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

Prevalence, Anatomical Distribution, and Risk Factors of Adipocytic Tumors and Xanthomas in Psittaciformes: 1096 Cases (1998-2018)

Adipocytic tumors are mesenchymal tumors that are commonly reported in psittacine birds; however, large-scale studies evaluating their prevalence and associated risk factors are lacking. A retrospective study of adipocytic tumors in psittacine birds was performed by reviewing pathology submissions from the University of California, Davis-Drury Reavill Pathology Database, containing 26 013 submissions from psittacine birds (1998-2018). Age, sex, genus, anatomic distribution, and pathological diagnosis were collected for each case when available. The prevalence, risk factors, and association with other lipid-accumulation disorders were reported. A total of 450 cases of lipoma, 129 cases of myelolipoma, 35 cases of hemangiolipoma, 31 cases of liposarcoma, and 451 cases of xanthoma were identified. The prevalence of adipocytic tumors and xanthomas on necropsy was 1.3% (158/11 737, 95% confidence interval [CI]: 1.1-1.6). Adipocytic tumors were identified in 27 genera. Amazona (odds ratio [OR] = 1.93, 95% CI: 1.24-2.99, p = 0.004), Myiopsitta (OR = 2.3, 95% CI: 1.0-5.2, p = 0.041), Melopsittacus (OR = 3.4, 95% CI: 2.1-5.5, p < 0.001), and Agapornis (OR = 3.5, 95% CI: 2.0-6.1, p < 0.001) had significantly higher odds of developing adipocytic tumors compared with other genera, whereas Ara had significantly lower odds (OR = 0.5, 95% CI: 0.3-0.9, p = 0.030). Age was also a significant risk factor for many types of adipocytic tumors. There was no significant association between general adipocytic tumor formation and atherosclerosis or hepatic lipidosis. Xanthomas were associated with atherosclerosis (OR = 1.88, 95% CI: 1.01-3.51, p = 0.048), but not hepatic lipidosis (p = 0.503). On necropsy, the trunk and air sacs were the most common sites of xanthoma formation, whereas the trunk and liver were the most common sites of lipoma and myelolipoma formation, respectively.

Pathological findings and their association with diseases of captive psittacine birds native to Mexico

The captivity and use of native psittacine birds is prohibited in Mexico. However, as these birds are among the groups most affected by illegal trafficking, they are commonly found as companion animals. Nevertheless, it is difficult to obtain information on their health. Therefore, a retrospective study was conducted of the clinical histories and necropsy reports of native psittacines that had been submitted to the Bird Disease Diagnostic and Research Laboratory of the Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, from 2006 to 2017. The lesions were classified according to type and anatomical location and the diseases were classified as infectious or non-infectious. During this period, 252 psittacines were submitted, the most frequent of which were the red-lored parrot (Amazona autumnalis), orange-fronted parakeet (Eupsittula canicularis) and scarlet macaw (Ara macao). The lesions were primarily located in the digestive and respiratory systems. By integrating the clinical histories and post-mortem findings, we concluded that nutritional disorders were the most frequent non-infectious diseases, systemic bacterial infections were the most frequent infectious conditions, the primary parasite was Sarcocystis spp and the most frequent neoplasm was multicentric lymphoma.

Palliative Radiation Therapy for Treatment of Cutaneous T-cell Lymphoma in a Double Yellow-headed Amazon Parrot (Amazona oratrix)

A 17-year-old captive female double yellow-headed Amazon parrot (Amazona oratrix) was presented to the Kansas State University Zoological Medicine Service (Manhattan, KS, USA) for a 2-month history of a left sided facial swelling. On examination, a red, raised mass was noted on the left side of the face. A whole-body computed tomography scan of the bird was performed to assess the extent of the mass and evaluate the patient for obvious evidence of disseminated disease. No systemic involvement was detected, and the swelling was localized to the cutaneous and subcutaneous tissues overlying the left rhamphotheca. Two punch biopsies were collected, and histopathology was consistent with cutaneous lymphoma, with strong positive CD3 staining congruous with a T-cell origin. Because of a lack of evidence for disseminated disease, the authors elected to pursue localized radiation therapy, and a single fraction of 8 Gray was administered. The swelling had resolved by the time of the recheck examination 4 weeks post-radiation therapy, and the patient remained clinically normal 52 weeks after radiation therapy.

Tiliroside targets TBK1 to induce ferroptosis and sensitize hepatocellular carcinoma to sorafenib

BACKGROUND

Combination therapy with other antineoplastic agent is a favorable approach for targeting the molecules involved in sorafenib resistance.

PURPOSE

In the present study, we determined whether tiliroside, a natural flavonoid glycoside isolated from oriental paperbush flower, could improve the sensitivity of hepatocellular carcinoma (HCC) cells to sorafenib. Furthermore, we investigated the mechanisms and identified the potential drug targets of tiliroside.

METHODS

Synergy was performed using CalcuSyn. Transcriptomic studies were adopted to investigate whether tiliroside could induce ferroptosis and inhibit the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in HCC cells. Ferroptosis was analyzed using western blotting, flow cytometry, and transmission electron microscopy. Immunofluorescence, co-immunoprecipitation, and Nrf2 knockdown or overexpression were performed to confirm the involvement of Nrf2 in tiliroside-induced ferroptosis. Additionally, molecular docking and biolayer interferometry-based measurements were used to confirm the direct target of tiliroside. Finally, subcutaneous xenograft and orthotopic xenograft tumors in nude mice were used to assess the effects of tiliroside in vivo.

RESULTS

Tiliroside significantly enhanced the anti-HCC activity of sorafenib without any discernible side effects. Moreover, the combination of tiliroside and sorafenib induced synergistic effects against HCC in vitro. The inhibitory effects of tiliroside on HCC were antagonized by N-acetylcysteine and the ferroptosis inhibitor liproxstatin-1. Studies on the mechanism of action revealed that tiliroside could directly bind to TANK-binding kinase 1 (TBK1) and inhibit its enzymatic activity. Inhibition of TBK1 by tiliroside decreased the phosphorylation of serine 349 on sequestosome-1 (p62) and the affinity of p62 for kelch like ECH-associated protein 1 (Keap1) and promoted Keap1-mediated Nrf2 ubiquitination and degradation. The downstream target proteins of Nrf2, including glutathione peroxidase 4, ferritin heavy chain 1, and glucose-6-phosphate dehydrogenase, demonstrated similar results to that of Nrf2 protein, inducing ferroptosis in tiliroside-treated HCC cells. We extended these findings in vivo and found that tiliroside inhibited the growth of HepG2 tumors in both subcutaneous xenograft and orthotopic xenograft tumor models of HCC.

CONCLUSION

Our findings imply that tiliroside is a potent TBK1 inhibitor and a candidate natural anti-cancer product that could function as a sensitizer of sorafenib in HCC treatment by targeting TBK1 to induce ferroptosis.

RETROSPECTIVE REVIEW OF MORBIDITY AND MORTALITY IN A POPULATION OF CAPTIVE BUDGERIGARS (MELOPSITTACUS UNDULATES)

This retrospective study reviews the diseases associated with morbidity and mortality in 221 budgerigars (Melopsittacus undulates) from a captive population from 2013 to 2019. The study aimed to evaluate the health status of a flock of budgerigars typical of today's zoologic collections. Based on previous literature, it was hypothesized that age-related conditions such as neoplasia would be common, whereas metabolic and nutritional disorders would be less common. Neoplasia was widespread among the population, affecting 34% of birds (75/221). Carcinomas made up most neoplastic processes and most commonly affected the renal system (n = 22), followed by the proventriculus (n = 7). Pituitary, adrenal, and hepatocellular carcinomas were less commonly diagnosed. Sarcomas affected the population less often than carcinomas and were found within the coelom (undifferentiated four cases), within the spleen (three cases), within the kidney (two cases), and one subcutaneous soft tissue sarcoma. There were five cases of multicentric lymphoma found most commonly affecting the spleen and liver. Benign neoplasms affected the pituitary most commonly (nine cases), followed by the reproductive system, with seminomas (seven cases) being most common. Macrorhabdus ornithogaster (MO) was found in 56 cases. The majority (38 cases) were found in conjunction with a range of comorbidities, but several birds experienced MO infections alone, and it was thought to have been the cause of death in these birds (22 cases). In contrast to our hypothesis, disease associated with nutritional or metabolic disorders impacted a substantial portion of the population; hepatic lipidosis (26 cases) was the most common along with obesity (26 cases), followed by atherosclerosis, xanthomas, and gout (8, 7, and 4 cases, respectively). Traumatic lesions were noted in 41 cases and were most commonly characterized by head trauma and cerebral hemorrhage. Toxicity was rare; five total cases caused by a single carbon monoxide event were identified.

Cardiovascular Diseases in Pet Birds: Therapeutic Options and Challenges

Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in avian species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the avian cardiac patient.

A Spectral Computed Tomography Contrast Study: Demonstration of the Avian Cardiovascular Anatomy and Function

As part of the cardiovascular examination, all birds underwent clinical and echocardiographic examinations. Radiographs and blood samples were taken. Each bird was premedicated with midazolam and medetomidin and anesthetized with inhalation anesthesia using isoflurane. We performed computed tomographic angiography (CTA) after intravenous injection of 1 to 2 mL contrast agent per kg followed by a 1 mL saline solution flush. We were been able to identify the arteries that previous studies revealed to be most likely affected by atherosclerotic lesions: the aorta, both pulmonary arteries, and both brachiocephalic trunks. CTA was safe and is of potential diagnostic value in birds.

Histopathological Findings in the Cardiovascular System of Psittacidae in Routine Diagnostics

Samples of 363 Psittacidae were included in this study with a focus on cardiovascular diseases. These were identified in 28.9% of the animals, with pericarditis and/or epicarditis and myocarditis representing approximately half of all lesions and bacteria being the most common infectious cause. Cardiac lymphoma was only seen in 5 birds, whereas degenerative vascular lesions were diagnosed in 26.7% of the cases. Histopathology in the context of clinical findings and complementary examination results is the most useful tool for the evaluation of cardiac diseases.

Disseminated coelomic xanthogranulomatosis in eclectus parrots (Eclectus roratus) and budgerigars (Melopsittacus undulatus)

Xanthogranulomatosis is an inflammatory lesion characterized by lipid-containing macrophages, extracellular lipid, hemorrhage, and necrosis. We describe disseminated intracoelomic xanthogranulomatosis in 5 eclectus parrots (Eclectus roratus) and 2 budgerigars (Melopsittacus undulatus). Postmortem, clinicopathologic, and historical case material was reviewed. Ages ranged from 3 to 24 years; there were 5 males and 2 females. Table food was included in the diet of 3/5 cases, and animal products were included in 2/3 cases. Common clinicopathologic abnormalities included leukocytosis (4/5 cases) and elevated concentrations of bile acids (3/4 cases) and cholesterol within 6 months prior to death (2/4 cases). At postmortem examination, all 7 birds had grossly visible, irregular, soft, tan to yellow, amorphous plaques distributed on the surfaces of the viscera and body wall. Histologic evaluation and oil red O stain revealed xanthogranulomatous inflammation with phagocytized and extracellular lipid, necrosis, cholesterol clefts, fibrosis, and mineralization. Infectious agents were not identified with special stains in all cases. Concurrent hepatobiliary disease was present in 6/7 cases, and 6/7 had lipid accumulation within the parenchyma of various visceral organs. Five cases had atherosclerosis of great vessels. We describe a unique form of disseminated coelomic xanthogranulomatosis in 2 psittacine species. This condition should be recognized as a differential diagnosis in cases of disseminated coelomic mass formation and coelomic distension in psittacine birds, particularly in eclectus parrots and budgerigars.

Evaluation of Atherosclerotic Lesions and Risk Factors of Atherosclerosis in Raptors in Northern California

Atherosclerosis is a chronic inflammatory disease that has been reported to affect the cardiovascular system of many avian species. However, atherosclerosis in raptor species has not been fully evaluated. The aim of this study was to histologically characterize central and peripheral atherosclerotic lesions in raptors that were submitted to a pathology service in Northern California from 1986 to 2013. We also evaluated risk factors, including age, gender, origin, and avian family. Atherosclerotic lesions were categorized as minimal, mild, moderate, or severe, based on the severity of the lesions and their distribution within the arterial wall. Among the central arteries, lesions were determined to be of greater severity in the aorta than in the pulmonary artery. More than 50% of the peripheral arteries were affected, including 53.1% (17/32) myocardial, 52% (13/25) coronary, 62.9% (22/35) arteries in the kidney, 52.2% (12/23) gonadal and 51.7% (15/29) splenic arteries; however, hepatic and pulmonary arteries were uncommonly affected. Atherosclerosis was diagnosed in 17 raptor species representing 4 families: Accipitridae, Cathartidae, Falconidae, and Strigidae. The overall prevalence (95% CI) of atherosclerosis in raptors was 2.3% (36/1574; range, 1.63%-3.19%) with the Falconidae having the highest prevalence at 7.4% (9/122; range 3.64%-13.93%) and with 0% detected in the Tytonidae and Pandionidae families. A multiple logistic regression model that jointly accounted for differences in risk by family, age, and gender found that the risk in Accipitridae was significantly less than that of Falconidae, that adult raptors were at greater risk of atherosclerotic lesions than juveniles were, and that females were more frequently affected than males were.

Cardiac disease in the Spix Macaw (Cyanopsitta spixii): two cases

Cardiovascular disease in avian species, other than poultry, is being increasingly reported. In psittacine birds, atherosclerosis and congestive heart failure are the leading cardiovascular diseases, often resulting in multiorgan dysfunction and demise. The Spix's macaw (Cyanopsitta spixii) is arguably the most endangered psittacine species worldwide. We aimed to describe the gross and microscopic findings in two adult Spix's macaws wherein severe cardiovascular pathology resulted in sudden death. Bird 1 had pathologic findings consistent with fibrinoheterophilic vegetative pulmonic valvular endocarditis with luminal obliterative thrombosis, myocarditis and epicarditis, myocardial fibrofatty infiltration and cardiomyocyte loss, as well as generalized septicaemia. Microbiological analysis yielded Pantoea septica from the intestines and Acinetobacter baylyi from the cerebrum. Bird 2 had changes suggestive of right brachiocephalic coarctation-like obliterative arteriopathy. The latter is a novel cardiovascular pathology in avian species, and its severity and extent likely led to acute decompensation of pre-existing cardiac disease. These results add to the body of knowledge on avian cardiovascular pathology and may aid in veterinary medical decisions on caged birds, including those part of ex situ conservation efforts.

Imaging features of disseminated xanthogranulomatous inflammation in eclectus parrots (Eclectus roratus)

Xanthogranulomatous disease is a rare condition, which can be caused by infection, inflammation, hemorrhage, immunologic disease, or inherited lysosomal disorders. It is characterized by non-intracellular lipid and cholesterol deposits among an inflammatory infiltrate of vacuolated macrophages and giant cells. The diagnosis of xanthogranulomatous disease is challenging, with nonspecific imaging findings often misinterpreted as aggressive neoplastic processes in humans. In this retrospective case series study, we describe the diagnostic imaging characteristics of a disseminated xanthogranulomatous condition identified in five eclectus parrots (Eclectus roratus). Decreased serosal detail and celomic distension were present in all three birds radiographed, with multifocal variably sized celomic mineralization (3/3 birds), and extracelomic mineralized masses (1/3 birds). Celomic effusion with foci of celomic mineralization and hepatomegaly were identified in all birds (3/3) imaged with ultrasound. Finally, a mineralized mural ventricular mass was present in one of three patients imaged with CT, multifocal celomic mineralization with moderate to severe celomic effusion in two of three patients, diffuse severe proventricular and intestinal dilation in all three patients, and atherosclerosis of the major arterial trunks in all three patients. Veterinary radiologists should be aware of this inflammatory condition in birds, especially in eclectus parrots, and should be able to recognize the imaging features of xanthogranulomatous inflammation.

Captive Psittacine Birds in Ontario, Canada: a 19-Year Retrospective Study of the Causes of Morbidity and Mortality

Psittacines (e.g. parrots, macaws and cockatoos) are common companion animals that are also kept in zoos and private breeding collections. Despite this popularity, long-term, comprehensive studies of diagnostic data from captive psittacines are rare. This study was conducted to assess trends in disease prevalence and to describe causes of morbidity and mortality in psittacines submitted for post-mortem examination to the veterinary hospital and diagnostic laboratory at the University of Guelph, Ontario, Canada. Post-mortem reports of 1,850 psittacines from 1998 to 2017 were assessed and included 110 species from 45 genera. Birds were often diagnosed with infectious disease processes (n = 823; 44.5%), including viral (n = 428; 23.1%), bacterial (n = 284; 15.4%) and fungal (n = 161; 8.7%). Non-infectious disease processes (n = 1,076; 58.2%) were most commonly degenerative (n = 465; 25.1%), metabolic (n = 392; 21.2%) or haemodynamic (n = 270; 14.6%). Exploratory statistical analyses, used to guide further research, revealed significant correlations and associations among disease processes and genera, age categories and sex. This 19-year retrospective study is the first to be conducted in Canada for psittacine birds and provides a broad overview of disease prevalence that can be used as a baseline to inform other studies addressing common and uncommon diseases affecting these birds in the future.

Lipid-Related Lesions in Quaker Parrots (Myiopsitta monachus)

The Quaker parrot has been used as a psittacine model to study clinical lipidology and lipid-related disorders. However, while Quaker parrots appear to be anecdotally susceptible to a variety of spontaneous dyslipidemic disorders and lesions caused by excess lipid accumulation, epidemiologic data are lacking. A multicenter retrospective study on 652 pathology submissions (411 necropsies and 243 biopsies) from Quaker parrots was performed by recording the final pathological diagnoses, age, and sex for each bird. The prevalence of lesions associated with lipid metabolism, such as hepatic lipidosis, atherosclerosis, xanthomas, adipose tumors, coelomic steatitis/steatonecrosis, endogenous lipid pneumonia, and acute pancreatic necrosis/pancreatitis, was reported. Multiple logistic regression models were used to characterize the effects of sex and age on these lesions, and the prevalence of hepatic lipidosis and atherosclerosis was compared to those in a random sample of control psittacine birds. The raw prevalence of atherosclerosis and hepatic lipidosis was 5.6% (95% confidence interval [CI], 3.4%–7.8%) and 21.2% (95% CI, 17.2%–25.1%), respectively. While the prevalence of atherosclerosis was similar to other psittacine species, hepatic lipidosis was more common in Quaker parrots. Quaker parrots also showed a unique susceptibility to acute pancreatic necrosis with a prevalence of 12.9% (95% CI, 9.7%–16.1%). Male parrots were found to be more susceptible than females to lipid accumulation lesions ( P = .0024), including atherosclerosis ( P = .018) and hepatic lipidosis ( P < .001). This retrospective study confirms the high susceptibility of Quaker parrots to lipid-related disorders and presents epidemiological data that may be useful to avian clinicians, pathologists, and researchers using Quaker parrots.

Cardiovascular Drugs in Avian, Small Mammal, and Reptile Medicine

Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds, small mammals, and reptiles. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in exotic species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the exotic cardiac patient.

Lipoidal corneal degeneration in aged falcons

OBJECTIVE

To present a case series of idiopathic lipoidal corneal degeneration in falcons.

ANIMALS STUDIED

Five falcons including three peregrine falcons (Falco peregrinus), one prairie falcon (Falco mexicanus), and one red-naped shaheen (Falco peregrinus babylonicus) were observed to develop slowly progressive corneal opacification that began at the temporal limbus and extended centripetally across the cornea over a period of years. Four of the birds were over 20 years old.

PROCEDURES

All animals underwent complete ophthalmic examinations. A red-naped shaheen underwent ocular imaging via spectral-domain optical coherence tomography. Two peregrine falcons were euthanized due to declining health, and their eyes were examined histologically.

RESULTS

The opacities were pale and granular, with frequent vascularization associated perilimbally. Diffuse neutral lipid was observed in stromal cells throughout the corneal stroma of both clear and opaque areas of the cornea, sparing only the acellular anterior limiting lamina. Clusters of cholesterol crystals surrounded by macrophages were present in the mid-stroma. Fibrosis was evident in a subepithelial location, which separated the epithelium from the anterior limiting lamina. Ultrastructurally, diffuse vacuolization of the keratocytes was observed. No other ophthalmic or systemic abnormalities were noted.

CONCLUSIONS

Results suggest that lipid degeneration occurs rarely in captive falcons of advanced age. The underlying cause is unclear. Though unsubstantiated, possible contributing factors include dyslipoproteinemia, corneal trauma, diet, and age-related alterations in corneal metabolism. The initiation of pathology at the temporal limbus, as well as slow progression, suggests that exposure contributes to the onset and progression of this unique keratopathy.

[Vergleichende Bestimmung von Gerinnungsparametern in Blutproben verschiedener Wild- und Ziervogelspezies]

OBJECTIVE

Information about the influence of species variety or diseases on coagulation values in avian blood is rare. The aim of this study was to assess the influence of species on measurements of coagulation parameters in avian plasma samples using commercially available reagents and to investigate potential influences of selected diseases on clotting times.

MATERIAL AND METHODS

Prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) were measured in citrated plasma of healthy individuals collected from eight different wild and captive avian species applying currently commercially available reagents prepared for use in humans, which were preselected in preliminary studies. The same parameters were tested in plasma samples from birds affected by aspergillosis, atherosclerosis, neoplasia and traumata.

RESULTS

PT and aPTT showed a high interspecies variety. Irrespective of species, aPTTs were extremely long and partially exceeded the measurement range limit. Minor variations between species were seen in TT measurements. Clotting times obtained from birds affected by aspergillosis, atherosclerosis and neoplasia were not significantly different when compared to healthy birds. Plasma obtained from traumatised individuals showed significantly shorter PT and aPTT than that in healthy birds.

CONCLUSION AND CLINICAL RELEVANCE

Differences between species must be considered in diagnostic coagulation measurements in avian blood. Regardless of the avian species, aPTT measurements on avian samples appear to be of limited value. Lower PT and aPTT values reflect coagulation activation in traumatised birds.

Malignant Melanoma of the Syrinx and Liver in an African Grey Parrot ( Psittacus erithacus erithacus)

A 20-year-old, female African grey parrot ( Psittacus erithacus erithacus) was examined because of ataxia and weakness. Radiographs were unremarkable, and results of a complete blood cell count revealed leukocytosis and heterophilia. Because of poor response to therapy with meloxicam, doxycycline, and enrofloxacin; deteriorating condition; and poor prognosis, the parrot was euthanatized. Postmortem examination revealed 2 dark red nodules in the liver. No grossly visible mass was observed in the syrinx. Histologic examination of the liver and syrinx revealed similar foci of round, oval, and polygonal cells exhibiting severe pleomorphism, with poorly demarcated cytoplasmic borders and moderate amounts of eosinophilic cytoplasm containing brown to black granules (melanin). The mitotic index was 15. The presence of melanin pigment is consistent with a diagnosis of melanoma at both sites. The multifocal distribution and intravascular invasion indicate metastasis; however, the site of origin was unknown. To our knowledge, this is the first recorded case of melanoma in an avian syrinx.

Association between serum N-terminal pro-B-type natriuretic peptide levels and characteristics of coronary atherosclerotic plaque detected by coronary computed tomography angiography

The aim of the present study was to explore the association between the levels of serum N-terminal pro-B-type natriuretic peptide (NT-pro BNP) and the characteristics of coronary atherosclerotic plaque detected by coronary computed tomography angiography (CCTA), in patients with unstable angina (UA). A total of 202 patients (age range, 47-82 years) were divided into the following three groups: Non-cardiac disease group (57 patients); stable angina pectoris (SAP) group (62 patients); and UA group (83 patients). There were significant differences between the serum NT-pro BNP levels among the three groups (P=0.007). However, in multivariant diagnoses, NT-pro BNP level was not an independent risk factor for UA. The levels of serum NT-pro BNP were observed to be positively correlated with the number of vessels involved (r=0.462; P<0.001), SIS (r=0.475; P<0.001), segment-stenosis score (r=0.453; P<0.001), coronary calcification score (r=0.412; P=0.001), number of obstructive diseases (r=0.346; P<0.001), and the number of segments with non-calcified plaque (r=0.235; P=0.017), mixed plaque (r=0.234; P=0.017) and calcified plaque (r=0.431; P<0.001). The levels of serum NT-pro BNP were significantly higher in patients with UA and left main-left anterior descending (LM-LAD) disease, compared with UA patients without LM-LAD disease (P<0.001). In addition, serum NT-pro BNP was significantly higher in patients with obstructive disease and UA than in those without obstructive disease (P<0.001). The area under the curve of log(NT-pro BNP) was 0.656 (P=0.006; optimal cut-off value, 1.74; sensitivity, 77.6%; specificity, 51.9%). In conclusion, the levels of serum NT-pro BNP are associated with the burden and severity of coronary artery atherosclerotic disease in patients with UA, and may be helpful in risk stratification of patients with UA.

[Pathologic-anatomic and morphometric examinations on the heart in feral cockatoos]

OBJECTIVE

To evaluate the heart of free-living psittacine birds macroscopically and morphologically, and to compare the results to findings published for psittacine birds living in captivity to obtain information on the influence of bird keeping in a human environment on the psittacine heart.

MATERIAL AND METHODS

In total, 84 wild-living cockatoos were examined, including 50 sulphur-crested cockatoos (Cacatua galerita), 31 galahs (Eolophus roseicapilla) and three long-billed corellas (Cacatua tenuirostris). The birds were euthanized because of a local cockatoo control program in Australia, and were examined pathologically within 8 hours of euthanasia. A macroscopic necropsy was performed, and the heart was assessed morphologically. Furthermore, a histological organ screening was conducted.

RESULTS

The birds demonstrated good body condition and excellent muscle condition. Except for some paleness of the heart muscle, none of the animals showed any pathological alteration of the heart or large vessels. The mean heart mass was 8.7 g for the sulphur-crested cockatoos, 5.3 g for the galahs and 8.6 g for the long-billed corellas. Independent of the species examined, a highly significant correlation was found between the heart and body masses (r = 0.91; p < 0.001), which was also confirmed as significant within the sulphur-crested cockatoo (r = 0.59; p < 0.001) and galah groups (r = 0.52; p = 0.003). This correlation can be used to calculate the expected heart mass based on the body mass, using the formula: heart mass (g) = 2.9 + 0.01 x body mass (g). In comparison to reports on Australian parakeets, the relative thickness of the heart muscle wall of the left ventricle found in this study was greater.

CONCLUSION

In comparison to psittacine birds kept in captivity, wild-living cockatoos have good body condition and rarely suffer from macroscopically detectable diseases of the heart or large vessels. The cardiac fitness level is superior in comparison to that found in healthy appearing psittacine birds kept in captivity.

CLINICAL RELEVANCE

The results can serve as a basis for the assessment of the heart in psittacine birds, because in contrast to earlier reports, the heart of healthy psittacine birds not previously exposed to any human influence could be assessed.

Central vestibular disease in a blue and gold macaw (Ara ararauna) with cerebral infarction and hemorrhage

A 24-year-old female blue and gold macaw (Ara ararauna) was presented for an acute onset of left head tilt. On examination, the macaw was dehydrated and had a 120-degree left head tilt, decreased proprioception of the left pelvic limb, and intermittent vertical nystagmus. Results of hematologic testing and biochemical analysis revealed severe leukocytosis with lymphopenia and heterophilia and a high uric acid concentration. Radiographs showed bilateral intertarsal joint osteoarthritis and a healed ulnar fracture. Magnetic resonance imaging of the brain revealed focal T2 and fluid-attenuated inversion recovery hyperintense lesions in the right cerebral hemisphere and in the midbrain. The midbrain lesion showed susceptibility artifact on the T2* sequence, suggesting hemorrhage. In the T2* sequence, iron accumulation (as seen with hemorrhage) distorts the magnetic signal, resulting in the production of a susceptibility artifact, which can then be visualized as a region of hypointensity. The bird was hospitalized but died despite intensive care. Necropsy revealed multiple cerebral vascular lesions including an acute cerebral infarct, a ruptured midbrain aneurysm, and multifocal systemic atherosclerosis. To our knowledge, this is the first report of a cerebral aneurysm in a bird. This report correlates the clinical presentation, imaging, and histopathologic findings in a macaw with central vestibular disease and demonstrates how advanced imaging techniques can identify hemorrhagic lesions through the T2* sequence.

Cluster of atherosclerosis in a captive population of black kites (Milvus migrans subsp.) in France and effect of nutrition on the plasma lipid profile

From January 2010 to March 2013, a captive colony of 83 black kites (Milvus migrans subsp.) in France experienced increased mortality related to atherosclerosis with an incidence of 4.4% per year. On histopathology, all kites had advanced atherosclerotic lesions, with several birds presenting abdominal hemorrhage and aortic rupture. In January 2012, a dietary change was instituted and consisted of introducing fish into the kites' diet. During the following 15 mo, the plasma lipid profile was monitored as well as body weight, food offered, and flight activity. Total and low-density lipoprotein cholesterol initially increased, but in December 2012 and March 2013, an overall decrease from initial values was observed. High-density lipoprotein cholesterol also increased during this period. Despite positive plasma lipid changes induced by dietary modifications, there was no decrease in mortality from atherosclerosis, which was probably associated with the severity of the atherosclerotic lesions at time of dietary management. However, owing to the long and progressive development of atherosclerotic lesions, long-term beneficial effects are probable. This report suggests that black kites are particularly susceptible to atherosclerosis and aortic dissection in captivity. To prevent degenerative diseases associated with captivity in birds of prey, species-specific lifestyle and dietary requirements and susceptibility to these diseases should be considered.

Experimental diet-induced atherosclerosis in Quaker parrots (Myiopsitta monachus)

Spontaneous atherosclerosis is common in psittaciformes, and clinical signs associated with flow-limiting stenosis are encountered in pet birds. Nevertheless, a psittacine model of atherosclerosis has not been developed for research investigations. Sixteen captive-bred Quaker parrots (Myiopsitta monachus) were used in this study. While 4 control birds were fed a maintenance diet, 12 other birds were fed an atherogenic diet composed of 1% cholesterol controlling for a calorie-to-protein ratio for periods ranging from 2 to 8 months. The birds were euthanized at the end of their respective food trial period. Histopathology, transmission electron microscopy, and cholesterol measurement were performed on the ascending aorta and brachiocephalic and pulmonary arteries. Plasma lipoproteins, cholesterol, and triglycerides were also measured on a monthly basis. Significant atherosclerotic lesions were induced within 2 months and advanced atherosclerotic lesions within 4 to 6 months. The advanced lesions were histologically similar to naturally occurring lesions identified in the same parrot species with a lipid core and a fibrous cap. Ultrastructurally, there were extracellular lipid, foam cell, and endothelial changes. Arterial cholesterol content increased linearly over time. Plasma cholesterol and low-density lipoprotein (LDL) significantly increased over time by an average of 5- and 15-fold, respectively, with a shift from high-density lipoprotein to LDL as the main plasma lipoprotein. Quaker parrots also exhibited high plasma cholesteryl ester transfer protein activity that increased, although not significantly, over time. This experiment demonstrates that in Quaker parrots fed 1% cholesterol, advanced atherosclerosis can be induced relatively quickly, and lesions resemble those found in other avian models and humans.