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Hypoxia/reoxygenation-induced myocardial lesions in newborn piglets are related to interindividual variability and not to oxygen concentration.

Faa A, Iacovidou N, Xanthos T, Locci A, Pampaloni P, Aroni F, Papalois A, Faa G, Fanos V - Clinics (Sao Paulo) (2012)

Bottom Line: No differences in the incidence of changes were observed among groups 1-4, whereas marked differences regarding the frequency and the degree of changes were found among groups A-E.The significant myocardial histological changes observed suggest that this experimental model might be a reliable model for investigating human neonatal cardiac hypoxia-related injury.No correlation was observed between the severity of histological changes and the fiO(2) used during reoxygenation.

View Article: PubMed Central - PubMed

Affiliation: University of Cagliari, Department of Pathology, Italy. armando.faa@hotmail.it

ABSTRACT

Objective: Evaluation of myocardial histological changes in an experimental animal model of neonatal hypoxia-reoxygenation.

Methods: Normocapnic hypoxia was induced in 40 male Landrace/Large White piglets. Reoxygenation was initiated when the animals developed bradycardia (HR <60 beats/min) or severe hypotension (MAP <15 mmHg). The animals were divided into four groups based on the oxygen (O(2)) concentration used for reoxygenation; groups 1, 2, 3, and 4 received 18%, 21%, 40%, and 100% O(2), respectively. The animals were further classified into five groups based on the time required for reoxygenation: A: fast recovery (<15 min); B: medium recovery (15-45 min); C: slow recovery (45-90 min); D: very slow recovery (>90 min), and E: nine deceased piglets.

Results: Histology revealed changes in all heart specimens. Interstitial edema, a wavy arrangement, hypereosinophilia and coagulative necrosis of cardiomyocytes were observed frequently. No differences in the incidence of changes were observed among groups 1-4, whereas marked differences regarding the frequency and the degree of changes were found among groups A-E. Coagulative necrosis was correlated with increased recovery time: this condition was detected post-asphyxia in 14%, 57%, and 100% of piglets with fast, medium, and slow or very slow recovery rates, respectively.

Conclusions: The significant myocardial histological changes observed suggest that this experimental model might be a reliable model for investigating human neonatal cardiac hypoxia-related injury. No correlation was observed between the severity of histological changes and the fiO(2) used during reoxygenation. Severe myocardial changes correlated strictly with recovery time, suggesting an unreported individual susceptibility of myocardiocytes to hypoxia, possibly leading to death after the typical time-sequence of events.

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Hypereosinophilia of cardiomyocytes.
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f2-cln_67p503: Hypereosinophilia of cardiomyocytes.

Mentions: The histological examination of H&E-stained sections revealed pathological changes in all of the specimens. Interstitial edema was observed in 37/40 cases (92.5%); the degree of edema varied among the cases. In four cases (one in group 1, two in group 2 and one in group 3), the edema was severe and diffuse, leading to disarrangement of the myocardial architecture (Figure 1). In the majority of cases, the interstitial edema was mild and focal, primarily localized around small, dilated vessels. A wavy arrangement of cardiomyocytes was detected in all but nine cases (77.5%). In 19 hearts, the wavy fibers were focal, whereas in the remaining specimens, the wavy arrangement was diffuse (Figure 1). Cardiomyocyte hypereosinophilia was observed in 28/40 cases (70%). This condition was characterized by cardiomyocyte cytoplasm with a homogeneous appearance, which was associated with an increase in the intensity of eosin staining (Figure 2). Hypereosinophilic fibers were mainly detected in small foci. Coagulative necrosis was detected in 26/40 hearts (65%). The degree of coagulative necrosis varied significantly among cases. In 13 hearts, this condition was mild and focal; in 12, it appeared in large foci; and in one case, coagulative necrosis diffused to large areas of the heart specimen examined (Figure 3).


Hypoxia/reoxygenation-induced myocardial lesions in newborn piglets are related to interindividual variability and not to oxygen concentration.

Faa A, Iacovidou N, Xanthos T, Locci A, Pampaloni P, Aroni F, Papalois A, Faa G, Fanos V - Clinics (Sao Paulo) (2012)

Hypereosinophilia of cardiomyocytes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351247&req=5

f2-cln_67p503: Hypereosinophilia of cardiomyocytes.
Mentions: The histological examination of H&E-stained sections revealed pathological changes in all of the specimens. Interstitial edema was observed in 37/40 cases (92.5%); the degree of edema varied among the cases. In four cases (one in group 1, two in group 2 and one in group 3), the edema was severe and diffuse, leading to disarrangement of the myocardial architecture (Figure 1). In the majority of cases, the interstitial edema was mild and focal, primarily localized around small, dilated vessels. A wavy arrangement of cardiomyocytes was detected in all but nine cases (77.5%). In 19 hearts, the wavy fibers were focal, whereas in the remaining specimens, the wavy arrangement was diffuse (Figure 1). Cardiomyocyte hypereosinophilia was observed in 28/40 cases (70%). This condition was characterized by cardiomyocyte cytoplasm with a homogeneous appearance, which was associated with an increase in the intensity of eosin staining (Figure 2). Hypereosinophilic fibers were mainly detected in small foci. Coagulative necrosis was detected in 26/40 hearts (65%). The degree of coagulative necrosis varied significantly among cases. In 13 hearts, this condition was mild and focal; in 12, it appeared in large foci; and in one case, coagulative necrosis diffused to large areas of the heart specimen examined (Figure 3).

Bottom Line: No differences in the incidence of changes were observed among groups 1-4, whereas marked differences regarding the frequency and the degree of changes were found among groups A-E.The significant myocardial histological changes observed suggest that this experimental model might be a reliable model for investigating human neonatal cardiac hypoxia-related injury.No correlation was observed between the severity of histological changes and the fiO(2) used during reoxygenation.

View Article: PubMed Central - PubMed

Affiliation: University of Cagliari, Department of Pathology, Italy. armando.faa@hotmail.it

ABSTRACT

Objective: Evaluation of myocardial histological changes in an experimental animal model of neonatal hypoxia-reoxygenation.

Methods: Normocapnic hypoxia was induced in 40 male Landrace/Large White piglets. Reoxygenation was initiated when the animals developed bradycardia (HR <60 beats/min) or severe hypotension (MAP <15 mmHg). The animals were divided into four groups based on the oxygen (O(2)) concentration used for reoxygenation; groups 1, 2, 3, and 4 received 18%, 21%, 40%, and 100% O(2), respectively. The animals were further classified into five groups based on the time required for reoxygenation: A: fast recovery (<15 min); B: medium recovery (15-45 min); C: slow recovery (45-90 min); D: very slow recovery (>90 min), and E: nine deceased piglets.

Results: Histology revealed changes in all heart specimens. Interstitial edema, a wavy arrangement, hypereosinophilia and coagulative necrosis of cardiomyocytes were observed frequently. No differences in the incidence of changes were observed among groups 1-4, whereas marked differences regarding the frequency and the degree of changes were found among groups A-E. Coagulative necrosis was correlated with increased recovery time: this condition was detected post-asphyxia in 14%, 57%, and 100% of piglets with fast, medium, and slow or very slow recovery rates, respectively.

Conclusions: The significant myocardial histological changes observed suggest that this experimental model might be a reliable model for investigating human neonatal cardiac hypoxia-related injury. No correlation was observed between the severity of histological changes and the fiO(2) used during reoxygenation. Severe myocardial changes correlated strictly with recovery time, suggesting an unreported individual susceptibility of myocardiocytes to hypoxia, possibly leading to death after the typical time-sequence of events.

Show MeSH
Related in: MedlinePlus