Maternal exposure to glyphosate-based herbicide causes vascular dysfunction in offspring female rats.

This study analyzed how glyphosate exposure in the gestational period affects vascular function in their female offspring and whether oxidative stress is involved in this effect. To this, pregnant Wistar rats were exposed through drinking water to 0.2% of a glyphosate commercial formulation, and we analyzed the response to acetylcholine and phenylephrine in the aorta from offspring of Glyphosate-based herbicide (O-GBH) and controls (O-CON) rats at six months of age. Relaxation to acetylcholine was reduced in O-GBH than in O-CON. Acute Indomethacin and Apocynin increased relaxation to acetylcholine in O-GBH. The aorta from O-GBH was hyperactive to phenylephrine; the preincubation with N-nitro-L-arginine methyl ester (L-NAME) increased contraction to phenylephrine more in O-CON than O-GBH. TEMPOL similarly reduced phenylephrine response, and L-NAME prevented this effect. The TBARS and GSH levels were increased in O-GBH than in O-CON. Results reinforce the concept that oxidative stress during the perinatal period contributes to the development of vascular changes in adulthood. Results also reveal that oxidative stress parameters altered, and the current levels considered safe for exposure to Glyphosate deserve further investigation, especially in the female gender.

Maternal exposure to glyphosate-based herbicide causes changes in the vascular function of offspring adult rats.

This study analyzed how glyphosate exposure in the gestational period affects vascular function in their offspring, focusing on the influence of age and whether oxidative stress is involved in this effect. To this, pregnant Wistar rats were exposed through drinking water to 0.2% of a glyphosate commercial formulation, and we analyzed the response to acetylcholine and phenylephrine in the aorta from offspring of glyphosate herbicide-based (O-GHB) and controls (O-CON) rats at 3, 6, and 12 months of age. O-GHB groups showed no changes in arterial blood pressure or aorta histological analysis. Relaxation to acetylcholine was reduced in O-GHB than O-CON. Acute TEMPOL increased relaxation to acetylcholine in O-GHB at 6 and 12 months of age. The aorta from O-GHB was hyperactive to phenylephrine only at 6 months of age. Preincubation with N-nitro-L-arginine methyl ester (L-NAME) increased contraction to phenylephrine more in O-CON than O-GHB. TEMPOL similarly reduced phenylephrine response. This effect was prevented by L-NAME. Results reinforce the concept that oxidative stress during the perinatal period contributes to the development of vascular changes in adulthood. Results also reveal that although no changes in cardiac or histological parameters have been demonstrated, the current levels considered safe for exposure to glyphosate deserve further investigation, especially during pregnancy.

Anthelmintic niclosamide attenuates pressure-overload induced heart failure in mice.

The heart is a high energy demand organ and enhancing mitochondrial function is proposed as the next-generation therapeutics for heart failure. Our previous study found that anthelmintic drug niclosamide enhanced mitochondrial respiration and increased adenosine triphosphate (ATP) production in cardiomyocytes, therefore, this study aimed to determine the effect of niclosamide on heart failure in mice and the potential molecular mechanisms. The heart failure model was induced by transverse aortic constriction (TAC) in mice. Oral administration of niclosamide improved TAC-induced cardiac hypertrophy, cardiac fibrosis, and cardiac dysfunction in mice. Oral administration of niclosamide reduced TAC-induced increase of serum IL-6 in heart failure mice. In vitro, niclosamide within 0.1 µM increased mitochondrial respiration and ATP production in mice heart tissues. At the concentrations more than 0.1 µM, niclosamide reduced the increased interleukin- 6 (IL-6) mRNA expression in lipopolysaccharide (LPS)-stimulated RAW264.7 and THP-1 derived macrophages. In cultured primary cardiomyocytes and cardiac fibroblasts, niclosamide (more than 0.1 µM) suppressed IL-6- and phenylephrine-induced cardiomyocyte hypertrophy, and inhibited collagen secretion from cardiac fibroblasts. In conclusion, niclosamide attenuates heart failure in mice and the underlying mechanisms include enhancing mitochondrial respiration of cardiomyocytes, inhibiting collagen secretion from cardiac fibroblasts, and reducing the elevated serum inflammatory mediator IL-6. The present study suggests that niclosamide might be therapeutic for heart failure.

PEX5 prevents cardiomyocyte hypertrophy via suppressing the redox-sensitive signaling pathways MAPKs and STAT3.

Peroxisomal biogenesis factor 5 (PEX5) is a member of peroxisome biogenesis protein family which serves as a shuttle receptor for the import of peroxisome matrix protein. The function of PEX5 on cardiomyocyte hypertrophy remained to be elucidated. Our study demonstrated that the protein expression level of PEX5 was declined in primary neonatal rat cardiomyocytes treated with phenylephrine (PE) and hearts from cardiac hypertrophic rats induced by abdominal aortic constriction (AAC). Overexpression of PEX5 alleviated cardiomyocyte hypertrophy induced by PE, while silencing of PEX5 exacerbated cardiomyocyte hypertrophy. PEX5 improved redox imbalance by decreasing cellular reactive oxygen species level and preserving peroxisomal catalase. Moreover, PEX5 knockdown aggravated PE-induced activation of redox-sensitive signaling pathways, including mitogen-activated protein kinase (MAPK) pathway and signal transducer and activator of transcription 3 (STAT3); whereas PEX5 overexpression suppressed activation of MAPK and STAT3. But PEX5 did not affect PE-induced phosphorylation of mammalian target of rapamycin (mTOR). In conclusion, the present study suggests that PEX5 protects cardiomyocyte against hypertrophy via regulating redox homeostasis and inhibiting redox-sensitive signaling pathways MAPK and STAT3.

Mitochondrial Disruption Is Involved in the Effect of Nuclear Factor of Activated T cells, Cytoplasmic 4 on Aggravating Cardiomyocyte Hypertrophy.

ABSTRACT: Nuclear factor of activated T cells, cytoplasmic 4 (NFATc4), a nuclear transcription factor, has been implicated in cardiac hypertrophy through the enhancement of hypertrophic gene expression. However, the role of NFATc4 in mitochondrial modulation is mostly unknown. The current study aimed to investigate the role of NFATc4 in regulating mitochondrial function during phenylephrine (PE)-induced cardiac hypertrophy. Our results showed that overexpression of NFATc4 aggravated the PE-induced decrease in mitochondrial genesis, membrane potential, and mitochondrial gene expression as well as impaired mitochondrial respiration. However, knockdown of NFATc4 relieved PE-induced perturbations in mitochondria and cardiomyocyte hypertrophy. Mechanistically, by activating phosphoinositide-dependent kinase 1 and promoting a combination of AKT and phosphoinositide-dependent kinase 1, phosphorylation and sequential acetylation of PGC-1α were aggravated by NFATc4 and suppressed the activity of PGC-1α. In conclusion, NFATc4-regulated factors were shown to be associated with mitochondrial function and exacerbated PE-induced mitochondrial dysfunction. These findings revealed new roles of NFATc4 in cardiac hypertrophy.

Pinoresinol diglucoside (PDG) attenuates cardiac hypertrophy via AKT/mTOR/NF-κB signaling in pressure overload-induced rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Pinoresinol diglucoside (PDG), the active compound extracted from Eucommia ulmoides, Styrax sp. and Forsythia suspensa, plays the roles in regulating hypertension, inflammation and oxidative stress. AIMS: Considering that hypertension and inflammation has been proved to contribute to cardiac remodeling, we tested the effects of PDG on cardiac hypertrophy (CM). METHODS: Male Sprague Dawley (SD) rats were used to construct hypertrophic rats by partial abdominal aortic constriction (AAC)-surgery. PDG solution (2 mg/ml) was used to treat AAC-induced rats by intraperitoneal injection at low dose (L-PDG, 2.5 mg/kg per day), medium dose (M-PDG, 5 mg/kg per day), and high dose (H-PDG, 7.5 mg/kg per day) for 3 weeks post AAC-surgery. CM was evaluated by the ratio of left ventricular weight to body weight ratio (LVW/BW), left ventricular wall thickness by H&E staining, and collagen content deposit by Masson's staining. Further, isoproterenol (ISO) and phenylephrine (PE) were used to produce cellular models of CM in neonatal rat ventricular cardiomyocytes (NRVMs). PDG pre-treated NRVMs 2 h at low dose (L-PDG, 2.5 µg/ml), medium dose (M-PDG, 5 µg/ml), and high dose (H-PDG, 7.5 µg/ml) for 24 h with or without PE- and ISO-stimulation. CM was evaluated by the expressions of hypertrophic biomarkers. Next, the hypertrophic biomarkers and pro-inflammatory cytokines were measured using quantitative real-time PCR (qRT-PCR), the expressions of protein kinase B (AKT)/mammalian target of rapamycin (mTOR)/transcription factor nuclear factor-kappa B (NF-kB) signaling pathway were determined by Western blotting. RESULTS: PDG treatment prevented cardiac histomorphology damages, decreased upregulations of hypertrophic biomarkers, and prevented fibrosis and inflammation after pressure overload resulting from AAC-surgery. Consistently, PDG remarkably inhibited the changes of cardiomyocyte hypertrophic biomarkers and inflammatory responses in cellular models of CM. Interestingly, PDG administration inhibited the activation of AKT/mTOR/NF-kB signaling pathway both in vivo and in vitro. CONCLUSIONS: PDG prevents AAC-induced CM in vivo, PE- and ISO-induced CM in vitro. The AKT/mTOR/NF-kB signaling pathway could be the potential therapeutic target involved in the protection of PDG. These findings provide novel evidence that PDG might be a promising therapeutic strategy for CM.

Microfibrillar-Associated Protein 4 Regulates Stress-Induced Cardiac Remodeling.

[Figure: see text].

Neonatal glucocorticoid overexposure alters cardiovascular function in young adult horses in a sex-linked manner.

Prenatal glucocorticoid overexposure has been shown to programme adult cardiovascular function in a range of species, but much less is known about the long-term effects of neonatal glucocorticoid overexposure. In horses, prenatal maturation of the hypothalamus-pituitary-adrenal axis and the normal prepartum surge in fetal cortisol occur late in gestation compared to other precocious species. Cortisol levels continue to rise in the hours after birth of full-term foals and increase further in the subsequent days in premature, dysmature and maladapted foals. Thus, this study examined the adult cardiovascular consequences of neonatal cortisol overexposure induced by adrenocorticotropic hormone administration to full-term male and female pony foals. After catheterisation at 2-3 years of age, basal arterial blood pressures (BP) and heart rate were measured together with the responses to phenylephrine (PE) and sodium nitroprusside (SNP). These data were used to assess cardiac baroreflex sensitivity. Neonatal cortisol overexposure reduced both the pressor and bradycardic responses to PE in the young adult males, but not females. It also enhanced the initial hypotensive response to SNP, slowed recovery of BP after infusion and reduced the gain of the cardiac baroreflex in the females, but not males. Basal diastolic pressure and cardiac baroreflex sensitivity also differed with sex, irrespective of neonatal treatment. The results show that there is a window of susceptibility for glucocorticoid programming during the immediate neonatal period that alters cardiovascular function in young adult horses in a sex-linked manner.

Phenylephrine induces necroptosis and apoptosis in corneal epithelial cells dose- and time-dependently.

In the present study, the toxicity of phenylephrine, a selective α1-adrenergic receptor agonist, in corneal epithelial cells and its underlying mechanisms were investigated using an in vitro model of human corneal epithelial cells (HCEPCs) and an in vivo model of New Zealand white rabbit corneas. The HCEPCs treated with phenylephrine at concentrations from 10% to 0.078125% displayed abnormal morphology, decline of cell viability and elevation of plasma membrane permeability time- and dose-dependently. Moreover, 10%-1.25% phenylephrine induce necrosis characteristics of marginalization and uneven distribution of chromatin through up-regulation of RIPK1, RIPK3 and MLKL along with inactivation of caspase-8 and caspase-2, whereas 0.625% phenylephrine induced condensed chromatin, S phase arrest, phosphatidylserine externalization, DNA fragmentation and apoptotic body formation in the HCECs through activation of caspase-2, -8, -9 and -3 as well as down-regulation of Bcl-2, up-regulation of Bad, ΔΨm disruption and release of cytochrome c and AIF into cytosol. At last, 10% phenylephrine induced destruction of the corneal epithelia and apoptosis of corneal epithelial cells in rabbit corneas. In conclusion, 10% to 1.25% phenylephrine cause necroptosis via RIPK1-RIPK3-MLKL axis and 0.625% phenylephrine induce apoptosis via a mitochondrion-dependent and death receptor-mediated signal pathway in HCEPCs.

Miro2 Regulates Inter-Mitochondrial Communication in the Heart and Protects Against TAC-Induced Cardiac Dysfunction.

Rationale: The constrained mitochondria in cardiomyocytes communicate with each other, through mitochondrial kissing or nanotunneling, forming a dynamically continuous network to share content and transfer signals. However, the molecular mechanism of cardiac inter-mitochondrial communication is unclear. Objective: To determine the molecular mechanism underlying the robust inter-mitochondrial communication and its pathophysiological relevance in the heart. Methods and Results: By mitochondria-targeted expressing the photoactivatable green fluorescent protein, we revealed that most mitochondrial nanotubes bridge communicating mitochondrial pairs were associated with microtubules. Miro2 (mitochondrial Rho GTPase), the outer mitochondrial membrane protein which usually mediates mitochondrial transport within cells, accompanied with mitochondrial nanotubes along microtubules in adult cardiomyocytes. Adenovirus mediated expression of Miro2 in cardiomyocytes accelerated inter-mitochondrial communication through increasing mitochondrial nanotunneling and mitochondrial kissing between adjacent mitochondrial pairs. In transverse aortic constriction-induced hypertrophic mouse hearts Miro2 protein was declined, accompanied with decreased inter-mitochondrial communication. Miro2 transgenic mice showed ameliorated cardiac function, increased mitochondrial nanotube formation and inter-mitochondrial communication, and improved mitochondrial function after transverse aortic constriction. E3 ubiquitin ligase Parkin was increased in transverse aortic constriction mouse hearts and phenylephrine stimulation-induced hypertrophic cardiomyocytes. Inhibition of proteasome blocked phenylephrine-induced decrease of Miro2, and Parkin overexpression led to the decrease of Miro2. Conclusions: Mitochondrial Miro2 expression levels regulate inter-mitochondrial communication along microtubules in adult cardiomyocytes, and degradation of Miro2 through Parkin-mediated ubiquitination contributes to impaired inter-mitochondrial communication and cardiac dysfunction during hypertrophic heart diseases.Visual Overview: An online visual overview is available for this article.

19-Hydroxyeicosatetraenoic acid analogs: Antagonism of 20-hydroxyeicosatetraenoic acid-induced vascular sensitization and hypertension.

19-Hydroxyeicosatetraenoic acid (19-HETE, 1), a metabolically and chemically labile cytochrome P450 eicosanoid, has diverse biological activities including antagonism of the vasoconstrictor 20-hydroxyeicosatetraenoic acid (20-HETE, 2). A SAR study was conducted to develop robust analogs of 1 with improved in vitro and in vivo efficacy. Analogs were screened in vitro for inhibition of 20-HETE-induced sensitization of rat renal preglomerular microvessels toward phenylephrine and demonstrated to normalize the blood pressure of male Cyp4a14(-/-) mice that display androgen-driven, 20-HETE-dependent hypertension.

The role of angiopoietin-like protein 4 in phenylephrine-induced cardiomyocyte hypertrophy.

Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional secreted protein that can be induced by fasting, hypoxia and glucocorticoids. ANGPTL4 has been associated with a variety of diseases; however, the role of ANGPTL4 in cardiac hypertrophy remains poorly understood. In our study, we aimed to explore the effect of ANGPTL4 on phenylephrine-induced cardiomyocyte hypertrophy. Our results showed that knockdown of ANGPTL4 expression significantly exacerbated cardiomyocyte hypertrophy, as demonstrated by increased hypertrophic marker expression, including ANP and cell surface area. Moreover, significantly reduced fatty acid oxidation, as featured by decreased CPT-1 levels, was observed in hypertrophic cardiomyocytes following ANGPTL4 down-regulation. Furthermore, knockdown of ANGPLT4 led to down-regulated expression of peroxisome proliferator-activated receptor α (PPARα), which is the key regulator of cardiac fatty acid oxidation. In addition, ANGPTL4 silencing promoted the activation of JNK1/2, and JNK1/2 signaling blockade could restore the level of PPARα and significantly ameliorate the ANGPTL4 knockdown-induced cardiomyocyte hypertrophy. Therefore, our study demonstrated that ANGPTL4 regulates PPARα through JNK1/2 signaling and is required for the inhibition of cardiomyocyte hypertrophy.

Study to Probe Subsistence of Host-Guest Inclusion Complexes of α and ß-Cyclodextrins with Biologically Potent Drugs for Safety Regulatory Dischargement.

Host-guest interaction of two significant drugs, phenylephrine hydrochloride and synephrine with α and ß-cyclodextrins were studied systematically. Initially two simple but reliable physicochemical techniques namely conductance and surface tension were employed to find out saturation concentration for the inclusion and its stoichiometry. The obtained 1:1 stoichiometry was further confirmed by two spectrometric methods, UV-Vis study and spectrofluorimetry. Significant shifts in IR stretching frequency also support the inclusion process. Relative stabilities of the inclusion complexes were established by the association constants obtained from UV-Vis spectroscopic measurements, program based mathematical calculation of conductivity data. Calculations of the thermodynamic parameters dictates thermodynamic feasibility of the inclusion process. Spectrofluorometric measurement scaffolds the UV-Vis spectroscopic measurement validating stability of the ICs once again. Mass spectroscopic measurement gives the molecular ion peaks corresponding to the inclusion complex of 1:1 molar ratio of host and guest molecules. The mechanism of inclusion was drawn by 1H-NMR and 2D ROESY spectroscopic analysis. Surface texture of the inclusion complexes was studied by SEM. Finally, the cytotoxic activities of the inclusion complexes were analyzed and found, Cell viability also balances for non-toxic behavior of the ICs. Moreover, all the studies reveal the formation of inclusion complexes of two ephedra free, alternatively emerging drugs (after their banned product having ephedra) SNP, PEH with α and ß-CD which enriches the drug delivery system with their regulatory release without any chemical modification.

PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2) regulates G-protein-coupled receptor kinase 5 (GRK5)-induced cardiac hypertrophy in vitro.

PH domain leucine-rich repeat protein phosphatase (PHLPP) is a serine/threonine phosphatase that has been shown to regulate cell growth and survival through dephosphorylation of several members of the AGC family of kinases. G-protein-coupled receptor kinase 5 (GRK5) is an AGC kinase that regulates phenylephrine (PE)-induced cardiac hypertrophy through its noncanonical function of directly targeting proteins to the nucleus to regulate transcription. Here we investigated the possibility that the PHLPP2 isoform can regulate GRK5-induced cardiomyocyte hypertrophy in neonatal rat ventricular myocytes (NRVMs). We show that removal of PHLPP2 by siRNA induces hypertrophic growth of NRVMs as measured by cell size changes at baseline, potentiated PE-induced cell size changes, and re-expression of fetal genes atrial natriuretic factor and brain natriuretic peptide. Endogenous GRK5 and PHLPP2 were found to interact in NRVMs, and PE-induced nuclear accumulation of GRK5 was enhanced upon down-regulation of PHLPP2. Conversely, overexpression of PHLPP2 blocked PE-induced hypertrophic growth, re-expression of fetal genes, and nuclear accumulation of GRK5, which depended on its phosphatase activity. Finally, using siRNA against GRK5, we found that GRK5 was necessary for the hypertrophic response induced by PHLPP2 knockdown. Our findings demonstrate for the first time a novel regulation of GRK5 by the phosphatase PHLPP2, which modulates hypertrophic growth. Understanding the signaling pathways affected by PHLPP2 has potential for new therapeutic targets in the treatment of cardiac hypertrophy and failure.

The Amino-Terminal Domain of GRK5 Inhibits Cardiac Hypertrophy through the Regulation of Calcium-Calmodulin Dependent Transcription Factors.

We have recently demonstrated that the amino-terminal domain of G protein coupled receptor kinase (GRK) type 5, (GRK5-NT) inhibits NFκB activity in cardiac cells leading to a significant amelioration of LVH. Since GRK5-NT is known to bind calmodulin, this study aimed to evaluate the functional role of GRK5-NT in the regulation of calcium-calmodulin-dependent transcription factors. We found that the overexpression of GRK5-NT in cardiomyoblasts significantly reduced the activation and the nuclear translocation of NFAT and its cofactor GATA-4 in response to phenylephrine (PE). These results were confirmed in vivo in spontaneously hypertensive rats (SHR), in which intramyocardial adenovirus-mediated gene transfer of GRK5-NT reduced both wall thickness and ventricular mass by modulating NFAT and GATA-4 activity. To further verify in vitro the contribution of calmodulin in linking GRK5-NT to the NFAT/GATA-4 pathway, we examined the effects of a mutant of GRK5 (GRK5-NTPB), which is not able to bind calmodulin. When compared to GRK5-NT, GRK5-NTPB did not modify PE-induced NFAT and GATA-4 activation. In conclusion, this study identifies a double effect of GRK5-NT in the inhibition of LVH that is based on the regulation of multiple transcription factors through means of different mechanisms and proposes the amino-terminal sequence of GRK5 as a useful prototype for therapeutic purposes.

The Involvement of Cytochrome c Oxidase in Mitochondrial Fusion in Primary Cultures of Neonatal Rat Cardiomyocytes.

Cytochrome c oxidase (CCO) is a copper-dependent enzyme of mitochondrial respiratory chain. In pressure overload-induced cardiac hypertrophy, copper level and CCO activity are both depressed, along with disturbance in mitochondrial fusion and fission dynamics. Copper repletion leads to recovery of CCO activity and normalized mitochondrial dynamics. The present study was undertaken to define the link between CCO activity and mitochondrial dynamic changes. Primary cultures of neonatal rat cardiomyocytes were treated with phenylephrine to induce cell hypertrophy. Hypertrophic cardiomyocytes were then treated with copper to reverse hypertrophy. In the hypertrophic cardiomyocytes, CCO activity was depressed and mitochondrial fusion was suppressed. Upon copper repletion, CCO activity was recovered and mitochondrial fusion was reestablished. Depression of CCO activity by siRNA targeting CCO assembly homolog 17 (COX17), a copper chaperone for CCO, led to fragmentation of mitochondria, which was not recoverable by copper supplementation. This study thus demonstrates that copper-dependent CCO is critical for mitochondrial fusion in the regression of cardiomyocyte hypertrophy.

Sestrin 1 ameliorates cardiac hypertrophy via autophagy activation.

Cardiac hypertrophy is one of the major risk factors of cardiovascular morbidity and mortality. Autophagy is acknowledged to be an important mechanism regulating cardiac hypertrophy. Sestrin 1, a downstream target gene of p53, has been proven to regulate autophagy. However, the role of Sestrin 1 in cardiac hypertrophy remains unknown. Our study showed that Sestrin 1 mRNA and protein expression declined in pressure overload cardiac hypertrophy and phenylephrine (PE)-induced cardiac hypertrophy. Knockdown of Sestrin 1 by RNAi deteriorated PE-induced cardiac hypertrophy, whereas the overexpression of Sestrin 1 by adenovirus transfection blunted hypertrophy. We discovered that knockdown of Sestrin 1 resulted in impaired autophagy while overexpression of Sestrin 1 resulted in increased autophagy without affecting lysosomal function. In addition, the antihypertrophic effect of Sestrin 1 overexpression was eliminated by autophagy blockade. Importantly, Sestrin 1 targets at the AMPK/mTORC1/autophagy pathway to inhibit cardiac hypertrophy by interaction with AMPK which is responsible for autophagy regulation. Taken together, our data indicate that Sestrin 1 regulates AMPK/mTORC1/autophagy axis to attenuate cardiac hypertrophy.

Lactobacillus rhamnosus GR-1 Attenuates Induction of Hypertrophy in Cardiomyocytes but Not through Secreted Protein MSP-1 (p75).

Previous animal studies have shown that the administration of probiotic Lactobacillus rhamnosus can provide a protective effect against ischemia/reperfusion and necrotic injury to the intestine, liver, and heart, as well as a therapeutic effect to the outcome of ischemic injury to the heart, including cardiac hypertrophy and heart failure. We hypothesized that L. rhamnosus GR-1 major secreted protein 1 (MSP-1), also known as p75, plays a major role in this phenomenon. Experiments using neonatal rat ventricular cardiomyocytes showed that live and dead GR-1 bacteria, probiotic-conditioned media, and other probiotic species and strains inhibited the α1-adrenergic receptor agonist phenylephrine-induced hypertrophy as assessed by markers atrial natriuretic peptide and α-skeletal actin. However, using a mutant strain, we showed that this MSP-1 was not required for the inhibition. The ability of factors produced by lactobacilli to improve cardiac function warrants further study for the management of cardiac hypertrophy and heart failure.

CaMKIIδ meditates phenylephrine induced cardiomyocyte hypertrophy through store-operated Ca2+ entry.

Evidence suggests that store-operated Ca2+ entry (SOCE) is involved in the hypertrophy of cardiomyocytes. The signaling mechanisms of SOCE contributing to cardiac hypertrophy following phenylephrine (PE) stimulation are not fully understood. Ca2+/calmodulin-dependent protein kinase II δ (CaMKIIδ) plays an important role in regulating intracellular Ca2+ hemostasis and function in the cardimyocytes. This study is aimed to determine the role of CaMKIIδ in regulating the PE-induced myocardial hypertrophy and the associated molecular signaling mechanisms. We used primary cultures of neonatal cardimyocytes isolated from the left ventricle of Sprague Dawley rats to investigate the effects of CaMKIIδ on myocardial hypertrophy and intracellular Ca2+ mobilization. We found that the expression of CaMKIIδ was enhanced in PE-induced hypertrophic cardiomyocytes. CaMKIIδ siRNA, CaMKII inhibitor KN93, and SOCE blocker BTP2 attenuated the increase in the expression of CaMKIIδ and normalized the hypertrophic markers, atrial natriuretic peptide and brain natriuretic peptide, and size of cardiomyocytes induced by PE stimulation. The protein level of stromal interaction molecule 1 and Orai1, the essential components of the SOCE, is also enhanced in hypertrophic cardiomyocytes, which were normalized by CaMKIIδ siRNA and KN93 treatment. Hypertrophic cardiomyocytes showed an increase in the peak of Ca2+ transient following store depletion, which was inhibited by SOCE blocker BTP2, CaMKIIδ siRNA, and KN93. The Ca2+ currents through Ca2+ release-activated Ca2+ channels were increased in PE-treated cardiomyocytes and were attenuated by CaMKIIδ siRNA and KN93. These data indicate that PE-induced myocardial hypertrophy requires a complex signaling pathway that involves activation of both CaMKIIδ and SOCE. In conclusion, these studies reveal that up-regulation of CaMKIIδ may contribute to the PE-induced myocardial hypertrophy through the activation of SOCE expressed in the cardiomyocytes.

Safety of Phenylephrine in Antihypotensive Treatment during Spinal Anesthesia for Cesarean Section.

OBJECTIVE: In Thailand, hypotension after spinal anesthesia for cesarean section is routinely treated by ephedrine. As incidence of fetal acidosis reportedly increases resulting from placental transfer of ephedrine, phenylephrine, an alpha-1 agonist with less lipid solubility, becomes an alternative. However, the potential development of serious bradycardia after phenylephrine is a concern. The objectives of this study were to investigate the incidence of serious bradycardia and identify risk factors associated with phenylephrine-induced serious bradycardia and other side effects of phenylephrine. MATERIAL AND METHOD: This descriptive cross-sectional study was conducted between July 1, 2014 and March 15, 2015 on 509 parturients undergoing cesarean section under spinal anesthesia. Predelivery hypotension was treated by intravenous phenylephrine 100 mcg and pretherapeutic heart rate (pHR) was recorded. If serious bradycardia (HR < 60 bpm and hypotension or HR <45 bpm) developed, atropine 0.6 mg was administered intravenously. Data were analyzed using multivariable logistic regression and AuROC. RESULTS: Incidence of serious bradycardia was 11% (95% CI: 8.0-14.0). A one bpm increment increase in pHR reduced this incidence by 4% (adjusted OR: 0.96; 95% CI: 0.94-0.98, p < 0.001; AuROC: 0.76). As compared to apHR greater than 80 bpm, apHR of 61 to 80 bpm and a pHR of 60 bpm or lower increased the risk of serious bradycardia by 3.55 times and 12.81 times, respectively. Other risk factors were height (adjusted OR: 0.94; 95% CI: 0.89-0.98, p = 0.015), baseline DBP (adjusted OR: 0.97; 95% CI: 0.94-0.99,p = 0.03), and anesthetic level at first minute (adjusted OR: 1.13; 95% CI: 1.02-1.23, p = 0.02). Benign and temporary abnormal ECG readings were noted. CONCLUSION: Phenylephrine for antihypotensive treatment in spinal anesthesia induces bradycardia. Findings indicate an association between slower HR at time phenylephrine is administered and serious bradycardia. Close ECG monitoring and prompt treatment are required.