Increased Plasma Cardiac Troponin I in Live-Stranded Cetaceans: Correlation with Pathological Findings of Acute Cardiac Injury

Abstract

capture myopathy (cM), is a syndrome that occurs as the result of the stress during and after capture, handling, restraint, and transport of wild animals. Although cM has been described for many species of cetaceans, characterization of the acute cardiac injury-an important component of this syndrome-are still scarce. In this study, we firstly estimated a normal range for cardiac troponin I (cTnI) on cetaceans. Here, through biochemical analysis (especially of ctni) and histopathological, histochemical, and immunohistochemical correlations with decreased troponin immunolabelling, we studied the cardiac injury in live-stranded cetaceans. nine cetaceans which stranded alive on the canary islands (January 2016-June 2019) were included in this study. Sampled individuals presented elevated values of plasma ctni, which were correlated to histopathological lesions comprised of vascular changes and acute degenerative lesions. immunohistochemically, injured cardiomyocytes showed a decreased intrafibrillar troponin immunoreaction. This is the first attempt to establish a normal baseline range for cTnI in cetaceans, and the first study comparing plasma biomarkers values with histopathological and immunohistochemical findings. This approach allowed us to demonstrate the degree of cardiac damage as a result of injury, consistent with ischemia-reperfusion lesions. the knowledge gained here could improve decision-making procedures during stressful situations, mainly in live-strandings, handling, and rehabilitation, thereby reducing the mortality of cetaceans. All life forms have evolved mechanisms to cope with stressful situations in their lives 1. For cetaceans, live-stranding is a situation in which they are alive on the beach or in shallow water, and in distress due to being unable to free themselves and resume normal activity 2-4. Similar to humans and other animals, once the central nervous system of a cetacean perceives an internal (physiologic or psychogenic) or environmental threat to their homeostasis, the threat being the stressor, a biological response is developed 5-7. Irrespective of the animal's previous health, stranding creates an anomalous and extreme situation for an organism that it is not anatomically or physiologically adapted to handle. It is a pathological entity in which acute stress is the central axis of its etiopathogenesis, presenting clinical and lesional findings that can cause the death of the animal or seriously aggravate a previous disease over the period of capture or captivity. This reaction may in turn influence the subsequent rehabilitation and recovery of affected animals, since live-stranded cetaceans are frequently debilitated when rescued. Therefore, although the stranding response is intended to improving the health and welfare of these animals, some "rescue and recovery" activities may in fact be counterproductive 4,8-13. Deaths of live-stranded cetaceans may be attributed to the so-called "stress response syndrome" or "alarm reaction, " which are thought to have analogous mechanisms t...

Microscopic Findings in the Cardiac Muscle of Stranded Extreme Deep-Diving Cuvier's Beaked Whales (Ziphius cavirostris)

“…These morphological alterations consist of vascular changes (i.e., congestion, interstitial edema, and hemorrhages) and acute degenerative lesions (i.e., contraction band necrosis, wavy fibers, hypereosinophilia, and cytoplasm vacuolization) with a perivascular distribution, indicative of ischemia–reperfusion damage. Additionally, infiltration of inflammatory cells, myoglobin globules and fibrotic tissue are also detected in this pathology (Herráez et al, 2007, 2013; Câmara et al, 2019 a , 2019 b , 2020 a , 2020 b ; Puig-Lozano et al, 2020).…”

Analyzing 13 Years of Cetacean Strandings: Multiple Stressors to Cetaceans in Taiwanese Waters and Their Implications for Conservation and Future Research

“…Cardiomyopathy was detected in a large proportion of cetaceans stranded on the coast of Taiwan (74%). SIC is caused by massive endogenous catecholamine release due to acute event, such as stranding itself or human rescue interaction (Turnbull and Cowan, 1998;Bossart et al, 2007;Herraez et al, 2013;Câmara et al, 2020). The major lesions of SIC are contraction band necrosis, interstitial edema, wavy myofibers, spasm of intramural coronary arteries, and myocardial ischemia (Turnbull and Cowan, 1998;Bossart et al, 2007;Cowan and Curry, 2008;Herraez et al, 2013;Câmara et al, 2019).…”

“…If the animal survives the acute, high stress event, myocardial necrosis, and ischemia may then form irregular patchy fibrosis, namely MPF (Cowan and Curry, 2008). The presence of fibrosis indicates an earlier cardiomyocyte damage has occurred before the latest stranding (Câmara et al, 2020). In contrast to SIC, DCM is associated with chronic stress (long-term excessive cortisol release or repeat stressful events) and nutrition deficiency (e.g., L-carnitine and taurine) (Bossart et al, 2007;Cowan and Curry, 2008;Shibusawa et al, 2013).…”

“…The present study demonstrated that cetaceans around Taiwanese waters are exposed to stress, and hence we suggest stress and related anthropogenic factors in cetaceans should be monitored and managed. Cardiomyopathy is an indicator of stress and nutritional deficiency (Bossart et al, 2007;Câmara et al, 2020), and thus periodic investigation of cardiomyopathy in stranded cetaceans is recommended for monitoring the level of stress in wild cetacean populations. Anthropogenic stress factors, including fishery bycatch, vessel traffic, whale-watching activities, and vessel noise, should be further monitored and managed.…”

Exploration of serum cardiac troponin I as a biomarker of cardiomyopathy in southern sea otters (Enhydra lutris nereis)

“…38 Plasma cTnI concentrations have been measured in live-stranded cetaceans and captive bottlenose dolphins (Tursiops truncatus), indicating high values in stranded animals, some of which had acute myocardial necrosis. 39 Regardless of etiology, myocardial damage and a high serum cTnI concentration have been associated with an increased risk of death in the short and long term in various species, emphasizing the utility of serum cTnI concentration as a prognostic indicator. 16,19,33,[40][41][42] This clinical tool may be particularly useful in wildlife rehabilitation.…”