Cytokine expression in peripheral blood mononuclear cells of dogs with mitral valve disease

Mitochondrial bioenergetic dysfunction linked to myxomatous mitral valve degeneration explored by PBMCs metabolism analysis

Impaired mitochondria cause an impressive decrease in ATP production becoming a common condition of cardiovascular diseases. Myxomatous mitral valve disease (MMVD) is characterized by mitochondrial dysfunction. By a non-invasive procedure of metabolism analysis on peripheral blood mononuclear cells, we exploit ex-vivo studies that directly constitute a translational approach to evaluate the cell bioenergetics. Cell ATP production decreased in the presence of MMVD, whereas glycolysis was unaffected. In MMVD, the mitochondrial activity underwent a significant reduction of basal respiration, maximal respiration, and ATP production. Our results depicted a pathological condition of MMVD characterized by cell metabolism deprived of mitochondrial energy support.

Key nutrients important in the management of canine myxomatous mitral valve disease and heart failure

The most common cause of heart failure in dogs is myxomatous mitral valve disease (MMVD), which accounts for approximately 75% of canine heart disease cases and is especially common in smaller dogs. Although low-sodium diets have been recommended for humans with heart diseases for decades, there is little evidence to support this practice in dogs. In recent years, however, it has become clear that other nutrients are important to heart health. Dogs with heart disease secondary to MMVD experience patterns of metabolic changes that include decreased mitochondrial energy metabolism and ATP availability, with increased oxidative stress and inflammation. These changes occur early in disease and progress with worsening heart disease. Key nutrients that may support normal function and address these changes include omega-3 fatty acids, medium-chain triglycerides, magnesium, antioxidants including vitamin E and taurine, and the amino acids methionine and lysine. The long-chain omega-3 fatty acids provide anti-inflammatory, antithrombotic, and other benefits. Medium-chain fatty acids and ketones derived from medium-chain triglycerides provide an alternative energy source for cardiac mitochondria and help reduce free radical production. Magnesium supports mitochondrial function, normal cardiac rhythm, and provides other benefits. Both vitamin E and taurine counter oxidative stress, and taurine also has direct cardiac benefits. Dogs with MMVD have reduced plasma methionine. Methionine and lysine are important for carnitine production as well as other functions. This article reviews the evidence supporting the functions and benefits of these and other nutrients in MMVD and other cardiac conditions.

Pro-Inflammatory and Immunological Profile of Dogs with Myxomatous Mitral Valve Disease

Simple Summary

Myxomatous mitral valve disease (MMVD) is the most commonly acquired cardiac disease in dogs and is responsible for congestive heart failure. In this research, some inflammatory, immunological, and echocardiographic parameters were evaluated in dogs affected by MMVD in order to assess the involvement of additional pathophysiological mechanisms during the disease. The main results revealed that inflammation parameters increased according to the severity of the disease and suggested that inflammatory activation may play an important role in cardiac remodeling associated with the progressive volumetric overload in MMVD. Also, a relative increase in Treg cells was detected, suggesting that they could represent a regulatory mechanism for limiting the inflammatory immune response.

Abstract

Myxomatous mitral valve disease (MMVD) is a very frequently acquired cardiac disease in dog breeds and is responsible for congestive heart failure (CHF). The involvement of the immune system and pro-inflammatory cytokines in dogs with CHF due to mitral valve disease has not yet been extensively investigated. Here, we investigate the role of pro-inflammatory cytokines and the dysfunction of the immune system in dogs with different stages of severity through the blood assessment of CD4⁺FoxP3⁺regulatory T cells (Treg) cells, leptin, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 pro-inflammatory cytokines, and immunological and echocardiographic parameters. A total of 36 cardiopathic dogs, 14 females and 22 males, with MMVD were included. Mean age and body weight (BW) at the time of enrollment were 10.7 ± 2.77 years and 10.9 ± 6.69 kg, respectively. For the comparison of the pro-inflammatory and immunological parameters, two groups of healthy dogs were also established. Control group 1 consisted of young animals (n. 11; 6 females and 5 males), whose age and mean weight were 4.1 ± 0.82 years and 13.8 ± 4.30 kg, respectively. Control group 2 consisted of elderly dogs (n. 12; 6 females and 6 males), whose age and BW were 9.6 ± 0.98 years and 14.8 ± 6.15 kg, respectively. Of particular interest, an increase in Treg cells was observed in the cohort of MMVD dogs, as compared to the healthy dogs, as Treg cells are involved in the maintenance of peripheral tolerance, and they are involved in etiopathogenetic and pathophysiological mechanisms in the dog. On the other hand, TNF-α, IL-1β, and IL-6 significantly increased according to the severity of the disease in MMVD dogs. Furthermore, the positive correlation between IL-6 and the left ventricle diastolic volume suggests that inflammatory activation may be involved in cardiac remodeling associated with the progressive volumetric overload in MMVD.

Tpl2 contributes to IL-1β-induced IL-8 expression via ERK1/2 activation in canine dermal fibroblasts

In autoimmune diseases, fibroblasts produce and secrete various cytokines and act as sentinel immune cells during inflammatory states. However, the contribution of sentinel immune cells (i.e. dermal fibroblasts) in autoimmune diseases of the skin, such as atopic dermatitis, has been obscure. The pro-inflammatory cytokine interleukin 1β (IL-1β) induces the expression of chemokines, such as interleukin 8 (IL-8), in autoimmune diseases of the skin. IL-8 induces the activation and recruitment of innate immune cells such as neutrophils to the site of inflammation. IL-1β-mediated induction of IL-8 expression is important for the pathogenesis of autoimmune diseases; however, the intracellular singling remains to be understood. To elucidate the mechanism of the onset of autoimmune diseases, we established a model for IL-1β-induced dermatitis and investigated MAPK signaling pathways in IL-1β-induced IL-8 expression. We also identified that a MAP3K Tpl2 acts as an upstream modulator of IL-1β-induced ERK1/2 activation in dermal fibroblasts. We observed an increase in the expression of IL-8 mRNA and protein in cells treated with IL-1β. ERK1/2 inhibitors significantly reduced IL-1β-induced IL-8 expression, whereas the inhibitor for p38 MAPK or JNK had no effect. IL-1β induced ERK1/2 phosphorylation, which was attenuated in the presence of an ERK1/2 inhibitor. IL-1β failed to induce IL-8 expression in cells transfected with siRNA for ERK1, or ERK2. Notably, a Tpl2 inhibitor reduced IL-1β-induced IL-8 expression and ERK1/2 phosphorylation. We confirmed that the silencing of Tpl2 in siRNA-transfected fibroblasts prevented both in IL-1β-induced IL-8 expression and ERK1/2 phosphorylation. Taken together, our data indicate the importance of Tpl2 in the modulation of ERK1/2 signaling involved in the IL-1β-induced development of autoimmune diseases affecting the dermal tissue, such as atopic dermatitis.

Cardiovascular-renal axis disorder and acute-phase proteins in cats with congestive heart failure caused by primary cardiomyopathy

BACKGROUND

Currently, the pathogenesis of congestive heart failure (CHF) in cats is not fully understood.

OBJECTIVE

To identify novel biomarkers for CHF in cats caused by primary cardiomyopathy, particularly related to cardiovascular-renal axis disorder and systemic inflammatory response.

ANIMALS

Twenty-five cats in CHF caused by primary cardiomyopathy, 12 cats with preclinical cardiomyopathy, and 20 healthy controls.

METHODS

Case control and observational case series. The following serum biomarkers were compared among the 3 cat groups: a cardiorenal profile that included N-terminal pro-brain natriuretic peptide (NT-proBNP), symmetric dimethylarginine (SDMA), and creatinine and an inflammatory profile that included 7 acute-phase proteins (APPs). Survival analyses and longitudinal studies were performed in CHF cats.

RESULTS

All cardiorenal biomarkers were positively correlated and higher in CHF cats, and high NT-proBNP and SDMA were associated with poor clinical outcome. Cats with CHF had significantly higher leucine-rich alpha-2-glycoprotein 1, serum amyloid A, and ceruloplasmin, and these APPs were positively correlated with NT-proBNP and left atrial size. In a multivariable survival analysis, alpha-1-acid glycoprotein concentration (P = .01), body weight (P = .02) and left atrial-to-aortic root ratio (P = .01) were independent prognostic factors for CHF in these cats.

CONCLUSIONS AND CLINICAL IMPORTANCE

In cats, CHF is an inflammatory disorder and outcome in CHF may be determined by the extent of inflammation and possibly the amount of residual renal function. These novel biomarkers have potential use for the clinical management, prognosis, and future research into CHF and cardiomyopathy in cats.

Safety and efficacy of a mesenchymal stem cell intramammary therapy in dairy cows with experimentally induced Staphylococcus aureus clinical mastitis

Although, antibiotics are effective in the treatment of bovine mastitis, they do not address the regeneration of mammary glandular tissue and have been associated to the increment in antimicrobial resistance worldwide. Considering the necessity of alternative therapies for this disease of high economic impact and the reported regenerative and antibacterial effects of mesenchymal stem cell (MSCs), we evaluated the safety and efficacy of an allogenic MSC-based intramammary therapy in dairy cows with experimentally induced Staphylococcus aureus clinical mastitis. In a safety trial, heifers were inoculated intramammarily with a 2.5 × 10⁷-suspension of bovine fetal AT-MSCs on experimental days 1 and 10. Animals were evaluated clinically on a daily basis during a 20-day experimental period and blood samples were collected for hemogram determination and peripheral blood leukocytes (PBLs) isolation. In an efficacy trial, Holstein Friesian cows were inoculated with S. aureus and treated intramammarily with vehicle (NEG; days 4 and 10), antibiotics (ATB; days 4 and 5) or a suspension of 2.5 × 10⁷ AT-MSCs (MSC; days 4 and 5). Cows were clinically evaluated daily and milk samples were collected for somatic cell count (SCC) and colony forming units (CFU). Blood samples were collected for serum haptoglobin and amyloid A determination. Intramammary administration of two doses of bovine fetal AT-MSCs in healthy cows did not induce changes in clinical or hematological variables, and gene expression profiles in PBLs associated to activation (CD4, CD8, CD25, CD62L and CD69) and proinflammatory cytokines (CCL2, CCL5, IL2, CXCL3, IFNγ, and TNFα). Quarters of MSC group of cows had similar SCC log/mL in milk compared to infected quarters of ATB or NEG cows. However, quarters of MSC cows had lower CFU log/mL in milk compared to quarters of NEG cows. Intramammarily inoculation of repeated doses of 2.5 × 10⁷ allogenic AT-MSCs did not induce clinical or immunological response in healthy cows. Moreover, MSC-intramammary treatment reduced bacterial count in milk of cows with S. aureus clinical mastitis compared to untreated cows. This work provides initial evidence for the safety and efficacy of an allogenic MSC-based intramammary therapy for the treatment of bovine mastitis.

Dietary intervention reduces left atrial enlargement in dogs with early preclinical myxomatous mitral valve disease: a blinded randomized controlled study in 36 dogs

Background

Myxomatous mitral valve disease (MMVD), the most common naturally-occurring heart disease in dogs, is associated with alterations in energy metabolism, oxidative stress and inflammation. Energy deprivation plays a causal role in the development of heart failure. This study was designed to determine if a cardiac protection blend (CPB) of nutrients containing medium-chain triglycerides as an alternative energy source, fish oil to reduce inflammation, antioxidants, and other key nutrients important to cardiac health and function could slow or prevent MMVD progression. Nineteen dogs with early stage MMVD and 17 breed-, age-, and sex-matched healthy dogs were enrolled for a 6-month blinded, placebo-controlled study. Dogs in each cardiac health group were randomly assigned to either control diet (CON) or CPB-supplemented diet. Echocardiography was performed at baseline, 3 months and 6 months.

Results

No changes were found in healthy dogs. While MMVD-CON dogs had an average 10% increase over baseline in left atrial diameter (LAD) and left atrial to aortic root ratio (LA/Ao) at 6 months, MMVD-CPB dogs showed 3% decreases, resulting significant diet by time interactions (P = 0.037, P = 0.005, respectively). More MMVD-CON dogs progressed from stage B1 to B2 during the study. A positive correlation was found between 6-month changes in LAD and blood pressures in MMVD-CPB dogs (systolic: P = 0.050, diastolic: P = 0.035) but not MMVD-CON dogs.

Conclusions

Our results demonstrated efficacy of CPB-based dietary intervention in reducing LA size and mitral regurgitation, and in slowing or preventing the progression of early MMVD in dogs.

Evaluation of canine 2D cell cultures as models of myxomatous mitral valve degeneration

The utility of cells cultured from the mitral valve as models of myxomatous diseases needs to be properly validated. In this study valve interstitial cells (VICs) and valve endothelial cells (VECs) were cultured from normal and diseased canine mitral valves in 2% (v/v) or 10% FBS media, in the presence of TGFβ1, 2 and 3, the TGFβ RI kinase inhibitor SB431542 and TGFβ neutralising antibodies, 5HT and the 5HT2RB antagonist LY272015. Cultures were examined by morphology, transcriptomic profiling, protein expression of the cell specific markers αSMA and SM22α (VICs), and CD31 (VECs), deposition of proteoglycans (PG), the PG versican, and the TGFβs themselves. VECs derived from normal valves were CD31+/αSMA-, but those from diseased valves were αSMA+, indicating endothelial-to-mesenchymal (EndoMT) transition had occurred. The TGFβs induced EndoMT in normal VECs, and this was abolished by SB431542, with significant changes in αSMA, CD31 and HAS2 expression (P<0.05). Normal VICs cultured in 10% FBS media were αSMA+ (activated myofibroblast (disease) phenotype), but were αSMA- when grown in 2% FBS. VICs from diseased dogs were αSMA+ in 2% FBS (retention of the activated myofibroblast disease phenotype), with significantly increased TGFβ1 expression (P<0.05) compared to normal cells. Treatment of normal and diseased VICs with the TGFβs significantly increased expression of αSMA, SM22α, versican, the TGFβs themselves, and deposition of PGs (P<0.05), with TGFβ1 being the most potent activator. These effects were either abolished or markedly reduced by SB431542 and a pan-TGFβ neutralizing antibody (P<0.05). SB431542 also markedly reduced αSMA expression in VICs from diseased valves, but 5HT and LY272015 had no effect on VIC phenotype. Transcriptomic profiling identified clear differences in gene expression for the different conditions and treatments that partially matched that seen in native diseased valve tissue, including changes in expression of ACTA2 (αSMA), 5HTR2B, TAGLN (SM22α) and MYH10 (SMemb), gene ontology terms and canonical signalling pathways. Normal and diseased VICs and normal VECs from canine mitral valves can be successfully grown in culture with retention of phenotype, which can be manipulated using TGFβ1 and the TGFβ RI kinase inhibitor SB431542. This optimized cell system can now be used to model MMVD to elucidate disease mechanisms and identify key regulators of disease progression.

Transplantation of Endothelial Progenitor Cells Overexpressing miR-126-3p Improves Heart Function in Ischemic Cardiomyopathy

BACKGROUND

In a previous study, a low level of miR-126-3p in endothelial progenitor cells (EPCs) was linked to the outcome of ischemic cardiomyopathy (ICM) patients. However, it remains unclear whether transplantation with miR-126-3p-overexpressing EPCs (MO-EPCs) can improve the cardiac function of ICM animal models. Methods and Results: miR-126-3p overexpression by lentiviral vector significantly increased migration and tube-like structures of EPCs from ICM patients. MO-EPCs or non-modified EPCs (NM-EPCs) were transplanted into nude rats with ICM induced by coronary artery ligation. MO-EPC transplantation increased capillary density and EPC survival rate in myocardial tissues of nude rats. Cytokines were also assessed by antibody array and real-time RT-PCR. G-CSF, VEGF-A, IL-3, IL-10, IGF-1, angiogenin, HGF, TIMP-1 and TIMP-2 were upregulated, and IL-8, MCP-1, MCP-2, TNF-α, TNF-β and MIP-1β were downregulated after miR-126-3p overexpression in EPCs. The same results were obtained in infarction tissues of nude rats after MO-EPC transplantation. Eight weeks after MO-EPC transplantation, left ventricular function improved significantly with clearly decreased infarction size, increased anterior wall thickness, and inhibition of inflammation compared with the results for NM-EPC transplantation. However, MO-EPC transplantation showed no increase in survival time of nude rats with ICM during 8 weeks of observation.

CONCLUSIONS

miR-126-3p can restore the biology of EPCs from ICM patients. Moreover, MO-EPC transplantation improves cardiac function effectively, representing a promising future treatment for ICM.