Pericytes in human cerebral microvasculature

Area of Science:

• Neuroscience
• Cell Biology
• Microcirculation Research

Background:

• Cerebral pericytes are crucial for blood-brain barrier integrity and function.
• Pericytes in cerebral microvasculature are traditionally classified as granular or agranular based on cytoplasmic granules.
• The existence and prevalence of agranular pericytes in the human brain remain debated.

Purpose of the Study:

• To investigate the presence and characteristics of cytoplasmic granules in human cerebral pericytes.
• To determine if distinct granular and agranular pericyte populations exist in the human brain microvasculature.
• To assess the influence of age and sex on pericyte granulation.

Main Methods:

• Examination of structurally normal human brain tissue from 17 patients (aged 14-77).
• Light microscopic analysis of single pericyte profiles.
• Serial reconstruction of 80 individual pericytes to analyze cytoplasmic content.

Main Results:

• Light microscopy of single sections showed 67% of pericyte profiles contained granules, irrespective of sex or age.
• Serial reconstructions revealed that all examined pericytes possessed characteristic cytoplasmic granules.
• The data indicate that truly agranular pericytes, if present, constitute less than 5% of the human cerebral pericyte population.

Conclusions:

• The study provides strong evidence that virtually all human cerebral pericytes contain cytoplasmic granules.
• The traditional classification of distinct granular and agranular pericytes may not accurately reflect the in vivo reality of human cerebral microvasculature.
• Further research is needed to understand the functional significance of these granules.