Ekkokardiografiske Strategier og Protokoller for omfattende fænotypisk karakterisering af Valvular hjertesygdom i mus
Summary
This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.
Abstract
The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.
Introduction
Aldring er forbundet med progressive stigninger i hjerte-kar-forkalkning 1. Hæmodynamisk signifikant aortaklappen stenose påvirker 3% af befolkningen over 65 år 2, og patienter med selv moderat aortaklappen stenose (peak hastighed på 3-4 m / s) har en 5 års hændelse overlevelse på mindre end 40% 3. I øjeblikket er der ingen effektive behandlinger til at bremse udviklingen af aortaklappen forkalkning, og kirurgisk aortaklappen udskiftning er den eneste behandling for avanceret aortaklappen stenose 4.
Undersøgelser med henblik på at opnå en dybere forståelse af de mekanismer, der bidrager til initiering og progression af aortaklappen forkalkning er et centralt første skridt i hen imod farmakologiske og ikke-kirurgiske metoder til at styre aortaklappen stenose 5, 6. genetiskely-ændrede mus har spillet en stor rolle i udviklingen af vores forståelse af de mekanismer, der bidrager til en lang række sygdomme og er nu kommer frem i forgrunden af mekanistiske undersøgelser med henblik på at forstå biologi aortaklappen stenose 6, 7, 8. I modsætning til andre cardiovaskulære sygdomme, såsom atherosklerose og hjerteinsufficiens-hvor standardprotokoller til evaluering vaskulære og ventrikelfunktion er for det meste veletablerede-der er unikke udfordringer forbundet med in vivo-fænotypebestemmelse af hjerteklap funktion i mus. Mens seneste anmeldelser har givet grundige drøftelser vedrørende de fordele og ulemper talrige billedbehandling og invasive modaliteter anvendes til at vurdere ventil funktion i gnavere 9, 10, 11, til dato, er vi ikke bekendt med en offentliggørelse, der giver en omfattende, trin-for-trin-protokollen for fænotypning hjerteklap funktion i mus.
Formålet med dette håndskrift er at beskrive de metoder og protokoller til fænotype hjerteklap funktion i mus. Alle metoder og procedurer er blevet godkendt af Mayo Clinic Institutional Animal Care og brug Udvalg. Vigtige komponenter i denne protokol omfatter anæstesidybden, evalueringen af hjertefunktionen, og evalueringen af hjerteklap funktion. Vi håber, at denne rapport vil ikke kun tjene til at vejlede efterforskerne interesseret i at forfølge forskning inden for hjerteklapsygdom, men vil også starte en national og international dialog relateret til protokol standardisering for at sikre data reproducerbarhed og validitet i dette hastigt voksende område. Vigtigere, vellykket billeddannelse ved hjælp af høj opløsning ultralyd systemer kræver et praktisk kendskab til de principper om sonografi (og terminologi almindeligvis anvendes i sonografi), en forståelse af den grundlæggende Principles af hjerte fysiologi, og betydelig erfaring med sonografi at give mulighed for præcis og tidsbesparende vurdering af hjertefunktionen hos gnavere.
Protocol
Representative Results
Discussion
Induktion af anæstesi
Korrekt induktion og vedligeholdelse af anæstesi er kritisk for nøjagtig vurdering af ændringer hjerteklap og hjertefunktion hos mus. I betragtning af den hurtige induktion af anæstesi fremkaldes af isofluran og den forholdsvis lange wash-out tid af denne bedøvelse efter dyb anæstesi, bruger vi ikke en stand-alone anæstesi kammer til induktion. Stedet, som nævnt detaljeret ovenfor, er dyrene ledes direkte til anæstesi kegle, som tillader hurtig o…
Divulgations
The authors have nothing to disclose.
Acknowledgements
This work was supported by NIH grants HL111121 (JDM) and TR000954 (JDM).
Materials
| High resolution ultrasound machine | VisualSonics, Fujifilm | Vevo 2100 | |
| Isoflurane diffuser (capable of delivering 1 % to 1.5 % isoflurane mixed with 1 L/min 100% O2 | VisualSonics, Fujifilm | N/A | |
| Transducers for small mice (550D) or larger mice (400) | MicroScan, VisualSonics, Fujifilm | MS 550D, MS 400 | |
| Animal platform | VisualSonics, Fujifilm | 11503 | |
| Advanced physiological monitoring unit | VisualSonics, Fujifilm | N/A | |
| Isoflurane | Terrell | NDC 66794-019-10 | |
| Nose cone and tubing connected to isoflurane diffuser and 100% O2 | Custom Engineered in-house | — | |
| Hair razor | Andis Super AGR+ vet pack clipper | AD65340 | |
| Ultrasound gel | Parker Laboratories | REF 01-08 | |
| Electrode gel | Parker Laboratories | REF 15-25 | |
| Adhesive tapes | Fisher Laboratories | 1590120B | |
| Paper towels |
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