Inflammatory Foreign Body Research Articles

Investigation of the impact of planar microelectrodes on macrophage-mediated mesenchymal stem cell osteogenesis.

Osseointegration commences with foreign body inflammation upon implant placement, where macrophages play a crucial role in the immune response. Subsequently, during the intermediate and late stages of osseointegration, mesenchymal stem cells (MSCs) migrate and initiate their osteogenic functions, while macrophages support MSCs in osteogenesis. The utilization of ferroelectric P(VDF-TrFE) covered ITO planar microelectrodes facilitated the simulation of various surface charge to investigate their effects on MSCs' osteogenic differentiation and macrophage polarization and the results indicated a parabolic increase in the promotional effect of both with the rise in piezoelectric coefficient. Furthermore, the surface charge with a piezoelectric coefficient of -18 exhibited the strongest influence on the promotion of M1 polarization of macrophages and the promotion of MSCs' osteogenic differentiation. The impact of macrophage polarization and MSC osteogenesis following the interaction of macrophages affected by surface charge and MSC was ultimately investigated. It was observed that macrophages affected by the surface charge of -18 piezoelectric coefficient still exerted the most profound induced osteogenic effect, validating the essential role of M1-type macrophages in the osteogenic differentiation of MSCs.

Is mesh pore size in polypropylene meshes associated with the outcome in Lichtenstein inguinal hernia repair: a registry-based analysis of 22,141 patients

IntroductionExperimental data show that large-pored meshes reduce foreign body reaction, inflammation and scar bridging and thus improve mesh integration. However, clinical data on the effect of mesh porosity on the outcome of hernioplasty are limited. This study investigated the relation of pore size in polypropylene meshes to the outcome of Lichtenstein inguinal hernioplasty using data from the Herniamed registry.MethodsThis analysis of data from the Herniamed registry evaluated perioperative and 1-year follow-up outcomes in patients undergoing elective, primary, unilateral Lichtenstein inguinal hernia repair using polypropylene meshes. Patients operated with a non-polypropylene mesh or a polypropylene mesh with absorbable components were excluded. Polypropylene meshes with a pore size of 1.0 × 1.0 mm or less were defined as small-pored meshes, while a pore size of more than 1.0 × 1.0 mm was considered large-pored.Unadjusted analyses and multivariable analyses were performed to investigate the relation of pore size of polypropylene meshes, patient and surgical characteristics to the outcome parameters.ResultsData from 22,141 patients were analyzed, of which 6853 (31%) were operated on with a small-pore polypropylene mesh and 15,288 (69%) with a large-pore polypropylene mesh. No association of mesh pore size with intraoperative, general or postoperative complications, recurrence rate or pain requiring treatment was found at 1-year follow-up. A lower risk of complication-related reoperation tended to be associated with small-pore size (p = 0.086). Furthermore, small-pore mesh repair was associated with a lower risk of pain at rest and pain on exertion at 1-year follow-up.ConclusionThe present study could not demonstrate an advantage of large-pore polypropylene meshes for the outcome of Lichtenstein inguinal hernioplasty.

TRPV4-driven Regulation of miR-146a Expression in Macrophages and in a Mouse Model of Atherosclerosis

MicroRNAs (miRs) are small, non-coding RNAs that have emerged as powerful regulators of gene expression. Emerging evidence suggests that miR-146a orchestrates anti-inflammatory/fibrotic processes in numerous cell types. Trpv4 (Transient Receptor Potential subfamily V member 4), a mechanosensitive, calcium-permeant channel/receptor, is expressed in numerous cell types including macrophages. Published work by our group and others show that Trpv4 is activated by a range of soluble and physical stimuli including matrix stiffness and cytokines. In mice, Trpv4 deficiency is associated with altered pressure responses, foreign body response, fibrosis, and inflammation. Previous work by our group and others suggest a pro-inflammatory/atherogenic role for Trpv4. Herein, we tested the hypothesis that Trpv4 regulates the expression of microRNA-146a in macrophages and in a mouse model of atherosclerosis. Our research found a 38% drop in miR-146a expression in macrophages treated with lipopolysaccharide (LPS) on a stiffer polyacrylamide hydrogel compared to a softer one as determined by RNAseq analysis, signifying miR-146a's sensitivity to mechanical factors. Trpv4's presence suppresses the LPS-induced increase of miR-146a in macrophages based on time and dosage. Trpv4 also plays a role in the suppression of miR-146a due to matrix stiffness. Notably, in mice, Trpv4 reduces the increase of macrophage miR-146a caused by a high-fat diet in aortic root regions. Given that matrix stiffening is common in atherosclerosis, this indicates a link between stiffness, Trpv4, and miR-146a. On the mechanism side, Trpv4 affects miR-146a expression not through its promoter methylation or activation of MAPKs, Stat1, AKT, and NFκB. Trpv4 residues 100 to 130 are required for suppression of LPS-induced upregulation of miR-146a. To sum up, Trpv4 appears to inhibit macrophage miR-146a expression through pathways that are distinct from those involving MAKPs/Stat1/AKT or NFκB. Understanding this mechanism could pave the way for new treatments targeting miR-146a to counter inflammatory diseases. Source of research support: NIH (R01 AI172086) grant to Shaik O. Rahaman. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Innate immunity response of zafirlukast treated-tilapia during foreign body inflammation

There is limited knowledge regarding the blockade of cysteinyl leukotriene receptors (CysLTRs) and their effects in teleost fish. The present study investigated the effects of Zafirlukast, antagonist of CysLTR1 receptor, on the foreign body inflammatory reaction in Nile tilapia (Oreochromis niloticus). Zafirlukast-treated tilapia demonstrated a decrease in the formation of multinucleated foreign body giant cells and Langhans cells on the round glass coverslips implanted in the subcutaneous tissue, along with a significant reduction in white blood cell counts and decreased production of reactive oxygen species. There was an increase in serum levels of α2-macroglobulins, as well as a decrease in ceruloplasmin and haptoglobin. Zafirlukast treatment led to a significant decrease in the area of splenic melanomacrophage centers and a reduction in the presence of lipofuscin. These findings highlight the potential anti-inflammatory effects of zafirlukast treatment in tilapia and indicate its action on CysLTR1 receptor, modulating the innate immune response of tilapia during the foreign body reaction. The comprehension of chronic inflammation mechanisms in fish has become increasingly relevant, especially concerning the utilization of biomaterials for vaccine and drug delivery.

Oxidation-treated carbon nanotube yarns accelerate neurite outgrowth and induce axonal regeneration in peripheral nerve defect

Carbon nanotubes (CNTs) have the potential to promote peripheral nerve regeneration, although with limited capacity and foreign body reaction. This study investigated whether CNTs hydrophilized by oxidation can improve peripheral nerve regeneration and reduce foreign body reactions and inflammation. Three different artificial nerve conduit models were created using CNTs treated with ozone (O group), strong acid (SA group), and untreated (P group). They were implanted into a rat sciatic nerve defect model and evaluated after 8 and 16 weeks. At 16 weeks, the SA group showed significant recovery in functional and electrophysiological evaluations compared with the others. At 8 weeks, histological examination revealed a significant increase in the density of regenerated neurofilament and decreased foreign body giant cells in the SA group compared with the others. Oxidation-treated CNTs improved biocompatibility, induced nerve regeneration, and inhibited foreign-body reactions.

Sulfobetaine-based ultrathin coatings as effective antifouling layers for implantable neuroprosthetic devices

Foreign body response (FBR), inflammation, and fibrotic encapsulation of neural implants remain major problems affecting the impedance of the electrode-tissue interface and altering the device performance. Adhesion of proteins and cells (e.g., pro-inflammatory macrophages, and fibroblasts) triggers the FBR cascade and can be diminished by applying antifouling coatings onto the implanted devices. In this paper, we report the deposition and characterization of a thin (±6 nm) sulfobetaine-based coating onto microfabricated platinum electrodes and cochlear implant (CI) electrode arrays. We found that this coating has stable cell and protein-repellent properties, for at least 31 days in vitro, not affected by electrical stimulation protocols. Additionally, its effect on the electrochemical properties relevant to stimulation (i.e., impedance, charge injection capacity) was negligible. When applied to clinical CI electrode arrays, the film was successful at inhibiting fibroblast adhesion on both the silicone packaging and the platinum/iridium electrodes. In vitro, in fibroblast cultures, coated CI electrode arrays maintained impedance values up to five times lower compared to non-coated devices. Our studies demonstrate that such thin sulfobetaine containing layers are stable and prevent protein and cell adhesion in vitro and are compatible for use on CI electrode arrays. Future in vivo studies should be conducted to investigate its ability to mitigate biofouling, fibrosis, and the resulting impedance changes upon long-term implantation in vivo.

Clearance of Metal Particles After Percutaneous Nephrolithotomy with Trilogy Lithotripter.

Purpose: To evaluate the clearance of metal particles produced and released in the pelvicaliceal system (PCS) during percutaneous nephrolithotomy (PCNL) with the use of the Swiss Lithoclast® Trilogy dual-energy (EMS Urology, Nyon, Switzerland) lithotripter. Methods: An experimental in vivo study and a clinical investigation of case series were conducted. An in vivo porcine model with two pigs for lithotripsy (after inserting artificial stones into the collecting system) and two pigs for submucosal injection of metal particles (provided by the manufacturer of Trilogy) was conducted. Porcine kidney histology analysis for metal leftovers was conducted immediately or 2 weeks after the surgery. A prospective observational study design included 10 consecutive patients treated with conventional 30F PCNL or with 22F mini-PCNL technique. Only the patients with the confirmed metal particles in the PCS during the initial PCNL and the need for additional retrograde intrarenal surgery over a period of 2-4 weeks were selected. The presence of metal particles was evaluated during the second endoscopic surgery. Results: The generated metal particles during PCNL and the submucosally injected particles were not found macroscopically 2 weeks postoperatively in porcine models. No pathologic changes such as foreign body granuloma or inflammation were found. Similarly, no metal particles were observed during the second look endoscopy (n = 10). Conclusion: Metal particles observed endoscopically using the Trilogy lithotripter are cleared with no pathologic evidence of tissue damage from the metal particles 2 weeks after the procedure. Thus, the intraoperative release of any particle by the Trilogy lithotripter should not raise any safety concerns.

Effect of Gentamicin Collagen Sponge on Wound Healing: In Vivo Study and Assessment of Its Effectiveness against Nosocomial Bacteria

Background: Gentamicin collagen sponge (Genta-Coll) reportedly has a hemostatic effect and promotes wound healing. However, it may also interfere with wound healing by causing foreign body reactions. We planned to analyze the effect of Genta-Coll on wound healing by inducing muscle defects in the rectus abdominis muscle of rats. We also assessed the effectiveness of Genta-Coll in preventing surgical site infections (SSIs) using the zone of inhibition tests to determine the sensitivity of pathogenic bacteria.Methods: We created an 8×8-mm muscle defect in both recti abdominis of 15 white Sprague-Dawley rats and distributed them into the control group (no care) and group A (Genta-Coll). Three biopsies were performed for histologic analysis (on days 3, 7, and 27). In the second study, we placed Genta-Coll on Mueller–Hinton agar plates seeded with pathogenic microorganisms commonly responsible for SSIs. The zone of inhibition was measured after 24 and 48 hours of incubation.Results: Group A showed a slightly higher score for foreign body giant cells and inflammation, with no significant difference. Granulation and neovascularization were constantly high in group A, and muscle regeneration was also high in group A. Extracellular matrix formation advanced at a similar pace in both groups. Genta-Coll created a zone of inhibition against all microorganisms except for Candida albicans. The effect lasted without change between 24 and 48 hours.Conclusion: While foreign body reactions and inflammation increased in group A, wound healing was unaffected. Genta-Coll can promote faster wound healing with an anti-bactericidal effect against SSI pathogens.

Clinical safety of zafirlukast treatment during a foreign body inflammatory reaction in nile tilapias, oreochromis niloticus

Seeking to understand the defense mechanisms of tilapia to assist in the sanitary management of fish farms, this study aimed to evaluate the clinical safety of Nile tilapia (Oreochromis niloticus) submitted to oral treatment with 500μg of zafirlukast/Kg of body weight during chronic inflammation, through the implantation of round glass coverslips in the subcutaneous tissue. For this study, 63 male tilapiawere randomly distributed in 9 aquariums to compose the following treatments: Control submitted to inflammatory stimulus without treatment; CT – Conventional treatment; PT – Prolonged treatment. Seven animals were evaluated per treatment in three periods: 2, 4 and 8 days post-implantation (DPI).Tilapia during foreign body reaction showed a decrease in erythrocyte counts and hematocrit values, as well as macrocytic changes, these effects were mitigated by treatment with zafirlukast. Control tilapia showed a gradual increase over time in serum values of total protein, cholesterol, and triglycerides. Serum values of ALT, AST and alkaline phosphatase of control tilapia showed an increase in the late phase of the chronic inflammatory process (8 DPI). Therefore, it was possible to conclude that tilapia treated with 500µg of zafirlukast showed attenuation of hematological changes resulting from fluid-electrolyte imbalance during a foreign body inflammation, as well as ameliorated serum biochemical disorders, demonstrating the clinical safety of oral treatment with this cys-leukotriene blocker.

Refractory Metal Coated Alumina Foams as Support Material for Stem Cell and Fibroblasts Cultivation.

Ceramics are widely used as implant materials; however, they are brittle and may emit particles when used in these applications. To overcome this disadvantage, alumina foams, which represent a 3D cellular structure comparable to that of human trabecular bone structures, were sputter coated with platinum, tantalum or titanium and modified with fibronectin or collagen type I, components of the extracellular matrix (ECM). To proof the cell material interaction, the unmodified and modified materials were cultured with (a) mesenchymal stem cells being a perfect indicator for biocompatibility and releasing important cytokines of the stem cell niche and (b) with fibroblasts characterized as mediators of inflammation and therefore an important cellular component of the foreign body reaction and inflammation after implantation. To optimize and compare the influence of metal surfaces on cellular behavior, planar glass substrates have been used. Identified biocompatible metal surface of platinum, titanium and tantalum were sputtered on ceramic foams modified with the above-mentioned ECM components to investigate cellular behavior in a 3D environment. The cellular alumina support was characterized with respect to its cellular/porous structure and niche accessibility and coating thickness of the refractory metals; the average cell size was 2.3 mm, the average size of the cell windows was 1.8 mm, and the total foam porosity was 91.4%. The Pt, Ti and Ta coatings were completely dense covering the entire alumina foam surface. The metals titanium and tantalum were colonized very well by the stem cells without a coating of ECM components, whereas the fibroblasts preferred components of the ECM on the alumina foam surface.

Comparison between Autologous Blood and Fibrin Glue for Adhering Conjunctival Autografts after Pterygium Excision- A Randomised Clinical Trial

Introduction: Fibrin glue is a biological tissue adhesive and acts on the principle of final stages of the coagulation cascade. The cost of commercially available products is very high and not affordable for the patients of low socio-economic strata. As an alternative, pterygium surgery was done using patient’s own blood to adhere the conjunctival autograft to scleral bed by the process of coagulation of fibrin from the oozing blood from the blood vessels under the flap. Aim: To compare autologous blood and fibrin glue for adhering conjunctival autografts after pterygium excision. Materials and Methods: It was a randomised clinical trial. Total 97 subjects with primary pterygium who visited the Ophthalmology Department were randomised into two groups. In group A (n=31), patients had undergone pterygium excision wherein conjunctival autograft was attached by fibrin glue. In group B (n=66) the graft was attached by autologous blood present on the scleral bed. Mean operative time for the procedures were compared. Follow- up was done for 12 months and all subjects were examined for postoperative pain, foreign body sensation, inflammation, graft stability and recurrence. Results: The mean age of patients in group A was 48.32±14.3 years (21-65 years), and in group B was 54.48±15.67 (23-74 years). Mean operating time in group A was 23.21±9.4 minutes and 13.7±4.3 minutes in group B, (p-value=0.001). Postoperative pain of mild degree was present in all the 31 (100%) subjects of group A. In group B, pain was absent in 32 (48.5%) and mild degree in 34 (51.5%) subjects. No recurrence was found in both the groups. Mean follow-up period was 11.4 months. Conclusion: This study concludes that autologous blood is a useful alternative method for graft attachment in pterygium surgery without the untoward complications related to fibrin glue.

Cyclophosphamide modulated the foreign body inflammatory reaction in tilapia (Oreochromis niloticus)

In order to understand events and mechanisms present in the pathophysiology of tilapia's chronic inflammation and based on the immunomodulatory activity attributed to cyclophosphamide which is widely used to suppress immune responses in human medicine, the present study investigated the effects of cyclophosphamide (CYP) treatment on the modulation of foreign body inflammatory reaction in Nile tilapia (Oreochromis niloticus) with round glass coverslip implanted in the subcutaneous tissue (9 mm of diameter). Forty tilapia (151 ± 10,2 g) were randomly distributed in 5 aquariums (n = 8) with a capacity of 250 L of water each, to compose two treatments (sampled 3 and 6 days post-implantation): implanted/untreated (control) and implanted/treated with 200 mg of CYP kg−1 of b.w., through i.p. route. A fifth group (n = 8) was sampled without any stimulus (naive) to obtain reference values. CYP-treated tilapia showed decrease in macrophage accumulation, giant cell formation and Langhans cells on the glass coverslip when compared to control fish. The treatment with CYP resulted in decrease of leukocyte and thrombocyte counts. Decrease in alpha-2-macroglobulin, ceruloplasmin, albumin and transferrin levels, as well as increase in haptoglobin, complement C3 and apolipoprotein A1 were observed in tilapias during foreign body inflammation. Blood levels of complement C3, alpha-2-macroglobulin, ceruloplasmin and transferrin were modulated by treatment with CYP. Therefore, the treatment with 200 mg of CYP kg−1 of b.w. in tilapia resulted in an anti-inflammatory effect by suppressing the dynamics between leukocytes in the bloodstream and macrophage accumulation with giant cell formation in the inflamed focus, as well as by modulating APPs during foreign body reaction.

Post thyroidectomy skin sinus formation

<p>Thyroid surgery is frequently complicated by hematoma collection, nerve injury, hypothyroidism and rarely infections but persistent discharge from the gland is unusual. We report a case of persistent sinus discharge from the thyroid of the patient who underwent thyroidectomy 5 years back. The patient had persistent discharge from the wound site along with recurrent swelling all the years afterward. Fine needle aspiration cytology proved it was recurrent papillary cancer. Swab culture from discharge showed no growth. Completion thyroidectomy with functional lymph node dissection was done and specimen was not harbouring any foreign body and biopsy showed recurrent papillary cancer. Although post thyroidectomy sinus discharges are usually secondary to foreign body or chronic inflammation like tuberculosis, the tumour itself can be considered as a cause.</p>

Wound healing effect of regenerated oxidized cellulose versus fibrin sealant patch: An in vivo study.

BackgroundTopical hemostatic agents are used when ligation, electrocauterization, or other conventional hemostatic methods are impractical. Because a hemostatic agent is a foreign body, it can cause foreign body reactions, inflammation, and infections that can interfere with the wound healing process. Therefore, we should select hemostatic agents after considering their effects on wound healing. Here, we compared the effects of hemostatic agents on wound healing in a rectus abdominis muscle defect in rats.MethodsTwelve Sprague Dawley rats were subjected to creation of a 6 × 6 mm defect in the rectus abdominis muscle and divided into four groups: control group; group A, Tachosil fibrin sealant patch; group B, Surgicel Fibrillar oxidized regenerated cellulose; and group C, Surgicel Snow oxidized regenerated cellulose. For the histologic analysis, biopsies were performed on the 3rd, 7th, and 27th days.ResultsThe foreign body reaction was the weakest in group A and most significant in group C. The inflammatory cell infiltration was the weakest in group A and similar in groups B and C. Muscle regeneration differed among periods. The rats in group A were the most active initially, while those in group C showed prolonged activity.ConclusionTachosil and Surgicel administration increased inflammation via foreign body reactions, but the overall wound healing process was not significantly affected. The increased inflammation in the Surgicel groups was due to a low pH. We recommend using Tachosil, because it results in less intense foreign body reactions than Surgicel and faster wound healing due to the fibrin action.

The Treatment of Foreign Body Reaction and Inflammation Caused by Prosthetic Material with Surgery and Negative Pressure Wound Therapy

The Treatment of Foreign Body Reaction and Inflammation Caused by Prosthetic Material with Surgery and Negative Pressure Wound Therapy

Clinicopathological Analysis of 90 Cases of Polyacrylamide Hydrogel Injection for Breast Augmentation Including 2 Cases Followed by Breast Cancer

Background: Although polyacrylamide hydrogel (PAAG) injection for breast augmentation has been prohibited for many years, the long-term complications will be significant for a long period. Few research articles have focused on the clinicopathological analysis. Materials and Methods: We summarized clinical and pathological features of 90 cases after PAAG-injected breast augmentation, including 2 cases of breast cancer developed following PAAG injection. Results: All patients were females between the ages of 30 and 64 years (mean, 44 years). The complications included masses (75.58%), pain (45.35%), migration (22.09%), deformation (18.60%), infection (16.28%), induration (4.65%), and psychological fear (2.33%). Microscopically, the PAAG presented as purple gel pools, and the foreign body reaction was noted in all 90 patients. The proportion of fibrous component exceeded 90% in 26 cases (28.89%). Chronic and acute inflammation was noted in 70 (77.78%) and 9 (10%) patients, respectively. The mammary gland around the gel displayed atrophy in 18 cases (20.00%), adenosis in 33 cases (36.67%), ductal carcinoma in situ in 1 case (1.11%), and invasive carcinoma in 1 case (1.11%). Conclusion: The long-term complications of PAAG-injected breast augmentation are various and complex. Pathologically, these complications are associated with foreign body reaction, fibrosis, and inflammation.

A Radiological Approach to Evaluate Bone Graft Integration in Reconstructive Surgeries

(1) Background: Bone tissue engineering is a promising tool to develop new smart solutions for regeneration of complex bone districts, from orthopedic to oral and maxillo-facial fields. In this respect, a crucial characteristic for biomaterials is the ability to fully integrate within the patient body. In this work, we developed a novel radiological approach, in substitution to invasive histology, for evaluating the level of osteointegration and osteogenesis, in both qualitative and quantitative manners. (2) SmartBone®, a composite xeno-hybrid bone graft, was selected as the base material because of its remarkable effectiveness in clinical practice. Using pre- and post-surgery computed tomography (CT), we built 3D models that faithfully represented the patient’s anatomy, with special attention to the bone defects. (3) Results: This way, it was possible to assess whether the new bone formation respected the natural geometry of the healthy bone. In all cases of the study (four dental, one maxillo-facial, and one orthopedic) we evaluated the presence of new bone formation and volumetric increase. (4) Conclusion: The newly established radiological protocol allowed the tracking of SmartBone® effective integration and bone regeneration. Moreover, the patient’s anatomy was completely restored in the defect area and functionality completely rehabilitated without foreign body reaction or inflammation.

The treatment of foreign body reaction and inflammation caused by prosthetic material with surgery and negative pressure wound therapy

The treatment of foreign body reaction and inflammation caused by prosthetic material with surgery and negative pressure wound therapy

MRI Tracking of the Effect of Bioabsorbable Pins on Bone Marrow Edema After Fixation of the Osteochondral Fragment in the Talus.

Large osteochondral lesions of the talus (OLT) with good articular cartilage can be fixed by using bioabsorbable pins. These pins have various advantages but they can have adverse effects such as foreign body inflammation. This negative impact of pins on subchondral bone can be seen as bone marrow edema (BME) on magnetic resonance imaging (MRI). The purpose of this study was to investigate the course of change in BME on MRI, including osteolytic change around pins in OLT treated with pin fixation. This study comprised 13 ankles in 12 patients, who underwent surgeries to fix an OLT using poly-l-lactide acid pins. MRIs were taken at preoperative, 3, 6, and 12 months after surgery. The area of BME was measured at each time point, and osteolytic change around pins was evaluated. Moreover, pin insertion angle was measured. BME significantly decreased from preoperative to 6 and 12 months. At 1 year, 28.1% of pins exhibited osteolytic change around them. Pin insertion angle was significantly lower in those with osteolytic change than those with no osteolytic change. At 3 and 6 months and 1 year postoperatively, BME with osteolytic change was significantly greater than those patients with no osteolytic change. The American Orthopaedic Foot & Ankle Society score significantly improved from preoperative (76.6±3.4 points) to 1 year after surgery (98.5±3.8 points). A shallow pin insertion angle was associated with osteolytic change around pins and persistence of BME on MRI, although excellent results were obtained at 1 year after surgery. Level III, retrospective comparative series.

Preservation of Cells of the Organ of Corti and Innervating Dendritic Processes Following Cochlear Implantation in the Human: An Immunohistochemical Study.

This study evaluates the degree of preservation of hair cells, supporting cells, and innervating dendritic processes after cochlear implantation in the human using immunohistochemical methods. Surgical insertion of a cochlear implant electrode induces various pathologic changes within the cochlea including insertional trauma, foreign body response, inflammation, fibrosis, and neo-osteogenesis. These changes may result in loss of residual acoustic hearing, adversely affecting the use of hybrid implants, and may result in loss of putative precursor cells, limiting the success of future regenerative protocols. Twenty-eight celloidin-embedded temporal bones from 14 patients with bilateral severe to profound sensorineural hearing loss and unilateral cochlear implants were studied. Two sections including the modiolus or basal turn from each temporal bone were stained using antineurofilament, antimyosin-VIIa, and antitubulin antibodies in both the implanted and unimplanted ears. Inner and outer hair cells: Immunoreactivity was reduced throughout the implanted cochlea and in the unimplanted cochlea with the exception of the apical turn.Dendritic processes in the osseous spiral lamina: Immunoreactivity was significantly less along the electrode of the implanted cochlea than in the other segments.Inner and outer pillars, inner and outer spiral bundles, and Deiters' cells: Immunoreactivity was similar in the implanted and unimplanted cochleae. Insertion of a cochlear implant electrode may significantly affect the inner and outer hair cells both along and apical to the electrode, and dendritic processes in the osseous spiral lamina along the electrode. There was less effect on pillar cells, Deiters' cells, and spiral bundles.