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Velocity of Candida albicans invasion into host tissues
1Department of Histology, 1st Leningrad Medical Institute, USSR.
Abstract:
Using 2 experimental models (candidal vaginitis in leukopenic mice and oral candidosis in neonatal rats) characterized by minimal inflammatory response to the pathogen, the rate of invasive growth of Candida albicans in stratified epithelia of mucosal membranes was defined. The pseudomycelium was found to invade animal epithelia at an average rate of 2 microns per hour, penetrating the entire epithelial thickness during 24-48 h. These data have been extrapolated to clinical pathology. On the basis of experimental data and by measuring the epithelial thickness in some human mucous membranes, the presumable periods of total epithelial penetration were calculated which may lead to vascular invasion and create the danger of dissemination. For different human mucous membranes these periods ranged from 22 to 59 h. These data emphasize the importance of cellular and tissue defense mechanisms, the inhibition of which may allow the fungi normally found on epithelial surfaces as commensals to invade the host tissues and to cause deep and disseminated mycotic lesions within several days.
Insights
Candida albicans invades epithelial tissues at a rate of 2 microns per hour. This fungal invasion can lead to disseminated candidiasis within days, highlighting the importance of host defense mechanisms.
Area of Science:
- Mycology
- Infectious Diseases
- Pathogenesis
Background:
- Candida albicans is a commensal fungus.
- In immunocompromised individuals, it can cause invasive infections.
- Understanding the rate of fungal invasion is crucial for predicting disease progression.
Purpose of the Study:
- To determine the rate of invasive growth of Candida albicans in stratified epithelia.
- To extrapolate experimental findings to human clinical pathology.
- To estimate the time to epithelial penetration and potential for dissemination.
Main Methods:
- Experimental models: candidal vaginitis in leukopenic mice and oral candidosis in neonatal rats.
- Measurement of pseudomycelial invasion rate in animal epithelia.
- Extrapolation of data to human mucous membranes based on measured epithelial thickness.
Main Results:
- Candida albicans pseudomycelium invades epithelia at an average rate of 2 microns per hour.
- Complete epithelial penetration occurred within 24-48 hours in experimental models.
- Estimated periods for total epithelial penetration in humans range from 22 to 59 hours, indicating risk of vascular invasion.
Conclusions:
- Inhibiting host defense mechanisms allows commensal fungi to invade tissues.
- Fungal invasion can lead to deep and disseminated infections within days.
- The rate of invasion is a critical factor in the pathogenesis of candidiasis.