Efficacy of autologous fat graft injection in the treatment of anovaginal fistulas

Stapled transperineal rectovaginal fistula repair for low- and mid-level rectovaginal fistulas: A comparison study with rectal mucosal advancement flap repair

BACKGROUND

As an innovative treatment, stapled transperineal rectovaginal fistula repair (STR) for rectovaginal fistula (RVF) has demonstrated effectiveness in preliminary reports. This study aims to compare STR with rectal mucosal advancement flap repair (RAF), a widely utilized surgical procedure, for the surgical outcome of the low- and mid-level RVF.

METHODS

In this retrospective cohort study, patients with low- and mid-level RVF who underwent STR or RAF were included from both the Sixth Affiliated Hospital of Sun Yat-sen University and Xi'an Daxing Hospital. Among the 99 total patients, 77 underwent STR and 22 underwent RAF. Patient demographics, operative data, and outcomes were collected and analyzed. Recurrence rate and associated risk factors were evaluated.

RESULTS

There were no statistically significant differences among patients in terms of clinical characteristics like age, BMI, aetiology, and fistula features. During the follow-up period of 20 months (interquartile range 3.0-41.8 months), a total of 28 patients relapsed, with a significantly lower recurrence rate in the STR group (20.8 %) than in the RAF group (54.6 %) (P = 0.005). In the multivariate Cox analysis, STR was an independent protective factor against recurrence (HR: 0.37, 95%CI: 0.17-0.79, P = 0.01). Logistic regression indicated that there was no statistically significant difference between these two procedures in terms of surgical complications (OR: 0.53, 95%CI: 0.19-1.48, P = 0.23).

CONCLUSION

For low- and mid-level RVF, STR may be an alternative option for treatment modality that offers a lower recurrence rate, without observed disadvantage in terms of surgical complication rates.

Efficacy of Injection of Freshly Collected Autologous Adipose Tissue Into Complex Cryptoglandular Anal Fistulas

BACKGROUND

Treatment of cryptoglandular anal fistulas with injection of autologous or allogenic adipose tissue-derived mesenchymal stem cells has shown promising results. However, allogenic adipose tissue-derived mesenchymal stem cells are expensive and use of autologous adipose tissue-derived mesenchymal stem cells requires preceding liposuction and isolation of stem cells, time for cell culture, and laboratory facilities. Freshly collected autologous adipose tissue may be an easily available and inexpensive alternative.

OBJECTIVE

This study aimed to investigate the efficacy of injection with freshly collected autologous adipose tissue into complex cryptoglandular anal fistulas.

DESIGN

Prospective cohort study.

SETTING

Single tertiary center for treatment of cryptoglandular fistulas in Denmark.

PATIENTS

This study included 77 patients with complex cryptoglandular anal fistulas.

INTERVENTIONS

The intervention included injections of freshly collected autologous adipose tissue. Patients not achieving healing after 8 to 12 weeks were offered a second injection.

MAIN OUTCOME MEASURES

Primary outcome was fistula healing defined as no symptoms of discharge and no visible external and palpable internal opening by anorectal digital examination at clinical evaluation 6 months after final treatment. Secondary end points were combined clinical and MRI fistula healing, reduced fistula secretion and anal discomfort, and complications to the treatment.

RESULTS

Thirty-nine patients (51%) achieved the primary outcome of fistula healing 6 months after their final treatment. Nine patients (12%) experienced reduced secretion and decreased anal discomfort. Thirty-seven patients (48%) achieved combined clinical and MRI fistula healing. Treatment was well tolerated; 5 patients (4%) experienced serious adverse events (infection or bleeding) requiring surgical intervention.

LIMITATIONS

No control group was included.

CONCLUSION

Injection of freshly collected autologous adipose tissue is a safe treatment of complex cryptoglandular anal fistulas and may be an easily accessible inexpensive alternative to cultured autologous and allogenic adipose tissue-derived mesenchymal stem cells. See Video Abstract at http://links.lww.com/DCR/C45 .

EFICACIA DE LA INYECCIN DE TEJIDO ADIPOSO AUTLOGO RECIN RECOLECTADO EN FSTULAS ANALES CRIPTOGLANDULARES COMPLEJAS

ANTECEDENTES:El tratamiento de las fístulas anales criptoglandulares con inyección de células madre mesenquimales derivadas de tejido adiposo autólogo o alogénico ha mostrado resultados prometedores. Sin embargo, las células madre mesenquimales derivadas de tejido adiposo alogénicas son costosas y el uso de células madre mesenquimales derivadas de tejido adiposo autólogas requiere una liposucción previa y el aislamiento de las células madre, tiempo para el cultivo celular e instalaciones de laboratorio. El tejido adiposo autólogo recién recolectado puede ser una alternativa económica y de fácil acceso.OBJETIVO:Investigar la eficacia de la inyección con tejido adiposo autólogo recién recolectado en fístulas anales criptoglandulares complejas.DISEÑO:Estudio de cohorte prospectivo.ESCENARIO:Centro terciario para el tratamiento de fístulas criptoglandulares en Dinamarca.PACIENTES:Setenta y siete pacientes con fístulas anales criptoglandulares complejas.INTERVENCIONES:Inyecciones de tejido adiposo autólogo recién recolectado. A los pacientes que no lograron la curación después de 8 a 12 semanas se les ofreció una segunda inyección.MEDIDAS DE RESULTADO PRINCIPALES:El resultado primario fue la cicatrización de la fístula definida como ausencia de síntomas de secreción, apertura externa visible e interna palpable mediante examen digital anorrectal en la evaluación clínica 6 meses después del tratamiento final. Los resultados secundarios fueron la combinación clínica y de curación en la resonancia magnética, la reducción de la secreción de la fístula y las molestias anales, y las complicaciones del tratamiento.RESULTADOS:Treinta y nueve pacientes (51%) lograron el resultado primario de curación de la fístula 6 meses después de su tratamiento final. Nueve pacientes (12%) experimentaron una reducción de la secreción y una disminución de las molestias anales. Treinta y siete pacientes (48%) lograron la curación combinada de la fístula clínica y en la resonancia magnética. El tratamiento fue bien tolerado; 5 pacientes (4%) experimentaron eventos adversos graves (infección o sangrado) que requirieron intervención quirúrgica.LIMITACIONES:No se incluyó ningún grupo de control.CONCLUSIÓN:La inyección de tejido adiposo autólogo recién recolectado es un tratamiento seguro de las fístulas anales criptoglandulares complejas y puede ser una alternativa económica de fácil acceso a las células madre mesenquimales derivadas de tejido adiposo autólogo y alogénico cultivadas. Consulte Video Resumen en http://links.lww.com/DCR/Cxx . (Traducción-Dr. Felipe Bellolio ).

Regenerative medicine for digestive fistulae therapy: Benefits, challenges and promises of stem/stromal cells and emergent perspectives via their extracellular vesicles

Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

Molecular differences of adipose-derived mesenchymal stem cells between non-responders and responders in treatment of transphincteric perianal fistulas

Background

Injection of autologous adipose tissue (AT) has recently been demonstrated to be an effective and safe treatment for anal fistulas. AT mesenchymal stem cells (AT-MSCs) mediate the healing process, but the relationship between molecular characteristics of AT-MSCs of the injected AT and fistula healing has not been adequately studied. Thus we aimed to characterize the molecular and functional properties of AT-MSCs isolated from autologous AT injected as a treatment of cryptogenic high transsphincteric perianal fistulas and correlate these findings to the healing process.

Methods

27 patients (age 45 ± 2 years) diagnosed with perianal fistula were enrolled in the study and treated with autologous AT injected around the anal fistula tract. AT-MSCs were isolated for cellular and molecular analyses. The fistula healing was evaluated by MRI scanning after 6 months of treatment. AT-MSC phenotype was compared between responders and non-responders with respect to fistula healing.

Results

52% of all patients exhibited clinical healing of the fistulas as evaluated 6 months after last injection. Cultured AT-MSCs in the responder group had a lower short-term proliferation rate and higher osteoblast differentiation potential compared to non-responder AT-MSCs. On the other hand, adipocyte differentiation potential of AT-MSCs was higher in non-responder group. Interestingly, AT-MSCs of responders exhibited lower expression of inflammatory and senescence associated genes such as IL1B, NFKB, CDKN2A, TPB3,TGFB1.

Conclusion

Our data suggest that cellular quality of the injected AT-MSCs including cell proliferation, differentiation capacity and secretion of proinflammatory molecules may provide a possible mechanism underlying fistula healing. Furthermore, these biomarkers may be useful to predict a positive fistula healing outcome.

Trial registration: NTC04834609, Registered 6 April 2021. https://clinicaltrials.gov/ct2/show/NCT04834609

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02644-8.

Efficacy and Safety of Treatment of Complex Idiopathic Fistula-in-Ano Using Autologous Centrifuged Adipose Tissue Containing Progenitor Cells: A Randomized Controlled Trial

BACKGROUND

Mesenchymal stem cells derived from adipose tissue have been successfully used to promote sphincter-saving anal fistula healing.

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of the use of autologous centrifuged adipose tissue in the healing process of cryptoglandular complex anal fistulas.

DESIGN

This is a randomized controlled trial.

SETTINGS

This study was conducted at a single center.

PATIENTS

Patients with complex perianal fistulas not associated with Crohn's disease were included. Rectovaginal fistulas were not included.

INTERVENTIONS

Patients were randomly allocated to receive treatment with centrifuged adipose tissue injection (experimental group) and without injection (control group) in combination with fistula surgery.

MAIN OUTCOME MEASURES

The primary outcome was defined as the proportion of patients with complete fistula closure at 4 weeks (short-term outcome) and 6 months after surgery (long-term outcome). Healing was defined as when the external opening was closed with no perianal discharge on clinical assessment. The secondary outcome was safety that was evaluated by the analysis of adverse events up to 3 months after surgery. Pelvic MRI was performed at 3 months to assure safety and the accuracy of the clinical determination of healing. Postoperative pain, return to work/daily activities, persistent closure at 6 months, fecal incontinence, and patient satisfaction were evaluated.

RESULTS

Fifty-eight patients who received centrifuged adipose tissue injection and 58 patients who did not receive centrifuged adipose tissue injection were included in the safety and efficacy analysis. After 4 weeks, the healing rate was 63.8% in the experimental group compared with 15.5% in the control group (p < 0.001). No major adverse events were recorded. Postoperative anal pain was significantly lower in the injection group. Time taken to return to work/daily activities was significantly shorter in the experimental group (3 days) than in the control group (17 days). At 6 months, persistent closure was similar in the 2 groups (86.2% vs 81%). Fecal Incontinence Score at 6 months after surgery was identical to the preoperative score. Patient satisfaction was high in both groups.

LIMITATIONS

The absence of blinding, the lack of correlation between stem cell content, and the clinical outcome were limitations of the study.

CONCLUSIONS

Autologous centrifuged adipose tissue injection may represent a safe, efficacious, and inexpensive option for the treatment of complex fistula-in-ano. See Video Abstract at http://links.lww.com/DCR/B607.

CLINICAL TRIALS REGISTRATION

URL: https://www.clinicaltrials.gov. Identifier: NCT04326907.

EFICACIA Y SEGURIDAD DEL TRATAMIENTO DE LA FSTULA ANAL COMPLEJA IDIOPTICA UTILIZANDO TEJIDO ADIPOSO CENTRIFUGADO AUTLOGO QUE CONTIENE CLULAS PROGENITORAS UN ENSAYO CONTROLADO ALEATORIO

ANTECEDENTES:Las células madre mesenquimales derivadas del tejido adiposo se han utilizado con éxito para promover la curación de la fístula anal con preservación de esfínter.OBJETIVO:El objetivo de este estudio fue evaluar la eficacia y seguridad del uso de tejido adiposo autólogo centrifugado en el proceso de cicatrización de fístulas anales complejas de origen criptoglandular.DISEÑO:Ensayo controlado aleatorio.ENTORNO CLÍNICO:Estudio unicéntrico.PACIENTES:Se incluyeron pacientes con fístulas perianales complejas no asociadas a Enfermedad de Crohn. No se incluyeron las fístulas rectovaginales.INTERVENCIONES:Los pacientes fueron asignados aleatoriamente para recibir tratamiento con inyección de tejido adiposo centrifugado (grupo experimental) y sin inyección (grupo de control) en combinación con cirugía de fístula.PRINCIPALES MEDIDAS DE VALORACIÓN:El resultado primario se definió como la proporción de pacientes con cierre completo de la fístula a las 4 semanas (resultado a corto plazo) y 6 meses después de la cirugía (resultado a largo plazo). La curación se definió cuando orificio externo se cerró sin secreción perianal en la valoración clínica. El resultado secundario fue la seguridad que se evaluó mediante el análisis de los eventos adversos (EA) hasta 3 meses después de la cirugía. La resonancia magnética pélvica se realizó a los 3 meses para garantizar la seguridad y la precisión clínica de la curación. Se evaluó el dolor postoperatorio, el regreso al trabajo / actividades diarias, el cierre persistente a los 6 meses, la incontinencia fecal y la satisfacción del paciente.RESULTADOS:Cincuenta y ocho pacientes que recibieron inyección de tejido adiposo centrifugado y 58 pacientes que no recibieron inyección de tejido adiposo centrifugado se incluyeron en el análisis de seguridad y eficacia. Después de 4 semanas, la tasa de curación fue del 63,8% en el grupo experimental en comparación con el 15,5% en el grupo de control (p <0,001). No se registraron eventos adversos importantes. El dolor anal posoperatorio fue significativamente menor en el grupo de inyección. El tiempo necesario para volver al trabajo / actividades diarias fue significativamente menor en el grupo experimental (3 días) con respecto al grupo de control (17 días). A los 6 meses, el cierre persistente fue similar en los dos grupos (86,2% vs 81%). La puntuación de incontinencia fecal a los 6 meses después de la cirugía fue idéntica a la puntuación preoperatoria. La satisfacción del paciente fue muy alta en ambos grupos.LIMITACIONES:Ausencia de cegamiento, falta de correlación entre el contenido de células madre y el resultado clínico.CONCLUSIONES:La inyección de tejido adiposo centrifugado autólogo puede representar una opción segura, eficaz y económica para el tratamiento de la fístula anal compleja.Registro de ensayos clínicos: www.clinicaltrials.gov, identificador NCT04326907; No patrocinado.Consulte Video Resumen en http://links.lww.com/DCR/B607.

Stapled transperineal repair for low- and mid-level rectovaginal fistulas: A 5-year experience and comparison with sutured repair

BACKGROUND

Currently, rectovaginal fistula (RVF) continues to be a surgical challenge worldwide, with a relatively low healing rate. Unclosed intermittent suture and poor suture materials may be the main reasons for this.

AIM

To evaluate the efficacy and safety of stapled transperineal repair in treating RVF.

METHODS

This was a retrospective cohort study conducted in the Coloproctology Department of The Sixth Affiliated Hospital of Sun Yat-sen University (Guangzhou, China). Adult patients presenting with RVF who were surgically managed by perineal repair between May 2015 and May 2020 were included. Among the 82 total patients, 37 underwent repair with direct suturing and 45 underwent repair with stapling. Patient demographic data, Wexner faecal incontinence score, and operative data were analyzed. Recurrence rate and associated risk factors were assessed.

RESULTS

The direct suture and stapled repair groups showed similar clinical characteristics for aetiology, surgical history, fistula features, and perioperative Wexner score. The stapled repair group did not show superior results over the suture repair group in regard to operative time, blood loss, and hospital stay. However, the stapled repair group showed better postoperative Wexner score (1.04 ± 1.89 vs 2.73 ± 3.75, P = 0.021), less intercourse pain (1/45 vs 17/37, P = 0.045), and lower recurrence rate (6/45 vs 17/37, P = 0.001). There was no protective effect from previous repair history, smaller diameter of fistula (< 0.5 cm), better control of defecation (Wexner < 10), or stapled repair. Direct suture repair and preoperative high Wexner score (> 10) were risk factors for fistula recurrence. Furthermore, stapled repair gave better efficacy in treating complex RVFs (i.e., multiple transperineal repair history, mid-level fistula position, and poor control of defecation).

CONCLUSION

Stapled transperineal repair is advantageous for management of RVF, providing a high primary healing rate and low recurrence rate.

Stromal vascular fraction injection to treat intractable radiation-induced rectovaginal fistula

Rectovaginal fistula, which can arise after an injury to the vaginal canal or rectum, is a troublesome obstacle for patients’ everyday life. In most cases, it can be covered with a local flap, but previous radiation therapy increases the recurrence rate, making it especially difficult to cure. As the application of stromal vascular fraction (SVF) obtained from enzymatically digested autologous adipose tissue has become increasingly common, several reports have advocated its effectiveness for the treatment of refractory wounds. In light of the angiogenic, regenerative characteristics of SVF, it was incorporated as a treatment option in two cases of rectovaginal fistula discussed here. As described in this report, irradiated rectovaginal fistulas in rectal cancer patients were successfully treated with SVF injection, and we suggest SVF as a feasible treatment option for cases of rectovaginal fistula that would otherwise be very difficult to cure.

Allogeneic expanded adipose-derived stem cells in the treatment of rectovaginal fistulas in Crohn's disease

AIM

Crohn's disease (CD)-related rectovaginal fistulas (RVFs) are rare, challenging to treat and associated with a high morbidity. Due to a significant lack of data, we aimed to analyse the safety and feasibility of allogeneic adipose-derived stem cells (ASCs) in the treatment of CD-related RVF.

METHOD

Four consecutive patients with CD-related RVF underwent treatment with expanded allogeneic ASCs extracted from a healthy donor in a tertiary referral centre in 2019. None of the patients had an intestinal diversion at the time of the treatment. Follow-up was performed 6 months postoperatively.

RESULTS

The median operation time was 45 min with a median hospital stay of 3 days. No intra-operative complications occurred. Three patients (75%) developed recurrent RVF after a median follow-up of 19 days. Two patients required surgical treatment including loose seton drainage due to discharge and pain. One patient developed recurrence of symptoms after 10 days, but refused further surgical therapy. Only one patient (25%) showed healing of the RVF, with re-epithelialization of both the vaginal and rectal opening and absence of clinical symptoms.

CONCLUSION

Expanded allogeneic ASC therapy represents a novel safe treatment option for CD-associated RVF. Although efficacy appears limited, further controlled studies are required to draw robust conclusions.

Rectovaginal Fistulas Secondary to Obstetrical Injury

Rectovaginal fistula (RVF), defined as any abnormal connection between the rectum and the vagina, is a complex and debilitating condition. RVF can occur for a variety of reasons, but frequently develops following obstetric injury. Patients with suspected RVF require thorough evaluation, including history and physical examination, imaging, and objective evaluation of the anal sphincter complex. Prior to attempting repair, sepsis must be controlled and the tract allowed to mature over a period of 3 to 6 months. All repair techniques involve reestablishing a healthy, well-vascularized rectovaginal septum, either through reconstruction with local tissue or tissue transfer via a pedicled flap. The selection of a specific repair technique is determined by the level of the fistula tract and the status of the anal sphincter. Despite best efforts, recurrence is common and should be discussed with patients prior to repair. As the ultimate goal of RVF repair is to minimize symptoms and maximize quality of life, patients should help to direct their own care based on the risks and benefits of available treatment options.

CELL THERAPY IN INFLAMMATORY BOWEL DISEASE

In recent years, cell-based therapies have been explored in various immune-mediated inflammatory diseases, including inflammatory bowel disease (IBD). Cell therapy is the process of introducing new cells into an organism or tissue in order to treat a disease. The most studied cellular treatment in IBD was "stem cells-based therapy", which was explored according to different protocols in terms of type of donors, stem cells sources, study design and clinical endpoints. More recently, preliminary studies have also described the clinical use of "regulatory cells", which include T-reg and Tr1 cells, and "tolerogenic" dendritic cells. Finally, induced pluripotent stem cells are the subject of an intensive preclinical research program on animal models, including those related to colitis.

Recommendations of the Crohn's Disease and Ulcerative Colitis Spanish Working Group (GETECCU) for the treatment of perianal fistulas of Crohn's disease

Recommendations are advice that is given and considered to be beneficial; however, they are still suggestions and are therefore open to different interpretations. In this sense, the final objective of the review has been to try to homogenize, with the evidence available, the approach to the diagnosis and medical/surgical treatment of one of the most complex manifestations of Crohn's disease, such as simple and complex perianal fistulas.

Evaluation and management of perianal abscess and anal fistula: SICCR position statement

Perianal sepsis is a common condition ranging from acute abscess to chronic anal fistula. In most cases, the source is considered to be a non-specific cryptoglandular infection starting from the intersphincteric space. Surgery is the main treatment and several procedures have been developed, but the risks of recurrence and of impairment of continence still seem to be an unresolved issue. This statement reviews the pertinent literature and provides evidence-based recommendations to improve individualized management of patients.

Use of the Martius advancement flap for low rectovaginal fistulas

AIM

The percentage recurrence after any surgical treatment for low rectovaginal fistula (LRVF) is unacceptably high. The aim of this study was to evaluate the short- and long-term results of the Martius procedure in a carefully selected series of patients with a LRVF of at least 1 cm diameter who had had at least two previous surgeries or in the presence of chronically inflamed local tissues.

METHOD

Between January 2009 and April 2017, 24 patients with the abovementioned features were prospectively included in this study. Success was defined both as the absence of any subjective symptoms and the fistula, as confirmed by evaluation under anaesthesia. Postoperative complications were assessed using the Clavien-Dindo classification. Quality of life (SF-12 score), quality of sexual life [Female Sexual Function Index (FSFI) score] and continence [Cleveland Clinic Incontinence Score (CCIS)] were also determined pre- and postoperatively.

RESULTS

The mean follow-up was 42 ± 29 months (range 3-101 months). The overall success rate was 91.3% (22/24 patients). The median operation time was 50 min (range 45-70 min), and the median hospital stay was 3.5 days (range 3-5 days). No major complications occurred. Pre- and postoperative CCIS did not differ [1 (range 0-3.5)]. The postoperative SF-12 score improved both in terms of the physical (33.6 ± 7.2 vs 50.8 ± 7.8; P < 0.001) and mental (32.6 ± 6.7 vs 56.3 ± 7.8; P < 0.001) components. FSFI improved from 19.5 ± 6.6 to 24.4 ± 6.3 (P < 0.001).

CONCLUSION

The Martius procedure should be considered as the first-line method of treatment in carefully selected cases of LRVF.

Efficacy of Injection of Freshly Collected Autologous Adipose Tissue Into Perianal Fistulas in Patients With Crohn's Disease

BACKGROUND & AIMS

Perianal fistulas are common in patients with Crohn's disease (CD). Injections of cultured autologous and allogeneic adipose tissue-derived stem cells have been shown to heal CD-associated fistulas. Unfortunately, this treatment is time consuming and expensive. We investigated the effects of injecting freshly collected autologous adipose tissue into perianal fistulas in patients with CD.

METHODS

In a prospective interventional study, freshly collected autologous adipose tissues were injected into complex perianal fistulas of 21 patients with CD, from March 2015 through June 2018. The primary endpoint was complete fistula healing (no symptoms of discharge, no visible external fistula opening in the perineum, and no internal opening detected by rectal digital examination) 6 months after the last injection. We performed pelvic magnetic resonance imaging to confirm fistula resolution in patients with intersphincter and transsphincter fistulas who showed complete healing at clinical examination. Patients without complete fistula healing after 6 weeks and those with later relapse were offered additional injections. No control individuals were included.

RESULTS

Six months after the last adipose tissue injection, 12 patients (57%) had complete fistula healing. Three patients (14%) had ceased fistula secretion, and 1 patient (5%) reported reduced secretion. Among 10 patients with trans-sphincter or inter-sphincter fistulas, magnetic resonance imaging showed complete fistula resolution in 9 patients and a markedly reduced gracile fistula in the remaining patient. Of the 12 patients with complete fistula healing, 9 (43%) required 1 injection, 2 (10%) required 2 injections, and 1 (5%) required 3 injections. The predominant adverse effect was postprocedure proctalgia lasting a few days. Two patients developed small abscesses, 1 had urinary retention, and 1 had minor bleeding during liposuction.

CONCLUSION

In a study of 21 patients with CD and perianal fistulas, we found injection of recently collected autologous adipose tissue to be safe and to result in complete fistula healing in 57% of patients. ClinicalTrials.gov, Number: NCT03803917.

Effects of VEGF-ANG-1-PLA nano-sustained release microspheres on proliferation and differentiation of ADSCs

The improvement of fat graft viability might depend on the presence of multipotent resident adipose derived stem cells (ADSCs) which is the important component of stromal vascular fraction (SVF). Vascular endothelial growth factor (VEGF) and angiogenin-1 (Ang-1) are responsible for neovascularization. However, their half-life is too short to produce a biological effect. We thus investigated whether VEGF-ANG-1-polylactic acid (PLA) microspheres could enhance the angiogenic properties of ADSCs. PLA microspheres containing VEGF and ANG-1 were prepared by in vitro ultrasonic emulsification and characterized according to their encapsulation efficiency (EE), drug-loading rate (DL), particle size, and drug release. The systemic toxicity of empty loaded nanospheres (NPs) and the ability of these microspheres to promote the proliferation and differentiation of ADSCs were evaluated. The EE and DL were above 86% and 0.0288%, respectively [corrected].The drug release was completed after 20 days. Systemic toxicity was verified in ADSCs that received the unloaded NPs. It was observed that ADSCs treated with VEGF-ANG-1-PLA microspheres had an increase in the proliferation and the number of CD31 positive cells. ADSCs proliferation and differentiation toward endothelial cells (ECs) could be enhanced by the addition of VEGF-ANG-1-PLA nano-sustained release microspheres.