Histopathological changes of pulmonary vascular remodeling in dogs affected with pulmonary hypertension secondary to degenerative mitral valve disease

Phosphoproteomics analysis of serum from dogs affected with pulmonary hypertension secondary to degenerative mitral valve disease

Pulmonary hypertension (PH), a common complication in dogs affected by degenerative mitral valve disease (DMVD), is a progressive disorder characterized by increased pulmonary arterial pressure (PAP) and pulmonary vascular remodeling. Phosphorylation of proteins, impacting vascular function and cell proliferation, might play a role in the development and progression of PH. Unlike gene or protein studies, phosphoproteomic focuses on active proteins that function as end-target proteins within signaling cascades. Studying phosphorylated proteins can reveal active contributors to PH development. Early diagnosis of PH is crucial for effective management and improved clinical outcomes. This study aimed to identify potential serum biomarkers for diagnosing PH in dogs affected with DMVD using a phosphoproteomic approach. Serum samples were collected from healthy control dogs (n = 28), dogs with DMVD (n = 24), and dogs with DMVD and PH (n = 29). Phosphoproteins were enriched from the serum samples and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data analysis was performed to identify uniquely expressed phosphoproteins in each group and differentially expressed phosphoproteins among groups. Phosphoproteomic analysis revealed nine uniquely expressed phosphoproteins in the serum of dogs in the DMVD+PH group and 15 differentially upregulated phosphoproteins in the DMVD+PH group compared to the DMVD group. The phosphoproteins previously implicated in PH and associated with pulmonary arterial remodeling, including small nuclear ribonucleoprotein G (SNRPG), alpha-2-macroglobulin (A2M), zinc finger and BTB domain containing 42 (ZBTB42), hemopexin (HPX), serotransferrin (TRF) and complement C3 (C3), were focused on. Their unique expression and differential upregulation in the serum of DMVD dogs with PH suggest their potential as biomarkers for PH diagnosis. In conclusion, this phosphoproteomic study identified uniquely expressed and differentially upregulated phosphoproteins in the serum of DMVD dogs with PH. Further studies are warranted to validate the diagnostic utility of these phosphoproteins.

Proteomic analysis of the serum in dogs with pulmonary hypertension secondary to myxomatous mitral valve disease: the preliminary study

Background

Pulmonary hypertension (PH) is a common complication in dogs with myxomatous mitral valve disease (MMVD), characterized by elevated blood pressure in pulmonary artery. Echocardiography is a reliable technique for PH diagnosis in veterinary medicine. However, it is limited to use as an early detection method. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has found extensive application in the discovery of serum protein biomarkers for various diseases. The objective of this study was to identify serum proteins in healthy control dogs and MMVD dogs both with and without PH using LC-MS/MS.

Materials and methods

In this research, a total of 81 small-breed dogs participated, and they were categorized into three groups: the control (n = 28), MMVD (n = 24) and MMVD+PH (n = 29) groups. Serum samples were collected and analyzed by LC-MS/MS.

Results

Differentially expressed proteins were identified, and the upregulated and downregulated proteins in MMVD+PH group including Myomesin 1 (MYOM1) and Histone deacetylase 7 (HDAC7), Pleckstrin homology domain containing M3 (PLEKHM3), Diacylglycerol lipase alpha (DAGLA) and Tubulin tyrosine ligase like 6 (TTLL6) were selected as proteins of interest in MMVD dogs with PH.

Conclusion

Different types of proteins have been identified in healthy dogs and MMVD dogs with and without PH. Additional studies are needed to investigate the potential of these proteins as biomarkers for PH in dogs with MMVD.

Proteomic analysis of pulmonary arteries and lung tissues from dogs affected with pulmonary hypertension secondary to degenerative mitral valve disease

In dogs with degenerative mitral valve disease (DMVD), pulmonary hypertension (PH) is a common complication characterized by abnormally elevated pulmonary arterial pressure (PAP). Pulmonary arterial remodeling is the histopathological changes of pulmonary artery that has been recognized in PH. The underlying mechanisms that cause this arterial remodeling are poorly understood. This study aimed to perform shotgun proteomics to investigate changes in protein expression in pulmonary arteries and lung tissues of DMVD dogs with PH compared to normal control dogs and DMVD dogs without PH. Tissue samples were collected from the carcasses of 22 small-sized breed dogs and divided into three groups: control (n = 7), DMVD (n = 7) and DMVD+PH groups (n = 8). Differentially expressed proteins were identified, and top three upregulated and downregulated proteins in the pulmonary arteries of DMVD dogs with PH including SIK family kinase 3 (SIK3), Collagen type I alpha 1 chain (COL1A1), Transforming growth factor alpha (TGF-α), Apoptosis associated tyrosine kinase (AATYK), Hepatocyte growth factor activator (HGFA) and Tyrosine-protein phosphatase non-receptor type 13 (PTPN13) were chosen. Results showed that some of the identified proteins may play a role in the pathogenesis of pulmonary arterial remodeling. This study concluded shotgun proteomics has potential as a tool for exploring candidate proteins associated with the pathogenesis of PH secondary to DMVD in dogs.

Perivascular inflammatory cells and their association with pulmonary arterial remodelling in dogs with pulmonary hypertension due to myxomatous mitral valve disease

Pulmonary hypertension (PH), an increase in pulmonary arterial pressure (PAP), may occur in dogs affected with myxomatous mitral valve disease (MMVD). Recent studies suggest that an accumulation of perivascular inflammatory cells may be involved with medial thickening which is a sign of the pulmonary artery remodelling in PH. The aim of this study was to characterise perivascular inflammatory cells in the surrounding pulmonary arteries of dogs with PH due to MMVD compared to MMVD dogs and healthy control dogs. Nineteen lung samples were collected from cadavers of small-breed dogs (control n = 5; MMVD n = 7; MMVD + PH n = 7). Toluidine blue stain and multiple IHC targeting α-SMA, vWF, CD20, CD68 and CD3 was performed to examine intimal and medial thickening, assess muscularisation of the small pulmonary arteries and characterise perivascular leucocytes. Medial thickening without intimal thickening of pulmonary arteries and muscularisation of normally non-muscularised small pulmonary arteries was observed in the MMVD and MMVD + PH groups compared with the control group. The perivascular numbers of B lymphocytes, T lymphocytes and macrophages was significantly increased in the MMVD + PH group compared with the MMVD and control groups. In contrast, the perivascular number of mast cells was significantly higher in the MMVD group compared with the MMVD + PH and control groups. This study suggested that pulmonary artery remodelling as medial thickening and muscularisation of the normally non-muscular small pulmonary arteries is accompanied by the accumulation of perivascular inflammatory cells.