Absence of cardiotrophin 1 is associated with decreased age-dependent arterial stiffness and increased longevity in mice

Cardiotrophin 1 (CT-1), an interleukin 6 family member, promotes fibrosis and arterial stiffness. We hypothesized that the absence of CT-1 influences arterial fibrosis and stiffness, senescence, and life span. In senescent 29-month- old mice, vascular function was analyzed by echotracking device. Arterial histomorphology, senescence, metabolic, inflammatory, and oxidative stress parameters were measured by immunohistochemistry, reverse transcription polymerase chain reaction, Western blot, and ELISA. Survival rate of wild-type and CT-1–null mice was studied. Vascular smooth muscle cells were treated with CT-1 (10 −9 mol/L) for 15 days to analyze senescence. The wall stress-incremental elastic modulus curve of old CT-1–null mice was shifted rightward as compared with wild-type mice, indicating decreased arterial stiffness. Media thickness and wall fibrosis were lower in CT-1–null mice. CT-1–null mice showed decreased levels of inflammatory, apoptotic, and senescence pathways, whereas telomere-linked proteins, DNA repair proteins, and antioxidant enzyme activities were increased. CT-1–null mice displayed a 5-month increased median longevity compared with wild-type mice. In vascular smooth muscle cells, chronic CT-1 stimulation upregulated apoptotic and senescence markers and downregulated telomere-linked proteins. The absence of CT-1 is associated with decreased arterial fibrosis, stiffness, and senescence and increased longevity in mice likely through downregulating apoptotic, senescence, and inflammatory pathways. CT-1 may be a major regulator of arterial stiffness with a major impact on the aging proces

Cardiotrophin 1 is involved in cardiac, vascular, and renal fibrosis and dysfunction

Cardiotrophin 1 (CT-1), a cytokine belonging to the interleukin 6 family, is increased in hypertension and in heart failure. We aimed to study the precise role of CT-1 on cardiac, vascular, and renal function; morphology; and remodeling in early stages without hypertension. CT-1 (20 g/kg per day) or vehicle was administrated to Wistar rats for 6 weeks. Cardiac and vascular functions were analyzed in vivo using M-mode echocardiography, Doppler, and echo tracking device and ex vivo using a scanning acoustic microscopy method. Cardiovascular and renal histomorphology were measured by immunohistochemistry, RT-PCR, and Western blot. Kidney functional properties were assessed by serum creatinine and neutrophile gelatinase-associated lipocalin and microalbuminuria/creatininuria ratio. Without alterations in blood pressure levels, CT-1 treatment increased left ventricular volumes, reduced fractional shortening and ejection fraction, and induced myocardial dilatation and myocardial fibrosis. In the carotid artery of CT-1–treated rats, the circumferential wall stress-incremental elastic modulus curve was shifted leftward, and the acoustic speed of sound in the aorta was augmented, indicating increased arterial stiffness. Vascular media thickness, collagen, and fibronectin content were increased by CT-1 treatment. CT-1–treated rats presented unaltered serum creatinine concentrations but increased urinary and serum neutrophile gelatinase-associated lipocalin and microalbuminuria/creatininuria ratio. This paralleled a glomerular and tubulointerstitial fibrosis accompanied by renal epithelial-mesenchymal transition. CT-1 is a new potent fibrotic agent in heart, vessels, and kidney able to induce cardiovascular-renal dysfunction independent from blood pressure. Thus, CT-1 could be a new target simultaneously integrating alterations of heart, vessels, and kidney in early stages of heart failure

O2 Level Controls Hematopoietic Circulating Progenitor Cells Differentiation into Endothelial or Smooth Muscle Cells

BACKGROUND:Recent studies showed that progenitor cells could differentiate into mature vascular cells. The main physiological factors implicated in cell differentiation are specific growth factors. We hypothesized that simply by varying the oxygen content, progenitor cells can be differentiated either in mature endothelial cells (ECs) or contractile smooth muscle cells (SMCs) while keeping exactly the same culture medium. METHODOLOGY/PRINCIPAL FINDINGS:Mononuclear cells were isolated by density gradient were cultivated under hypoxic (5% O2) or normoxic (21% O2) environment. Differentiated cells characterization was performed by confocal microscopy examination and flow cytometry analyses. The phenotype stability over a longer time period was also performed. The morphological examination of the confluent obtained cells after several weeks (between 2 and 4 weeks) showed two distinct morphologies: cobblestone shape in normoxia and a spindle like shape in hypoxia. The cell characterization showed that cobblestone cells were positive to ECs markers while spindle like shape cells were positive to contractile SMCs markers. Moreover, after several further amplification (until 3(rd) passage) in hypoxic or normoxic conditions of the previously differentiated SMC, immunofluorescence studies showed that more than 80% cells continued to express SMCs markers whatever the cell environmental culture conditions with a higher contractile markers expression compared to control (aorta SMCs) signature of phenotype stability. CONCLUSION/SIGNIFICANCE:We demonstrate in this paper that in vitro culture of peripheral blood mononuclear cells with specific angiogenic growth factors under hypoxic conditions leads to SMCs differentiation into a contractile phenotype, signature of their physiological state. Moreover after amplification, the differentiated SMC did not reverse and keep their contractile phenotype after the 3rd passage performed under hypoxic and normoxic conditions. These aspects are of the highest importance for tissue engineering strategies. These results highlight also the determinant role of the tissue environment in the differentiation process of vascular progenitor cells

The Nebivolol action on vascular tone is dependent on actin cytoskeleton polymerization and Rho-A activity into ECs and SMCs

International audienceNitric oxide is implicated in the target action of Nebivolol, a selective beta 1 adrenoceptor blocker used in hypertension treatment. As the Nitric Oxide (NO) production and the actin cytoskeleton are linked, the aim of this work was to study the involvement of actin cytoskeleton on mechanism of action of Nebivolol in cultured endothelial cells. We studied the effect of Nebivolol (200 mu M) on actin filaments remodeling and its impact on NO production and eNOS activation. Results showed that Nebivolol perturbs actin filaments polymerization, increases NO production and eNOS activity between 30 minutes and 1 h. Stabilization of actin filaments with phalloidine (50 mu M) abolishes Nebivolol effects on eNOS activation and NO production. Furthermore, Rho-kinase activity decreased during the first hour of Nebivolol treatment, then increased after 3 h, while actin filaments repolymerized, eNOS activation and NO production decreased. In SMCs, Nebivolol induced a decrease in the Rhokinase activity from 1 h until 24 h of incubation. In conclusion, we suggest that Nebivolol induced NO production in Endothelial Cells (ECs) via complementary actions between actin cytoskeleton remodeling inducing eNOS activation and Rho-kinase implication. The effect of Nebivolol on ECs occurs during the first hour, this effect on SMCs seems to be maintained until 24 h, explaining persisted action of Nebivolol observed in vivo

Absence of cardiotrophin 1 is associated with decreased age-dependent arterial stiffness and increased longevity in mice

Cardiotrophin 1 (CT-1), an interleukin 6 family member, promotes fibrosis and arterial stiffness. We hypothesized that the absence of CT-1 influences arterial fibrosis and stiffness, senescence, and life span. In senescent 29-month- old mice, vascular function was analyzed by echotracking device. Arterial histomorphology, senescence, metabolic, inflammatory, and oxidative stress parameters were measured by immunohistochemistry, reverse transcription polymerase chain reaction, Western blot, and ELISA. Survival rate of wild-type and CT-1–null mice was studied. Vascular smooth muscle cells were treated with CT-1 (10 −9 mol/L) for 15 days to analyze senescence. The wall stress-incremental elastic modulus curve of old CT-1–null mice was shifted rightward as compared with wild-type mice, indicating decreased arterial stiffness. Media thickness and wall fibrosis were lower in CT-1–null mice. CT-1–null mice showed decreased levels of inflammatory, apoptotic, and senescence pathways, whereas telomere-linked proteins, DNA repair proteins, and antioxidant enzyme activities were increased. CT-1–null mice displayed a 5-month increased median longevity compared with wild-type mice. In vascular smooth muscle cells, chronic CT-1 stimulation upregulated apoptotic and senescence markers and downregulated telomere-linked proteins. The absence of CT-1 is associated with decreased arterial fibrosis, stiffness, and senescence and increased longevity in mice likely through downregulating apoptotic, senescence, and inflammatory pathways. CT-1 may be a major regulator of arterial stiffness with a major impact on the aging proces

Hemodynamic phenotyping.

<p>Invasive blood pressure measurements were obtained on anesthetized rats during vascular phenotyping of the animals. <b>A</b>- Systolic (SBP), Diastolic (DBP) Blood Pressures and Pulse Pressure (PP) were measured at both the earliest and latest ages. Results showed that over time only SHHF^cp/cp rats increased their SBP and PP becoming significantly higher at 14 months of age compared to SHHF^+/? animals. <b>B</b>- Distensibility, <b>C</b>- Incremental Elastic modulus (E_inc) to Wall Stress (WS) curves and <b>D</b>- WS at Einc 600 kPa were recorded. Values are mean ± sem of 5 to 14 measurements depending on the genotype and age. Fisher's LSD Multiple-Comparison Test * p<0.05 for comparing of SHHF^cp/cp<i>vs.</i> SHHF^+/? rats at the same age; § p<0.05 for comparison of 14 month-old <i>vs.</i> 1.5-month-old rats of the same genotype.</p

Renal parameters.

<p><b>KW</b>, Kidney Weight; <b>Na⁺</b>, sodium, <b>K⁺</b>, potassium, <b>eGFR</b>, estimated Glomerular filtration rate; Values are the mean±sem. Non-parametric ANOVAs analysis with two factors allowed the evaluation of interaction between aging and genotype. Student's T test *, ** and *** p<0.01, p<0.001 and p<0.0001 respectively when comparing SHHF ^+/?<i>vs.</i> SHHF^cp/cp at same time point; § p<0.05, §§ p<0.01 and §§§ p<0.001 to compare T14-mo <i>vs</i> T1.5-mo for a same genotype; <b>N</b> stands for the number of samples; <b>ns</b> stands for not significant.</p

Metabolic follow-up.

<p><b>A</b>- The monitoring of body weight shows that the onset of obesity occurs during the first three months after birth of SHHF^cp/cp rats. Progressively, the SHHF^cp/cp rats continue to gain weight accentuating their differences with the SHHF^+/? (n = 5 to 14 rats per genotype). (<b>B–C</b>) Paraffin embedded tissues dissected from SHHF^cp/cp and SHHF^+/? rats at 14 months of age showing metabolic disorder related-tissue alterations <b>B</b>- Peri-renal visceral fat of SHHF^cp/cp rats stained with Sirius red exhibited marked fibrosis (arrows) and hypertrophic adipocytes. <b>C</b>- Hemaetoxylin & Eosin staining shows the deposition of lipid droplets (arrows) in the liver dissected from SHHF^cp/cp rats suggesting the development of non-alcoholic hepatic steatosis. Pictures are representative of each analyzed group (n = 5 to 7 rats per genotype). Values are mean ± sem. Non-parametric ANOVA analysis with two factors allowed the evaluation of an interaction between aging and genotype. * p<0.05, ** p<0.01, *** p<0.001 for comparing SHHF^cp/cp vs. SHHF^+/? at the same time point.</p