Implantation of amniotic membrane to reduce postlaminectomy epidural adhesions

Docosahexaenoic Acid-Infused Core-Shell Fibrous Membranes for Prevention of Epidural Adhesions

Avoiding epidural adhesion following spinal surgery can reduce clinical discomfort and complications. As the severity of epidural adhesion is positively correlated with the inflammatory response, implanting a fibrous membrane after spinal surgery, which can act as a physical barrier to prevent adhesion formation while simultaneously modulates postoperative inflammation, is a promising approach to meet clinical needs. Toward this end, we fabricated an electrospun core-shell fibrous membrane (CSFM) based on polylactic acid (PLA) and infused the fiber core region with the potent natural anti-inflammatory compound docosahexaenoic acid (DHA). The PLA/DHA CSFM can continuously deliver DHA for up to 36 days in vitro and reduce the penetration and attachment of fibroblasts. The released DHA can downregulate the gene expression of inflammatory markers (IL-6, IL-1β, and TNF-α) in fibroblasts. Following an in vivo study that implanted a CSFM in rats subjected to lumbar laminectomy, the von Frey withdrawal test indicates the PLA/DHA CSFM treatment can successfully alleviate neuropathic pain-like behaviors in the treated rats, showing 3.60 ± 0.49 g threshold weight in comparison with 1.80 ± 0.75 g for the PLA CSFM treatment and 0.57 ± 0.37 g for the untreated control on day 21 post-implantation. The histological analysis also indicates that the PLA/DHA CSFM can significantly reduce proinflammatory cytokine (TNF-α and IL-1β) protein expression at the lesion and provide anti-adhesion effects, indicating its vital role in preventing epidural fibrosis by mitigating the inflammatory response.

The Categorization of Perinatal Derivatives for Orthopedic Applications

Musculoskeletal (MSK) pathology encompasses an array of conditions that can cause anything from mild discomfort to permanent injury. Their prevalence and impact on disability have sparked interest in more effective treatments, particularly within orthopedics. As a result, the human placenta has come into focus within regenerative medicine as a perinatal derivative (PnD). These biologics are sourced from components of the placenta, each possessing a unique composition of collagens, proteins, and factors believed to aid in healing and regeneration. This review aims to explore the current literature on PnD biologics and their potential benefits for treating various MSK pathologies. We delve into different types of PnDs and their healing effects on muscles, tendons, bones, cartilage, ligaments, and nerves. Our discussions highlight the crucial role of immune modulation in the healing process for each condition. PnDs have been observed to influence the balance between anti- and pro-inflammatory factors and, in some cases, act as biologic scaffolds for tissue growth. Additionally, we assess the range of PnDs available, while also addressing gaps in our understanding, particularly regarding biologic processing methods. Although certain PnD biologics have varying levels of support in orthopedic literature, further clinical investigations are necessary to fully evaluate their impact on human patients.

PURION® processed human amnion chorion membrane allografts retain material and biological properties supportive of soft tissue repair

The reparative properties of amniotic membrane allografts are well-suited for a broad spectrum of specialties. Further enhancement of their utility can be achieved by designing to the needs of each application through the development of novel processing techniques and tissue configurations. As such, this study evaluated the material characteristics and biological properties of two PURION® processed amniotic membrane products, a lyophilized human amnion, intermediate layer, and chorion membrane (LHACM) and a dehydrated human amnion, chorion membrane (DHACM). LHACM is thicker; therefore, its handling properties are ideal for deep, soft tissue deficits; whereas DHACM is more similar to a film-like overlay and may be used for shallow defects or surgical on-lays. Characterization of the similarities and differences between LHACM and DHACM was conducted through a series of in vitro and in vivo studies relevant to the healing cascade. Compositional analysis was performed through histological staining along with assessment of barrier membrane properties through equilibrium dialysis. In vitro cellular response was assessed in fibroblasts and endothelial cells using cell proliferation, migration, and metabolic assays. The in vivo cellular response was assessed in an athymic nude mouse subcutaneous implantation model. The results indicated the PURION® process preserved the native membrane structure, nonviable cells and collagen distributed in the individual layers of both products. Although, LHACM is thicker than DHACM, a similar composition of growth factors, cytokines, chemokines and proteases is retained and consequently elicit comparable in vitro and in vivo cellular responses. In culture, both treatments behaved as potent mitogens, chemoattractants and stimulants, which translated to the promotion of cellular infiltration, neocollagen deposition and angiogenesis in a murine model. PURION® processed LHACM and DHACM differ in physical properties but possess similar in vitro and in vivo activities highlighting the impact of processing method on the versatility of clinical use of amniotic membrane allografts.

Postoperative Epidural Fibrosis: Challenges and Opportunities - A Review

Postoperative epidural fibrosis (EF) is still a major limitation to the success of spine surgery. Fibrotic adhesions in the epidural space, initiated via local trauma and inflammation, can induce difficult-to-treat pain and constitute the main cause of failed back surgery syndrome, which not uncommonly requires operative revision. Manifold agents and methods have been tested for EF relief in order to mitigate this longstanding health burden and its socioeconomic consequences. Although several promising strategies could be identified, few have thus far overcome the high translational hurdle, and there has been little change in standard clinical practice. Nonetheless, notable research progress in the field has put new exciting avenues on the horizon. In this review, we outline the etiology and pathogenesis of EF, portray its clinical and surgical presentation, and critically appraise current efforts and novel approaches toward enhanced prevention and treatment.

The current status and development trend of hydrogel application in spinal surgery

Spinal diseases often result in compromised mobility and diminished quality of life due to the intricate anatomy surrounding the nervous system. Medication and surgical interventions remain the primary treatment methods for spinal conditions. However, currently available medications have limited efficacy in treating spinal surgical diseases and cannot achieve a complete cure. Furthermore, surgical intervention frequently results in inevitable alterations and impairments to the initial anatomical integrity of the spinal structure, accompanied by the consequential loss of certain physiological functionalities. Changes in spine surgery treatment concepts and modalities in the last decade have led to a deepening of minimally invasive treatment, with treatment strategies focusing more on repairing and reconstructing the patient's spine and preserving physiological functions. Therefore, developing novel and more efficient treatment strategies to reduce spinal lesions and iatrogenic injuries is essential. In recent years, significant advancements in biomedical research have led to the discovery that hydrogels possess excellent biocompatibility, biodegradability, and adjustable mechanical properties. The application of hydrogel-based biotechnology in spinal surgery has demonstrated remarkable therapeutic potential. This review presents the therapeutic strategies for spinal diseases based on hydrogel tissue engineering technology.

Chronic pain after spine surgery: Insights into pathogenesis, new treatment, and preventive therapy

Chronic pain after spine surgery (CPSS) is often characterized by intractable low back pain and/or radiating leg pain, and has been reported in 8-40% of patients that received lumbar spine surgery. We conducted a literature search of PubMed, MEDLINE/OVID with a focus on studies about the etiology and treatments of CPSS and low back pain. Our aim was to provide a narrative review that would help us better understand the pathogenesis and current treatment options for CPSS. This knowledge will aid in the development of optimal strategies for managing postoperative pain symptoms and potentially curing the underlying etiologies. Firstly, we reviewed recent advances in the mechanistic study of CPSS, illustrated both structural (e.g., fibrosis and scaring) and non-structural factors (e.g., inflammation, neuronal sensitization, glial activation, psychological factor) causing CPSS, and highlighted those having not been given sufficient attention as the etiology of CPSS. Secondly, we summarized clinical evidence and therapeutic perspectives of CPSS. We also presented new insights about the treatments and etiology of CPSS, in order to raise awareness of medical staff in the identification and management of this complex painful disease. Finally, we discussed potential new targets for clinical interventions of CPSS and future perspectives of mechanistic and translational research. CPSS patients often have a mixed etiology. By reviewing recent findings, the authors advocate that clinicians shall comprehensively evaluate each case to formulate a patient-specific and multi-modal pain treatment, and importantly, consider an early intraoperative intervention that may decrease the risk or even prevent the onset of CPSS.

Translational potential statement

CPSS remains difficult to treat. This review broadens our understanding of clinical therapies and underlying mechanisms of CPSS, and provides new insights which will aid in the development of novel mechanism-based therapies for not only managing the established pain symptoms but also preventing the development of CPSS.

Exploration of 2D and 2.5D Conformational Designs Applied on Epoxide/Collagen-Based Integrative Biointerfaces with Device/Tissue Heterogeneous Affinity

Collagen and multifunctional epoxides, which are respectively the common constituents of natural and polymer interfaces, were combined to fabricate integrative biointerfaces with device/tissue heterogeneous affinity. Further, the traditional 2D and advanced 2.5D conformational designs were achieved on collagen-based biointerfaces. The 2D conformational biointerfaces were formed by the self-entanglement of collagen molecules based on extensive hydrogen bonds among molecules, and the lamellar structures of 2D conformational biointerfaces could act as barriers to protect both biointerfaces and substrates from enzymes and corrosion. The unique stacking structures of 2.5D conformational biointerfaces were formed by cross-linking microaggregates that were established and connected by epoxy cross-linking bonds and provided the extra 0.5D degree of freedom on structure design and functional specialization through artificially manipulating the constituents and density of microaggregates. Besides, the intersecting channels among microaggregates gave 2.5D biointerfaces diffusion behaviors, which further brought good wettability and biodegradability. The integrative biointerfaces behaved well on cell viability and enhanced the cell adhesion strength in vitro, which could be attributed to the collaborations of collagen and epoxy groups. The subcutaneous implant model in rats was utilized to investigate soft tissue response, and the results demonstrated that the tissues around implantation areas healed well and without calcification or infection. The coating of integrative biointerfaces alleviated the fibrosis around implantation areas, and the inflammatory responses and foreign body reactions were improved.

Protective and Therapeutic Effects of Bovine Amniotic Fluids Collected in Different Trimesters on the Epidural Fibrosis After Experimental Laminectomy in Rats

BACKGROUND

The aim of this study was to investigate the protective and therapeutic effects of bovine amniotic fluid (BAF) on the inhibition of epidural fibrosis (EF) after experimental laminectomy.

METHODS

Forty female Sprague Dawley rats were used. The amniotic fluids were collected from each trimester of a pregnant cow. The rats were divided into 5 groups. Whereas no laminectomy was applied to the control group, animals in the sham group underwent laminectomy. Laminectomy was performed in the animals in other groups and the operation area was closed by dripping 1 mL of BAF collected in 3 trimesters of pregnancy. Animals were killed 28 days after the operation.

RESULTS

Compared with control, VEGF gene expression levels were downregulated approximately 5-fold in BAF-2. Whereas IL-6 was upregulated approximately 8-fold in the sham, it was downregulated 5-fold and 3-fold in BAF-1 and BAF-2, respectively. There was downregulation in BAF-2 and BAF-3 in terms of CD105 gene expression levels. TGFβ1 was upregulated approximately 2-fold in the sham group and downregulated in BAF-1 and BAF-2. Although histopathologic alterations including EF grade and fibroblast cell density were found to increase in the sham group, all BAF treatment decreased those of alterations. The highest CD105 immunoreactivity was detected in the sham group. All BAF treatment markedly aggravated fibrosis via decreasing CD105 immunoreactivity. In terms of grading parameters, almost the closest grades to the control were determined in the BAF-2. BAF collected in the second trimester is most effective in healing of scar tissue and preventing fibrosis via decreasing microvessel and fibroblast densities.

CONCLUSIONS

The results indicate that BAF may be used as a potential protective agent to prevent EF.

The Effect of Amniotic Tissue on Spinal Interventions: A Systematic Review

BACKGROUND

Amniotic membrane tissue has been thought to potentiate healing in many soft tissue conditions. Specifically, recent studies have shown its therapeutic potential for treatment in the setting of spinal pathologies. The purpose of this study is to thoroughly review the existing scientific literature and evidence concerning the clinical use of amniotic membrane-derived biologic agents on postoperative outcomes following spinal surgery.

METHODS

A systematic review was conducted following preferred reporting items for systematic reviews and meta-analyses guidelines using PubMed, Embase, and Cochrane databases up to December 2020 to identify animal and clinical studies examining the therapeutic potential for amniotic membrane tissue in the setting of spinal pathologies (including disc herniation, prevention of epidural fibrosis, and spinal fusion). Studies were broken down into 2 categories: experimental model type and the type of amnion product being analyzed.

RESULTS

A total of 12 studies (4 clinical studies and 8 studies utilizing animal models) met inclusion criteria. Additionally, the major types of amnion product were divided into cryopreserved/freeze-dried amniotic membrane, human amniotic fluid, human amniotic membrane, cross-linked amniotic membrane, and amnion-derived epithelial cells. While heterogeneity of study design precludes definitive specific results reporting, most studies showed positive benefits on healing/outcomes with amniotic augmentation. Specifically, amnion products have shown promising effects in reducing epidural adhesions and scar tissue after spine surgery, improving spinal fusion rate and postoperative pain scores, and promoting better functional outcomes after spine surgery.

CONCLUSIONS

A review of the limited number of reported studies revealed a wide variety of amniotic membrane preparations, treatment regimens, and indications, which limit definitive conclusions. To date, while there is no definitive clinical proof that amniotic tissues enhance tissue repair or regeneration, the aggregate results demonstrate promising basic science and outcomes potential in spinal surgery. Further study is warranted to determine whether this application is appropriate in the clinical setting.

CLINICAL RELEVANCE

This systematic review provides a summary of the existing literature regarding the use of amniotic membrane preparations, treatment regimens, and indications within spinal surgery. With the growing popularity and utilization of biologic agents such as amniotic membrane-derived products in orthopedic and neurologic surgery, this systematic review gives physicians a concise summary on the outcomes and indications associated with amniotic membrane products.

LEVEL OF EVIDENCE: 4

Amniotic membrane attenuates heterotopic ossification following high-dose bone morphogenetic protein-2 treatment of segmental bone defects

Treatment of large bone defects with supraphysiological doses of bone morphogenetic protein-2 (BMP-2) has been associated with complications including heterotopic ossification (HO), inflammation, and pain, presumably due to poor spatiotemporal control of BMP-2. We have previously recapitulated extensive HO in our rat femoral segmental defect model by treatment with high-dose BMP-2 (30 μg). Using this model and BMP-2 dose, our objective was to evaluate the utility of a clinically available human amniotic membrane (AM) around the defect space for guided bone regeneration and reduction of HO. We hypothesized that AM surrounding collagen sponge would attenuate heterotopic ossification compared with collagen sponge alone. In vitro, AM retained more BMP-2 than a synthetic poly(ε-caprolactone) membrane through 21 days. In vivo, as hypothesized, the collagen + AM resulted in significantly less heterotopic ossification and correspondingly, lower total bone volume (BV), compared with collagen sponge alone. Although bone formation within the defect was delayed with AM around the defect, by 12 weeks, defect BVs were equivalent. Torsional stiffness was significantly reduced with AM but was equivalent to that of intact bone. Collagen + AM resulted in the formation of dense fibrous tissue and mineralized tissue, while the collagen group contained primarily mineralized tissue surrounded by marrow-like structures. Especially in conjunction with high doses of growth factor delivered via collagen sponge, these findings suggest AM may be effective as an overlay adjacent to bone healing sites to spatially direct bone regeneration and minimize heterotopic ossification.

Human Amniotic Membrane Wrapping of the Ulnar Nerve During Cubital Tunnel Surgery Reduces Recurrence of Symptoms

Background

Compare the recurrence rate of paresthesias in patients undergoing primary cubital tunnel surgery in those with and without wrapping of the ulnar nerve with the human amniotic membrane (HAM).

Methods

A retrospective investigation of patients undergoing primary cubital tunnel surgery with a minimum 90-day follow-up was performed. Patients were excluded if the nerve was wrapped using another material, associated traumatic injury, simultaneous Guyon's canal release, or revision procedures. Failure was defined as those patients who experienced initial complete resolution of symptoms (paresthesias) but then developed recurrence of paresthesias.

Results

A total of 57 controls (CON) and 21 treated with HAM met our inclusion criteria. There was a difference in the mean age of CON (48.4 ± 13.5 years) and HAM (30.6 ± 15) (P< 0.0001). There was no difference in gender mix (P=0.4), the severity of symptoms (P=0.13), and length of follow-up (P=0.084). None of 21 (0%) treated with HAM developed recurrence of symptoms compared to 11 of 57 (19.3%) (P=0.03) (CON). Using a multivariate regression model adjusted for age and procedure type, CON was 24.4 (95% CI=1.26-500, P=0.0348) times higher risk than HAM of developing a recurrence of symptoms.

Conclusion

The HAM wrapping used in primary cubital tunnel surgery significantly reduced recurrence rates of paresthesias. Further prospective studies with randomization should be carried out to better understand the role HAM can play in cubital tunnel surgery.

Epidural Fat Tissue Is More Effective for Scar Prevention Than Conventional Subcutaneous Fat Grafting After Laminectomy in a Mouse Model

STUDY DESIGN

Basic science study.

OBJECTIVE

The aim of this study was to examine whether epidural fat tissue (EFT) transplantation can prevent epidural adhesion after laminectomy more efficiently than subcutaneous fat tissue (SFT) transplantation.

SUMMARY OF BACKGROUND DATA

Epidural adhesion is almost inevitable after laminectomy. Although many materials have been used to prevent adhesion, none has been widely accepted. As EFT is an ectopic fat tissue located on the dura mater and there is no adhesion between EFT and the dura mater, we focused on the efficacy of EFT for adhesion prevention.

METHODS

We examined the differences in histology and gene expression between EFT and SFT of mice. We performed laminectomy at the 10th thoracic level and immediately transplanted EFT or SFT to the dura mater in mice. At 6 weeks after transplantation, we performed histological and gene expression analyses and evaluated the adhesion tenacity. In addition, we examined the characteristic differences between human EFT and SFT.

RESULTS

The adipocytes of EFT were significantly smaller than those of SFT in mice and humans. The gene expression of inflammatory cytokine and fibrosis-related factors was significantly higher in SFT than in EFT. At 6 weeks after transplantation, the percentage of the remaining fat area over the dura mater was significantly greater in the EFT group than in SFT group, and the adhesion tenacity score was significantly lower in the EFT group than that in the SFT group. An RNA sequencing analysis revealed 1921 differentially expressed genes (DEGs) between human EFT and SFT, and a Gene Ontology term associated with the inflammatory response was most highly enriched in SFT.

CONCLUSION

EFT has different molecular and histological profiles from SFT and EFT grafting is more effective for epidural adhesion prevention than conventional SFT transplantation after laminectomy in a mouse model.Level of Evidence: N/A.

Placental Tissues as Biomaterials in Regenerative Medicine

Placental tissues encompass all the tissues which support fetal development, including the placenta, placental membrane, umbilical cord, and amniotic fluid. Since the 1990s there has been renewed interest in the use of these tissues as a raw material for regenerative medicine applications. Placental tissues have been extensively studied for their potential contribution to tissue repair applications. Studies have attributed their efficacy in augmenting the healing process to the extracellular matrix scaffolds rich in collagens, glycosaminoglycans, and proteoglycans, as well as the presence of cytokines within the tissues that have been shown to stimulate re-epithelialization, promote angiogenesis, and aid in the reduction of inflammation and scarring. The compositions and properties of all birth tissues give them the potential to be valuable biomaterials for the development of new regenerative therapies. Herein, the development and compositions of each of these tissues are reviewed, with focus on the structural and signaling components that are relevant to medical applications. This review also explores current configurations and recent innovations in the use of placental tissues as biomaterials in regenerative medicine.

Proteomic Analysis and Cell Viability of Nine Amnion, Chorion, Umbilical Cord, and Amniotic Fluid-Derived Products

OBJECTIVE

Amnion products are used in various musculoskeletal surgeries and as injections for joint pain with conflicting reports of cell viability and protein contents. The objective of this study was to determine the full proteome and examine cell viability in 9 commercial amnion products using an unbiased bottom-up shotgun proteomics approach and confocal microscopy.

DESIGN

Products were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and searched against a UniProt Homo sapiens database. Relative protein abundance was determined for each sample. Based on proteomics results, lumican was measured by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis was performed for interleukin-1 receptor antagonist (IL-1Ra) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2). Cell viability was determined by calcein AM (live) and ethidium homodimer (dead) staining and confocal microscopy.

RESULTS

Proteomic analysis revealed 919 proteins in the nine products. Proteins were primarily collagens, keratin, and albumin. Lumican, a small leucine-rich proteoglycan (SLRP) was found in all samples. Western blot analysis for IL-1Ra and TIMP-2 indicated presence of both proteins, with nonspecific antibody binding also present in all samples. No live cells were identified in any product.

CONCLUSIONS

Several novel proteins were identified through proteomics that might impart the beneficial effects of amnion products, including SLRPs, collagens, and regulators of fibroblast activity. IL-1Ra and TIMP-2 were identified, but concentrations measured by ELISA may be falsely increased due to nonspecific antibody binding. The concept that the amnion tissues provide live cells to aid in tissue regeneration cannot be supported by the findings of this study.

Dissection of an Ulnar Nerve Previously Transposed and Wrapped with Human Amniotic Membrane: A Report of 3 Cases

CASES

We present 3 patients who underwent ulnar nerve transposition and wrapping of the nerve with human amniotic membrane (HAM). All 3 patients subsequently required a reoperation for the original pathologic condition (not for ulnar nerve symptoms), necessitating the exploration and dissection of the transposed ulnar nerve. We demonstrate the lack of scar formation and ease of separation between nerve and surrounding tissue, as well as histology in one case taken from the perineural tissues (previous amniotic membrane), demonstrating no inflammatory cells or absence of scar tissue formation.

CONCLUSION

Exploration and dissection of a previously transposed ulnar nerve can be facilitated by wrapping the nerve with HAM to prevent scarring and perineural fibrosis.

An Evidence Based Review of Epidurolysis for the Management of Epidural Adhesions

PURPOSE OF REVIEW

This review presents epidurolysis as a procedure to alleviate pain and disability from epidural adhesions. It reviews novel and groundbreaking evidence, describing the background, indications, benefits and adverse events from this procedure in an effort to provide healthcare experts with the data required to decide on an intervention for their patients.

RECENT FINDINGS

Epidural adhesions (EA) or epidural fibrosis (EF) is defined as non-physiologic scar formation secondary to a local inflammatory reaction provoked by tissue trauma in the epidural space. Often, it is a sequelae of surgical spine intervention or instrumentation. The cost associated with chronic post-operative back pain has been reported to be up to nearly $12,500 dollars per year; this, coupled with the increasing prevalence of chronic lower back pain and the subsequent increase in surgical management of back pain, renders EF a significant cost and morbidity in the U.S. Though risk factors leading to the development of EA are not well established, epidural fibrosis has been reported to be the culprit in up to 46% of cases of Failed Back Surgery Syndrome (FBSS), a chronic pain condition found in up to 20-54% of patients who receive back surgery. Moreover, EF has also been associated with lumbar radiculopathy after lumbar disc surgery. Epidurolysis is defined as the mechanical dissolution of epidural fibrotic scar tissue for persistent axial spine or radicular pain due to epidural fibrosis that is refractory to conservative therapy Endoscopic lysis of adhesions is a procedural technique which has been shown to improve chronic back pain in one-third to one-half of patients with clinically symptomatic fibrous adhesions. Here we review some of the novel evidence that supports this procedure in EA and FBSS.

SUMMARY

The literature concerning epidurolysis in the management of epidural adhesions is insufficient. Prospective studies, including randomized controlled trials and observational studies, have suggested epidurolysis to be effective in terms of pain reduction, functional improvement, and patient satisfaction scores. Observational studies report epidurolysis as a well-tolerated, safe procedure. Current evidence suggests that epidurolysis may be used as an effective treatment modality for epidural adhesions. Nonetheless, further high quality randomized controlled studies assessing the safety and efficacy of epidurolysis in the management of epidural adhesions is needed.

The Preventive Effect of Curcumin on the Experimental Rat Epidural Fibrosis Model

OBJECTIVE

The aim of the study was to evaluate the effect of systemically administrated curcumin on the prevention of peridural fibrotic tissue and adhesion formation in a rat laminectomy model.

METHODS

Thirty-two Wistar albino rats were randomly selected and equally divided into 4 groups as follows: negative control group (group I) did not undergo operation; positive control group (group II) underwent laminectomy without treatment; group III (low-dose curcumin; 100 mg/kg); and group IV (high-dose curcumin; 200 mg/kg). Curcumin was administered intraperitoneally per day for 7 days after surgery starting from day 0. Twenty-eight days after surgery, T12 and L4 vertebral columns, paraspinal tissues, and epidural scar tissue were dissected en bloc and prepared for histopathologic examinations. All specimens were examined for inflammation, epidural fibrosis (EF), foreign body reaction, medulla spinalis retraction, granulation tissue, and arachnoid involvement. A Kruskal-Wallis test followed by a Dunn multiple comparison test were used for statistical analysis, and a P value <0.05 was considered as statistically significant.

RESULTS

Curcumin treatment significantly reduced inflammation, foreign body reaction, granulation tissue formation, medulla spinalis retraction, and EF formation compared with positive control group (P < 0.05); however, no significant differences were found between the 2 groups that received different doses of curcumin.

CONCLUSIONS

The results of the present study showed that systemic administration of curcumin was effective in reducing EF formation, inflammation, granulation tissue formation, medulla spinalis retraction, and foreign body reaction in the laminectomy area. Our results suggest that antiinflammatory activities of curcumin are beneficial for attenuation of EF formation.

Expression of Lubricin in the Human Amniotic Membrane

PURPOSE

Lubricin, a boundary lubricant, is the body's unique antiadhesive, antifibrotic, antifriction, and antiinflammatory glycoprotein. This amphiphile is produced by numerous tissues and acts to regulate a number of processes, such as homeostasis, shear stress, tissue development, innate immunity, inflammation, and wound healing. We hypothesize that lubricin is also synthesized and expressed by the amniotic membrane (AM), which also possesses antiadhesive, antifibrotic, and antiinflammatory properties. We also hypothesize that lubricin, at least in part, mediates these AM capabilities. Our goal was to test our hypothesis.

METHODS

We obtained multiple samples of fresh, cryopreserved (CP), and freeze-dried (FD) human AMs, as well as fresh placental tissue as positive controls, and processed them for light microscopy, immunofluorescence, and western blot analyses. We also evaluated the ability of recombinant human lubricin to associate with FD-AMs.

RESULTS

Our results demonstrate that all fresh placental, fresh AM, and CP-AM samples contained lubricin. Lubricin was expressed in placental chorionic villi, AM epithelial and stromal cells, and CP-AM epithelia. No lubricin could be detected in FD-AMs but could be restored in FD-AMs after overnight incubation with recombinant human lubricin.

CONCLUSIONS

This study supports our hypothesis that lubricin is expressed in human AMs. In addition, our data show that preservation methods influence the extent of this expression. Indeed, the disappearance of lubricin in FD-AMs may explain why dried AM reportedly loses its antiinflammatory and antiscarring abilities. It is possible that lubricin may mediate, at least in part, many of the biological properties of AMs.

Human Amniotic Membrane for the Prevention of Intradural Spinal Cord Adhesions: Retrospective Review of its Novel Use in a Case Series of 14 Patients

BACKGROUND

Tethering after spinal surgery is caused by adhesions that arise from intradural tissue manipulation. Microsurgical detethering is the only treatment for symptomatic patients, but retethering occurs commonly and no treatment is widely available to prevent this complication.

OBJECTIVE

To apply human amniotic membrane (HAM) grafts, which are immune-privileged and known to possess antifibrogenic properties, in patients requiring microsurgical detethering. For this first-in-human use, we evaluated the safety and potential efficacy of these grafts for preventing retethering.

METHODS

We retrospectively reviewed the medical records of all patients who required detethering surgery and received an HAM graft between 2013 and 2016 at our institution after various previous intradural spinal surgeries. In all 14 cases, intradural lysis of adhesions was achieved, an HAM graft was sewn in place intradurally, and a dural patch was closed in a watertight fashion over the graft.

RESULTS

Fourteen patients had received HAM grafts to prevent retethering. All patients had at least 6 mo of follow-up (mean follow-up, 14 mo). Retethering was noted in only 1 patient. Surgical re-exploration showed that the retethering occurred caudal to the edge of the HAM graft, with no tethering underneath the original graft. No complications were attributed specifically to the HAM graft placement.

CONCLUSION

This first-in-human series provides evidence that HAM grafts are a safe and potentially efficacious method for preventing retethering after microsurgical intradural lysis of adhesions. These results lay the groundwork for further prospective controlled trials in patients with this difficult-to-treat pathology.

Apigenin inhibits fibroblast proliferation and reduces epidural fibrosis by regulating Wnt3a/β-catenin signaling pathway

BACKGROUND

Failed back surgery syndrome (FBSS) is a common complication after the laminectomy. Epidural fibrosis is the major cause of lower back pain and other complications. Numerous studies have shown that apigenin (API) could treat various fibrotic diseases by regulating various signaling pathways, whereas no study has discussed whether API can inhibit fibroblast proliferation and reduce epidural fibrosis after the laminectomy by regulating Wnt3a/β-catenin signaling pathway.

METHODS

Human fibroblasts were cultured and treated with API in different concentrations for 24 h. CCK-8 detection and EdU incorporation assay were performed to detect cell viability and cell proliferation. Western blotting analysis was applied to detect expressions of proliferative proteins, Wnt3a, and its downstream proteins. Moreover, the Wnt3a gene was overexpressed in fibroblasts to define the relationship between Wnt3a/β-catenin signaling pathway and fibroblast proliferation. Wnt3a overexpressed fibroblasts were treated with API to verify if it could reverse the effects of API treatment. Twenty-four Sprague-Dawley rats were randomly divided into four groups. Laminectomy was performed and the rats were gavaged with different doses of API or 5% sodium carboxyl methyl cellulose (CMC-Na) solution for 1 month. The abilities of API to inhibit fibroblast proliferation and to reduce epidural fibrosis were evaluated using histological and immunohistochemical analysis.

RESULTS

CCK-8 detection and EdU incorporation assay demonstrated that API could inhibit the viability and proliferation rate of fibroblasts in a concentration-dependent manner. The Western blotting analysis revealed that API could inhibit the expressions of PCNA, cyclinD1, Wnt3a, and its downstream proteins. The overexpression of Wnt3a in fibroblasts could upregulate the expressions of proliferative proteins such as PCNA and cyclinD1. The inhibitory effect of API on PCNA, Wnt3a, and its downstream proteins was partially reversed by overexpression of Wnt3a. Moreover, the results of the histological and immunohistochemical analysis revealed that API could reduce the epidural fibrosis in rats by inhibiting fibroblast proliferation in a dose-dependent manner.

CONCLUSIONS

API can inhibit fibroblast proliferation and reduce epidural fibrosis by suppressing Wnt3a/β-catenin signaling pathway, which can be adopted as a new option to prevent epidural fibrosis after the laminectomy.

Comparative Biological Effects of Human Amnion and Chorion Membrane Extracts on Human Adipose-Derived Stromal Cells

Although therapies with human amnion/chorion are used to ameliorate acute and chronic wounds, it is unclear which component of the amnion/chorion tissue promotes wound healing. To characterize the comparative effects of amnion and chorion in wound healing, we used human adipose-derived stromal cells to assess cell viability, migration, and gel contraction after treatment with amnion membrane extract (AME) or chorion membrane extract (CME). We then correlated the possible effectors via AME and CME protein profiling, and compared them by enzyme-linked immunosorbent assay (ELISA), western blotting, and immunocytochemistry. Cell viability was significantly increased with 50 and 100 μg/mL AME treatment, but with CME treatment, a significant increase was only observed with 100 μg/mL. With CME treatment, cell migration was 2.22-fold greater than the control, and collagen gels showed 20% greater contraction. Compared to control, the expression levels of α-smooth muscle actin (SMA) and smooth muscle protein 22-alpha (SM22α) increased both with AME and CME treatments, whereas calponin expression decreased. Protein profiling revealed significantly higher tissue inhibitor of metalloproteinase-1 (TIMP-1), interleukin-8, exotoxin, and adiponectin levels in CME than in AME, and ELISA revealed 8-fold higher adiponectin levels in cells treated with CME than those treated with AME. Immunocytochemistry revealed that α-SMA, SM22α, and calponin were significantly higher in CME- than AME-treated cells; however, adiponectin treatment did not enhance α-SMA, SM22α, or calponin expression. In conclusion, amnion and chorion membrane extracts exerted differential effects on proliferation and contraction of human adipose-derived stromal cells. Amnion extract was superior at inducing cell proliferation and migration, whereas CME was superior at inducing cell contraction.

Can the amniotic membrane be used to treat peripheral nerve defects? A review of literature

Human amniotic membrane is currently being used in ophthalmology and dermatology applications. The objective of this review was to establish proof-of-concept for using amniotic membrane to treat peripheral nerve defects. We performed a search using: 1) PubMed with the keywords/MeSH terms: "amnion", "amniotic membrane", "angiogenesis", "anti-microbial", "characteristic", "chorion", "epithelialization", "fibrosis", "gap", "growth factors", "use", "nerve"; 2) the American clinical trials registry with "amniotic membrane"; 3) Lim Jeremy's book "A primer on amniotic membrane regenerative healing"; 4) the search engine Google. Our findings pointed to the amniotic membrane being a biodegradable and bioactive scaffold that contains many growth factors important for efficient nerve regeneration. Multiple animal studies and the single human clinical trial performed up to now have highlighted its role in preventing recurrence of perineural adhesions, reducing fibrosis, accelerating nerve repair and improving nerve function. Thus, the amniotic membrane has ideal properties for treating peripheral nerve injuries. It could very likely prevent neuroma formation. The best format would be a freeze-dried one containing the amnion and chorion layers in order to preserve all its growth factors, and facilitate its handling and storage in the operating room.

Prospective application of stem cells to prevent post-operative skeletal fibrosis

Post-operative skeletal fibrosis is considered one of the major complications causing dysfunction of the skeletal system and compromising the outcomes of clinical treatment. Limited success has been achieved using current therapies; more effective therapies to reduce post-operative skeletal fibrosis are needed. Stem cells possess the ability to repair and regenerate damaged tissue. Numerous studies show that stem cells serve as a promising therapeutic approach for fibrotic diseases in tissues other than the skeletal system by inhibiting the inflammatory response and secreting favorable cytokines through activating specific signaling pathways, acting as so-called medicinal signaling cells. In this review, current therapies are summarized for post-operative skeletal fibrosis. Given that stem cells are used as a promising therapeutic approach for fibrotic diseases, little effort has been undertaken to use stem cells to prevent post-operative skeletal fibrosis. This review aims at providing useful information for the potential application of stem cells in preventing post-operative skeletal fibrosis in the near future. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1236-1245, 2019.

10‑Hydroxycamptothecin induces apoptosis in human fibroblasts by regulating miRNA‑23b‑3p expression

10-Hydroxycamptothecin (HCPT) effectively controls epidural fibrosis, but the exact underlying mechanisms remain ambiguous. Abnormal microRNA (miR)-23b-3p expression has been detected in various types of fibrotic tissues that are present in different diseases. The aim of the present study was to elucidate the mechanisms through which HCPT induces fibroblast apoptosis. Reverse transcription-quantitative polymerase chain reactions were performed on six traumatic scar samples and matched normal skin samples; traumatic scar formation was revealed to be significantly inversely associated with miR-23b-3p expression. In addition, the miR-23b-3p expression level in human fibroblasts was examined following HCPT treatment. The effects of HCPT and miR-23b-3p on fibroblast apoptosis were assessed using terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling, flow cytometry and western blot analysis. The results demonstrated that HCPT treatment notably increased miR-23b-3p expression levels and accelerated fibroblast apoptosis. Therefore, upregulation of miR-23b-3p expression was demonstrated to promote fibroblast apoptosis, consistently with the effects of HCPT. The results of the present study indicated that HCPT may induce fibroblast apoptosis by regulating miR-23b-3p expression.

Effects of Cryopreserved Amniotic Membrane-Umbilical Cord Allograft on Total Ankle Arthroplasty Wound Healing

Relatively high rates of wound healing complications continue to be reported with a total ankle arthroplasty (TAA) anterior incision. The amniotic membrane-umbilical cord (AM-UC) allograft is a regenerative orthobiologic adjunct that modulates wound healing by down-regulating inflammation, enhancing local healing and antimicrobial factors, and reducing scar formation. The purpose of this study was to determine whether local application of a cryopreserved AM-UC allograft enhances soft tissue healing after TAA. A total of 104 patients with symptomatic ankle arthritis who failed conservative management underwent standard TAA. At skin closure, patients were allocated to either the treatment (local application of AM-UC) or control (no allograft) group. Demographic data, patient comorbidities, and radiographic findings were collected. The primary outcome was a major complication necessitating reoperation. Secondary outcomes were time to healing, minor complications (i.e., skin dehiscence, local wound care, use of antibiotics), and patient scar assessment. Local application of an AM-UC allograft significantly decreased the overall time to skin healing (28.5 days vs 40 days; p = .03). Two patients required a reoperation for soft tissue wound complications, with no difference (p = 1.00) between the groups. No statistically significant difference was detected in terms of skin dehiscence, local wound care, or antibiotic prescriptions in the 2 groups. Regenerative technology using local application of a cryopreserved AM-UC allograft may enhance TAA outcomes by decreasing the time to healing. Larger randomized controlled trials are needed to determine whether an AM-UC allograft enhances soft tissue wound healing and ultimately reduces the incidence of devastating soft tissue complications.

Application of amniotic membrane in reconstructive urology; the promising biomaterial worth further investigation

Introduction: In reconstructive urology, autologous tissues such as intestinal segments, skin, and oral mucosa are used. Due to their limitations, reconstructive urologists are waiting for a novel material, which would be suitable for urinary tract wall replacement. Human amniotic membrane (AM) is a naturally derived biomaterial with a capacity to support reepithelization and inhibit scar formation. AM has a potential to become a considerable asset for reconstructive urology, i.e., reconstruction of ureters, urinary bladder, and urethrae. Areas covered: This review aims to discuss the potential application of human AM in reconstructive urology. The environment for urinary tract healing is particularly unfavorable due to the presence of urine. Due to its fetal origin, the bioactivity of AM is orientated to induce intrinsic regeneration mechanisms and inhibit scarring. This review introduces the concept of applying human AM in reconstructive urology procedures to improve their outcomes and future tissue engineering based strategies. Expert opinion: Many fields of medicine that have accomplished translational research have proven the usefulness of AM in clinical practice. There is an urgent need for studies to be conducted on large animal models that might convincingly demonstrate the underestimated potential of AM to urologists around the world.

The Science and Clinical Applications of Placental Tissues in Spine Surgery

STUDY DESIGN

Narrative literature review.

OBJECTIVES

Placental tissue, amniotic/chorionic membrane, and umbilical cord have seen a recent expansion in their clinical application in various fields of surgery. It is important for practicing surgeons to know the underlying science, especially as it relates to spine surgery, to understand the rationale and clinical indication, if any, for their usage.

METHODS

A literature search was performed using PubMed and MEDLINE databases to identify studies reporting the application of placental tissues as it relates to the practicing spine surgeon. Four areas of interest were identified and a comprehensive review was performed of available literature.

RESULTS

Clinical application of placental tissue holds promise with regard to treatment of intervertebral disc pathology, preventing epidural fibrosis, spinal dysraphism closure, and spinal cord injury; however, there is an overall paucity of high-quality evidence. As such, evidence-based guidelines for its clinical application are currently unavailable.

CONCLUSIONS

There is no high-level clinical evidence to support the application of placental tissue for spinal surgery, although it does hold promise for several areas of interest for the practicing spine surgeon. High-quality research is needed to define the clinical effectiveness and indications of placental tissue as it relates to spine surgery.

Biochemical characterization of pure dehydrated binate amniotic membrane: role of cytokines in the spotlight

AIM

Placental allografts used for tissue regeneration differ in membrane compositions and processing techniques. A uniquely folded dehydrated binate amniotic membrane (DBAM) was biochemically characterized to evaluate its potential role in wound healing.

METHODS

Histology, Luminex-based immunoassay and standard in vitro cell biology techniques were employed.

RESULTS

Histological staining confirmed that the DBAM was chorion free with epithelial cell layer of the respective amnion membranes facing outward. DBAM had quantifiable levels of relevant cytokines that induced proliferation and migration while bolstering secretory activity of the cells. DBAM retained biological efficacy at a broad range of temperatures.

CONCLUSION

Cytokines in DBAM stimulate bone marrow stromal and stem cells that may lead to tissue regeneration and wound healing in a clinical setup.

Homologous cryopreserved amniotic membrane in the repair of myelomeningocele: preliminary experience

OBJECTIVE

Surgical management of spinal dysraphism often requires the use of dural substitutes. Amniotic membrane (AM) has drawn the interest of clinicians for its valuable concentration of cytokines and factors capable of promoting wound healing, re-epithelialization, inhibiting fibrosis and regulating angiogenesis. These beneficial qualities could make AM an interesting dural substitute for spina bifida repair. In this study, we describe the use of banked homologous AM as a dural substitute for the repair of spinal dysraphism in newborns. Our purpose is to test the mechanical characteristics, as well as the safety and effectiveness of AM in preventing postoperative complications and re-tethering.

METHODS

The AM patch was carefully detached from the chorion of donors undergoing caesarean section, rinsed in saline solution, and cryopreserved in liquid nitrogen. Five newborns were treated using AM: three affected by open spinal dysraphism and two by spina bifida occulta. The AM patch was used as a dural substitute with two different positions and purposes: the amnion-side down covering the placode to prevent adhesions or placed extradurally facing the dura to avoid scarring and facilitating the sliding of the dural sac itself under the extradural tissue layers.

RESULTS

No adverse events occurred, and the surgical wounds healed without complications. MRI scans taken at 3 and 6 months after surgery showed a satisfying de-tethering of the spinal cord with no obvious evidence of new adherence formation.

CONCLUSIONS

We present a multimodal interposition technique using AM as a reconstructive and anti-adhesive tissue for the treatment of open myelomeningocele (MMC) and lipomeningocele (LMC) treatment. In our experience, AM proved its efficacy in restoring the dural sac integrity without complications. We support the use of AM as a promising dural substitute, speculating on how the use of AM could potentially change reconstructive strategies for spinal dysraphism.

Application of a Novel Anti-Adhesive Membrane, E8002, in a Rat Laminectomy Model

Neuropathic pain after spinal surgery, so-called failed back surgery syndrome, is a frequently observed common complication. One cause of the pain is scar tissue formation, observed as post-surgical epidural adhesions. These adhesions may compress surrounding spinal nerves, resulting in pain, even after successful spinal surgery. E8002 is an anti-adhesive membrane. In Japan, a clinical trial of E8002 is currently ongoing in patients undergoing abdominal surgery. However, animal experiments have not been performed for E8002 in spinal surgery. We assessed the anti-adhesive effect of E8002 in a rat laminectomy model. The dura matter was covered with an E8002 membrane or left uncovered as a control. Neurological evaluations and histopathological findings were compared at six weeks postoperatively. Histopathological analyses were performed by hematoxylin–eosin and aldehyde fuchsin-Masson Goldner staining. Three assessment areas were selected at the middle and margins of the laminectomy sites, and the numbers of fibroblasts and inflammatory cells were counted. Blinded histopathological evaluation revealed that adhesions and scar formation were reduced in the E8002 group compared with the control group. The E8002 group had significantly lower numbers of fibroblasts and inflammatory cells than the control group. The present results indicate that E8002 can prevent epidural scar adhesions after laminectomy.

Update on biomaterials for prevention of epidural adhesion after lumbar laminectomy

Lumbar laminectomy often results in failed back surgery syndrome. Most scholars support the three-dimensional theory of adhesion: Fibrosis surrounding the epidural tissues is based on the injured sacrospinalis behind, fibrous rings and posterior longitudinal ligaments. Approaches including using the minimally invasive technique, drugs, biomaterial and nonbiomaterial barriers to prevent the postoperative epidural adhesion were intensively investigated. Nevertheless, the results are far from satisfactory. Our review is based on various implant biomaterials that are used in clinical applications or are under study. We show the advantages and disadvantages of each method. The summary will help us to figure out ideas towards new techniques. The translational potential of this article: This review summarises recent biomaterials-related clinical and basic research that focuses on prevention of epidural adhesion after lumbar laminectomy. We also propose a novel possible translational method where a soft scaffold acts as a physical barrier in the early stage, engineered adipose tissue acts as a biobarrier in the later stage in the application of biomaterials and adipose-derived mesenchymal stem cells are used for prevention of epidural adhesion.

Cryopreserved Amniotic Membrane Improves Clinical Outcomes Following Microdiscectomy

STUDY DESIGN

Prospective, randomized controlled trial.

OBJECTIVE

To compare pain, physical/mental functional recovery and recurrent herniation for patients following lumbar microdiscectomy with and without the use of a cryopreserved amniotic tissue graft.

SUMMARY OF BACKGROUND DATA

Although microdiscectomy procedures are routinely successful for patients with lumbar radiculopathy due to herniated disc disease, residual low back pain, and recurrent herniation remain unsolved clinical problems.

METHODS

Following Investigated Review Board approval, 80 subjects were randomized in a 1:1 ratio to either receive cryopreserved amniotic (cAM) tissue or no tissue following elective lumbar microdiscectomy surgery. cAM grafts were applied to the annular defect at the conclusion of the procedure. Patients provided preoperative and postoperative clinical assessment data out to 24 months using the Oswestry Disability Index (ODI), Short Form-12 (SF-12) Health Survey, and Visual Analog Pain Scale for back and leg pain. Patients with symptomatic recurrent disc herniation were recorded.

RESULTS

In total, 48 males and 32 females with an average age of 47.2 years were included. Mean ODI scores for subjects treated with cAM graft demonstrated statistically greater improvement at 6 weeks (14.49 vs. 21.82; P=0.05) and 24 months (6.62 vs. 14.40; P=0.02) compared with controls. Similarly, SF-12 Physical Component Scores demonstrated statistically greater gains in the cAM group at both the 6 weeks and 24 months. None of the subjects in the cAM graft group sustained a recurrent herniation at the same surgical level, whereas 3 patients in the control group sustained a recurrent herniation at the same surgical level, with 2 requiring fusion to manage persistent pain.

CONCLUSIONS

The data demonstrate statistically superior clinical outcomes following lumbar microdiscectomy as measured by ODI and SF-12 (physical composite scale) and a lower rate of recurrent herniation with the use of a cAM tissue graft compared with traditional microdiscectomy.

Amniotic therapeutic biomaterials in urology: current and future applications

To examine the rationale and applications of amniotic tissue augmentation in urological surgery. Published literature in English-language was reviewed for basic science and clinical use of amniotic or amnion-chorionic tissue in genitourinary tissues. Basic science and animal studies support the likely benefit of clinical applications of amnion-derived tissues in a variety of urologic interventions. The broad number of properties found in amniotic membrane, coupled with its immunologically privileged status presents a number of future applications in the urological surgical realm. These applications are in their clinical infancy and suggest that further studies are warranted to investigate the use of these products in a systematic fashion.

MMC controlled-release membranes attenuate epidural scar formation in rat models after laminectomy

Epidural scar formation after laminectomy impede surgical outcomes of decompression. Mitomycin C (MMC) has been demonstrated to have significant inhibitory effects on epidural scar. This study was undertaken to develop an effective MMC controlled-release membrane and to investigate its effects on epidural scar in rat models of laminectomy. A total of 72 rats that underwent laminectomy were divided into three groups. Among them, 24 were treated with mitomycin C-polylactic acid (MMC-PLA) controlled-release membrane, 24 with mitomycin C-polyethylene glycol (MMC-PEG) controlled-release membrane, and no treatment was performed for the remaining 24 rats (control group). In the following 4 weeks, magnetic resonance image (MRI), macroscopic observation, histology and hydroxyproline (Hyp) concentration analysis were performed to explore the effects of these three therapies on epidural scar. MRI revealed a significant reduction of epidural fibrosis in MMC-PLA and MMC-PEG treatment groups, compared with the control group. Histological results also showed that collagen deposition was significantly reduced after being treated with MMC-PLA or MMC-PEG membranes. Likewise, Hyp concentrations of the epidural scar tissue in MMC-PLA and MMC-PEG groups were markedly lower than those in the control group. However, regarding the effects on reducing epidural scar, no significant difference was found between the MMC-PLA and MMC-PEG groups. In conclusion, MMC-PLA and MMC-PEG membranes are safe and effective in reducing fibrosis. Thus, MMC-controlled-release membranes promises to be a potential therapeutic in preventing epidural scar formation after laminectomy.

Upregulation of NOXA by 10-Hydroxycamptothecin plays a key role in inducing fibroblasts apoptosis and reducing epidural fibrosis

The fibrosis that develops following laminectomy or discectomy often causes serious complications, and the proliferation of fibroblasts is thought to be the major cause of epidural fibrosis. 10-Hydroxycamptothecin (HCPT) has been proven to be efficient in preventing epidural fibrosis, but the exact mechanism is still unclear. NOXA is a significant regulator of cell apoptosis, which has been reported to be beneficial in the treatment of fibrosis. We performed a series of experiments, both in vitro and in vivo, to explore the intrinsic mechanism of HCPT that underlies the induction of apoptosis in fibroblasts, and also to investigate whether HCPT has positive effects on epidural fibrosis following laminectomy in rats. Fibroblasts were cultured in vitro and stimulated by varying concentrations of HCPT (0, 1, 2, 4 µg/ml) for various durations (0, 24, 48, 72 h); the effect of HCPT in inducing the apoptosis of fibroblasts was investigated via Western blots and TUNEL assay. Our results showed that HCPT could induce apoptosis in fibroblasts and up-regulate the expression of NOXA. Following the knockdown of NOXA in fibroblasts, the results of Western blot analysis showed that the level of apoptotic markers, such as cleaved-PARP and Bax, was decreased. The results from the TUNEL assay also showed a decreased rate of apoptosis in NOXA-knocked down fibroblasts. For the in vivo studies, we performed a laminectomy at the L1-L2 levels in rats and applied HCPT of different concentrations (0.2, 0.1, 0.05 mg/ml and saline) locally; the macroscopic histological assessment, hydroxyproline content analysis and histological staining were performed to evaluate the effect of HCPT on reducing epidural fibrosis. The TUNEL assay in epidural tissues showed that HCPT could obviously induce apoptosis in fibroblasts in a dose-dependent manner. Also, immunohistochemical staining showed that the expression of NOXA increased as the concentrations of HCPT increased. Our findings are the first to demonstrate that upregulation of NOXA by HCPT plays a key role in inducing fibroblast apoptosis and in reducing epidural fibrosis. These findings might provide a potential therapeutic target for preventing epidural fibrosis following laminectomy.

Anti-adhesive effect of poloxamer-based thermo-sensitive sol-gel in rabbit laminectomy model

Poloxamer-based thermo-sensitive sol-gel has been developed to reduce the incidence of postoperative scar formation at the laminectomy site. The purpose of this study was to evaluate the anti-adhesive effect of poloxamer based thermo-sensitive sol-gel compared to hyaluronate based solution after laminectomy, using a rabbit model. A thermo-sensitive anti-adhesive with a property of sol-gel transition was manufactured by a physical mixture of Poloxamer188/407, Chitosan and Gelatin. The viscosity in different temperatures was assessed. 72 adult New Zealand rabbits underwent lumbar laminectomy and were randomly divided into experimental (treated with the newly developed agent), positive (treated with hyaluronate based solution), and negative control groups. Each group was subdivided into 1 and 4-week subgroups. Gross and histological evaluations were performed to assess the extent of epidural adhesion. The experimental group showed significantly higher viscosity compared to the positive control group and showed a significant increase of viscosity as the temperature increased. Gross evaluation showed no statistically significant differences between the 1- and 4-week subgroups. However, histologic evaluation showed significant differences both in 1- and 4-week subgroups. Although the 4-week histologic results of the experimental and the positive control subgroups showed no significant difference, both subgroups revealed higher value compared to the negative control subgroup with regard to the ratio of adhesion less than 50 %. The new poloxamer based thermo-sensitive agent showed superior efficacy over the hyaluronate based agent at 1 week postoperatively. At 4 weeks postoperatively, there were no statistically significant differences between the two agents, although both showed efficacy over the sham group.

Utility of human amniotic membrane allograft in re-epithelialization of the nasal tip

Variations in skin thickness and contours pose significant challenges to reconstruction of the lower third of the nose. Human amniotic membrane allograft offers a potential alternative to tissue transfer in reconstruction of the lower third of the nose. We reviewed the procedure and photographs of a healthy 56-year-old male with a 22 × 18 mm lower third nasal defect involving full thickness skin and subcutaneous tissue. Following preparation for grafting, dehydrated human amniotic membrane was fashioned to the dimensions of the defect and applied. No further surgical intervention was provided for 3 months. Complete re-epithelialization of the nasal and adjacent defects was achieved with minimal scar formation. Human amniotic membrane allograft provides an efficacious and cosmetically acceptable alternative to local and regional tissue transfer.

The effect of suramin on inhibiting fibroblast proliferation and preventing epidural fibrosis after laminectomy in rats

Background

Epidural fibrosis often causes serious complications in patients after lumbar laminectomy and discectomy and is associated with the proliferation of fibroblasts. Suramin is known to have an obvious inhibitory effect on the coactions of many growth factors and their receptors, but little was previously known about the effect of suramin on fibroblast proliferation and the progress of epidural fibrosis.

Methods

We illustrated the effect of suramin on cultured fibroblasts of rats with different concentrations (0, 200, 400, 600 mg/l). The proliferation of suramin-treated fibroblasts was evaluated by CCK-8 and western blot analysis. Additionally, in a rat model of laminectomy, different concentrations of suramin (100, 200, and 300 mg/ml) and saline were applied to the laminectomy sites locally. The effect of suramin on preventing epidural fibrosis was detected by the Rydell classification, hydroxyproline content, histological analysis, and collagen density analyses.

Results

The results of CCK-8 shown that suramin could significantly inhibit fibroblasts proliferation in a dose-dependent manner. The western blotting shown that the expression levels of the cell proliferation markers such as cyclin D1, cyclin E, and PCNA were down-regulated. Moreover, in a rat model, we found that suramin could reduce epidural fibrosis as well as inhibit fibroblast proliferation, and 300 mg/ml suramin had better effect.

Conclusions

Topical application of suramin could reduce epidural fibrosis after laminectomy, and the application of suramin could inhibit the proliferation of fibroblasts in rats. This study indicates that suramin is a potent antifibrotic agent that may have therapeutic potential for patients with epidural fibrosis.

Effects of cepae extract, allantoin, and heparin mixture on developing andalready formed epidural fibrosis in a rat laminectomy model

BACKGROUND/AIM

The study was designed to investigate whether local administration of a mixture composed of cepae extract, allantoin, and heparin (CAH) decreased already formed epidural fibrosis (EF) at the laminectomy site.

MATERIALS AND METHODS

Twenty-four adult male Sprague Dawley rats were equally divided into four groups. Laminectomy was performed at the L5 level in all rats. The group 2 and group 4 rats were treated with local drug administration. While the group 1 and 2 rats were sacrificed after 6 weeks, the remaining rats were reoperated and CAH mixture was applied in group 4. The vertebral columns of all rats were removed en bloc. Fibroblast numbers, EF, and arachnoidal involvement (AI) were evaluated.

RESULTS

The results of the treatment groups were separately compared with the control groups. The numbers of fibroblasts in the treatment groups were significantly lower than those in the control groups (P < 0.001). The grade of EF in group 2 was significantly less than that in group 1 (P < 0.05). There was no statistically significant difference regarding EF and AI grade between group 3 and group 4, and local application of the drug on EF and AI yielded better results than in the control groups.

CONCLUSION

The mixture composed of CAH might be a successful candidate for preventing EF in clinical practice.

The Effects of Rifampin, Povidone-Iodine and Hydrogen Peroxide on the Formation of Epidural Fibrosis in the Experimental Epidural Fibrosis Model

The aim of the study was to determine the effect of direct application of rifampin, povidone-iodine, and hydrogen peroxide on the formation of epidural fibrosis in rats. Forty-eight adult male Wistar albino rats were equally and randomly divided into four groups (laminectomy, topical rifampin, topical povidone-iodine, and topical hydrogen peroxide). Laminectomy was performed at the T12 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically. ANOVA test was used for the evaluation of dural thickness. Kruskal-Wallis test was used for the pathology and macroscopic evaluation. Chi-square test was used for evaluation of the arachnoid involvement. p value <0.05 was accepted as statistically significant. Our data revealed that topical application of both povidone-iodine and hydrogen peroxide were effective in reducing epidural fibrosis formation. The results of our study provide the experimental evidence of the preventive effects of topical application of povidone-iodine and hydrogen peroxide over epidural fibrosis.

Local application of rapamycin reduces epidural fibrosis after laminectomy via inhibiting fibroblast proliferation and prompting apoptosis

Background

Epidural fibrosis is a common complication after laminectomy. It is associated with intractable lower back pain and additional complications. To date, no study has evaluated whether the local application of rapamycin (RAPA) can inhibit fibroblast proliferation and reduce epidural scar adhesion after laminectomy. The results of the present study showed that the local application of RAPA reduces epidural fibrosis after laminectomy in rats.

Methods

In this study, 32 male Sprague-Dawley rats were randomly divided into four groups (0.2 mg/ml RAPA-treated group, 0.1 mg/ml RAPA-treated group, 0.05 mg/ml RAPA-treated group and physiological saline group). Laminectomy was performed at the level of lumbar segment 1 to 2, and different concentrations of RAPA or saline were applied to the laminectomy sites for 10 min. Four weeks after laminectomy, the rats were sacrificed, and the degrees of epidural adhesion in each group were evaluated. Macroscopic assessment, analysis of hydroxyproline content, and histological analysis were used to determine the therapeutic effect of the local application of RAPA on the inhibition of fibroblast proliferation and the reduction of epidural fibrosis after laminectomy. Next, we cultured fibroblasts from epidural scar tissues of rats that had undergone laminectomy. Fibroblasts were exposed to the indicated concentrations of RAPA, and western blotting and TUNEL assays were used to assess the effects of RAPA on inhibiting fibroblasts proliferation and promoting fibroblast apoptosis.

Results

The results of macroscopic assessments, analysis of hydroxyproline content, and histological analyses indicated that RAPA significantly inhibited fibroblast proliferation and reduced epidural fibrosis in the treated groups in the rat model. The western blotting results indicated that the expression levels of the pro-apoptotic proteins cleaved-PARP and Bax were up-regulated, whereas those of Bcl-2 were reduced. TUNEL assay indicated that the apoptosis rates of fibroblasts were significantly increased after exposure to the indicated concentrations of RAPA.

Conclusions

The local application of RAPA reduced epidural fibrosis after laminectomy by inhibiting the proliferation of fibroblasts, stimulating their apoptosis, and decreasing collagen synthesis. This protocol may be used in new clinical treatment strategies to reduce epidural fibrosis after laminectomy.

New Amniotic Membrane Based Biocomposite for Future Application in Reconstructive Urology

Objective

Due to the capacity of the amniotic membrane (Am) to support re-epithelisation and inhibit scar formation, Am has a potential to become a considerable asset for reconstructive urology i.e., reconstruction of ureters and urethrae. The application of Am in reconstructive urology is limited due to a poor mechanical characteristic. Am reinforcement with electrospun nanofibers offers a new strategy to improve Am mechanical resistance, without affecting its unique bioactivity profile. This study evaluated biocomposite material composed of Am and nanofibers as a graft for urinary bladder augmentation in a rat model.

Material and Methods

Sandwich-structured biocomposite material was constructed from frozen Am and covered on both sides with two-layered membranes prepared from electrospun poly-(L-lactide-co-E-caprolactone) (PLCL). Wistar rats underwent hemicystectomy and bladder augmentation with the biocomposite material.

Results

Immunohistohemical analysis (hematoxylin and eosin [H&E], anti-smoothelin and Masson’s trichrome staining [TRI]) revealed effective regeneration of the urothelial and smooth muscle layers. Anti-smoothelin staining confirmed the presence of contractile smooth muscle within a new bladder wall. Sandwich-structured biocomposite graft material was designed to regenerate the urinary bladder wall, fulfilling the requirements for normal bladder tension, contraction, elasticity and compliance. Mechanical evaluation of regenerated bladder wall conducted based on Young’s elastic modulus reflected changes in the histological remodeling of the augmented part of the bladder. The structure of the biocomposite material made it possible to deliver an intact Am to the area for regeneration. An unmodified Am surface supported regeneration of the urinary bladder wall and the PLCL membranes did not disturb the regeneration process.

Conclusions

Am reinforcement with electrospun nanofibers offers a new strategy to improve Am mechanical resistance without affecting its unique bioactivity profile.

Topical Review: Use of Fetal Tissue in Foot and Ankle Surgery

Fetal tissues are well known for their therapeutic potential. They contain numerous growth factors, cytokines, and matrix components that promote regeneration of tissues while downregulating inflammation and scar formation. As a result, use of these treatments has expanded over the previous 20 years throughout various surgical specialties, including orthopaedics. With improved methods of sterilization, processing, and storage, surgeons need to be informed about the potential benefits of fetal tissue in foot and ankle surgery. The aim of this review is to provide a brief historical background, basic anatomy and physiology, and a current review of the literature in regard to chronic wounds, diabetic foot ulcerations, plantar fasciitis, tendon repair, adhesion prevention, nerve repair, and bone healing.

LEVELS OF EVIDENCE

Level V: Expert Opinion.