Echocardiographic Evaluation of Coronary Abnormalities and Cardiac Function in a Murine Model of Kawasaki Disease Using High-frequency Ultrasound

Positive Echocardiographic Association between Carotid Artery and Coronary Artery Diameter and Z-Score in a Mouse Model of Kawasaki Disease

Kawasaki disease (KD) occurs in young children, has an unknown etiology, and can cause such life-threatening complications as coronary artery aneurysm. A mouse model using Lactobacillus casei cell wall extract (LCWE) with intraperitoneal injection was established for KD years ago. Histological examination of coronary artery lesions indicated features similar to those of vascular lesions of patients with KD. Since animals must be sacrificed during histological examination, the longitudinal survey of coronary artery lesions (CALs) is difficult. The aim of this study was to survey the vasculitis status of the coronary artery and the carotid artery in a KD mouse model.

METHOD

LCWE was intraperitoneally injected into 5-week-old male C57BL/6 mice to induce CALs. We studied the longitudinal status of the carotid and coronary arteries and analyzed the Z-score of coronary artery diameter.

RESULTS

Carotid artery wall thickness (day 7) and diameter (day 14) significantly increased in the LCWE group with a dose-dependent effect (p < 0.05). Aortic diameter and wall thickness demonstrated significant increases on day 28 and day 7, respectively (p < 0.05). Carotid artery outer diameter and wall thickness were positively associated with coronary artery diameter on day 28 (p < 0.01). Coronary artery diameter significantly increased in the LCWE group after day 7 (p < 0.05). The percentage of Z > 3.0 indicated was more than 80% in the high-dose LCWE group and 0% in the control group.

CONCLUSIONS

This report is the first to use coronary artery Z-score in a mouse model of KD by echocardiography and to find a positive association between carotid artery and coronary artery diameter.

Subcutaneous Alfaxalone-XylazineBuprenorphine for Surgical Anesthesia and Echocardiographic Evaluation of Mice (Mus musculus)

Alfaxalone is a commonly used injectable anesthetic in dogs and cats due to its minimal cardiovascular side effects. Data for its use in mice are limited and demonstrate strain- and sex-associated differences in dose-response relationships. We performed a dose-comparison study of alfaxalone-xylazine-buprenorphine (AXB) in Crl: CFW (SW) mice. Subcutaneous injection of 50 mg/kg alfaxalone-10 mg/kg xylazine-0.1 mg/kg buprenorphine HCl consistently achieved a surgical plane of anesthesia (loss of toe pinch) for 48.6 ± 4.7 and 60.8 ± 9.6 min in females and males, respectively. The same dose and route of AXB induced a surgical plane of anesthesia in C57Bl/6NCrl (females: 42.3 ± 11.2 min; males: 51.6 ± 12.3 min), NCr-Foxn1nu (females: 76.8 ± 32.5 min; males: 80.0 ± 1.2 min), and NOD. Cg-Prkdc SCID Il2rg tm1Wjl /SzJCr (females: 56.0 ± 37.2 min and males: 61.2 ± 10.2 min) mice. We found no significant difference in the duration of the surgical plane of anesthesia between males and females within the mouse strains Crl: CFW (SW), C57Bl/6NCrl, NCr-Foxn1nu, and NOD. Cg-PrkdcSCID Il2rgtm1Wjl /SzJCr. We next performed an echocardiography study (n = 5 per group) of Crl: CFW (SW) mice ( n = 5 per group) to compare subcutaneous AXB anesthesia with that produced by intraperitoneal injection of 100 mg/kg ketamine and 10 mg/kg xylazine (KX). AXB induced significantly less bradycardia (295.4 ± 29 bpm) than KX (185.8 ± 38.9 bpm) did, with no significant differences in cardiac output, ejection fraction, end-diastolic volume, end-systolic volume, or fractional shortening. These results suggest that subcutaneous administration of AXB is a viable alternative to KX for inducing a surgical plane of anesthesia in Crl: CFW (SW), C57Bl/6NCrl, NCr-Foxn1nu, and NOD. Cg-PrkdcSCID Il2rgtm1Wjl /SzJCr mice, regardless of sex. AXB may also be a better injectable anesthetic option as compared with KX for avoiding adverse cardiac effects in mice.

Peptidyl arginine deiminase inhibition alleviates angiotensin II-induced fibrosis

OBJECTIVES

The conversion of protein arginine residues to citrulline by calcium-dependent peptidyl arginine deiminases (PADs) has been implicated in the pathogenesis of several diseases, indicating that PADs are therapeutic targets. A recent study indicated that PAD4 regulates age-related organ fibrosis and dysfunction; however, the specific role of this PAD and its citrullination substrate remains unclear. We investigated whether pharmacological inhibition of PAD activity could affect the progression of fibrosis and restore heart function.

METHODS

Cardiac hypertrophy was induced by chronic infusion of angiotensin (Ang) II. After 2 weeks of AngII infusion, a PAD inhibitor (Cl-amidine hydrochloride) or vehicle (saline) was injected every other day for the next 14 days together with the continued administration of AngII for a total of up to 28 days. Cardiac fibrosis and remodeling were evaluated by quantitative heart tissue histology, echocardiography, and mass spectrometry.

RESULTS

A reverse AngII-induced effect was observed in PAD inhibitor-treated mice (n=6) compared with AngII vehicle-treated mice, as indicated by a significant reduction in the heart/body ratio (AngII: 6.51±0.8 mg/g vs. Cl-amidine: 5.27±0.6 mg/g), a reduction in fibrosis (AngII: 2.1-fold increased vs. Cl-amidine: 1.8-fold increased), and a reduction in left ventricular posterior wall diastole (LWVPd) (AngII: 1.1±0.04 vs. Cl-amidine: 0.78±0.02 mm). Label-free quantitative proteomics analysis of heart tissue indicated that proteins involved in fibrosis (e.g., periostin), cytoskeleton organization (e.g., transgelin), and remodeling (e.g., myosin light chain, carbonic anhydrase) were normalized by Cl-amidine treatment.

CONCLUSION

Our findings demonstrate that pharmacological inhibition of PAD may be an effective strategy to attenuate cardiac fibrosis.