A Preliminary Study On The Mechanism Of Circumcision On Reduced Transmission Of HIV To Adult Men

Background:Three randomized controlled trials(Uganda, Kenya and South Africa) have approved that circumcision could reduce rate of male HIV infection. Subsequently, WHO announced that circumcision reduced male HIV infection by60%. According to clinical phenomenon, inner foreskin seems to be more vulnerable than outer foreskin, especially in phimosis cases. Thus, biomechanics and pathological detection were applied to compare different strength between inner foreskin and outer foreskin.Objective:Ultimate strength of adult inner foreskin and outer foreskin composite tissue were tested in longitudinal, transversal and vertical directions. Keratinized layer of epithelium were compare between inner foreskin and outer foreskin. Keratinization and number of layers of epithelium were also compared in other positions of penis, oral mucosa, vaginal mucosa and labia minora.Methods:44cases of adult foreskin were harvested from Peking University First Hospital Andrology Center. The patients aged from15-54years old, the median age was26.9±6.8year old. Rectangular preputial test pieces were fixed and broke after a uniform velocity of10mm/min in longitudinal, transversal direction. The test pieces were broke with a uniform velocity of10mm/min in vertical direction. The following measurements were compared, including breaking load, tensile strength, rigidity and displacement. Histology examination of foreskin tissue, other positions of penis, oral mucosa, vaginal mucosa and labia minora were compared.Results:22pairs of longitudinal foreskin tissues were tested. The median value of breaking load of inner foreskin was1.046±0.3367N, and outer foreskin was1.356±0.4345N(P<0.01)。 The displacement of inner foreskin was9.56±4.12mm, and outer foreskin was9.18±3.47mm(P>0.05).20pairs of transversal foreskin tissues were tested. The median value of breaking load of inner foreskin was0.99±0.50N, and outer foreskin was1.75±0.55N(P<0.001)。 The displacement of inner foreskin was10.00±5.60mm, and outer foreskin was12.07±3.92mm.20pairs of vertical test of foreskin tissues were tested. The median value of breaking load of inner foreskin was0.79±0.25N, and outer foreskin was1.55±0.71N(P<0.01)。 The displacement of inner foreskin was4.90±1.46mm, and outer foreskin was6.66±2.30mm.7cases of longitudinal foreskin tissues were tested. Median keratinization of inner foreskin was6.83±1.40μm, outer foreskin was11.43±3.10μm(P<0.05).12cases of transversal foreskin tissues were tested. Median keratinization of distal inner foreskin was7.04±3.08μm, which was thinner than proximal inner foreskin(10.83±8.02μm, P<0.05), distal outer foreskin(11.30±2.31μm, P<0.05) and proximal outer foreskin (12.63±2.51μm,P<0.05).No major differences of thickness of epithelium were found among inner foreskin and outer foreskin, while both of them were thinner than vaginal mucosa and oral mucosa.Conclusion:Inner foreskin composite tissue were vulnerable than outer foreskin composite tissue in longitudinal, transversal and vertical directions. No major differences of submucous tissue were tested. Thus, epithelium of inner foreskin may be more vulnerable than outer foreskin.Keratinization of distal inner foreskin(7.04±3.08μm) was thinner than proximal inner foreskin(10.83±8.02μm,P<0.05), distal outer foreskin(11.30±2.31μm,P<0.05) and proximal outer foreskin (12.63±2.51μm, P<0.05). Resection of inner foreskin may lead to less rate penis injury. Objective:To investigate HIV target cell, Langerhans cell of epithelium were compare among inner foreskin, outer foreskin, oral mucosa, vaginal mucosa and labia minora.Methods:10cases of adult foreskin were harvested from Peking University First Hospital Andrology Center. The patients aged from18-45years old.3cases of phimosis,4case of preputial inflammation,11cases of oral mucosa,7cases of vaginal mucosa and1case of labia minora were harvested respectively in Plastic Surgery Hospital of Chinese Academy of Medical Sciences. After pathological detection, density and depth of Langerhans cell were measured by LEIC A microscope.Results:10cases of foreskin with normal appearance were tested. Median density of Langerhans cell of inner foreskin(7cases) was167.3±23.0/mm2, which was larger than outer foreskin(65.1±20.7/mm2, P<6.05), vaginal mucosa(87.2±35.2mm2, P<0.05), oral mucosa(79.2±31.7/mm2,P<0.05) and labia minora (52.8/37.2/mm2). However, the number was smaller than preputial inflammation group(261.1±31.3/mm2).Median depth of Langerhans cell of inner foreskin(7cases) was25.60±5.11μm. which was smaller than outer foreskin (35.35±6.16μm, P<0.05), vaginal mucosa (88.96±41.24μm,P<0.05) and oral mucosa(91.94±34.47μm,P<0.05).Conclusion:Epithelium of inner foreskin composite tissue had a higher density of Langerhans cell than outer foreskin, oral mucosa, vaginal mucosa and labia minora. Meantime, the depth of Langerhans cell inner foreskin was lower than outer foreskin, oral mucosa and vaginal mucosa. Innner foreskin with preputial inflammation or crack had a higher density of Langerhans cell than normal inner foreskin and other groups of tissues. Thus, inner foreskin, especially infected or injured cases, may have a higher rate of HIV infection. No major differences of density of Langerhans cell were found between vaginal mucosa and oral mucosa. Objective:To investigate the usage and effect of inner foreskin resection for surgical treatment of redundant prepuce, phimosis and HIV prevention.Methods:54cases of redundant prepuce and phimosis were treated in Plastic Surgery Hospital of Chinese Academy of Medical Sciences. The method of inner foreskin resection alone or combined with phimosis correction was applied. The patients aged from5-62years old.Results:All cases were followed up for1～6months.1case of wound dehiscence occurred, which was cured by dressing changing. The rest of cases showed satisfactory result. No complications, including operative bleeding, edema of foreskin, were reported. The sensation of frenulum was reserved.Conclusion:Inner foreskin resection is an effective way for surgical treatment of redundant prepuce and phimosis. Randomized controlled trial is needed to investigate the effect of HIV prevention.