relationship between tissue periostin and cardiac variables in the chronic cardiac remodeling induced by myocardial infarction.

METHODS:

Male Wistar rats were assigned to 2 groups: a simulated surgery group (SHAM; n = 8) and a myocardial infarction group (myocardial infarction; n = 13). After 3 months, morphological, functional and biochemical analyses were performed. The data are expressed as means±SD or medians (including the lower and upper quartiles).

RESULTS:

Myocardial infarctions induced increased left ventricular diastolic and systolic areas associated with a decreased fractional area change and a posterior wall shortening velocity. With regard to the extracellular matrix variables, the myocardial infarction group presented with higher values of periostin and types I and III collagen and higher interstitial collagen volume fractions and myocardial hydroxyproline concentrations. In addition, periostin was positively correlated with type III collagen levels (r = 0.673, p = 0.029) and diastolic (r = 0.678, p = 0.036) and systolic (r = 0.795, p = 0.006) left ventricular areas. Considering the relationship between periostin and the cardiac function variables, periostin was inversely correlated with both the fractional area change (r = -0.783, p = 0.008) and the posterior wall shortening velocity (r = -0.767, p = 0.012).

CONCLUSIONS:

Periostin might be a modulator of deleterious cardiac remodeling in the chronic phase after myocardial infarction in rats.