High bacterial colonization and lipase activity in microcomedones

Area of Science:

• Dermatology
• Microbiology
• Biophysics

Background:

• Acne vulgaris pathogenesis involves comedogenesis and bacterial colonization.
• The precise timing and location of early Propionibacterium acnes colonization remain unclear.
• Understanding early bacterial interactions in the pilosebaceous unit is crucial for acne research.

Purpose of the Study:

• To precisely analyze the structure of microcomedones.
• To investigate the interplay between Propionibacterium acnes and follicular units.
• To elucidate the role of this interplay in acne lesion formation.

Main Methods:

• Microcomedones sampled via cyanoacrylate skin surface stripping (CSSS).
• Morphology analyzed using multiphoton imaging.
• Ultrastructure examined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
• Bacterial lipase activity quantified via enzymatic tests and Fourier Transform Infra-Red (FTIR) analysis.
• Bacterial porphyrin analyzed using HPTLC and fluorescence spectroscopy.

Main Results:

• Microcomedones exhibit a pouch-like structure filled with lipids and bacteria, enclosed by corneocyte layers.
• Extensive bacterial colonization within microcomedones confirmed by TEM.
• Significant lipase activity detected even after sampling.
• High correlation (r=0.85) between porphyrin content measured by HPTLC and fluorescence spectroscopy.

Conclusions:

• Microcomedones, even when clinically subtle, harbor substantial bacterial colonization.
• The study provides structural and biochemical evidence of early bacterial involvement in acne.
• Findings enhance understanding of acne vulgaris initiation and development.