Characterization of Atherosclerosis by Histochemical and Immunohistochemical Methods in African Grey Parrots (Psittacus erithacus) and Amazon Parrots (Amazona spp.)

Abstract

The aim of the study was to characterize atherosclerotic changes in African grey parrots (Psittacus erithacus) and Amazon parrots (Amazona spp.) by histochemical and immunohistochemical methods. Samples of the aorta ascendens and trunci brachiocephalici from 62 African grey parrots and 35 Amazon parrots were stained by hematoxylin and eosin and Elastica van Gieson for grading of atherosclerosis in these birds. Four different stages were differentiated. The incidence of atherosclerosis in the examined parrots was 91.9% in African grey parrots and 91.4% in Amazon parrots. To evaluate the pathogenesis in birds, immunohistochemical methods were performed to demonstrate lymphocytes, macrophages, smooth muscle cells, and chondroitin sulfate. According to the missing lymphocytes and macrophages and the absence of invasion and proliferation of smooth muscle cells in each atherosclerotic stage, "response-to-injury hypothesis" seems inapplicable in parrots. Additionally, we found alterations of vitally important organs (heart, lungs) significantly correlated with atherosclerosis of the aorta ascendens.

Characterization and classification of psittacine atherosclerotic lesions by histopathology, digital image analysis, transmission and scanning electron microscopy

“…In birds, particularly the pigeon, similar pathological and ultrastructural studies have been performed and lead to similar findings (Lauper et al, 1975;Hansen, 1977;Stout & Thorpe, 1980;Barr et al, 1991;Casale et al, 1992). Recent studies have evaluated the characteristics of psittacine atherosclerosis using histopathology and IHC (Bavelaar & Beynen, 2003;Krautwald-Junghanns et al, 2004;Schenker & Hoop, 2007;Fricke et al, 2009). However, there are some limitations to light microscopy alone in describing atherosclerotic lesions such as difficulties in characterizing cell types, describing the fine structure of the atherosclerotic plaques, and quantifying the lesion composition.…”

“…The prevalence of atherosclerosis in psittacines, reported from post-mortem surveys, ranges from 2.6 to 91.8% depending on the geographical areas, the time span of the study, the species, and the inclusion criteria (Garner & Raymond 2003;Bavelaar & Beynen, 2004;KrautwaldJunghanns et al, 2004;Fricke et al, 2009). Prevalences by age groups are unknown but the prevalence and severity of the lesions appear increased in older psittacine birds (Bavelaar & Beynen, 2004;Fricke et al, 2009). All psittacine species appear susceptible but the disease is most frequently reported in Amazon parrots (-Amazona spp.…”

“…), cockatoos (Cacatua spp.) and cockatiels (Nymphicus hollandicus) (Johnson et al, 1992;Garner & Raymond, 2003;Bavelaar & Beynen, 2004;Fricke et al, 2009;Krautwald-Junghanns et al, 2004;Pilny, 2004;Schenker & Hoop, 2007;StLeger, 2007). Avian models, such as pigeons, Japanese quails, turkeys, and chickens, are an integral and important part of the research conducted on atherosclerosis, and these models significantly contributed to the understanding of many aspects of the disease (St Clair, 1998;Moghadasian, 2002).…”

“…Moreover, pigeons are considered one of the best models for studying human atherosclerosis (St Clair, 1998;Moghadasian, 2002;Moghadasian et al, 2001). Despite the high incidence of atherosclerosis in parrots and the high number of clinical case reports (Johnson et al, 1992;Phalen et al, 1996;Vink-Nooteboom et al, 1998;Pees et al, 2001Pees et al, , 2006Pilny, 2004;Mans & Brown, 2007;SimoneFreilicher, 2007;Sedacca et al, 2009;Beaufrere et al, 2011), there are few pathologic investigations on the lesions in this group of birds (Bavelaar & Beynen, 2003;Schenker & Hoop, 2007;Fricke et al, 2009). Detailed pathological description and categorization of atherosclerotic lesions, as can be found in the human literature and in reports from the Council on Arteriosclerosis of the American Heart Association (AHA) (Nakamura & Ohtsubo, 1992;Stary et al, 199219941995;Stary, 2000Stary, , 2003Stary, , 2005Virmani et al, 2000), are a prerequisite to understanding the pathogenesis of psittacine atherosclerosis and its clinical impact, designing further experiments, and comparing the disease with other avian and mammalian species.…”

Vascular Smooth Muscle Cells and the Comparative Pathology of Atherosclerosis

“…Furthermore, immunization with turkey herpesvirus vaccine or SB -1 vaccine prevented atherosclerotic lesions. Hajjar et al [103] demonstrated histologically that infection of normocholesterolemic, specific-pathogen-free chickens with Marek's disease herpesvirus (MDV) lead to chronic atherosclerosis like that in humans (Figures 2 and 3). …”