Pulmonary and Systemic Pathology in COVID-19—Holistic Pathological Analyses

Area of Science:

• Pathology
• Vascular Biology
• Infectious Diseases

Background:

• COVID-19 is the third coronavirus outbreak in 20 years, primarily affecting lungs but also other organs.
• The pathophysiology of COVID-19 organ damage was initially poorly understood.
• Severe cases involve acute respiratory distress syndrome (ARDS).

Purpose of the Study:

• To review structural changes and pathophysiology of COVID-19.
• To focus on the role of imaging techniques in understanding COVID-19.
• To elucidate the mechanisms behind organ damage in COVID-19.

Main Methods:

• Selective literature search on COVID-19 publications.
• Analysis of autopsy tissues using immunohistochemistry, electron microscopy, and molecular pathology.
• Review focused on structural changes and pathophysiology.

Main Results:

• Intussusceptive angiogenesis (IA), a vessel remodeling process, is a key pathological finding.
• IA leads to altered blood flow and promotes further microthrombi formation.
• Microthrombi were found in lungs, heart, liver, kidneys, brain, and placenta of COVID-19 patients.

Conclusions:

• Autopsy studies show altered microvascularity, IA, and multifocal thrombi in COVID-19 patients.
• These vascular changes contribute to organ damage and interstitial fibrosis.
• Findings may explain the pathophysiology of long COVID.