Host inflammatory response to polypropylene implants: insights from a quantitative immunohistochemical and birefringence analysis in a rat subcutaneous model

To describe acute and sub acute aspects of histological and immunohistochemical response to PP implant in a rat subcutaneous model based on objective methods. Thirty rats had a PP mesh subcutaneously implanted and the same dissection on the other side of abdomen but without mesh (sham). The animals were euthanized after 4 and 30 days. Six slides were prepared using the tissue removed: one stained with hematoxylin-eosin (inflammation assessment); one unstained (birefringence evaluation) and four slides for immunohistochemical processing: IL-1 and TNF-α (pro-inflammatory cytokines), MMP-2 (collagen metabolism) and CD-31 (angiogenesis). The area of inflammation, the birefringence index, the area of immunoreactivity and the number of vessels were objectively measured. A larger area of inflammatory reaction was observed in PP compared to sham on the 4th and on the 30th day (p=0.0002). After 4 days, PP presented higher TNF (p=0.0001) immunoreactivity than sham and no differences were observed in MMP-2 (p=0.06) and IL-1 (p=0.08). After 30 days, a reduction of IL-1 (p=0.010) and TNF (p=0.016) for PP and of IL-1 (p=0.010) for sham were observed. Moreover, area of MMP-2 immunoreactivity decreased over time for PP group (p=0.018). Birefringence index and vessel counting showed no differences between PP and sham (p=0.27 and p=0.58, respectively). The implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in increased inflammatory activity and higher TNF production in the early post implant phase. After 30 days, PP has similar cytokines immunoreactivity, vessel density and extracellular matrix organization423585593FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2011/11522-

A synthetic three-dimensional pelvic model as an effective didactic tool compared to cadaveric pelvis

Anatomy is considered a fundamental subject of medical education. Practical classes which involve the use of manipulable anatomic components are essential to teaching and learning. The aim of this study was to evaluate the synthetic pelvic model (SPM) as a didactic tool, compared to the traditionally- -used cadaveric pelvis (CP), as well as student satisfaction in relation to both methods. Sixty-seven students were given a theory class following the preliminary theoretical test (PTT). The study sample was randomized in three groups: G1 had a traditional practical class (TPC); G2 had a practical class with SPM (PCS); and G3 had no practical class. A final test (FTT) was applied to all the groups. G1 and G2 were subjected to method evaluation (ME). Statistical analysis was conducted using analysis of variance (ANOVA) and the Mann-Whitney U test. In the FTT, G3 presented scores lower than G1 (p = 0.041) and G2 (p = 0.000). No statistically significant difference was found between G1 and G2 (p >0.05). G2 presented greater satisfaction with the method (p = 0.001). In conclusion, both CP and SPM proved to be effective didactic tools and student satisfaction was greater with G2.A anatomia é considerada matéria essencial à educação médica. Aulas práticas com uso de componentes anatômicos manipuláveis são fundamentais ao ensino e à aprendizagem. O objetivo deste estudo foi avaliar o Modelo Sintético de Pelve (Masp) como ferramenta didática, comparada à pelve cadavérica (PC) tradicionalmente utilizada, bem como a satisfação dos estudantes em relação a ambos os métodos. Sessenta e sete estudantes receberam aula teórica após teste teórico preliminar (TTP). Foram randomizados em três grupos: G1 teve aula prática tradicional (APT); G2, aula prática com Masp (APM); e G3 não teve aula prática. Um teste final (TTF) foi aplicado a todos os grupos. G1 e G2 submeteram-se à avaliação do método (AM). A análise estatística foi realizada utilizando-se Anova (Análise de Variância) e teste não paramétrico Mann-Whitney. No TTF, G3 apresentou escores mais baixos do que G1 (p = 0,041) e G2 (p = 0,000). Não foi encontrada diferença estatisticamente significante entre G1 e G2 (p >0,05). G2 apresentou maior satisfação com o método (p = 0,001). Concluiu-se que PC e Masp provaram ser ferramentas didáticas efetivas e que G2 mostrou maior satisfação.502506

Treatment of Anterior Vaginal Wall Prolapse Using Transvaginal Anterior Mesh With Apical Fixation: A Prospective Multicenter Study With up to 2 Years of Follow-up

Purpose To evaluate the safety and efficacy of a surgical polypropylene mesh for correction of anterior vaginal prolapse, with or without apical defects, by providing simultaneous reinforcement at the anterior and apical aspects of the vagina with a single-incision approach. Methods This was a prospective, multicenter, single-arm study involving women with baseline stage ≥2 anterior and/or apical vaginal wall prolapse according to the Pelvic Organ Prolapse Quantification (POP-Q) system. The primary endpoint was defined as achievement of POP-Q stage ≤1 status. Additionally, patient-reported outcomes were assessed using the International Consultation on Incontinence Questionnaire-Vaginal Symptoms (ICIQ-VS). The device under evaluation was Calistar A, which is fixed posteriorly to the sacrospinous ligaments with a novel tissue-anchoring system (TAS) and anteriorly to the obturator internus muscles. Postoperative follow-ups were scheduled at 7 days and at 6, 12, and 24 months. Results Ninety-seven women were treated and assessed for the primary outcome. They were followed for up to 2 years (n=43), with a median of 12 months. Objective cure was achieved in 86 of the 97 patients (88.7%) (P<0.0005). The mean reduction in the ICIQ-VS scores was in the range of 70%–90% for every time point (P<0.05). No bleeding or surgical revision was reported. Mesh exposure occurred in 7 patients (7.2%), urinary retention in 5 (5.2%), de novo dyspareunia in 3 (3.1%), and urinary tract infections in 7 (7.2%). Conclusions This midterm follow-up showed that apical and anterior vaginal reinforcement with a polypropylene implant fixed with a TAS provided good anatomical correction, with no major complications

Pro - inflammatory cytokines and metalloproteinase activation in polypropylene mesh implant in rat subcutaneous tissue

ABSTRACT Aims and Objectives: Polypropylene meshes have been increasingly adopted for correction of pelvic organ prolapse due to its lower recurrence rate when compared to surgeries without meshes. The study of the interaction of these materials with the host tissue may contribute to the development of materials with best biocompatibility and, consequently, less complication rates. Materials and Methods: The present study compares the inflammatory reaction of standard-weight (SW) and lightweight (LW) meshes (72 g/m216g/m2 respectively), implanted in the abdomen of 20 adult rats, which were euthanized in four or 30 days. Quantification of pro-inflammatory markers, IL-1 and TNF-α, and of metalloproteinases, MMP2 and MMP3, were carried out through immunohistochemistry with AxioVision® software. Results: There were no significant differences in the quantification of IL-1 and TNF-α in LW versus SW meshes. However, IL-1 quantification increased along time (30 days >4 days, p=0.0269). Also, MMP-2 quantification was similar to SW and LW and both presented a significant increase along time (30 days >4 days, p 4 days, p=0.02). Conclusions: Mesh's density did not influence the quantification of pro-inflammatory cytokines IL-1 and TNF-α and metalloproteinases 2 and 3. The increased expression of IL-1, MMP-2 and MMP-3 over time could represent a longstanding inflammatory response after PP mesh implantation. Possibly, the occurrence of adverse events following PP prosthetic implants can be influenced by other factors, not solely related to the amount of implanted material

Host inflammatory response to polypropylene implants: insights from a quantitative immunohistochemical and birefringence analysis in a rat subcutaneous model

ABSTRACT Objectives To describe acute and sub acute aspects of histological and immunohistochemical response to PP implant in a rat subcutaneous model based on objective methods. Materials and Methods Thirty rats had a PP mesh subcutaneously implanted and the same dissection on the other side of abdomen but without mesh (sham). The animals were euthanized after 4 and 30 days. Six slides were prepared using the tissue removed: one stained with hematoxylin-eosin (inflammation assessment); one unstained (birefringence evaluation) and four slides for immunohistochemical processing: IL-1 and TNF-&#945; (pro-inflammatory cytokines), MMP-2 (collagen metabolism) and CD-31 (angiogenesis). The area of inflammation, the birefringence index, the area of immunoreactivity and the number of vessels were objectively measured. Results A larger area of inflammatory reaction was observed in PP compared to sham on the 4th and on the 30th day (p=0.0002). After 4 days, PP presented higher TNF (p=0.0001) immunoreactivity than sham and no differences were observed in MMP-2 (p=0.06) and IL-1 (p=0.08). After 30 days, a reduction of IL-1 (p=0.010) and TNF (p=0.016) for PP and of IL-1 (p=0.010) for sham were observed. Moreover, area of MMP-2 immunoreactivity decreased over time for PP group (p=0.018). Birefringence index and vessel counting showed no differences between PP and sham (p=0.27 and p=0.58, respectively). Conclusions The implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in increased inflammatory activity and higher TNF production in the early post implant phase. After 30 days, PP has similar cytokines immunoreactivity, vessel density and extracellular matrix organization

Experimental Animal Model For Training Transobturator And Retropubic Sling Techniques.

Suburethral slings have become the treatment of choice for stress urinary incontinence. However, the lack of experimental models for surgical training is a problem for beginners. We present a model for sling training and evaluate its acceptance by surgeons who have had prior experience. There were 32 surgeons who performed the training program and filled out a questionnaire to evaluate the animal model. Eleven-month-old Santa Inês sheep were selected. The techniques used for minimally invasive transobturator and retropubic sling implantation were reproduced followed by cystoscopy. The anatomical similarities of sheep and humans were evaluated, in addition to the reproducibility of surgical techniques. As far as anatomical similarities of vaginal structures are concerned, 13 surgeons (40.6%) reported similarities and 18 (56.2%) reported a strong correlation. Concerning cystoscopy, 18 (56.2%) found similarities and 13 (40.6%) a strong similarity. As for the transvaginal sling, 10 (3.1%) reported similarities and 19 (59.3%) a strong similarity. Among those who had previous experience with transobturator slings, 91.6% considered that the model presented a similarity or strong similarity. Regarding the degree of recommendation, 9 surgeons (28.1%) would recommend it and 22 (68.7%) would strongly recommend it. Ninety-seven percent of the surgeons would recommend this experimental model for training purposes. To our knowledge this is the first description of a successful animal model for transobturator sling training.78130-

A new experimental model for inducing interstitial cystitis by oxidative stress using intravesical instillation of a nitric oxide donor gel

Objective: The aim of this study was to develop an experimental model of inducing interstitial cystitis through intravesical instillation of a polymeric solution containing the NO donor S-nitrousglutathione (GSNO) and to compare it to the experimental interstitial cystitis induced by vesical instillation of protamine and potassium chloride. Methods: A total of 40 female Wistar rats were used and divided into four groups: 1 – ten rats treated with saline solution + GSNO; 2 – ten rats treated with saline solution + polymeric solution (without GNSO); 3 – ten rats treated with protamine sulphate + KCl; 4 – ten rats treated with protamine sulphate + GSNO. The rats received one application (five animals in each group) or three applications (five animals in each group) of the corresponding substance through intravesical instillation, and after six days (five animals in each group) or nine days (five animals in each group) they were euthanized and their bladders were removed for macroscopic evaluation and histological study. Results: In the macroscopic evaluation edema and hyperemia of the mucosa were observed in 2 (22%) animals in Group 1, in no (0%) animal in Group 2, in 10 (100%) animals in Group 3, and in 5 (50%) animals in Group 4. In the protamine + KCl group and in saline + GSNO, similar effects were observed in the bladder wall. The animals in Group 2 (saline + polymeric solution) showed significantly less vascular congestion compared to the other groups after 9 days of the instillation (p = 0.0035). Significant fibrosis was observed in Groups 3 and 4, 6 days (p = 0.3781) and 9 days (p = 0.0459) after instillations, when compared to controls (Group 2). All groups presented neutrophilic infiltrate of variable intensity, 6 days after instillations (p = 0.7277). After 9 days, there was a regression of the infiltrate, with no evidence of accentuated neutrophilic reaction in all the groups (p = 0.2301). Conclusions: The inflammatory response to bladder instillation with an aqueous solution of S-nitrousglutathione was very similar to that induced by bladder instillation of protamine and KCl. Instillation of an aqueous solution of S-nitrousglutathione can be considered a new model for experimental induction of interstitial cystitis