Relationship between a deep learning model and liquid-based cytological processing techniques.

OBJECTIVE: Artificial intelligence (AI)-based cytopathology studies conducted using deep learning have enabled cell detection and classification. Liquid-based cytology (LBC) has facilitated the standardisation of specimen preparation; however, cytomorphology varies according to the LBC processing technique used. In this study, we elucidated the relationship between two LBC techniques and cell detection and classification using a deep learning model. METHODS: Cytological specimens were prepared using the ThinPrep and SurePath methods. The accuracy of cell detection and cell classification was examined using the one- and five-cell models, which were trained with one and five cell types, respectively. RESULTS: When the same LBC processing techniques were used for the training and detection preparations, the cell detection and classification rates were high. The model trained on ThinPrep preparations was more accurate than that trained on SurePath. When the preparation types used for training and detection were different, the accuracy of cell detection and classification was significantly reduced (P < 0.01). The model trained on both ThinPrep and SurePath preparations exhibited slightly reduced cell detection and classification rates but was highly accurate. CONCLUSIONS: For the two LBC processing techniques, cytomorphology varied according to cell type; this difference affects the accuracy of cell detection and classification by deep learning. Therefore, for highly accurate cell detection and classification using AI, the same processing technique must be used for both training and detection. Our assessment also suggests that a deep learning model should be constructed using specimens prepared via a variety of processing techniques to construct a globally applicable AI model.

The prebiotic fiber inulin ameliorates cardiac, adipose tissue, and hepatic pathology, but exacerbates hypertriglyceridemia in rats with metabolic syndrome.

Prebiotics ameliorate dysbiosis and influence metabolism and the immune system, but their effects on cardiovascular complications in metabolic disorders remain largely unknown. We here investigated the effects of the soluble fiber inulin on cardiac, adipose tissue, and hepatic pathology as well as on metabolic disorders in DahlS.Z-Leprfa/Leprfa (DS/obese) rats, an animal model of metabolic syndrome (MetS). DS/obese rats and their homozygous lean (DahlS.Z-Lepr+/Lepr+, or DS/lean) littermate controls were fed a purified diet containing 5% or 20% inulin from 9 to 13 wk of age. The high-fiber diet ameliorated hypertension, left ventricular inflammation, fibrosis and diastolic dysfunction; attenuated adipose tissue inflammation and fibrosis; and alleviated the elevation of interleukin-6 levels, without affecting insulin resistance, in DS/obese rats. In addition, high fiber intake ameliorated lipid accumulation, inflammation, and fibrosis; attenuated the reduction in AMPK activity; upregulated sterol regulatory element-binding protein-1c gene expression; and increased the expression of microsomal triglyceride transfer protein gene in the liver of DS/obese rats. It also mitigated increases in total and non-high-density lipoprotein cholesterol levels but increased the triglyceride concentration in serum in these rats. None of these parameters were affected by high dietary fiber in DS/lean rats. The proportion of regulatory T cells in adipose tissue was influenced by dietary fiber but not by genotype. Our results indicate that inulin exacerbates hypertriglyceridemia but alleviates hypertension and cardiac injury as well as adipose tissue and hepatic pathology in MetS rats.NEW & NOTEWORTHY Prebiotics ameliorate dysbiosis and influence metabolism and the immune system, but their effects on cardiovascular complications in metabolic disorders remain largely unknown. Inulin ameliorated hypertension, cardiac injury, and diastolic dysfunction without affecting obesity or insulin resistance in a rat model of metabolic syndrome. The favorable cardiac effects of inulin may be related to inhibition of systemic inflammation associated with a reduction in circulating interleukin-6 levels. Additionally, inulin exacerbated hypertriglyceridemia but alleviates adipose tissue and hepatic pathology in these animals, as well as increased the number of regulatory T cells in adipose tissue.

Evaluation of dermal wound healing activity of synthetic peptide SVVYGLR.

SVVYGLR peptide (SV peptide) is a 7-amino-acid sequence with angiogenic properties that is derived from osteopontin in the extracellular matrix and promotes differentiation of fibroblasts to myofibroblast-like cells and the production of collagen type Ⅲ by cardiac fibroblasts. However, the effects of SV peptide on dermal cells and tissue are unknown. In this study, we evaluated the effects of this peptide in a rat model of dermal wound healing. The synthetic SV peptide was added to dermal fibroblasts or keratinocytes, and their cellular motility was evaluated. In an in vivo wound healing exeriment, male rats aged 8 weeks were randomly assigned to the SV peptide treatment, non-treated control, or phosphate-buffered saline (PBS) groups. Wound healing was assessed by its repair rate and histological features. Scratch assay and cell migration assays using the Chemotaxicell method showed that SV peptide significantly promoted the cell migration in both fibroblasts and keratinocytes. In contrast the proliferation potency of these cells was not affected by SV peptide. In the rat model, wound healing progressed faster in the SV peptide-treated group than in the control and PBS groups. The histopathological analyses showed that the SV peptide treatment stimulated the migration of fibroblasts to the wound area and increased the number of myofibroblasts. Immunohistochemical staining showed a marked increase of von Willebland factor-positive neomicrovessels in the SV peptide-treated group. In conclusion, SV peptide has a beneficial function to promote wound healing by stimulating granulation via stimulating angiogenesis, cell migration, and the myofibroblastic differentiation of fibroblasts.

Effects of various types of anesthesia on hemodynamics, cardiac function, and glucose and lipid metabolism in rats.

Anesthesia can affect respiratory, circulatory, and endocrine systems but is necessary for certain experimental procedures such as echocardiography and blood sampling in small animals. We have now investigated the effects of four types of anesthesia [pentobarbital sodium (PENT), ketamine-xylazine (K/X), and low- or high-dose isoflurane (ISO)] on hemodynamics, cardiac function, and glucose and lipid metabolism in Sprague-Dawley rats. Aortic pressure, heart rate, and echocardiographic parameters were measured at various time points up to 45 min after the induction of anesthesia, and blood was then collected for measurement of parameters of glucose and lipid metabolism. Systolic aortic pressure remained constant in the PENT group, whereas it showed a biphasic pattern in the K/X group and a gradual decline in the ISO groups. Marked bradycardia was observed in the K/X group. The serum glucose concentration was increased and the plasma insulin level was reduced in the K/X and ISO groups compared with the PENT group. The concentrations of free fatty acids and norepinephrine in plasma were increased in the K/X group. Despite the metabolic effects of K/X and ISO, our results suggest that the marked bradycardic effect of K-X renders this combination appropriate for measurement of Doppler-derived indexes of left ventricular diastolic function, whereas the relative ease with which the depth of anesthesia can be controlled with ISO makes it suitable for manipulations or data collection over long time periods. On the other hand, PENT may be best suited for experiments that focus on measurement of cardiac function by M-mode echocardiography and metabolic parameters.

Restraint stress exacerbates cardiac and adipose tissue pathology via ß-adrenergic signaling in rats with metabolic syndrome.

Restraint stress stimulates sympathetic nerve activity and can affect adiposity and metabolism. However, the effects of restraint stress on cardiovascular and metabolic disorders in metabolic syndrome (MetS) have remained unclear. We investigated the effects of chronic restraint stress and ß-adrenergic receptor (ß-AR) blockade on cardiac and adipose tissue pathology and metabolic disorders in a rat model of MetS. DahlS.Z-Lepr(fa)/Lepr(fa) (DS/obese) rats, derived from a cross between Dahl salt-sensitive and Zucker rats. Rats were exposed to restraint stress (restraint cage, 2 h/day) for 4 wk from 9 wk of age with or without daily subcutaneous administration of the ß-AR blocker propranolol (2 mg/kg). Age-matched homozygous lean littermates of DS/obese rats (DahlS.Z-Lepr(+)/Lepr(+) rats) served as control animals. Chronic restraint stress exacerbated hypertension as well as left ventricular hypertrophy, fibrosis, diastolic dysfunction, and oxidative stress in a manner sensitive to propranolol treatment. Restraint stress attenuated body weight gain in DS/obese rats, and this effect tended to be reversed by propranolol (P = 0.0682). Restraint stress or propranolol did not affect visceral or subcutaneous fat mass. However, restraint stress potentiated cardiac and visceral adipose tissue inflammation in DS/obese rats, and these effects were ameliorated by propranolol. Restraint stress also exacerbated glucose intolerance, insulin resistance, and abnormal lipid metabolism in a manner sensitive to propranolol. In addition, restraint stress increased urinary norepinephrine excretion, and propranolol attenuated this effect. Our results thus implicate ß-ARs in the exacerbation of cardiac and adipose tissue pathology and abnormal glucose and lipid metabolism induced by restraint stress in this model of MetS.

Roles of oxidative stress and the mineralocorticoid receptor in cardiac pathology in a rat model of metabolic syndrome.

Oxidative stress and the mineralocorticoid receptor (MR) are implicated in the pathogenesis of salt-induced left ventricular (LV) diastolic dysfunction associated with metabolic syndrome (MetS). We recently characterized DahlS.Z-Lepr(fa) /Lepr(fa) (DS/obese) rats, derived from a cross between Dahl salt-sensitive and Zucker rats, as a new animal model of MetS. We investigated the pathophysiological roles of increased oxidative stress and MR activation in cardiac injury with this model. DS/obese rats were treated with the antioxidant tempol (1 mmol/L in drinking water) or the selective MR antagonist eplerenone (15 mg/kg per day, per os) for 5 weeks beginning at 10 weeks of age. The increased systolic blood pressure and LV hypertrophy that develop in untreated DS/obese rats were substantially ameliorated by eplerenone but not by tempol. Eplerenone also attenuated LV fibrosis and diastolic dysfunction more effectively than did tempol in DS/obese rats, whereas cardiac oxidative stress and inflammation were reduced similarly by both drugs. Both the ratio of plasma aldosterone concentration to plasma renin activity and cardiac expression of the MR and serum/glucocorticoid-regulated kinase 1 genes were decreased to a greater extent by eplerenone than by tempol. Our results indicate that both increased oxidative stress and MR activation in the heart may contribute to the development of LV remodeling and diastolic dysfunction in DS/obese rats. The superior cardioprotective action of eplerenone is likely attributable to its greater antihypertensive effect, which is likely related to its greater inhibition of aldosterone-MR activity in the cardiovascular system.

Premature cardiac senescence in DahlS.Z-Lepr(fa)/Lepr(fa) rats as a new animal model of metabolic syndrome.

Aging is accelerated by metabolic and cardiovascular diseases, and the risk of these diseases increases with age. Obesity is an important risk factor for many age-related diseases and is linked to reduced telomere length in white blood cells. We investigated whether cardiac senescence might be enhanced in DahlS.Z-Lepr(fa)/Lepr(fa) (DS/obese) rats, which we recently established as a new animal model of metabolic syndrome. The heart of DS/obese rats was compared with that of homozygous lean littermates (DahlS.Z-Lepr+/Lepr+, or DS/lean, rats). DS/obese rats manifested hypertension as well as left ventricular hypertrophy, fibrosis, and diastolic dysfunction at 18 weeks of age. Myocardial oxidative stress and inflammation were increased in DS/obese rats compared with DS/lean rats. Telomere length in myocardial cells did not differ between the two rat strains, whereas telomerase activity and expression of the telomerase reverse transcriptase gene were increased in DS/obese rats. Expression of the senescence-associated genes for checkpoint kinase 2 (Chk2), p53, and p21 as well as that of genes related to the renin-angiotensin-aldosterone system were also up-regulated in the DS/obese rat heart. Our results indicate that DS/obese rats undergo premature cardiac senescence as well as cardiac remodeling in association with the development of diastolic dysfunction in these animals.

Glucocorticoids activate cardiac mineralocorticoid receptors in adrenalectomized Dahl salt-sensitive rats.

We previously showed that selective mineralocorticoid receptor (MR) blockade by eplerenone is cardioprotective in Dahl salt-sensitive (DS) rats. To clarify the consequences of glucocorticoid-mediated MR activation in these animals, we investigated the effects of exogenous corticosterone on blood pressure as well as cardiac remodeling and function after adrenalectomy. DS rats were subjected to adrenalectomy at 6 weeks of age and thereafter fed a high-salt diet and administered corticosterone (20 mg/kg per day) or vehicle. Systolic blood pressure was higher in the corticosterone group than in the vehicle group at 7 weeks and thereafter. By 11 weeks, corticosterone had reduced left ventricular (LV) mass and induced LV diastolic dysfunction. The ratio of collagen type I to type III mRNA levels in the left ventricle was increased in the corticosterone group compared with the vehicle group. Administration of a non-antihypertensive dose of the MR antagonist spironolactone (20 mg/kg per day) from 6 weeks inhibited the effects of corticosterone on both the collagen type I to type III mRNA ratio and diastolic function without affecting the decrease in LV mass. Spironolactone attenuated both the increase in NADPH oxidase activity in the left ventricle and coronary vascular inflammatory responses apparent in the corticosterone group. These results indicate that exogenous glucocorticoids induce hypertension, cardiac remodeling, and diastolic dysfunction in adrenalectomized DS rats fed a high-salt diet. The cardiac effects of exogenous glucocorticoids are likely attributable, at least in part, to myocardial oxidative stress and coronary vascular inflammation induced by glucocorticoid-activated MRs.

Staining, magnification, and algorithmic conditions for highly accurate cell detection and cell classification by deep learning.

OBJECTIVES: Research into cytodiagnosis has seen an active exploration of cell detection and classification using deep learning models. We aimed to clarify the challenges of magnification, staining methods, and false positives in creating general purpose deep learning-based cytology models. METHODS: Using 11 types of human cancer cell lines, we prepared Papanicolaou- and May-Grünwald-Giemsa (MGG)-stained specimens. We created deep learning models with different cell types, staining, and magnifications from each cell image using the You Only Look Once, version 8 (YOLOv8) algorithm. Detection and classification rates were calculated to compare the models. RESULTS: The classification rates of all the created models were over 95.9%. The highest detection rates of the Papanicolaou and MGG models were 92.3% and 91.3%, respectively. The highest detection rates of the object detection and instance segmentation models, which were 11 cell types with Papanicolaou staining, were 94.6% and 91.7%, respectively. CONCLUSIONS: We believe that the artificial intelligence technology of YOLOv8 has sufficient performance for applications in screening and cell classification in clinical settings. Conducting research to demonstrate the efficacy of YOLOv8 artificial intelligence technology on clinical specimens is crucial for overcoming the unique challenges associated with cytology.

Comparison of the effects of renal denervation at early or advanced stages of hypertension on cardiac, renal, and adipose tissue pathology in Dahl salt-sensitive rats.

Renal denervation (RDN) has emerged as a novel therapy for drug-resistant hypertension. We here examined the effects of RDN at early versus advanced stages of hypertension on blood pressure and organ pathology in rats with salt-sensitive hypertension. Dahl salt-sensitive (DahlS) rats fed an 8% NaCl diet from 6 weeks of age were subjected to RDN (surgical ablation and application of 10% phenol in ethanol) or sham surgery at 7 (early stage) or 9 (advanced stage) weeks and were studied at 12 weeks. RDN at early or advanced stages resulted in a moderate lowering of blood pressure. Although RDN at neither stage affected left ventricular (LV) and cardiomyocyte hypertrophy, it ameliorated LV diastolic dysfunction, fibrosis, and inflammation at both stages. Intervention at both stages also attenuated renal injury as well as downregulated the expression of angiotensinogen and angiotensin-converting enzyme (ACE) genes and angiotensin II type 1 receptor protein in the kidney. Furthermore, RDN at both stages inhibited proinflammatory gene expression in adipose tissue. The early intervention reduced both visceral fat mass and adipocyte size in association with downregulation of angiotensinogen and ACE gene expression. In contrast, the late intervention increased fat mass without affecting adipocyte size as well as attenuated angiotensinogen and ACE gene expression. Our results thus indicate that RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated cardiac and renal injury and adipose tissue inflammation in DahlS rats. They also suggest that cross talk among the kidney, cardiovascular system, and adipose tissue may contribute to salt-sensitive hypertension. Supposed mechanism for the beneficial effects of RDN on hypertension and target organ damage in DahlS rats. RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated renal injury in DahlS rats. Cross talk among the kidney, cardiovascular system, and adipose tissue possibly mediated by circulating RAS may contribute to salt-sensitive hypertension. LV; left ventricular, NE; norepinephrine, RAS; renin-angiotensin system, RDN; renal denervation.

Dipeptidyl peptidase-4 modulates left ventricular dysfunction in chronic heart failure via angiogenesis-dependent and -independent actions.

BACKGROUND: The inhibition of dipeptidyl peptidase-4 (DPP4) protects the heart from acute myocardial ischemia. However, the role of DPP4 in chronic heart failure independent of coronary artery disease remains unclear. METHODS AND RESULTS: We first localized the membrane-bound form of DPP4 to the capillary endothelia of rat and human heart tissue. Diabetes mellitus promoted the activation of the membrane-bound form of DPP4, leading to reduced myocardial stromal cell-derived factor-1α concentrations and resultant angiogenic impairment in rats. The diabetic rats exhibited diastolic left ventricular dysfunction (DHF) with enhanced interstitial fibrosis caused partly by the increased ratio of matrix metalloproteinase-2 to tissue inhibitor of metalloproteinase-2 in a DPP4-dependent fashion. Both genetic and pharmacological DPP4 suppression reversed the stromal cell-derived factor-1α-dependent microvasculopathy and DHF associated with diabetes mellitus. Pressure overload induced DHF, which was reversed by DPP4 inhibition via a glucagon-like peptide-1/cAMP-dependent mechanism distinct from that for diabetic heart. In patients with DHF, the circulating DPP4 activity in peripheral veins was associated with that in coronary sinus and with E/e', an echocardiographic parameter representing DHF. Comorbid diabetes mellitus increased the circulating DPP4 activities in both peripheral veins and coronary sinus. CONCLUSIONS: DPP4 inhibition reverses DHF via membrane-bound DPP4/stromal cell-derived factor-1α-dependent local actions on angiogenesis and circulating DPP4/glucagon-like peptide-1-mediated inotropic actions. Myocardium-derived DPP4 activity in coronary sinus can be monitored by peripheral vein sampling, which partly correlates with DHF index; thus, circulating DPP4 may potentially serve as a biomarker for monitoring DHF.

Glucocorticoid-induced hypertension and cardiac injury: effects of mineralocorticoid and glucocorticoid receptor antagonism.

Glucocorticoids are widely administered for the treatment of various disorders, although their long-term use results in adverse effects associated with glucocorticoid excess. We investigated the pathophysiological roles of glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs) in the cardiac changes induced by exogenous corticosterone in rats. Corticosterone or vehicle was injected twice daily in rats from 8 to 12 weeks of age. The effects of the GR antagonist RU486, the MR antagonist spironolactone, or both agents on corticosterone action were also determined. Corticosterone induced hypertension, left ventricular (LV) fibrosis, and LV diastolic dysfunction. Neither RU486 nor spironolactone affected corticosterone-induced hypertension, whereas spironolactone, but not RU486, attenuated the effects of corticosterone on LV fibrosis and diastolic function. Corticosterone also increased cardiac oxidative stress and inflammation in a manner sensitive to spironolactone but not to RU486. The corticosterone-induced LV atrophy was not affected by either RU486 or spironolactone. Our results implicate MRs in the cardiac fibrosis and diastolic dysfunction, but not MRs or GRs in the cardiac atrophy, induced by corticosterone. Neither MRs nor GRs appear to contribute to corticosterone-induced hypertension.

Relationship between Liquid-Based Cytology Preservative Solutions and Artificial Intelligence: Liquid-Based Cytology Specimen Cell Detection Using YOLOv5 Deep Convolutional Neural Network.

INTRODUCTION: Deep learning is a subset of machine learning that has contributed to significant changes in feature extraction and image classification and is being actively researched and developed in the field of cytopathology. Liquid-based cytology (LBC) enables standardized cytological preparation and is also applied to artificial intelligence (AI) research, but cytological features differ depending on the LBC preservative solution types. In this study, the relationship between cell detection by AI and the type of preservative solution used was examined. METHODS: The specimens were prepared from five preservative solutions of LBC and stained using the Papanicolaou method. The YOLOv5 deep convolutional neural network algorithm was used to create a deep learning model for each specimen, and a BRCPT model from five specimens was also created. Each model was compared to the specimen types used for detection. RESULTS: Among the six models, a difference in the detection rate of approximately 25% was observed depending on the detected specimen, and within specimens, a difference in the detection rate of approximately 20% was observed depending on the model. The BRCPT model had little variation in the detection rate depending on the type of the detected specimen. CONCLUSIONS: The same cells were treated with different preservative solutions, the cytologic features were different, and AI clarified the difference in cytologic features depending on the type of solution. The type of preservative solution used for training and detection had an extreme influence on cell detection using AI. Although the accuracy of the deep learning model is important, it is necessary to understand that cell morphology differs depending on the type of preservative solution, which is a factor affecting the detection rate of AI.

Characterizing the Effect of Processing Technique and Solution Type on Cytomorphology Using Liquid-Based Cytology.

INTRODUCTION: Liquid-based cytology (LBC) is increasingly used for nongynecologic applications. However, the cytological preparation of LBC specimens is influenced by the processing technique and the preservative used. In this study, the influence of the processing techniques and preservatives on cell morphology was examined mathematically and statistically. METHODS: Cytological specimens were prepared using the ThinPrep (TP), SurePath (SP), and AutoSmear methods, with 5 different preservative solutions. The cytoplasmic and nuclear areas of Papanicolaou-stained specimens were measured for all samples. RESULTS: The cytoplasmic and nuclear areas were smaller in cells prepared using the 2 LBC methods, compared to that prepared using the AutoSmear method, irrespective of the preservative used. The cytoplasmic and nuclear areas of cells prepared using the SP method were smaller than those of cells prepared using the TP method, irrespective of the preservative used. There were fewer differences among the cytoplasmic areas of cells prepared with different preservative solutions using the TP method; however, the cytoplasmic areas of cells prepared using the SP method changed with the preservative solution used. CONCLUSIONS: The most significant difference affecting the cytoplasmic and nuclear areas was the processing technique. The TP method increased the cytoplasmic and nuclear areas, while the methanol-based PreservCyt solution enabled the highest enlargement of the cell. LBC is a superior preparation technique for standardization of the specimens. Our results offer a better understanding of methods suitable for specimen preparation for developing precision AI-based diagnosis in cytology.

Pharmacological inhibition of the lipid phosphatase PTEN ameliorates heart damage and adipose tissue inflammation in stressed rats with metabolic syndrome.

Phosphatidylinositol 3-kinase (PI3K) signaling promotes the differentiation and proliferation of regulatory B (Breg) cells, and the lipid phosphatase phosphatase and tensin homolog deleted on chromosome 10 (PTEN) antagonizes the PI3K-Akt signaling pathway. We previously demonstrated that cardiac Akt activity is increased and that restraint stress exacerbates hypertension and both heart and adipose tissue (AT) inflammation in DS/obese rats, an animal model of metabolic syndrome (MetS). We here examined the effects of restraint stress and pharmacological inhibition of PTEN on heart and AT pathology in such rats. Nine-week-old animals were treated with the PTEN inhibitor bisperoxovanadium-pic [bpV(pic)] or vehicle in the absence or presence of restraint stress for 4 weeks. BpV(pic) treatment had no effect on body weight or fat mass but attenuated hypertension in DS/obese rats subjected to restraint stress. BpV(pic) ameliorated left ventricular (LV) inflammation, fibrosis, and diastolic dysfunction as well as AT inflammation in the stressed rats. Restraint stress reduced myocardial capillary density, and this effect was prevented by bpV(pic). In addition, bpV(pic) increased the proportions of Breg and B-1 cells as well as reduced those of CD8+ T and B-2 cells in AT of stressed rats. Our results indicate that inhibition of PTEN by bpV(pic) alleviated heart and AT inflammation in stressed rats with MetS. These positive effects of bpV(pic) are likely due, at least in part, to a reduction in blood pressure, an increase in myocardial capillary formation, and an altered distribution of immune cells in fat tissue that result from the activation of PI3K-Akt signaling.

Angiotensin-converting enzyme inhibition promotes coronary angiogenesis in the failing heart of Dahl salt-sensitive hypertensive rats.

BACKGROUND: The biologic response to angiotensin-converting enzyme (ACE) inhibitors may be influenced by the local environment. The effect of ACE inhibition on coronary angiogenesis was investigated in a rat model of hypertensive heart failure. METHODS AND RESULTS: Dahl salt-sensitive (DS) rats fed a high-salt diet from 6 weeks of age were treated with a nonantihypertensive dose of the ACE inhibitor perindopril or vehicle from 9 to 18 weeks. Treatment of rats with perindopril attenuated the heart failure as well as cardiac hypertrophy and fibrosis that were manifest in the vehicle-treated animals. Myocardial capillary density as well as the expression of the bradykinin B(2) receptor, endothelial nitric oxide synthase, and vascular endothelial growth factor were reduced in the heart of vehicle-treated rats compared with that of nonhypertensive control rats, and all of these changes were attenuated by treatment with perindopril. CONCLUSIONS: These results indicate that ACE inhibition by perindopril promotes myocardial capillary formation as well as attenuates cardiac remodeling and failure in a manner independent from the antihypertensive effect of the drug in DS hypertensive rats. The beneficial cardiac effects of perindopril were associated with activation of the bradykinin-nitric oxide pathway in the heart.

Cardioprotective mechanisms of lifestyle modifications and pharmacotherapies on cardiac remodeling and dysfunction in hypertensive heart disease: an overview.

The incidence of cardiovascular events in hypertensive patients is clearly related to a left ventricular mass during treatment, and a regression of left ventricular hypertrophy is associated with a better prognosis. This is the case even independently of changes in other risk factors, including blood pressure. Evidence indicates that lifestyle modifications such as dietary salt restriction and weight loss are effective means in preventing the development of hypertension and reducing blood pressure and left ventricular mass in hypertensive patients. Salt restriction may also reduce the long-term risk of cardiovascular events. It has been recognized that the primary targets of current antihypertensive drugs are the renin-angiotensin-aldosterone system, calcium homeostasis, the ionic transport mechanisms in the kidneys, and the sympathetic nervous system. Clinical as well as experimental studies have demonstrated the cardioprotective effects of antihypertensive drugs independently of their blood pressure lowering effects. Hypertension is often complicated by other disease states including diabetes, dyslipidemia, and ischemic heart disease. Some of the drugs used for the treatment of such complications are also shown to produce cardioprotective effects in addition to their original effects. We ought to better understand these pleiotropic effects for the most effective treatments of hypertension and its complications.

Surgical ablation of whitened interscapular brown fat ameliorates cardiac pathology in salt-loaded metabolic syndrome rats.

Brown adipose tissue (BAT) is an endocrine organ that contributes to thermogenesis and energy consumption. We investigated the effects of salt loading and surgical removal of whitened interscapular BAT (iBAT) on cardiac and adipose tissue pathology in DahlS.Z-Leprfa /Leprfa (DS/obese) rats, an animal model of metabolic syndrome (MetS). DS/obese rats were subjected to surgical removal of iBAT or sham surgery at 8 weeks of age and were provided with drinking water containing or not containing 0.3% NaCl for 4 weeks beginning at 9 weeks of age. Removal of iBAT suppressed the salt-induced exacerbation of left ventricular inflammation, fibrosis, and diastolic dysfunction, but not that of hypertension development, in DS/obese rats. Salt loading attenuated adipocyte hypertrophy but enhanced inflammation in both visceral white adipose tissue (WAT) and iBAT. Although iBAT removal did not affect visceral WAT pathology in salt-loaded DS/obese rats, it attenuated the elevation of circulating interleukin-6 levels in these animals. Downregulation of uncoupling protein-1 expression in iBAT of DS/obese rats was not affected by salt loading. Our results suggest that the conversion of iBAT to WAT-like tissue contributes to a salt-induced elevation of circulating proinflammatory cytokine levels that leads to exacerbation of cardiac pathology in this model of MetS.

Beneficial effects of growth hormone-releasing peptide on myocardial oxidative stress and left ventricular dysfunction in dilated cardiomyopathic hamsters.

BACKGROUND: Growth hormone-releasing peptide (GHRP) may act directly on the myocardium and improve left ventricular (LV) function, suggesting a potential new approach to the treatment of cardiomyopathic hearts. The present study tested the hypothesis that the beneficial cardiac effects of GHRP might include attenuation of myocardial oxidative stress. METHODS AND RESULTS: Dilated cardiomyopathic TO-2 hamsters were injected with GHRP-2 (1 mg/kg) or saline from 6 to 12 weeks of age. F1B hamsters served as controls. Untreated TO-2 hamsters progressively developed LV dilation, wall thinning, and systolic dysfunction between 6 and 12 weeks of age. Marked myocardial fibrosis was apparent in untreated hamsters at 12 weeks of age in comparison with F1B controls. The ratio of reduced to oxidized glutathione (GSH/GSSG) was decreased and the concentration of 4-hydroxynonenal (4-HNE) was increased in the hearts of untreated TO-2 hamsters. Treatment with GHRP-2 attenuated the progression of LV remodeling and dysfunction, as well as myocardial fibrosis, in TO-2 hamsters. GHRP-2 also inhibited both the decrease in the GSH/GSSG ratio and the increase in the concentration of 4-HNE in the hearts of TO-2 hamsters. CONCLUSIONS: GHRP-2 can suppress the increase in the level of myocardial oxidative stress, leading to attenuation of progressive LV remodeling and dysfunction in dilated cardiomyopathic hamsters. (Circ J 2010; 74: 163 - 170).

Relation of functional and morphological changes in mitochondria to myocardial contractile and relaxation reserves in asymptomatic to mildly symptomatic patients with hypertrophic cardiomyopathy.

AIMS: To examine the relation between mitochondrial dysfunction and myocardial contractile and relaxation reserves in hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: Thirty HCM patients (LVEF >or=60%) underwent biventricular cardiac catheterization analysis both at rest and during atrial pacing as well as myocardial (99m)Tc-sestamibi scintigraphy at rest to calculate washout rate. Endomyocardial biopsy specimens were obtained for quantitative mRNA analysis and electron microscopy. The HCM patients were divided into two groups-group A: normal force-frequency relation and a pressure half-time (T(1/2)) of <30 ms (n = 15); group B: abnormal force-frequency relation or T(1/2) of >or=30 ms (n = 15). The (99m)Tc-sestamibi washout rate was significantly correlated with T(1/2) for all patients (r = 0.74, P < 0.01) and was also significantly greater in group B (29.2 +/- 6.3%) than in group A (19.3 +/- 3.1%). The abundance of mRNAs for mitochondrial electron transport-related enzymes was significantly higher in group A than in group B. Mitochondria showed a greater variation in size and were more disorganized in group B than in group A. CONCLUSION: Mitochondria showed functional impairment and morphological disorganization in the left ventricle of HCM patients without baseline systolic dysfunction. These mitochondrial changes were associated with impaired myocardial contractile and relaxation reserves.