How to improve the overall quality of cardiac morphometric data

Abstract

Gerdes AM. How to improve the overall quality of cardiac morphometric data.

Morphological arrangement of the coronary vasculature in a shark (Squalus sucklei) and a teleost (Oncorhynchus mykiss)

“…This is the first quantitative evaluation of coronary microvascular morphology for any elasmobranch heart and only the second study for a fish species. Moreover, the data generated here for rainbow trout can be compared directly with earlier data for the same species (Egginton and Cordiner, 1997), a study that used methods that work well with a regular capillary architecture, such as that found in the avian and mammalian compact myocardium, as well as skeletal muscle (e.g., Egginton and Cordiner, 1997;Scott et al, 2011;Gerdes, 2015). We are confident of the methodological approach used for this work because our measurements of vascular density in the compact myocardium of rainbow trout are comparable with previous measurements of the capillary density in rainbow trout (Egginton and Cordiner, 1997; Table 2).…”

“…Where applicable, the methods used here followed the suggestions made recently by Gerdes (2015) for improving mammalian cardiac morphometric data. For example, the selection of tissue regions with minimal tissue separation and containing primarily circular vessel cross-sections free of red blood cells indicate adequate perfusion of fixative, which increases result consistency and reduces error (Gerdes, 2015). Differences in the contraction state of the heart, however, can contribute to variation in vascular density observed between individuals of the same species (Gerdes, 2015).…”

“…For example, the selection of tissue regions with minimal tissue separation and containing primarily circular vessel cross-sections free of red blood cells indicate adequate perfusion of fixative, which increases result consistency and reduces error (Gerdes, 2015). Differences in the contraction state of the heart, however, can contribute to variation in vascular density observed between individuals of the same species (Gerdes, 2015). If individuals varied in contraction state at the time of fixation, vascular density could be slightly overestimated or underestimated, with more contracted hearts having lower vascular densities due to the capillaries being further apart.…”

“…Following perfusion fixation and tissue sectioning, dehydration in ethanol can produce up to 30% tissue shrinkage. This is unavoidable for tissue staining procedures (Preece, 1972;Gerdes, 2015), but a constant for histological practices. Therefore, our comparisons between the two fish species and between the different tissue types remain valid as all tissues were treated in the same manner.…”

Thyroid Hormone and Cardioprotection

“…To my knowledge, none of the studies making this claim used reliable cell sizing techniques. Instead, data were collected from H&E tissue sections with no corrections for known sources of error (65). Data collected with more reliable isolated myocyte techniques are uniformly consistent in showing cell lengthening with no change in cross-sectional area in the noninfarct zone (28,29,143,283).…”