Acetogenin-induced fibrotic heart disease from avocado (Persea americana, Lauraceae) poisoning in horses.

The research article investigates the effect of avocado, and specifically its toxin acetogenin, on causing heart diseases in horses. The study took place over 2 years focused on a horse farm where the animals regularly ingested parts of the avocado plant, leading two deaths and suggestive evidence of the fruit’s harmful impact.

Introduction

• The article begins by acknowledging known cases of poisoning from avocado (Persea americana) consumption in various animals like sheep, goats, dogs, rabbits, and ostriches.
• The toxic effect is attributed to an acetogenin compound called persin present in the avocado.
• The research aims to explore the effects and possible treatment for heart damage caused by acetogenin.

Methods and Findings

• The researchers observed a horse farm over two years, where six horses would eat from avocado leaves or ripe fruit fallen on the ground.
• Two of these horses passed away, and one was further studied through necropsy, histopathology, and immunohistochemistry utilizing anti-cardiac troponin C (cTnC).
• Upon examination, there was evidence of severe cardiac fibroplasia or abnormal growth of fibrous tissue in the heart muscles.
• Immunohistochemically, there was a multifocal decrease or negative expression in the cTnC cardiomyocytes’ cytoplasm, indicating altered cellular activity.

Confirmation of Persin Presence

• Moreover, using botanical anatomy and molecular techniques, the presence of P. americana leaves was confirmed in the horse’s digestive system.
• Chemical analysis utilizing (LC-ESI-MS) also revealed the presence of the acetogenin persin, as well as another acetogenin called avocadene 1-acetate from P. americana.
• These toxins were found in leaves and various parts of the fruit, with avocadene 1-acetate showing a higher concentration in the pulp of the fruit.

Further Investigation

• Furthermore, four other horses were examined using electrocardiogram, echocardiogram and blood tests for serum Troponin 1 (cTnI), a protein that indicates heart damage.
• To establish a definitive cause-and-effect relationship between P. americana consumption and heart fibroplasia in horses, further longitudinal studies are recommended.