Effect of 11-Deoxycorticosterone in the Transcriptomic Response to Stress in Rainbow Trout Skeletal Muscle.

In aquaculture, many stressors can negatively affect growth in teleosts. It is believed that cortisol performs glucocorticoid and mineralocorticoid functions because teleosts do not synthesize aldosterone. However, recent data suggest that 11-deoxycorticosterone (DOC) released during stress events may be relevant to modulate the compensatory response. To understand how DOC modifies the skeletal muscle molecular response, we carried out a transcriptomic analysis. Rainbow trout (Oncorhynchus mykiss) were intraperitoneally treated with physiological doses of DOC in individuals pretreated with mifepristone (glucocorticoid receptor antagonist) or eplerenone (mineralocorticoid receptor antagonist). RNA was extracted from the skeletal muscles, and cDNA libraries were constructed from vehicle, DOC, mifepristone, mifepristone plus DOC, eplerenone, and eplerenone plus DOC groups. The RNA-seq analysis revealed 131 differentially expressed transcripts (DETs) induced by DOC with respect to the vehicle group, mainly associated with muscle contraction, sarcomere organization, and cell adhesion. In addition, a DOC versus mifepristone plus DOC analysis revealed 122 DETs related to muscle contraction, sarcomere organization, and skeletal muscle cell differentiation. In a DOC versus eplerenone plus DOC analysis, 133 DETs were associated with autophagosome assembly, circadian regulation of gene expression, and regulation of transcription from RNA pol II promoter. These analyses indicate that DOC has a relevant function in the stress response of skeletal muscles, whose action is differentially modulated by GR and MR and is complementary to cortisol.

Clinical features and long-term management of cats with primary hypoadrenocorticism using desoxycorticosterone pivalate and prednisolone.

BACKGROUND: Primary hypoadrenocorticism (PH) is rare in cats and knowledge about treatment is sparse. OBJECTIVE: To describe cats with PH with a focus on long-term treatment. ANIMALS: Eleven cats with naturally occurring PH. METHODS: Descriptive case series with data on signalment, clinicopathological findings, adrenal width, and doses of desoxycorticosterone pivalate (DOCP) and prednisolone during a follow-up period of >12 months. RESULTS: Cats ranged from 2 to 10 years (median 6.5); 6 cats were British Shorthair. Most common signs were reduced general condition and lethargy, anorexia, dehydration, obstipation, weakness, weight loss, and hypothermia. Adrenal glands on ultrasonography were judged small in 6. Eight cats could be followed for 14 to 70 months (median: 28). Two were started on DOCP doses ≥2.2 mg/kg (2.2; 2.5) and 6 < 2.2 mg/kg (1.5-2.0 mg/kg, median 1.8) q28 days. Both high-dose cats and 4 low-dose cats needed a dose increase. Desoxycorticosterone pivalate and prednisolone doses at the end of the follow-up period were 1.3 to 3.0 mg/kg (median: 2.3) and 0.08 to 0.5 mg/kg/day (median: 0.3), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Desoxycorticosterone pivalate and prednisolone requirements in cats were higher than what is currently used in dogs; thus, a DOCP starting dose of 2.2 mg/kg q28 days and a prednisolone maintenance dose of 0.3 mg/kg/day titrated to the individual need seems warranted. Small adrenal glands (width < 2.7 mm) on ultrasonography in a cat suspected of hypoadrenocorticism can be suggestive of the disease. The apparent predilection of British Shorthaired cats for PH should be further evaluated.

Ameliorative effect of phosphodiesterase 4 and 5 inhibitors in deoxycorticosterone acetate-salt hypertensive uni-nephrectomized KKAy mice.

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Hypertension increases kidney stress, which deteriorates function, and leads to peripheral renal vascular resistance. Long-term hypoperfusion promotes interstitial fibrosis and glomerular sclerosis, resulting in nephrosclerosis. Although hypertension and DN are frequent ESRD complications, relevant animal models remain unavailable. We generated a deoxycorticosterone acetate (DOCA)-salt hypertensive uni-nephrectomized (UNx) KKAy mouse model demonstrating hypertension, hyperglycemia, cardiac hypertrophy, kidney failure, increased urinary albumin creatinine ratio (UACR), and increased renal PDE4D and cardiac PDE5A mRNA levels. We hypothesized that the novel PDE4 selective inhibitor, compound A, and PDE5 inhibitor, sildenafil, exhibit nephroprotective, and cardioprotective effects in this new model. Compound A, sildenafil, and the angiotensin II receptor blocker, irbesartan, significantly reduced ventricular hypertrophy and pleural effusion volume. Meanwhile, compound A and sildenafil significantly suppressed the UACR, urinary kidney injury molecule-1, and monocyte chemoattractant protein-1 levels, as well as that of renal pro-fibrotic marker mRNAs, including collagen 1A1, fibronectin, and transforming growth factor-beta (TGF-ß). Moreover, compound A significantly suppressed TGF-ß-induced pro-fibrotic mRNA expression in vitro in all major kidney lesions, including within the glomerular mesangial region, podocytes, and epithelial region. Hence, PDE4 and PDE5 inhibitors may be promising treatments, in combination with irbesartan, for DN with hypertension as they demonstrate complementary mechanisms.

Effect of selected drugs on zinc accumulation in teeth of laboratory animals.

BACKGROUND: Zinc (Zn) is a micronutrient and essential element of life and its deficiency causes severe disorders of numerous body systems, such as immune, reproductive and central nervous system. Zinc supplementation affects wound healing and sexual development. The interactions between drugs administration and Zn level in tissues are not fully understood. The aim of the study was to demonstrate differences in Zn content in teeth of laboratory animals that have undergone pharmacological tests. METHODS: The teeth were extracted from laboratory animals after chronic administration of a non-steroidal anti-inflammatory drug (8-[4-[4-(4-chlorophenyl) piperazine-1-sulfonylphenyl]]-1-propylxanthine), a steroid anti-inflammatory drug (deoxycorticosterone) and an anti-cancer drug (oxaliplatin used acutely). The method of flame atomic absorption spectrometry was used to determine the Zn content in the teeth of the laboratory animals. RESULTS: Based on the studies conducted, the administration of the anti-inflammatory drug PSB-603 and deoxycorticosterone results in an increase in Zn accumulation in the teeth of laboratory animals, which may be indicative of the effect of anti-inflammatory drugs on the metabolism of this bioelement. Oxaliplatin has the opposite effect, after which the level of the measured bioelement in the teeth of mice depended on the administered dose. This level was on average 21.0-28.1% lower than the Zn level in the teeth of the control group. Anti-cancer drugs may interfere with Zn accumulation in the teeth and cause the removal of this metal from bone tissue. CONCLUSION: It can be assumed that the Zn content in teeth can be markedly affected by the drugs that were administrated to animals.

DOCA/salt hypertension alters Period1 and orexin-related gene expression in the medulla and hypothalamus of male rats: Diurnal influences.

In peripheral tissues, aldosterone alters expression of multiple genes, including the clock gene Period 1 (Per1), 11 beta-hydroxysteroid dehydrogenase-2 (11-HSD2), and α-ENAC, the epithelial sodium channel subunit. We evaluated the impact of chronic aldosterone exposure (DOCA) and salt intake on nocturnal changes in gene expression in the male Sprague Dawley rat brain. Additionally, genes associated with the orexin (ORX) system were also evaluated based on the role of this neuropeptide in arousal, feeding and hypertension and an interconnection with Per1 expression. DOCA/salt treatment increased saline intake primarily at night, elevated arterial pressure and lowered heart rate. In the medulla oblongata, DOCA/salt upregulated Per1, 11-HSD2, and α-ENAC expression independent of time of day, but did not change ORX receptor type 1 (ORX-R1) or type 2 (ORX-R2) expression. ORX-R1, and ORX-R2 expression in the medulla did however correlate with Per1 expression following DOCA/salt treatment but not in controls. In the hypothalamus, DOCA/salt treatment upregulated Per1, ORX-A, and ORX-R2 expression, in general, and Per1 and ORX-A expression at night. ORX-A, ORX-R1 and ORX-R2 expression in the hypothalamus correlated with Per1 expression following DOCA/salt but not in controls. These findings demonstrate for the first time that DOCA/salt hypertension modulates ORX gene expression in the brain and suggest that changes in expression in the ORX system may occur directly or indirectly via aldosterone-induced changes in Per1 expression. Our findings also build on emerging evidence that monitoring gene expression during both the day and night is critical to understanding the role of specific genes in hypertension.

High-Affinity Nucleic-Acid-Based Receptors for Steroids.

Artificial receptors for hydrophobic molecules usually have moderate affinities and limited selectivities. We describe three new classes of high affinity hydrophobic receptors for nonaromatic steroids based on deoxyribonucleotides, obtained through five high stringency selections coupled with tailored counter-selections. The isolation of multiple classes of high affinity steroid receptors demonstrates the surprising breadth of moderately sized hydrophobic binding motifs (<40 nucleotides) available to natural nucleic acids. Studies of interactions with analogs indicate that two classes, four-way junctions and 4XGN motifs, comprise receptors with shapes that prevent binding of specific steroid conjugates used in counter-selections. Furthermore, they strongly prefer nonhydroxylated steroid cores, which is typical for hydrophobic receptors. The third new class accommodates hydroxyl groups in high-affinity, high-selectivity binding pockets, thus reversing the preferences of the first two classes. The high-affinity binding of aptamers to targets efficiently inhibits double-helix formation in the presence of the complementary oligonucleotides. The high affinity of some of these receptors and tailored elimination of binding through counter-selections ensures that these new aptamers will enable clinical chemistry applications.

Low-dose sustained-release deoxycorticosterone acetate-induced hypertension in Bama miniature pigs for renal sympathetic nerve denervation.

Recently, the effectiveness of renal sympathetic nerve denervation for treatment of hypertension has been doubted after SYMPLICITY HTN-3 trial. An ideal animal model is still unavailable for preclinical study about catheter-based renal sympathetic nerve denervation for treatment of hypertension. Traditional high-dose deoxycorticosterone acetate (DOCA)-induced hypertension pig model has some problems due to extensive end-organ damage. Based on the similarity in the anatomic characteristics of renal artery between pigs and humans, this study was undertaken to establish a low-dose sustained-release DOCA-induced hypertension model in pigs. A total of 14 pigs were subcutaneously implanted with low-dose DOCA in the abdomen and cannulated from the femoral artery for the measurement of blood pressure (BP). Plasma angiotensin I (Ang I), angiotensin II (Ang II), plasma renin activity (PRA), aldosterone (Ald), creatinine, epinephrine, and norepinephrine (NE) were determined before and after treatments. The kidneys were collected and processed for hematoxylin and eosin staining, Masson-Goldner trichromic, and periodic acid Schiff staining. Ten pigs survived for 1 month. Mean BP significantly increased after 2-week treatment (P < .001). The plasma Ang I, Ang II, PRA, and Ald significantly decreased (Ang I: 6.92 ± 6.06 vs. 2.22 ± 3.08, P = .002; Ang II: 768.85 ± 525.8 vs. 213.76 ± 148.63, P = .003; PRA: 1.68 ± 1.67 vs. 0.29 ± 0.39, P = .008; Ald: 0.37 ± 0.12 vs. 0.25 ± 0.09, P < .001), but norepinephrine significantly increased (7.59 ± 4.57 vs. 16.96 ± 10.38, P = .021). Plasma creatinine remained unchanged. Hisotological examination showed mild damage to the kidney. Low-dose sustained-release DOCA is able to induce hypertension in pigs. A femoral catheter is not only helpful for monitoring BP, but can be used to quickly exchange the renal sympathetic nerve denervation equipment.

Potent antihypertensive effect of Hancornia speciosa leaves extract.

BACKGROUND: Hancornia speciosa Gomes is an herb traditionally used in Brazil for blood pressure control. PURPOSE: The present work investigated the antihypertensive effect of an extract from Hancornia speciosa leaves (SFH) and analyzed its underlying mechanisms of action. METHODS: Hypertension was induced in mice by surgical removal of a kidney and by subcutaneous administration of a pellet with deoxycorticosterone. Vasodilatation was measured in mesenteric arteries with a wire myograph. Nitrites were measured by fluorescence with 2,3-diaminonaphthalene and H2O2 was measured with carbon microsensors. RESULTS: SFH (0.03, 0.1 or 1 mg/kg; po) induced a dose-dependent, long-lasting reduction in the systolic blood pressure in conscious DOCA-salt hypertensive mice (DOCA). Administration of SFH produced a significant increase in the plasmatic level of nitrites. The systemic inhibition of nitric oxide synthase by L-NAME (20 mg/kg) reduced its antihypertensive effect. SFH also induced a concentration-dependent vasodilatation of mesenteric resistance arteries contracted with phenylephrine, which was more potent in arteries from DOCA mice. Removal of the endothelium or pretreatment with L-NAME or catalase reduced the vasodilator response for SFH. The nitrite production induced by SFH was significantly bigger in mesenteric arteries from DOCA than in SHAM mice. However, the production of H2O2 induced by SFH was twice higher in DOCA mice. CONCLUSION: Altogether, our results point to an antihypertensive effect of SFH due to a reduction in peripheral resistance through the production of NO and by a mechanism involving an increased production of H2O2 in the mesenteric arteries from hypertensive mice. These findings are further evidence to support the use of Hancornia speciosa by traditional medicine as an antihypertensive drug.

Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats

CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.

Successful treatment of a cat with primary hypoadrenocorticism and severe hyponatremia with desoxycorticosterone pivalate (DOCP).

A 6-year-old, castrated male Siamese cat was diagnosed with primary hypoadrenocorticism, confirmed by an adrenocorticotopic hormone (ACTH) stimulation test documenting both hypocortisolism and hypoaldosteronism. The cat was successfully treated using a combination of prednisolone and desoxycorticosterone pivalate (DOCP). This case demonstrates that DOCP can be used successfully as mineralocorticoid supplementation in cats with hypoadrenocorticism and may have a longer therapeutic duration than that in dogs.

Traitement réussi d'un chat atteint d'hypoadrénocorticisme primaire et d'hyponatrémie à l'aide de pivalate de désoxycorticostérone (DOCP). Un diagnostic d'hypoadrénocorticisme primaire a été posé pour un chat Siamois castré âgé de 6 ans et confirmé par un test de stimulation de l'hormone adrénocorticotope (ACTH) qui a documenté l'hypocortisolisme et l'hypoaldostéronisme. Le chat a été traité avec succès à l'aide d'une combinaison de prednisolone et de pivalate de désoxycorticostérone (DOCP). Ce cas démontre que le DOCP peut être utilisé avec succès en tant que supplément de minéralocorticoïdes chez les chats atteints d'hypoadrénocorticisme et peut présenter une durée thérapeutique plus longue que chez les chiens.(Traduit par Isabelle Vallières).

Beyond T and DHT - novel steroid derivatives capable of wild type androgen receptor activation.

While androgen deprivation therapy (ADT) remains the primary treatment for metastatic prostate cancer (PCa), castration does not eliminate androgens from the prostate tumor microenvironment, and residual intratumoral androgens are implicated in nearly every mechanism by which androgen receptor (AR)-mediated signaling promotes castration-resistant disease. The uptake and intratumoral (intracrine) conversion of circulating adrenal androgens such as dehydroepiandrosterone sulfate (DHEA-S) to steroids capable of activating the wild type AR is a recognized driver of castration resistant prostate cancer (CRPC). However, less well-characterized adrenal steroids, including 11-deoxcorticosterone (DOC) and 11beta-hydroxyandrostenedione (11OH-AED) may also play a previously unrecognized role in promoting AR activation. In particular, recent data demonstrate that the 5α-reduced metabolites of DOC and 11OH-AED are activators of the wild type AR. Given the well-recognized presence of SRD5A activity in CRPC tissue, these observations suggest that in the low androgen environment of CRPC, alternative sources of 5α-reduced ligands may supplement AR activation normally mediated by the canonical 5α-reduced agonist, 5α-DHT. Herein we review the emerging data that suggests a role for these alternative steroids of adrenal origin in activating the AR, and discuss the enzymatic pathways and novel downstream metabolites mediating these effects. We conclude by discussing the potential implications of these findings for CRPC progression, particularly in context of new agents such as abiraterone and enzalutamide which target the AR-axis for prostate cancer therapy.

Aldosterone synthase inhibition for the treatment of hypertension and the derived mechanistic requirements for a new therapeutic strategy.

CONTEXT: We describe the clinical investigation of the first generation aldosterone synthase inhibitor, LCI699, in patients with essential, uncontrolled, resistant, or secondary hypertension. LCI699 competitively reduced blood pressure at lower doses yet counterintuitive effects were observed at higher doses. OBJECTIVE AND METHOD: An extensive endocrine biomarker analysis was performed to better understand the pharmacological mechanism of the drug. RESULTS: The interference of LCI699 in the renin-angiotensin-aldosterone system occurred with limited target selectivity, as a dose-dependent compensatory stimulation of the hypothalamic-pituitary-adrenal feedback axis was discovered. Thus, LCI699 affected two endocrine feedback loops that converged at a single point, inhibiting the 11ß-hydroxylase reaction in the adrenal gland, leading to supraphysiological levels of 11-deoxycortiscosterone. The accumulation of this potent mineralocorticoid may explain the blunted blood pressure response to LCI699. CONCLUSION: Future aldosterone synthase inhibitors may improve their target selectivity by sparing the 11ß-hydroxylase reaction and preferentially inhibiting one of the two other enzymatic reactions mediated by aldosterone synthase.

Cardiovascular effects of the essential oil of Croton zehntneri leaves in DOCA-salt hypertensive, conscious rats.

This study investigated the cardiovascular effects of the essential oil of Croton zehntneri (EOCZ) in deoxycorticosterone-acetate (DOCA)-salt hypertensive rats. Furthermore, in vitro experiments using isolated thoracic aortic rings were performed to assess the vascular effects of the EOCZ. In conscious hypertensive rats, intravenous (i.v.) injections of EOCZ (1-20 mg/kg) induced rapid (2-4 s) and dose-dependent hypotension and bradycardia (phase 1). The hypotension was followed by a significant pressor effect that was more evident at the higher doses (10 and 20 mg/kg) of EOCZ. Hypotension and bradycardia of EOCZ (phase 1) were abolished and respectively reversed into pressor and tachycardiac effects by methylatropine (1 mg/kg, i.v.) pretreatment. In isolated endothelium-intact aortic preparations, increasing concentrations (1-1000 microg/mL) of EOCZ relaxed the potassium-induced contraction in a concentration-dependent manner with an IC50 (geometric mean [95% confidence interval]) value of 202.0 [92.0-443.7] microg/mL. This vasorelaxant effect remained unaffected by either mechanical removal of functional vascular endothelium (IC50 = 189.0 [159.4-224.7] microg/mL) or the addition of atropine (1 microM) (IC50 = 158.6 [79.8-316.2] microg/mL) in the perfusion medium. These data show that i.v. administration of EOCZ in DOCA-salt hypertensive rats induces a vago-vagal reflex decreases in heart rate and blood pressure (phase 1). EOCZ may induce a second and delayed hypotension due to its direct endothelium-independent vasorelaxant effects, but it seems to be buffered by the pressor component (subsequent to phase 1) of EOCZ. This pattern of blood pressure and heart rate responses to EOCZ seems unaltered by DOCA-salt hypertension, as was similar to that previously reported in conscious normotensive rats.

Synthesis, characterization and biological evaluation of some novel P-heterocyclic androst-4-ene derivatives.

The reactions of 21-hydroxyprogesterone with Lawesson's reagent in toluene or [Formula: see text] gave four P-heterocyclic androst-4-ene derivatives (two tautomeric pairs): 4-(3-thioxoandrost-4-en-17[Formula: see text]-yl)-1,3,2-oxathiaphosphole-2- sulfide (2), 4-(3-thioxoandrost-4-en-17[Formula: see text]-ylidene)-1,3,2-oxathiaphospholane-2-sulfide (3), 4-(3-oxoandrost-4-en-17[Formula: see text]-yl)-1,3,2-oxathiaphosphole-2-sulfide (4), and 4-(3-oxoandrost-4-en-17[Formula: see text]-ylidene)-1,3,2- oxathiaphospholane-2-sulfide (5). The structures of all novel 17-substituted steroids were elucidated from their analytic and spectral data (HRMS, IR, 1D NMR and 2D NMR-HSQC, HMBC, NOESY, COSY). The detailed NMR analysis for all compounds revealed the presence of two pairs of signals in approx. 8:2 ratio indicating the existence of two diastereoisomers (a and b) with different configurations at the phosphorus atom. A parallel analysis of heteronuclear 2D [Formula: see text]-[Formula: see text] spectra (HSQC and HMBC) and homonuclear 2D spectra (NOESY and COSY) enabled complete [Formula: see text] and [Formula: see text] assignments of each isomer and provided evidence for the preferred configuration on phosphorus atom. Cytotoxic activity in vitro was tested against four tumor cell lines (human cervix carcinoma HeLa cells, chronic myelogenous leukemia K-562 and two human breast carcinoma MDA-MB-361 and MDA-MB-453 cells). Compounds 3a,b and 4a,b showed a poor activity against HeLa and MDA-MB-453 cell lines, while against MDA-MB-361 cell line, all tested compounds exerted very weak cytotoxic effect. All compounds exerted moderate activity against K562 cells. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, and toxicity to brine shrimp Artemia salina were evaluated. All tested compounds showed strong antifungal activity.

First evidence of the possible implication of the 11-deoxycorticosterone (DOC) in immune activity of Eurasian perch (Perca fluviatilis, L.): comparison with cortisol.

Cortisol, the main corticosteroid in fish, is frequently described as a modulator of fish immune system. Moreover, 11-deoxycorticosterone (DOC) was shown to bind and transcriptionally activate the mineralocorticoid receptor and may act as a mineralocorticoid in fish. Immune modulations induced by intraperitoneal injections of these two corticosteroids were assessed in Eurasian perch juveniles. Cortisol and DOC were injected at 0.8 mg kg(-1) and 0.08 mg kg(-1) body weight respectively. Cortisol increased plasma lysozyme activity 72 h post-injection, C-type lysozyme expression in spleen from 1 to 72 h post-injection, and favoured blood neutrophils at the expense of a mixture of lymphocytes and thrombocytes. Moreover, 6 h after injection, cortisol reduced expression levels of the pro-inflammatory cytokine TNF-α in spleen. DOC had no effects on the immune variables measured in plasma, but increased expression levels of C-type lysozyme and apolipoprotein A1 mRNA in both gills and spleen. Meanwhile, DOC stimulated its putative signalling pathway by increasing expression of mineralocorticoid receptor and 11ß-hydroxysteroid dehydrogenase-2 in spleen. These results confirmed the role of cortisol as an innate, short term immune stimulator. For the first time, DOC is described as a possible immune stimulator in fish.

Effects of oligomeric grape seed proanthocyanidins on heart, aorta, kidney in DOCA-salt mice: role of oxidative stress.

Growing experimental and clinical data highlights the important roles of increased reactive oxygen species production in cardiovascular remodeling (CR). Oligomeric grape seed proanthocyanidins (GSPs) have been shown to be potent antioxidants and free radical scavengers. Mice were treated with DOCA-salt to induce CR and were given distilled water or oligomeric GSPs for 4 weeks. The heart weight (HW) index and kidney weight (KW) index were expressed as heart weight/body weight (HW/BW) and kidney weight/body weight (KW/BW); the histological changes were investigated by hematoxylin and eosin and Van Gieson staining.The endothelial-dependent vasodilation function induced by acetylcholine was investigated in isolated thoracic aorta ring. Colorimetric analysis was used to assay superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and nitric oxide (NO) content in serum and hydroxyproline content in cardiac tissue. Administration of GSPs markedly alleviated the elevation of HW/BW ratio, KW/BW ratio and cross-sectional area of cardiomyocytes, decreased collagen deposition in heart and attenuated histopathology injury, and improves endothelial-dependent aorta ring relaxation in vitro accompany by increasing of NO content in serum. Meanwhile, treatment with GSPs significantly ameliorated oxidative stress via increasing SOD activities and decreasing MDA formation. These findings suggest that administration of GSPs has the potential to attenuate DOCA-salt induced CR and KH and preserve NO activity and endothelial function, which mechanism may contribute to its antioxidant characteristic, at least in part.

Tetrahydrobiopterin improves diastolic dysfunction by reversing changes in myofilament properties.

Despite the increasing prevalence of heart failure with preserved left ventricular function, there are no specific treatments, partially because the mechanism of impaired relaxation is incompletely understood. Evidence indicates that cardiac relaxation may depend on nitric oxide (NO), generated by NO synthase (NOS) requiring the co-factor tetrahydrobiopterin (BH(4)). Recently, we reported that hypertension-induced diastolic dysfunction was accompanied by cardiac BH(4) depletion, NOS uncoupling, a depression in myofilament cross-bridge kinetics, and S-glutathionylation of myosin binding protein C (MyBP-C). We hypothesized that the mechanism by which BH(4) ameliorates diastolic dysfunction is by preventing glutathionylation of MyBP-C and thus reversing changes of myofilament properties that occur during diastolic dysfunction. We used the deoxycorticosterone acetate (DOCA)-salt mouse model, which demonstrates mild hypertension, myocardial oxidative stress, and diastolic dysfunction. Mice were divided into two groups that received control diet and two groups that received BH(4) supplement for 7days after developing diastolic dysfunction at post-operative day 11. Mice were assessed by echocardiography. Left ventricular papillary detergent-extracted fiber bundles were isolated for simultaneous determination of force and ATPase activity. Sarcomeric protein glutathionylation was assessed by immunoblotting. DOCA-salt mice exhibited diastolic dysfunction that was reversed after BH(4) treatment. Diastolic sarcomere length (DOCA-salt 1.70±0.01 vs. DOCA-salt+BH(4) 1.77±0.01µm, P<0.001) and relengthening (relaxation constant, τ, DOCA-salt 0.28±0.02 vs. DOCA-salt+BH(4) 0.08±0.01, P<0.001) were also restored to control by BH(4) treatment. pCa(50) for tension increased in DOCA-salt compared to sham but reverted to sham levels after BH(4) treatment. Maximum ATPase rate and tension cost (ΔATPase/ΔTension) decreased in DOCA-salt compared to sham, but increased after BH(4) treatment. Cardiac MyBP-C glutathionylation increased in DOCA-salt compared to sham, but decreased with BH(4) treatment. MyBP-C glutathionylation correlated with the presence of diastolic dysfunction. Our results suggest that by depressing S-glutathionylation of MyBP-C, BH(4) ameliorates diastolic dysfunction by reversing a decrease in cross-bridge turnover kinetics. These data provide evidence for modulation of cardiac relaxation by post-translational modification of myofilament proteins.

Beneficial effects of stress-dose corticosteroid therapy in canines depend on the severity of staphylococcal pneumonia.

PURPOSE: The effects of stress-dose corticosteroid therapy were studied in a canine staphylococcal pneumonia model of septic shock. METHODS: Immediately following intrabronchial bacterial challenge, purpose-bred beagles were treated with stress doses of desoxycorticosterone (DOC), a mineralocorticoid agonist, and dexamethasone (DEX), a glucocorticoid agonist, or with placebo for 96 h. Oxacillin (30 mg/kg every 8 h) was started 4 h after infection onset. Bacterial dose was titrated to achieve 80-90 % lethality (n = 20) using an adaptive design; additional animals (n = 18) were investigated using the highest bacterial dose. RESULTS: Initial analysis of all animals (n = 38) demonstrated that the effects of DOC + DEX were significantly altered by bacterial dose (p = 0.04). The treatment effects of DOC + DEX were different in animals administered high or relatively lower bacterial doses in terms of survival (p = 0.05), shock reversal (p = 0.02), interleukin-6 levels (p = 0.02), and temperature (p = 0.01). DOC + DEX significantly improved the above parameters (p ≤ 0.03 for all) and lung injury scores (p = 0.02) after high-dose bacterial challenges, but not after lower challenges (p = not significant for all). Oxacillin trough levels were below the minimum inhibitory concentration of the infecting organism, and DOC + DEX increased the frequency of persistent staphylococcal bacteremia (odds ratio 3.09; 95 % confidence interval 1.05-9.11; p = 0.04). CONCLUSIONS: Stress-dose corticosteroids were only beneficial in cases of sepsis with high risk for death and even short courses may interfere with host mechanisms of bacterial clearance.

Potassium restores vasorelaxation of resistance arterioles in non-hypertensive DOCA/salt fed mice.

BACKGROUND: Potassium-enriched diets exert renal and cardiovascular protective effects, but the underlying mechanisms are largely unknown. METHODS: Using the dorsal skinfold chamber model for intravital microscopy, we examined endothelium-dependent vasorelaxation of precapillary resistance arterioles in response to acetylcholine or the NO donor SNAP in awake mice. Experiments were performed in uni-nephrectomized one renin gene (Ren-1c) C57BL/6 mice (control group) and in mice having received a continuous administration of deoxycorticosterone acetate and a dietary supplementation of 1% sodium chloride for 8 weeks (DOCA/salt group). An additional group of DOCA/salt treated animals received a dietary supplement of 0.4% KCl for 3 weeks prior to the experiments (DOCA/salt + potassium group). RESULTS: DOCA/salt treatment for 8 weeks resulted in hypokalemia, but blood pressure remained unchanged. In DOCA/salt mice, relaxation of resistance arterioles was blunted in response to acetylcholine, and to a lesser extent to SNAP, suggesting endothelial dysfunction. Endothelium-dependent vasorelaxation was restored by the potassium-enriched diet. CONCLUSION: This study is the first to demonstrate a protective effect of potassium on endothelium-dependent vasorelaxation in the absence of confounding anti-hypertensive effects, as observed in most animal models and the clinical situation. We propose that the known cardio- and nephro-protective effects of potassium might - at least in part - be mediated by the salutary effects on endothelium-dependent arteriolar relaxation.

The flavonoid morin restores blood pressure and lipid metabolism in DOCA-salt hypertensive rats.

OBJECTIVE: This study was undertaken to investigate the antihypertensive and antihyperlipedimic potential of morin against deoxycorticosterone acetate (DOCA)-salt hypertensive rats. METHODS: Hypertension was induced in uninephrectomized rats (UNX) by weekly twice subcutaneous injection of DOCA (25 mg/kg) and 1% NaCl in the drinking water for six consecutive weeks. Morin (50 mg/kg) was administered to DOCA-salt rats orally using an intragastric tube daily for a period of 6 weeks. RESULTS: The DOCA-salt hypertensive rats showed significant elevation in mean arterial pressure (MAP), heart rate (HR) and reduction in body weight. A significant increase in the concentrations of plasma and tissue (liver, kidney, heart, and aorta) lipids such as total cholesterol, triglycerides, free fatty acids, phospholipids, plasma low-density and very low-density lipoproteins cholesterol, and a decrease in the concentration of high-density lipoprotein cholesterol were noticed in DOCA-salt hypertensive rats. Also, the levels of urinary protein and the activity of 3-hydroxy 3-methylglutaryl coenzyme A reductase in the plasma and tissues were increased, and lecithin cholesterol acyl transferase activity in the plasma was decreased in DOCA-salt rats. Morin supplementation (50 mg/kg) throughout the experimental period restored all the above parameters significantly. CONCLUSION: Morin has a potential role in attenuating severe hypertension and hyperlipedimia.