Changes In Cardiac Muscle Research Articles

Enhanced therapeutic efficacy of SERCA2a gene-modified adipose-derived mesenchymal stem cell exosomes in doxorubicin-induced cardiomyopathy in male albino rats.

Worldwide, cancer is still the primary cause of death, and one of the most widely used anthracyclines for treating cancer is doxorubicin (DOX). But a major worry is DOX-induced cardiomyopathy, which is primarily resulted from an excess of reactive oxygen species. Heart sarcoplasmic reticulum calcium ion ATPase2a (SERCA2a) controls the amount of calcium ions stored in the sarcoplasmic reticulum (SR). This study aims to evaluate and compare the efficacy of SERCA2a gene modified adipose mesenchymal stem cell-derived exosomes (AMSCs-dE) to nontransfected AMSCs-dE, in DOX induced cardiomyopathy in adult male albino rat. Thirty one adult male albino rats were randomly divided into control group and DOX group that further subdivided into three DOX, AMSCs-dE and SERCA2a AMSCs-dE subgroups. AMSCs-dE were administered intravenously (IV). The levels of serum creatine kinase MB (CK-MB) were assessed after DOX injection and before sacrifice. Cardiac muscle samples were taken for histological analysis using Masson's trichrome and hematoxylin and eosin stains two months after the experiment. Proliferating cell nuclear antigen (PCNA) and connexin 43 were stained using immunohistochemistry. The expression of TNF and SERCA2a genes and proteins was measured by real-time polymerase chain reaction (PCR) and Western blot (Wb) analysis, respectively. Fluorescent microscopy demonstrated non-transfected and transfected exosomes labeled with PKH26 and GFP, respectively, in culture and cardiac muscle. DOX induced myocarditis progressing to degenerative and fibrotic changes in cardiac muscle that regressed in response to AMSCs-dE therapy. However, SERCA2a gene modified AMSCs-dE treatment reversed the mentioned parameters to nearly its normal level. These findings suggest that SERCA2a gene modification enhances the therapeutic efficacy of AMSCs-dE in treating DOX-induced cardiomyopathy.

The possible protective effect of querectin and omega 3 on cardiac muscle changes caused by energy drinks in adult male albino rats: Histological and immunohistochemical study

The possible protective effect of querectin and omega 3 on cardiac muscle changes caused by energy drinks in adult male albino rats: Histological and immunohistochemical study

High Prevalence of Bovine Cardiac Cysticercosis in Upper Egypt: An Epidemiological and Histopathological Study.

Bovine cysticercosis is categorized as a serious parasitic zoonotic infestation. The infection is mainly caused by the tapeworm Taenia saginata, which infects cattle and humans. The larval stage, Cysticercus bovis (C. bovis), is found in the skeletal and cardiac muscles of infected cattle. Despite its potential public health concern, few studies have been conducted on cardiac cysticercosis in Upper Egypt. This study investigates the prevalence, epidemiology, and impact of cardiac cysticercosis in Upper Egypt, emphasizing how histopathological changes in cardiac muscle and physiological parameters might be associated with the infection. From December 2022 to October 2023, a total of 941 animals from Assiut province, Upper Egypt, were slaughtered and their cardiac muscles were examined for the presence of C. bovis. Cysts were classified as viable or degenerated through macroscopic inspection. The overall prevalence of C. bovis infected hearts made up 10.8% of the total examined. The highest prevalence rate was in the summer season followed by spring; winter had the lowest infections. The histopathological examination of infected tissues revealed immune cell infiltration around Cysticercus-infected areas. Additionally, Bax immunostaining demonstrated the apoptotic effect of cysticercosis. Regarding the measured physiological parameters, there were non-significant changes in plasma levels of total protein and albumin in cattle infected with cysticercosis compared with control animals. Moreover, there was a significant decrease in total antioxidant capacity (TAC) combined with a significant increase in lipid peroxide (Malondialdehyde) (MDA), troponin T, and lactate dehydrogenase (LDH) activity in infected animals. The present work documented a set of epidemiological and pathological findings, revealing that C. bovis is a potentially harmful parasite and can cause significant health problems in both cattle and humans.

Three-dimensional mitochondria reconstructions of murine cardiac muscle changes in size across aging.

With sparse treatment options, cardiac disease remains a significant cause of death among humans. As a person ages, mitochondria breakdown and the heart becomes less efficient. Heart failure is linked to many mitochondria-associated processes, including endoplasmic reticulum stress, mitochondrial bioenergetics, insulin signaling, autophagy, and oxidative stress. The roles of key mitochondrial complexes that dictate the ultrastructure, such as the mitochondrial contact site and cristae organizing system (MICOS), in aging cardiac muscle are poorly understood. To better understand the cause of age-related alteration in mitochondrial structure in cardiac muscle, we used transmission electron microscopy (TEM) and serial block facing-scanning electron microscopy (SBF-SEM) to quantitatively analyze the three-dimensional (3-D) networks in cardiac muscle samples of male mice at aging intervals of 3 mo, 1 yr, and 2 yr. Here, we present the loss of cristae morphology, the inner folds of the mitochondria, across age. In conjunction with this, the three-dimensional (3-D) volume of mitochondria decreased. These findings mimicked observed phenotypes in murine cardiac fibroblasts with CRISPR/Cas9 knockout of Mitofilin, Chchd3, Chchd6 (some members of the MICOS complex), and Opa1, which showed poorer oxidative consumption rate and mitochondria with decreased mitochondrial length and volume. In combination, these data show the need to explore if loss of the MICOS complex in the heart may be involved in age-associated mitochondrial and cristae structural changes.NEW & NOTEWORTHY This article shows how mitochondria in murine cardiac changes, importantly elucidating age-related changes. It also is the first to show that the MICOS complex may play a role in outer membrane mitochondrial structure.

Three-Dimensional Mitochondria Reconstructions of Murine Cardiac Muscle Changes in Size Across Aging.

Three-Dimensional Mitochondria Reconstructions of Murine Cardiac Muscle Changes in Size Across Aging.

Black Seed Oil Improves Beef Fat-induced Blood-biochemical Abnormalities in Swiss Albino Mice

Background: The high saturated fatty acid content of beef has been linked to obesity and cardiovascular diseases. The study investigated the impact of black seed oil (BSO) on beef fat-altered hemato-biochemical and pathophysiological alterations in albino mice. Methods: Twenty four Swiss Albino mice (Mus musculus) of 25-28 days old were equally divided into three groups (n=8) namely A, B and C. Mice of group A was designated as the untreated control group. Groups B and C were fed pellets containing 10% beef fat and 10% BSO, respectively for 9 weeks. Result: The results revealed that beef fat-fed mice gained weight and BSO normalized the weight gain. The hematological values of beef fat supplemented mice improved after being supplemented with 10% BSO. LDL-c, Triglycerides and total cholesterol levels were all significantly lower in mice fed BSO plus beef fat. HDL-c levels were significantly higher in BSO plus beef fat-fed mice. Spleens in BSO plus beef fat-fed mice were slightly enlarged without gross abnormalities. 10% beef fat caused minor changes in the histostructures of the kidney, heart and liver. There were significant changes in cardiac muscle and massive fatty changes in kidney tissue. This study concluded that BSO has beneficial effects on the body and can prevent beef fat-induced abnormalities.

Developmental Aspects of Cardiac Adaptation to Increased Workload

The heart is capable of extensive adaptive growth in response to the demands of the body. When the heart is confronted with an increased workload over a prolonged period, it tends to cope with the situation by increasing its muscle mass. The adaptive growth response of the cardiac muscle changes significantly during phylogenetic and ontogenetic development. Cold-blooded animals maintain the ability for cardiomyocyte proliferation even in adults. On the other hand, the extent of proliferation during ontogenetic development in warm-blooded species shows significant temporal limitations: whereas fetal and neonatal cardiac myocytes express proliferative potential (hyperplasia), after birth proliferation declines and the heart grows almost exclusively by hypertrophy. It is, therefore, understandable that the regulation of the cardiac growth response to the increased workload also differs significantly during development. The pressure overload (aortic constriction) induced in animals before the switch from hyperplastic to hypertrophic growth leads to a specific type of left ventricular hypertrophy which, in contrast with the same stimulus applied in adulthood, is characterized by hyperplasia of cardiomyocytes, capillary angiogenesis and biogenesis of collagenous structures, proportional to the growth of myocytes. These studies suggest that timing may be of crucial importance in neonatal cardiac interventions in humans: early definitive repairs of selected congenital heart disease may be more beneficial for the long-term results of surgical treatment.

Fluorescence lifetime-based assay reports structural changes in cardiac muscle mediated by effectors of contractile regulation.

Cardiac muscle contraction is regulated by Ca2+-induced structural changes of the thin filaments to permit myosin cross-bridge cycling driven by ATP hydrolysis in the sarcomere. In congestive heart failure, contraction is weakened, and thus targeting the contractile proteins of the sarcomere is a promising approach to therapy. However, development of novel therapeutic interventions has been challenging due to a lack of precise discovery tools. We have developed a fluorescence lifetime-based assay using an existing site-directed probe, N,N'-dimethyl-N-(iodoacetyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)ethylenediamine (IANBD) attached to human cardiac troponin C (cTnC) mutant cTnCT53C, exchanged into porcine cardiac myofibrils. We hypothesized that IANBD-cTnCT53C fluorescence lifetime measurements provide insight into the activation state of the thin filament. The sensitivity and precision of detecting structural changes in cTnC due to physiological and therapeutic modulators of thick and thin filament functions were determined. The effects of Ca2+ binding to cTnC and myosin binding to the thin filament were readily detected by this assay in mock high-throughput screen tests using a fluorescence lifetime plate reader. We then evaluated known effectors of altered cTnC-Ca2+ binding, W7 and pimobendan, and myosin-binding drugs, mavacamten and omecamtiv mecarbil, used to treat cardiac diseases. Screening assays were determined to be of high quality as indicated by the Z' factor. We conclude that cTnC lifetime-based probes allow for precise evaluation of the thin filament activation in functioning myofibrils that can be used in future high-throughput screens of small-molecule modulators of function of the thin and thick filaments.

MRI Evaluation of Gene Therapy in the Canine Model of Duchenne Muscular Dystrophy.

Magnetic resonance imaging (MRI) is a well-established and widely used technique to characterize and quantify skeletal and cardiac muscle changes in Duchenne muscular dystrophy (DMD). Recently, MRI has been explored to study disease progression and response to gene therapy in the canine DMD model. Using traditional sequences, delayed gadolinium enhancement, novel sequences, and spectroscopy, investigators have begun to (i) establish the baseline MRI characteristics of the muscles in normal and affected dogs and (ii) evaluate gene therapy outcomes in treated dogs. As a noninvasive assay, MRI offers an excellent opportunity to study longitudinal muscle changes in long-term gene therapy studies in the canine model. In this chapter, we outline the MRI method used to study DMD in the canine model.

Management of Psychiatric Disorders in Patients with Cardiovascular Diseases.

Management of Psychiatric Disorders in Patients with Cardiovascular Diseases.

Cardiac miRNAs were involved in the regulation of pathophysiological mechanisms underlying HF in pediatric patients after ventricular assist device implantation

Abstract Background VAD use in heart failure (HF) children have undergone rapid progress in the last three decades through pump technological innovation and improvement of perioperative care. Studies in HF adults showed that VAD put native heart at rest and lead to molecular changes in cardiac muscle, including at microRNA (miRNA) level. However, little is known on changes induced by VAD implant in cardiac miRNA expression and their putative targets in HF children. Purpose The aims of this study were to evaluate: 1) modification of miRNA expression in cardiac muscle from HF children after VAD support; 2) the putative targets of selected miRNAs by in silico analysis; 2) the role of the identify miRNAs on putative targets by in vitro study. Methods Cardiac biopsies were collected from HF children at the moment of VAD implant [n=8; 20 (7.5–64.5) months, 2 males; 19 (15.75–32.25) LVEF%] and at the time of heart transplant after VAD support [n=5; 32 (5–204) months; 4 males; 13.5 (10–18) LVEF%]. Cardiac miRNA expression was evaluated by NGS. The potential miRNA targets were identified by bioinformatics analyses and their cardiac expression by real-time PCR was evaluated. HL-1 cell line was used for testing the regulatory role of selected miRNA on predicted targets by miRNA mimic transfection study. Results At NGS, 465 miRNA were found on average in each sample and the cardiac expression levels of miR19a-3p, miR-1246 and miR-199b-5p decreased in HF children after VAD support compared to pre-implant (Fig. 1A-B). In silico analysis showed that more than 5000 potential gene targets regulated by miR-19a-3p, miR-1246 and miR-199b-5p. Among them, adiponectin receptors (AdipoR1, AdipoR2, T-CAD) were identified as common targets for 3 miRNAs. Real-time PCR data showed that levels of all adiponectin receptors increased significantly whilst the expression of 3 miRNAs decreased after VAD support (Fig. 1C). Moreover, AdipoR2 and T-CAD were inversely related to miRNA levels (Fig. 1D). In vitro studies confirmed the regulatory role of miR-1246 and miR-199b-5p on AdipoR2 (Fig. 1E-F), whilst only miR-199b-5p reduced the expression of T-CAD (Fig. 1G). Finally, AdipoR1 expression levels are not modified compared to control by miRNAs mimic transfection (data not shown). Conclusion In HF children the use of VAD could modify the expression of several miRNAs potentially involved in the regulation of several pathophysiological mechanisms underlying HF. Specifically, the reductions of miR-1246, mir-19a-3p, miR-199b-5p were associated with an increase of the adiponectin receptors AdipoR2 and T-CAD mRNA, suggesting the existence of a miRNAs related fine tuning of the adiponectin system at cardiac tissue level by VAD implant, able to favour the protective effect of adiponectin in HF cardiac muscle. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): FP7-ICT-2009 Project, Grant Agreement 24863 Figure 1

The Possible Ameliorative Influence of Quercetin on Cardiac Muscle Changes induced by High Fat Diet in Adult Male Albino Rats: Light and Electron Microscopic Study

Background and Objectives: Cardiovascular diseases is a primary health concern. Recent studies have demonstrated that high-fat diet (HFD)-induced obesity could lead to cardiac dysfunction, hypertrophy, fibrosis and even heart failure. Quercetin (Q) is a common nontoxic polyphenol having a broad range of pharmacological and biological activities. The present study aimed at evaluating the histological and ultrastructural effects of high fat diet on cardiac muscle of adult male albino rat and the possible protective role of quercetin.Materials and Methods: Forty adult male albino rats were used and divided into four groups. Group I: Control group (10% of energy from fat). Group II: Quercetin group (10% of energy from fat + 60 mg/kg quercetin). Group III: HFD group (60% of energy from fat). Group IV: HFDQ group (60% of energy from fat + 60 mg/kg quercetin).At the end of experiment after12 weeks, all rats were sacrificed, and hearts were taken and processed for light (H&E and Mallory’s trichrome stains) and electron microscopic examination. Histological, morphometric and statistical studies were performed. Results: Sections from rats of group III showed widely separated cardiomyocytes, some atrophic degenerated fibers, vacuoles in the cytoplasm, engorged capillaries and marked increase in collagen deposition. Electron microscopic examination showed disorganized fragmented myofibrils, few swollen mitochondria and bizarre indented nuclei. Sections from rats of group IV revealed obvious improvement of the previous alterations. There was highly statistically significant difference between group I and group III and between group II and group III as regard collagen area percent. Conclusion: The results obtained from the current study confirmed the negative influence of high fat diet intake on cardiomyocytes. Concomitant administration of quercetin markedly improved myocardial damage so, it could be used as an effective cardioprotective agent against hyperlipidemia and aging insults.

Changes in circulating levels and cardiac expression of adiponectin system in children with heart failure after Ventricular Assist Device support

Abstract Background Ventricular Assist Device (VAD) is increasingly used as bridge to transplantation for the treatment adult and pediatric patients with end-stage Heart Failure (HF). Unloading of heart by VAD can lead to significant molecular, structural and functional changes of cardiac muscle in HF adult patients, including an improvement of the inflammatory process. Adiponectin (ADN), an anti-inflammatory adipokine, exerts anti-hypertrophic, anti-fibrotic and anti-apoptotic effects after binding to AdipoR1, AdipoR2 and T-CAD receptors. There is an apparently paradoxical increase of ADN levels in HF adult patients, probably due ADN resistance. VAD treatment leads to an increased cardiac expression of ADN receptors in HF adults. However, little is known about the role of ADN in HF children and the effects of VAD support on ADN system in these patients. Purpose The aims of this study were to evaluate: 1) the circulating ADN levels from HF children and a control group of healthy children; 2) the effects of VAD treatment both on circulating levels of ADN and on the cardiac expression of ADN system in pediatric patients with HF. Methods Circulating levels of ADN were measured in plasma samples collected from 8 HF children [age:57±33 (mean±SD) months; 2 males; 14.2±13.5 weight; 29±8 LVEF%] before and at 4 hrs, 1, 3, 7, 14 and 30 days after VAD implant. The ADN levels of paediatric patients at baseline were compared with a group of 107 [58±7 months; 67 males] healthy children. Expression levels of AdipoR1, AdipoR2, T-CAD were determined by real-time PCR in cardiac biopsies collected from HF children at the time of VAD implant (Pre-VAD) and at the time of heart transplantation (Post-VAD). Results Circulating levels of ADN were significantly higher in HF compared to healthy children (Figure 1A). In HF children, plasma ADN decreased significantly in early post-operative time-course (up to 3 days Post-VAD implant) and returned to pre-operative levels in 1 month (Figure 1B). In cardiac biopsies, mRNA expression of AdipoR1, AdipoR2, T-CAD increased significantly after VAD treatment compared to Pre-VAD (Figure 2A–C). Conclusion In pediatric patients, high circulating levels of ADN were associated with presence of HF and were modified by VAD implant, but remained significantly abnormal. On the other hand, an increased cardiac mRNA expression of ADN receptors was observed after VAD. These results could suggest the existence of a fine tuning of the ADN system at cardiac tissue level, able to mitigate plasma abnormality and favour the cardio-protective effect of ADN. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): SensorART-A Remote Controlled Sensorized ARTificial Heart Enabling Patients Empowerment and New Therapy Approaches

Arterial hypertension: a path from unchanged transmitral bloodstream to dysfunction

Objective: assess the parameters characterizing the structural and functional features of the cardiovascular system in patients with arterial hypertension (AH) with signs of diastolic dysfunction of the left ventricle (DDLV), to determine the dynamics of changes in the heart and vessels from the unchanged spectrum of transmitral bloodstream (USTB) to diastolic dysfunction (DD) in AH patients. Material and methods. An open prospective study of patients with essential AH and USTB (n = 34) and with DDLV signs (n = 45) was organized in the state institution «Republican Research Center for Radiation Medicine and Human Ecology». The examined individuals are comparable in terms of sex and age features. Standard transtoracal echocardiography with the determination of standard indices, ultrasonic examination of the extranial department of the brachyocephalic arteries (BCA) with the determination of the thickness of the intima-media complex (CIM), duplex scanning of the arteries of the upper and lower limbs with the determination of the ankle-shoulder index and endothelium-dependent were performed in all the participants of the study. In addition, global longitudinal deformation was evaluated by two-dimensional tracking of the grey spots of the ultrasonic image scale (speckle tracking), parameters of the movement of the fibrous ring of the mitral valve into systole and diastole with the determination of the myocardial index by the method of tissue dopplerography. Results. The examination of the heart by the method of standard transtoracal echocardiography has revealed that AH patients with DDLV (2nd group) in comparison with AH patients with the unchanged spectrum of transmitral bloodstream (1st group) detected higher values of interventricular partition (12 mm versus 9 mm, р = 0.001), relative wall thickness (0.41 versus 0.35, р = 0.033), the index of myocardial mass (65 g versus 58.5 g, р = 0.015). The isovolumetric relaxation time of the PG (81 ms versus 67 ms, p = 0.043), the rate of tricuspidal regurgitation and systolic pressure in the pulmonary artery were significantly higher in the group of AH patients with DDLV (p = 0.005). The analysis of the movement of the fibrous ring of the mitral valve by tissue dopplerography has showed that in the second group of the patients (AH with DDLV), there are signs of regional systolic dysfunction of the medial part of the fibrous ring of the mitral valve (0.08 cm/s versus 0.09, p = 0.047). E/Em was higher in the second group, a statistically significant difference was found for the lateral portion of the fibrous ring of the mitral valve (5.7 vs. 7, p = 0.019). The ultrasonic duplex scanning of the extranial part of the BCA revealed that in the AH patients with DDLV compared to the AH patients with the unchanged spectrum of transmitral bloodstream, the value of the thickness of the CIM is reliably higher (right 0.8 mm versus 0.65 mm, p = 0.001, left 0.8 mm versus 0.7 mm, p = 0.001). The study of the endothelium function has revealed that the second group of the patients compared to the first one, recorded reliably lower values of endothelium dependent vasodilation (10 % versus 14 %, p = 0.009). The analysis of subclinical lesion of the arteries of the lower limbs has revealed that in the group of patients with DDLV compared to the group of the AH patients with the unchanged spectrum of transmitral bloodstream, the ankle-shoulder index value is reliably higher (right 1.1 versus 1.07, p = 0.013, left 1.1 versus 1.07, p = 0.05). Conclusion. The protocol method of research - standard transthoracic echocardiography - does not allow to estimate fully the functional changes of cardiac muscle in AH patients with DDLV in comparison with AH patients with the unchanged spectrum of transmitral bloodstream. The application of additional diagnostic techniques (TDG and speckle tracking) makes it possible to get missing data. Pathologic transformation of transmitral bloodstream occurs when signs of systolic and diastolic dysfunction of the left ventricle already exist. The appearance of signs of diastolic dysfunction of the left ventricle during standard echocardiography is accompanied by pathologic remodeling of the vascular system.

EFFECT OF SPEXIN TREATMENT ON CARDIOMETABOLIC CHANGES IN OBESE TYPE 2 DIABETIC RATS

Background: Spexin is a peptide hormone that was expressed in brain regions and peripheral tissues of many species including human and rat. Several studies investigated its blood level changes with obesity and type 2 diabetes, but few studies assessed its effect on cardiometabolic, histological and morphometric changes in diabetes with some controversies in their results. Objective: To explore the effect of spexin treatment on cardiometabolic, histological and morphometric changes of pancreas and heart tissue in obese type 2 diabetic rats, and the possible mechanisms involved. Materials and Methods: Thirty adult male albino rats were divided randomly into 5 equal groups; control (fed ordinary laboratory chow along this 8 weeks’ study), diabetic [fed high fat diet along this 8 weeks’ study, but at the start of the 4th week, overnight fasted rats were injected with a single streptozotocin injection intraperitoneally (40 mg/kg body weight, dissolved in 0.01M citrate buffer, pH 4.5) to induce diabetes], diabetic metformin-treated [rats were managed as in diabetic group and in addition to that, metformin was given orally (300 mg/kg/day) by oral gavage to rats for 4 weeks from the start of 5th week to the end of 8th week], diabetic vildagliptin treated [rats were manipulated as in diabetic group and in addition to that, vildagliptin was given orally (10 mg/kg/day) using oral gavage to rats for 4 weeks from the start of 5th week to the end of 8th week], and diabetic spexin treated [rats were managed as in diabetic group and in addition to that, spexin dissolved in normal saline was injected intraperitoneally (35 μg/kg/day) for 4 weeks from the start of 5th week to the end of 8th week] groups. For histological, immunohistochemical and morphometric examinations, fresh heart and pancreatic specimens were collected from rats that were sacrificed. Results: In diabetic group, a significant increase was detected in final body mass index, serum glucose, serum insulin, homeostasis model assessment-insulin resistance, serum total cholesterol, serum triglycerides, serum low density lipoprotein, atherogenic index, serum dipeptidyl peptidase-IV, serum tumor necrosis factor alpha serum interleukin-1 beta, serum malondialdehyde, serum lactate dehydrogenase, serum creatine kinase-myoglobin binding and mean arterial blood pressure, with a significant decrease in homeostasis model assessment-beta cell functionserum high density lipoprotein, serum superoxide dismutase and serum spexin in comparison to that in the control group. With spexin treatment (as well as with the administration of standard drugs metformin and vildagliptin), all these changes were reversed significantly in comparison with those in the diabetic group. Diabetes induced histopathological changes in cardiac muscle and pancreatic structure which were ameliorated by treatment with spexin as well as with the standard anti-diabetic drugs (metformin and vildagliptin). The morphometric analysis confirmed the histopathological results, as a statistically significant difference was detected in area percent of collagen deposition, area percent of insulin immune-reaction in pancreas and cardiac muscle Bax expression between both diabetic group and all other groups, with no statistically significant difference between diabetic metformin treated, diabetic vildagliptin treated and diabetic spexin treated groups. Conclusion: Spexin ameliorated diabetes induced deleterious cardiometabolic, histopathological and morphometric disturbances. The anti-obesity, dipeptidyl peptidase-IV inhibitory, hypoglycemic, hypolipidemic, antioxidant, anti-inflammatory and cardio-protective properties of spexin may contribute to its useful effects.

EFFECT OF SPEXIN TREATMENT ON CARDIOMETABOLIC CHANGES IN OBESE TYPE 2 DIABETIC RATS

Background: Spexin is a peptide hormone that was expressed in brain regions and peripheral tissues of many species including human and rat. Several studies investigated its blood level changes with obesity and type 2 diabetes, but few studies assessed its effect on cardiometabolic, histological and morphometric changes in diabetes with some controversies in their results. Objective: To explore the effect of spexin treatment on cardiometabolic, histological and morphometric changes of pancreas and heart tissue in obese type 2 diabetic rats, and the possible mechanisms involved. Materials and Methods: Thirty adult male albino rats were divided randomly into 5 equal groups; control (fed ordinary laboratory chow along this 8 weeks’ study), diabetic [fed high fat diet along this 8 weeks’ study, but at the start of the 4th week, overnight fasted rats were injected with a single streptozotocin injection intraperitoneally (40 mg/kg body weight, dissolved in 0.01M citrate buffer, pH 4.5) to induce diabetes], diabetic metformin-treated [rats were managed as in diabetic group and in addition to that, metformin was given orally (300 mg/kg/day) by oral gavage to rats for 4 weeks from the start of 5th week to the end of 8th week], diabetic vildagliptin treated [rats were manipulated as in diabetic group and in addition to that, vildagliptin was given orally (10 mg/kg/day) using oral gavage to rats for 4 weeks from the start of 5th week to the end of 8th week], and diabetic spexin treated [rats were managed as in diabetic group and in addition to that, spexin dissolved in normal saline was injected intraperitoneally (35 μg/kg/day) for 4 weeks from the start of 5th week to the end of 8th week] groups. For histological, immunohistochemical and morphometric examinations, fresh heart and pancreatic specimens were collected from rats that were sacrificed. Results: In diabetic group, a significant increase was detected in final body mass index, serum glucose, serum insulin, homeostasis model assessment-insulin resistance, serum total cholesterol, serum triglycerides, serum low density lipoprotein, atherogenic index, serum dipeptidyl peptidase-IV, serum tumor necrosis factor alpha serum interleukin-1 beta, serum malondialdehyde, serum lactate dehydrogenase, serum creatine kinase-myoglobin binding and mean arterial blood pressure, with a significant decrease in homeostasis model assessment-beta cell functionserum high density lipoprotein, serum superoxide dismutase and serum spexin in comparison to that in the control group. With spexin treatment (as well as with the administration of standard drugs metformin and vildagliptin), all these changes were reversed significantly in comparison with those in the diabetic group. Diabetes induced histopathological changes in cardiac muscle and pancreatic structure which were ameliorated by treatment with spexin as well as with the standard anti-diabetic drugs (metformin and vildagliptin). The morphometric analysis confirmed the histopathological results, as a statistically significant difference was detected in area percent of collagen deposition, area percent of insulin immune-reaction in pancreas and cardiac muscle Bax expression between both diabetic group and all other groups, with no statistically significant difference between diabetic metformin treated, diabetic vildagliptin treated and diabetic spexin treated groups. Conclusion: Spexin ameliorated diabetes induced deleterious cardiometabolic, histopathological and morphometric disturbances. The anti-obesity, dipeptidyl peptidase-IV inhibitory, hypoglycemic, hypolipidemic, antioxidant, anti-inflammatory and cardio-protective properties of spexin may contribute to its useful effects.

Carnosine Essential For Cardiac Function. A Study With Knockout Rats For The Carnosine Synthase Gene

Carnosine is present in high concentrations in heart, where it appears to increase the sensitivity of the contractile apparatus to Ca2+. However, it is currently unknown whether this role is relevant to the cardiac physiology. PURPOSE: To evaluate the impact of the lack of carnosine on myocardial contractile function in rats knockout (KO) for the CARNS1 gene (carnosine synthase1). METHODS: We developed the first KO animal model for the CARNS1 gene through CRISPR-Cas9 technology. Male wild-type (WT) and KO rats (4 months-old) were used. In vivo cardiac function was assessed by echocardiography (ECO) and cardiac electrical activity by electrocardiography (ELECTRO). Cardiomyocyte contractile function was assessed in isolated cardiomyocytes by measuring cardiomyocyte and sarcomere contractility analysis, along with the determination of Ca2+ transient. Unpaired t-tests were used to compare variables between WT and KO. The study was approved by the Ethics Committee on the Use of Animals of USP. RESULTS: ECO (WT:n=4; KO:n=6) showed that KO rats presented a higher systolic diameter (WT:0.008±0.001mm/g; KO:0.011±0.001mm/g; p=0.002), lower Fraction of Left Ventricular Ejection (WT:80.26±6.86%; KO:69.86±4.67%; p=0.01) and lower Fraction of Left Ventricular Shortening (WT:51.12±7.39%; KO:40.88±3.92%; p=0.01), characterizing systolic dysfunction. ELECTRO (WT: n=8; KO:n=8) showed higher T wave amplitude in the KO group (WT:0.06±0.02mV; KO:0.13±0.03mV; p=0.005), indicating a disturbance in the Ca2+ channels. In vitro contractility data (WT: n=3; KO:n=3) showed that sarcomere shortening is reduced in the KO (WT:11.75±4.20%; KO:9.28±3.71%) (WT:6.81±3.15s; KO:4.33±1.87s ; p<0.0001), and the time to reach 50% of maximal shortening is longer in the KO (WT:0.04±0.01s; KO:0.05±0.01s; p<0.0001). Ca2+ transient analysis showed lower amplitude of Ca2+ in the KO group (WT:0.20±0.10; KO:0.16±0.06 F340/380 ratio; p=0.001) and longer time for to reach 50% of the Ca2+ decay rate (WT:0.21±0.04s; KO:0.24±0.03s; p=0.001). CONCLUSION: Absence of carnosine resulted in systolic dysfunction associated with Ca2+ transient changes in cardiac muscle. This is the first evidence to demonstrate in vivo, ex vivo and in vitro that carnosine is essential for normal cardiac function. Supported by FAPESP 2014/11948-8 and CAPES

Astragaloside IV alleviates heart failure via activating PPAR\u03b1 to switch glycolysis to fatty acid \u03b2-oxidation

In heart failure (HF), energy metabolism pathway in cardiac muscle changes from fatty acid β-oxidation to glycolysis. However, the exact mechanism is unknown. Sarcoendoplasmic reticulum Ca2+α ATPase (SERCA) expression is downregulated and mitochondrial function is reduced in HF, perhaps partly due to a substantially reduced energy supply for excitation–contraction coupling resulting from a lower fatty acid β-oxidation rate. We investigated whether Astragaloside IV can activate peroxisome proliferator-activated receptor alpha (PPARα) to stimulate fatty acid β-oxidation and increase cardiac energy production, improving mitochondrial function and the efficiency of SERCA in HF. In pressure overload-induced HF mice and isolated hypertrophic myocardial cells, fatty acid β-oxidation and heart function were substantially strengthened following Astragaloside IV treatment, as demonstrated by the increased expression of PPARα and SERCA2a. In vitro, Astragaloside IV regulated energy metabolism by increasing ATP production and enhancing mitochondrial function, attributable to increased oxygen consumption and slightly increased mitochondrial Ca2+ uptake. In HF, Astragaloside IV switched glycolysis to fatty acid β-oxidation, as confirmed by reduced anaerobic glycolysis and an increased oxygen consumption ratio. These results suggest that Astragaloside IV can stimulate fatty acid β-oxidation and improve mitochondrial function, which may present a novel cardioprotective treatment that inhibits the progress of HF.

Postmortem changes in sarcoplasmic proteins associated with color stability in lamb muscle analyzed by proteomics

The aim of this research was to correlate the postmortem changes of sarcoplasmic proteins with instrumental color and various biochemical parameters relating to color attributes. Two-dimensional electrophoresis was used to investigate sarcoplasmic protein changes in cardiac muscle during refrigerated storage. Eleven differentially abundant protein spots were identified between storage time at day 1 and day 5 (P < 0.05). The functional category of proteins consisted of metabolic enzymes, binding proteins, chaperone proteins, and antioxidant proteins. These proteins demonstrated positive correlation with a*-value (creatine kinase M-type and malate dehydrogenase), metmyoglobin-reducing activity (aconitate hydratase, creatine kinase, and thioredoxin-dependent peroxide reductase), tissue oxygen consumption rate (creatine kinase and malate dehydrogenase), and mitochondrial respiration control ratio (thioredoxin-dependent peroxide reductase and mitochondrial superoxide dismutase). The protein patterns were likely to have impact on postmortem metabolism, thereby protecting muscle against discoloration.

Abstract 403: Metabolic Characteristics of Spontaneously Hypertensive Rats Compared With Normotensive Controls

Objectives: To differentiate the metabolic responses of spontaneously hypertensive rats (SHR) compared to normotensive Wistar Kyoto (WKY) rats. Methods: Blood pressure and pulse wave velocity (PWV) measurements were conducted on 25 week old SHR and WKY rats. At the time of termination, vital organs were harvested and weighed, and serum was collected for analysis of blood lipids, liver enzymes, and urea levels. Results: SHR exhibited higher readings for mean arterial pressure (MAP) (p&lt; 0.0001), peak velocity (PWV) (p=0.017), heart/body weight (BW) ratio (p&lt;0.0001), and left ventricular wall/BW ratio (p&lt;0.0001) compared to WKY. WKY displayed higher weight gain and blood lipid levels (serum triglycerides, total cholesterol, LDL-C, and HDL-C) compared to SHR (p&lt;0.0001). Blood lipid levels were positively correlated with weight gain, and negatively correlated with MAP and left ventricular wall/body weight ratio. Weight gain and MAP were negatively correlated (r=-0.60, p&lt;0.0001). Serum AST levels were higher among SHR compared to WKY (p=0.026), and serum AST was positively correlated with left ventricular wall/BW ratio (r=0.35, p=0.030). There was no correlation between AST levels and liver/BW ratio or MAP. Serum urea levels were higher among SHR compared to WKY (p=0.0032), and positively correlated with MAP (r=0.42, p=0.011) and heart/BW ratio (r=0.43, p=0.0096). There were no differences in kidney/BW ratios, however, the peri-renal adipose/BW ratio was lower in SHR compared to WKY (p=0.001), and negatively correlated with MAP (r=-0.41, p=0.018). Conclusion: The positive relationship between serum AST and left ventricular wall/BW ratio, but not liver/BW ratio, suggests a possible response to changes in cardiac muscle, independent of blood pressure. Serum urea levels responded to MAP and heart/BW ratio. These metabolic responses of SHR compared to WKY invite further investigation of possible mechanisms underlying the link with cardiovascular dysfunction.