Pathogenesis and persistence of cryptoglandular anal fistula: a systematic review

Abstract

Anal fistulas continue to be a problem for patients and surgeons alike despite scientific advances. While patient and anatomical characteristics are important to surgeons who are evaluating patients with anal fistulas, their development and persistence likely involves a multifaceted interaction of histological, microbiological, and molecular factors. Histological studies have shown that anal fistulas are variably epithelialized and are surrounded by dense collagen tissue with pockets of inflammatory cells. Yet, it remains unknown if or how histological differences impact fistula healing. The presence of a perianal abscess that contains gut flora commonly leads to the development of anal fistula. This implies a microbiological component, but bacteria are infrequently found in chronic fistulas. Recent work has shown an increased expression of proinflammatory cytokines and epithelial to mesenchymal cell transition in both cryptoglandular and Crohn's perianal fistulas. This suggests that molecular mechanisms may also play a role in both fistula development and persistence. The aim of this study was to examine the histological, microbiological, molecular, and host factors that contribute to the development and persistence of anal fistulas.

Role of interleukin‐17 in the pathogenesis of perianal abscess and anal fistula: a clinical study on 50 patients with perianal abscess

“…Clinically, about 60% of perianal abscess cases progress to anal fistula, which requires more complicated surgery. The development of anal fistula is attributed to the primary infection resulted from the entry of rectal contents into anal sinus, which if not promptly controlled, would lead to chronic inflammation and recurrent infection, leading to the formation of fibrotic canal wall in abscess cavity and in turn inadequate drainage . Along with these findings, by showing the association of IL‐17 with anal fistula formation, the present study implicated the potential involvement of IL‐17 in the pathophysiology of anal fistula.…”

“…Perianal abscess can be treated straightforwardly by surgical incision and draining. Clinically, 40–60% of perianal abscess cases will develop to anal fistula, of which the management can be more complicated . The molecular pathogenesis underlying the progression from perianal abscess to anal fistula has remained to be fully understood.…”

The Efficacy and Mechanism of Autologous Fat Stem Cells Combined with Microcarrier 6 Transplantation for Anal Fistula Treatment

“…2c), which might be caused by reactive hyperplasia of tissues surrounding the stula tract under stimulation from the thread. 4. ASC-microcarrier 6 transplantation for anal stula mainly promotes tissue regeneration through multi-directional differentiation, and it has been found that PI3K/AKT signaling pathway molecules are signi cantly enriched…”

“…Adipose-derived stem cells (ASCs) are mesenchymal stem cells that are found in adipose tissues. They possess self-regeneration and multi-differential potential and belong to the class of adult stem cells [4].…”

Fistulotomy for the Surgical Treatment of Perianal Fistula of Cryptoglandular Origin

“…Patient predisposition may explain the latter observation, as it has been shown that there is an increased expression of pro-inflammatory cytokines and epithelial-to-mesenchymal cell transition in CPF. Therefore, molecular mechanisms may also interfere in pathogenesis and also persistence of CPF [47].…”