Abstract P234: Arterial Hypertension, Insulin Resistance And Depressive-like Behavior In Crtc1 -deficient Mice

Background: Epidemiological evidence has demonstrated a link between cardiovascular disease, metabolic syndrome and depression. Whether this association is causal and what mechanisms may be involved is still unknown. Studies in humans and mice suggest that alterations of the CREB-BDNF pathway can contribute to the development of both, eating disorders and major depressive disorders. Mice deficient in the CREB-regulated transcriptional coactivator 1 (Crtc1) have been shown to become overweight and display depressive-like behavior. Here, we investigated whether Crtc1 -deficient mice concomitantly exhibit a hypertensive, insulin resistant and depression-like phenotype.

Methods: Mean arterial blood pressure and heart rate were measured by radiotelemetry in unrestrained Crtc1 -deficient mice (KO) and wildtype littermates (WT). Renal renin expression was quantified by qPCR. Insulin resistance was determined by the i.p. glucose tolerance test, and depressive-like behavior was assessed by the soiled bedding preference test.

Results: Crtc1 -deficient mice had higher arterial blood pressures (dark: KO 117±2 mm Hg, WT 107±2 mm Hg, p<0.05; light: KO 102±2 mm Hg, WT 94±2 mm Hg, p<0.05, 1-way ANOVA, n=8-11) and heart rates (dark: KO 593±11 bpm, WT 596±7 bpm; light: KO 529±12 bpm, WT 494±8 bpm, p<0.05, 1-way ANOVA, n=8-11). Relative renin mRNA expression was not different between genotypes (KO 0.86±0.07, WT 1.00±0.10, n=10). Glucose tolerance was significantly impaired in Crtc1 -deficient mice (maximum plasma glucose concentrations KO 423±27 mg/dl, WT 295±27 mg/dl, p<0.0001, 2-way ANOVA, n=9). In the soiled bedding preference test, male Crtc1 -deficient mice exhibited a lack of preference for female-soiled bedding over clean bedding (female vs. clean KO 75.3±11.2 s vs 79.0±11.0 s, WT 119.5±13.5 s vs. 51.5±10.5 s, n=2-3).

Conclusions: Crtc1 might be a molecular component of a pathway that connects arterial hypertension, metabolic syndrome and depression.

Arginine:Glycine Amidinotransferase Is Essential for Creatine Supply in Mice During Chronic Hypoxia

Objective: Chronic hypoxia induces pulmonary and cardiovascular pathologies, including pulmonary hypertension (PH). L-arginine:glycine amidinotransferase (AGAT) is essential for homoarginine (hArg) and guanidinoacetate synthesis, the latter being converted to creatine by guanidinoacetate methyltransferase. Low hArg concentrations are associated with cardiovascular morbidity and predict mortality in patients with PH. We therefore aimed to investigate the survival and cardiac outcome of AGAT knockout (Agat^−/−) mice under hypoxia and a possible rescue of the phenotype.

Methods:Agat^−/− mice and wild-type (WT) littermates were subjected to normoxia or normobaric hypoxia (10% oxygen) for 4 weeks. A subgroup of Agat^−/− mice was supplemented with 1% creatine from weaning. Survival, hematocrit, blood lactate and glucose, heart weight-to-tibia length (HW/TL) ratio, hArg plasma concentration, and Agat and Gamt expression in lung, liver, and kidneys were evaluated.

Results: After 6 h of hypoxia, blood lactate was lower in Agat^−/−-mice as compared to normoxia (p < 0.001). Agat^−/− mice died within 2 days of hypoxia, whereas Agat^−/− mice supplemented with creatine and WT mice survived until the end of the study. In WT mice, hematocrit (74 ± 4 vs. 55 ± 2%, mean ± SD, p < 0.001) and HW/TL (9.9 ± 1.3 vs. 7.3 ± 0.7 mg/mm, p < 0.01) were higher in hypoxia, while hArg plasma concentration (0.25 ± 0.06 vs. 0.38 ± 0.12 μmol/L, p < 0.01) was lower. Agat and Gamt expressions were differentially downregulated by hypoxia in lung, liver, and kidneys.

Conclusion:Agat and Gamt are downregulated in hypoxia. Agat^−/− mice are nonviable in hypoxia. Creatine rescues the lethal phenotype, but it does not reduce right ventricular hypertrophy of Agat^−/− mice in hypoxia.

B6.Rag1 Knockout Mice Generated at the Jackson Laboratory in 2009 Show a Robust Wild-Type Hypertensive Phenotype in Response to Ang II (Angiotensin II)

A key finding supporting a causal role of the immune system in the pathogenesis of hypertension is the observation that RAG1 knockout mice on a C57Bl/6J background (B6.Rag1^-/-), which lack functional B and T cells, develop a much milder hypertensive response to Ang II (angiotensin II) than control C57Bl/6J mice. Here, we report that we never observed any Ang II resistance of B6.Rag1^-/- mice purchased directly from the Jackson Laboratory as early as 2009. B6.Rag1^-/- mice displayed nearly identical blood pressure increases monitored via radiotelemetry and hypertensive end-organ damage in response to different doses of Ang II and different levels of salt intake (0.02%, 0.3%, and 3% NaCl diet). Similarly, restoration of T-cell immunity by adoptive cell transfer did not affect the blood pressure response to Ang II in B6.Rag1^-/- mice. Full development of the hypertension-resistant phenotype in B6.Rag1^-/- mice appears to depend on the action of yet unidentified nongenetic modifiers in addition to the absence of functional T cells.

The chemokine receptor CX3CR1 reduces renal injury in mice with angiotensin II-induced hypertension

The role of CX₃CR1, also known as fractalkine receptor, in hypertension is unknown. The present study determined the role of the fractalkine receptor CX₃CR1 in hypertensive renal and cardiac injury. Expression of CX₃CR1 was determined using CX₃CR1^GFP/+ mice that express a green fluorescent protein (GFP) reporter in CX₃CR1⁺ cells. FACS analysis of leukocytes isolated from the kidney showed that 34% of CD45⁺ cells expressed CX₃CR1. Dendritic cells were the majority of positive cells (67%) followed by macrophages (10%), NK cells (6%), and T cells (10%). With the use of confocal microscopy, the receptor was detected in the kidney only on infiltrating cells but not on resident renal cells. To evaluate the role of CX₃CR1 in hypertensive end-organ injury, an aggravated model of hypertension was used. Unilateral nephrectomy was performed followed by infusion of angiotensin II (ANG II, 1.5 ng·g^-1·min^-1) and a high-salt diet in wild-type ( n = 15) and CX₃CR1-deficient mice ( n = 18). CX₃CR1 deficiency reduced the number of renal dendritic cells and increased the numbers of renal CD11b/F4/80⁺ macrophages and CD11b/Ly6G⁺ neutrophils in ANG II-infused mice. Surprisingly, CX₃CR1-deficient mice exhibited increased albuminuria, glomerular injury, and reduced podocyte density in spite of similar levels of arterial hypertension. In contrast, cardiac damage as assessed by increased heart weight, cardiac fibrosis, and expression of fetal genes, and matrix components were not different between both genotypes. Our findings suggest that CX₃CR1 exerts protective properties by modulating the invasion of inflammatory cells in hypertensive renal injury. CX₃CR1 inhibition should be avoided in hypertension because it may promote hypertensive renal injury.

Smooth muscle BK channel activity influences blood pressure independent of vascular tone in mice

The large conductance voltage- and Ca(2+)-activated K(+) (BK) channel is an important determinant of vascular tone and contributes to blood pressure regulation. Both activities depend on the ancillary BKβ1 subunit. To determine the significance of smooth muscle BK channel activity for blood pressure regulation, we investigated the potential link between changes in arterial tone and altered blood pressure in BKβ1 knockout (BKβ1(-/-)) mice from three different genetically defined strains. While vascular tone was consistently increased in all BKβ1(-/-) mice independent of genetic background, BKβ1(-/-) strains exhibited increased (strain A), unaltered (strain B) or decreased (strain C) mean arterial blood pressures compared to their corresponding BKβ1(+/+) controls. In agreement with previous data on aldosterone regulation by renal/adrenal BK channel function, BKβ1(-/-) strain A mice have increased plasma aldosterone and increased blood pressure. Consistently, blockade of mineralocorticoid receptors by spironolactone treatment reversibly restored the elevated blood pressure to the BKβ1(+/+) strain A level. In contrast, loss of BKβ1 did not affect plasma aldosterone in strain C mice. Smooth muscle-restricted restoration of BKβ1 expression increased blood pressure in BKβ1(-/-) strain C mice, implying that impaired smooth muscle BK channel activity lowers blood pressure in these animals. We conclude that BK channel activity directly affects vascular tone but influences blood pressure independent of this effect via different pathways.

Disruption of vascular Ca2+-activated chloride currents lowers blood pressure

High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. Ca2+-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor treatment. There was no difference in contractility of medium-sized mesenteric arteries; however, responsiveness of the aorta and small retinal arterioles to the vasoconstriction-inducing drug U46619 was reduced. TMEM16A also was required for peripheral blood vessel contractility, as the response to U46619 was attenuated in isolated perfused hind limbs from mutant mice. Out data suggest that TMEM16A plays a general role in arteriolar and capillary blood flow and is a promising target for the treatment of hypertension.

Functional coupling of renal K+ and Na+ handling causes high blood pressure in Na+ replete mice

A network of kinases, including WNKs, SPAK and Sgk1, is critical for the independent regulation of K+ and Na+ transport in the distal nephron. Angiotensin II is thought to act as a key hormone in orchestrating these kinases to switch from K+ secretion during hyperkalaemia to Na+ reabsorption during intravascular volume depletion, thus keeping disturbances in electrolyte and blood pressure homeostasis at a minimum. It remains unclear, however, how K+ and Na+ transport are regulated during a high Na+ intake, which is associated with suppressed angiotensin II levels and a high distal tubular Na+ load. We therefore investigated the integrated blood pressure, renal, hormonal and gene and protein expression responses to large changes of K+ intake in Na+ replete mice. Both low and high K+ intake increased blood pressure and caused Na+ retention. Low K+ intake was accompanied by an upregulation of the sodium-chloride cotransporter (NCC) and its activating kinase SPAK, and inhibition of NCC normalized blood pressure. Renal responses were unaffected by angiotensin AT1 receptor antagonism, indicating that low K+ intake activates the distal nephron by an angiotensin-independent mode of action. High K+ intake was associated with elevated plasma aldosterone concentrations and an upregulation of the epithelial sodium channel (ENaC) and its activating kinase Sgk1. Surprisingly, high K+ intake increased blood pressure even during ENaC or mineralocorticoid receptor antagonism, suggesting the contribution of aldosterone-independent mechanisms. These findings show that in a Na+ replete state, changes in K+ intake induce specific molecular and functional adaptations in the distal nephron that cause a functional coupling of renal K+ and Na+ handling, resulting in Na+ retention and high blood pressure when K+ intake is either restricted or excessively increased.

Myeloperoxidase acts as a profibrotic mediator of atrial fibrillation

Observational clinical and ex vivo studies have established a strong association between atrial fibrillation and inflammation. However, whether inflammation is the cause or the consequence of atrial fibrillation and which specific inflammatory mediators may increase the atria's susceptibility to fibrillation remain elusive. Here we provide experimental and clinical evidence for the mechanistic involvement of myeloperoxidase (MPO), a heme enzyme abundantly expressed by neutrophils, in the pathophysiology of atrial fibrillation. MPO-deficient mice pretreated with angiotensin II (AngII) to provoke leukocyte activation showed lower atrial tissue abundance of the MPO product 3-chlorotyrosine, reduced activity of matrix metalloproteinases and blunted atrial fibrosis as compared to wild-type mice. Upon right atrial electrophysiological stimulation, MPO-deficient mice were protected from atrial fibrillation, which was reversed when MPO was restored. Humans with atrial fibrillation had higher plasma concentrations of MPO and a larger MPO burden in right atrial tissue as compared to individuals devoid of atrial fibrillation. In the atria, MPO colocalized with markedly increased formation of 3-chlorotyrosine. Our data demonstrate that MPO is a crucial prerequisite for structural remodeling of the myocardium, leading to an increased vulnerability to atrial fibrillation.

Virulence factors and in vitro adherence of Enterococcus strains to urinary catheters

The ability to adhere in vitro to urinary catheters and the presence of enterococcal virulence factors was determined in 30 Enterococcus urinary isolates (12 E. faecalis, 12 E. faecium, 3 E. casseliflavus, 3 E. gallinarum). Silicone, siliconized latex and polyvinyl chloride (PVC) were examined by sonication quantitative culture technique and scanning electron microscope. As compared to E. faecalis and E. faecium, E. casseliflavus and E. gallinarum displayed lower adhesion to all synthetic materials. All the tests performed showed higher adherence of all tested strains to siliconized latex and silicone than to PVC. Biofilmforming ability was observed in 5 E. faecalis but in none of the remaining strains. The gene coding enterococcal surface protein (Esp) was detected in 7 E. faecalis and 6 E. faecium strains. Gelatinase was found in 1 E. faecalis, 2 E. faecium and hemolysins were found in 6 E. faecalis and 1 E. faecium strains. All E. casseliflavus and E. gallinarum strainswere negative for these traits. Hydrophobic type of cell surface (measured by its affinity for n-hexadecane) was shown in a few isolates. Bacterial adherence was not significantly associated with the above pathogenic factors.

[The metal concentration in water and ground deposit in the area of Upper Silesia]

The metal concentration in water and ground deposits of 6 collapse water reservoirs in the area of Upper Silesia was tested. The examined reservoirs are situated in the so-called cross-town tract near Swietochłowice and Ruda Slaska. It was concluded that the metal concentration in water samples was low. In accordance with the present regulations, this allows to classify the water in these reservoirs to the 1st class purity water. The metal content in the ground deposits is high. Iron (Fe) concentration in the deposits ranged from 28288.9 mg/kg to 39162.9 mg/kg; the concentration of manganese (Mn) ranged from 2557.95 mg/kg to 3398.52 mg/kg and that of zinc (Zn) was 1288.78 mg/kg average through the year. The highest zinc concentration reached 2834.74 mg/kg. Cadmium (Cd) occurred in the deposits in the content of 10.4 mg/kg. The average year concentration of lead (Pb) in the deposits was 252.4 mg/kg. Copper (Cu) was found in the deposits in the amount of 45.0 mg/kg. The highest concentration of this metal in the ground deposits was 103.14 mg/kg. Magnesium (Mg) was on average present in the deposits in the concentration of 1913 mg/kg and its highest concentration reached 6777.89 mg/kg.

[Extensivity of infection of Fasciola hepatica L. in cattle in Lublin's voivodship in the years 1993-2001]

Extensivity of infection of Fasciola hepatica L. among cattle in Lublin's voivodship from 1993-2001. Aim of the work was to determine extensitivity of appearance of hepatica among catlle put to slaughter in slaughtershouses in Lublin's voivodship from 1993 to 2001. Substance for the work was braught from the annual reports of official examination of slaughtered animals, reached from both main Inspectorate (department) of Veterinary in the Ministry of Agriculture and from Regional Institute of Veterinar's Hygiene in Lublin. Results of researches are as follow: extensivity of infection of Fasciola hepatica among cattle in Lublin and voivodship between 1993 - 1999 oscillates about 5%. In 2000 extensivity of invasion reached 10,9%.

[Extensivity of appearance of echinococcosis among swine in Lublin's voivodship in period 1993-2000]

Aim of the work was presentation of appearance of hydatid among swine in Lublin' s voivodship between 1993-2000. Substance for researches was brought from annual reports inserted into journals of official examination leaded by Veterinary's Inspenction of Sanitation in slaughterhouses. It was proved that average 10,1% of swine on territory of Lublin's voivodship in period 1993-2000 was infected. Frequency of infection among examined animals were the highest in last year of researches 200 and reached 13,4%.

Studies of antibacterial activity of binuclear rhodium (II) complexes with heterocyclic nitrogen ligands

Binuclear rhodium (II) complexes, [Rh2(OOCPh)2(phen)2(H2O)2] (OOCPh)2 (1), [Rh2(OOCPh)2(bpy)2(H2O)2] (OOCPh)2 (2), [Rh2(OOCBu(n))2 (bpy)2(H2O)2] (OOCBu(n)2 (3), and [Rh2(OOCPr(n)2 (phen)2(H2O)2] (OOCPr(n)2 (4) (Phen = 1,10-phenanthroline and bpy = 2,2'-bipyridine), have been synthesized and characterized using NMR, IR and electronic spectra. Activity of these compounds against Gram-positive bacteria decreases in the order: 1?2?3 > 4. Complex 1 is active against many Staphylococcus strains resistant to commonly used antibiotics. The complexes 1-4 are much less active agents against Gram-negative bacteria.

Synthesis and cytotoxic evaluation of some Mannich bases of alicyclic ketones

A number of Mannich bases of alicyclic ketones containing one and two basic centres were prepared in order to evaluate the theory of sequential cytotoxicity and develop structure-activity relationships in these series of compounds. The compounds were evaluated in vitro against murine P388 D1 lymphocytic leukemia cells. The data generated supported the theory of sequential cytotoxicity and in general, compounds containing alicyclic rings of five and six carbon atoms possessed greater activity than the corresponding dodecyl analogues. Those Mannich bases containing dialkylamino groups were associated with greater cytotoxicity than related compounds possessing a basic heterocycle. Calculations of the atomic charges of the enone groups from selected compounds afforded some rationalization for the cytotoxic screening results.