Structural and functional changes in the microcirculation of lepromatous leprosy patients - Observation using orthogonal polarization spectral imaging and laser Doppler flowmetry iontophoresis

• Published in: PloS one 2017-04, Vol.12 (4), p.e0175743-e0175743
• Main Authors: Treu, Curt, de Souza, Maria das Graças Coelho, Lupi, Omar, Sicuro, Fernando Lencastre, Maranhão, Priscila Alves, Kraemer-Aguiar, Luiz Guilherme, Bouskela, Eliete
• Format: Article
• Language: English
• Subjects: Acetylcholine; Acetylcholine - administration & dosage; Adult; Age; Analysis; Arches; Arterioles; Assessments; Autonomic nervous system; Biology and Life Sciences; Blood; Blood flow; Blood vessels; Body mass; Body mass index; Ca2+-transporting ATPase; Cadmium; Calcium (reticular); Calcium influx; Capillaries; Capillaries - physiopathology; Cardiac muscle; Cardiovascular diseases; Chronic infection; Cigarette smoking; Circulatory system; Clinical trials; Computed tomography; Cross-Sectional Studies; Density; Diabetes; Diabetes mellitus; Diabetic neuropathy; Disabilities; Dosage and administration; Drug delivery; Endothelium; Engineering and Technology; Epidemiology; Evaluation; Female; Females; Fibers; Gerontology; Health care; Health risks; Heart; Heart diseases; Humans; Hypertension; Immunology; In vivo methods and tests; Incidence; Inhibition; Insulin; Iontophoresis; Laser-Doppler Flowmetry; Lasers; Leprosy; Leprosy, Lepromatous - diagnosis; Leprosy, Lepromatous - physiopathology; Male; Males; Mathematical analysis; Medical wastes; Medicine and Health Sciences; Microcirculation; Mycobacterium leprae - isolation & purification; Nitric oxide; Nitroprusside - administration & dosage; Nutrients; Obesity; Patient outcomes; Pharmacology; Polarization; Public health; Reflexes; Regional Blood Flow; Rhythms; Risk; Risk factors; Risk management; Sensitivity; Sensory neurons; Skin; Skin - blood supply; Skin - physiopathology; Skin Diseases, Bacterial - diagnosis; Skin Diseases, Bacterial - physiopathology; Smoking; Smooth muscle; Sodium; Spectra; Spectral analysis; Topography; Vasodilation
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0175743

Leprosy is a chronic granulomatous infection of skin and peripheral nerves caused by Mycobacterium leprae and is considered the main infectious cause of disability worldwide. Despite the several studies regarding leprosy, little is known about its effects on microvascular structure and function in vivo. Thus, we have aimed to compare skin capillary structure and functional density, cutaneous vasomotion (spontaneous oscillations of arteriolar diameter), which ensures optimal blood flow distribution to skin capillaries) and cutaneous microvascular blood flow and reactivity between ten men with lepromatous leprosy (without any other comorbidity) and ten age- and gender-matched healthy controls. Orthogonal polarization spectral imaging was used to evaluate skin capillary morphology and functional density and laser Doppler flowmetry to evaluate blood flow, vasomotion and spectral analysis of flowmotion (oscillations of blood flow generated by vasomotion) and microvascular reactivity, in response to iontophoresis of acetylcholine and sodium nitroprusside. The contribution of different frequency components of flowmotion (endothelial, neurogenic, myogenic, respiratory and cardiac) was not statistically different between groups. However, endothelial-dependent and -independent vasodilatations elicited by acetylcholine and sodium nitroprusside iontophoresis, respectively, were significantly reduced in lepromatous leprosy patients compared to controls, characterizing the existence of microvascular dysfunction. These patients also presented a significant increase in the number of capillaries with morphological abnormalities and in the diameters of the dermal papilla and capillary bulk when compared to controls. Our results suggest that lepromatous leprosy causes severe microvascular dysfunction and significant alterations in capillary structure. These structural and functional changes are probably induced by exposure of the microvascular bed to chronic inflammation evoked by the Mycobacterium leprae.