Chemical Injury Research Articles

Airway consequences of alendronic acid aspiration.

Bisphosphonates are commonly prescribed medications to prevent and treat osteoporosis. Although possessing low side effect profiles, the potential for severe topical effects is rare but important. Irritation of the upper gastrointestinal tract is well documented; however, the risk and effects of accidental aspiration are rarely reported.Attention is drawn to a case recently managed at a tertiary head and neck centre where a patient in their 70s was admitted in respiratory distress 3 days after aspirating alendronic acid. This case highlights the potential risk of topical chemical injury posed to the airway by bisphosphonates.Bisphosphonates should be prescribed with detailed and specific counselling regarding this risk. Pharmacological product literature should be updated to reflect the risk. Clinical teams should be aware of and vigilant for the delayed presentation and prolonged symptom course of such injuries. Prompt airway intervention and techniques to minimise further mucosal trauma ensure optimal outcomes.

Regulatory Considerations for Development of Wound Dressing Devices Used for Chemical and Radiation Injuries.

Regulatory Considerations for Development of Wound Dressing Devices Used for Chemical and Radiation Injuries.

Corneal stromal changes following simple limbal epithelial transplantation on Scheimpflug densitometry: Early results.

Chemical injury to eyes causes limbal stem cell deficiency (LSCD), which leads to conjunctival epithelium and underlying stromal changes. Simple limbal epithelial transplant helps to restore corneal epithelium and corneal stromal clarity. These changes are documented in this prospective eye study. To report the changes in epithelial/stromal (E/S) reflectivity ratio and corneal stromal densitometry following simple limbal epithelial transplantation (SLET) in patients with unilateral chemical burn-induced LSCD. It is a prospective imaging study of cornea before and after SLET. Corneal densitometry with Pentacam and epithelial and stromal reflectivity on anterior segment optical coherence tomography were analyzed for five patients (n = 5 eyes), who underwent autologous SLET for unilateral chemical burn-induced LSCD. Mann-Whitney U-test and Pearson correlation. A significant improvement in E/S reflectivity was noted at 1 month (P < 0.05) after SLET, and this was maintained until the end of 6 months. The densitometry measurements decreased in the entire cornea at every level, that is, anterior, central, and posterior cornea. However, the values did not normalize till the last follow-up at 6 months. A trend of normal corneal epithelization exists in eyes undergoing SLET. Densitometry at all the levels, the anterior, central, and posterior cornea, also decreases after SLET. SLET improves visual outcomes in LSCD eyes not only by epithelization but also by reducing stromal scarring.

Necrostatin-1 protects corneal epithelial cells by inhibiting the RIPK1/RIPK3/MLKL cascade in a benzalkonium chloride-induced model of necroptosis

PurposeBenzalkonium chloride (BAC) is commonly used as a preservative in ophthalmic medications, despite its potential to induce chemical injury. Extensive research has demonstrated that BAC can lead to adverse effects, including injuries to the ocular surface. Our study aimed to elucidate the underlying mechanism of necroptosis induced by BAC. MethodsHuman corneal epithelial (HCE) cells and mouse corneas were subjected to chemical injury, and the necrostatin-1 (Nec1) group was compared to the dimethylsulfoxide (DMSO) group. The extent of damage to HCE cells was assessed using CCK-8 and flow cytometry. Hematoxylin and eosin staining, as well as fluorescein sodium staining, were used to detect and characterize corneal injury. The activation of inflammatory cytokines and necroptosis-related proteins and genes was evaluated using Western blotting, immunofluorescence staining, and quantitative RT‒PCR. ResultsIn our study, the induction of necroptosis by a hypertonic solution was not observed. However, necroptosis was observed in HCE cells exposed to NaOH and BAC, which activated the receptor-interacting protein kinase 1 (RIPK1) - receptor-interacting protein kinase 3 (RIPK3) - mixed lineage kinase domain-like protein (MLKL) signaling pathway. In mouse corneal tissues, BAC could induce necroptosis and inflammation. The administration of Nec1 mitigated the inflammatory response and ocular surface damage caused by BAC-induced necroptosis in our experimental models. Furthermore, our in vivo experiments revealed that the severity of necroptosis was greater in the 3-day group than in the 7-day group. ConclusionsNecroptosis plays a role in the pathological development of ocular surface injury caused by exposure to BAC. Furthermore, our study demonstrated that the administration of Nec1 could mitigate the pathological effects of necroptosis induced by BAC in clinical settings.

The profile of patients attending to the general emergency department with ocular complaints within the last year: is it a true ocular emergency?

PurposeOcular emergencies require immediate intervention to prevent rapid vision loss or functional impairment. The aim of this study was to determine the proportion of true ocular emergencies among patients who presented to the general emergency department with ocular complaints and were referred to the Eye Clinic.MethodsIn a retrospective cross-sectional study in a tertiary hospital in Istanbul, patients aged 0–100 years who presented to the general emergency department with ocular complaints between January and December 2022 were included. Inconclusive diagnoses and incomplete records were excluded. Patients were divided into three groups: top eye emergencies (TE), relative eye emergencies (REE), and non-emergency eyes (NEE).ResultsAmong the 652,224 individuals seeking care, 9,982 (1.5%) were referred to the Eye Emergency Clinic. Of these, 2,788 (27.9%) were female, and 7,194 (72.1%) were male, with ages ranging from 0 to 98 years. TopEye Emergencies (TEE), Relative Eye Emergencies (REE), and Non-Eye Emergencies (NEE) accounted for 13%, 60%, and 27% of the cases, respectively. Common top-eye emergencies (TEE) include chemical injuries, orbital-preseptal cellulitis, and orbital fractures. Relative eye emergencies (REEs) commonly feature corneal foreign bodies, corneal erosion, and conjunctivitis. Nonemulsion eye (NEE) methods involve simple eye redness, trauma without eye involvement, and subconjunctival haemorrhage.ConclusionsConsistent with the literature, 1.5% of patients presenting to the general emergency department had eye complaints.However, 27% of those referred to the ophthalmological clinic did not have an urgent eye condition. This is partly due to the high proportion of patients presenting to the emergency department with ocular complaints and the lack of knowledge of ophthalmological diseases by emergency physicians, leading to unnecessary referrals to the ophthalmology clinic, resulting in a loss of the workforce and reduced time allocated to patients with true ocular emergencies.

Histological Analysis of Enamel Microstructure in Response to Dietary Habits: Comparative Study A cross Different Populations

Background: The protective role of enamel against physical and chemical injury is well documented. Despite being classified as connective tissue, with its composition and microstructure dominated by hydroxyapatite crystals it is the hardest in the human body Objective: The purpose of this study is to investigate the histological changes in enamel microstructure that occur when distinct populations follow different food habits. Study Design: This study employs a comparative cross-sectional design. Duration and Place of the Study: This study was conducted at Department of pathology Watim medical and dental college, Rawat , from 3rd June 2022 to 2nd May 2023. Material and Methods: A sum of 300 dental examples were acquired from members having a place with one or the other, High Carbohydrate Diet Group (n=95): people accounting their principle dietary consumption high-carb nourishments like grains/pay/aries and starches. High-Proteins Diet Group (n=108): participants who had the highest consumption of protein-rich foods, such as meat products, legumes and dairy. Mixed Diet Group (n=97): People with intermediate consumptions of carbohydrates, proteins and fats Subsequently, study participants were determined to best represent the two diet groups based on dietary surveys and medical histories. Results: In total, 300 participants are considered in this research, with the mean age of the group on HC totals 3.5 ± 1.3 years, HP group 3.4 ± 9.2 years, and MD group 3.6 ± 1.1 years. The gender distribution also shows similar characteristics, males are 55.8% in HC group, 46.3% in HP group, and 52.6% in MD group; females are 44.2%, 53.7%, and 47.4%, respectively. Concerning the age range, the major cluster is 26-35 years old and 36-45 years old cohorts, which proves the majority of the middle ages. Conclusion: Our results indicate that decomposition is a major factor affecting the surface morphology, structure and health of enamel.

OCCUPATIONAL AND ENVIRONMENTAL FACTORS ASSOCIATED WITH OCULAR TRAUMA AMONG PATIENTS ATTENDING EYE CARE SERVICES AT JINJA REGIONAL REFERRAL HOSPITAL. A CROSS-SECTIONAL STUDY.

Background Ocular trauma refers to any injury to the eyeball, its adnexa, orbit, and periorbital structures due to direct contact with fixed or mobile, blunt or sharp objects. The study aims to assess the factors associated with ocular trauma among patients attending eye care services at Jinja Regional Referral Hospital. Methodology A cross-sectional descriptive study design that collected quantitative data from 100 respondents using a non-probability consecutive sampling process from September 2022 to March 2023. Results 70% of the respondents were male while 30% were females. 55% of the respondents were 21-40 years, 32% were 0-20 years, 10% were 41-60 years and 3% were &gt;60 years. Ocular injuries were caused by a foreign body (40%) followed by work-related activities with 20%, accidents with 18%, assault-related actions with 20%, and the least were chemical injuries with 5%. (65%) didn’t have eye protective equipment while 35% had. 40% of the respondents knew about awareness programs on ocular trauma while 60% had not received these programs. (43%) obtained trauma from the workplace, 25% from bars, 17% from homes, and 15% from schools. 55% had used nontherapeutic drugs like alcohol. 50% were using water from protected streams, 30% were using water from taps, 15% were using water from wells and the least were those using water from rivers (05%). Conclusion The most affected age group was 21-40. Males were more affected than females. Literates were most affected, and most cases of ocular trauma were obtained from the workplace. Ocular trauma was associated with the use of non-therapeutic drugs like alcohol. Recommendations Health education on ocular injuries should be adopted by the relevant authorities to increase awareness of the dangers, causes, predisposing factors, and burden of ocular trauma in the community.

Awareness of school teachers about students common emergencies during school time in the eastern region, Saudi Arabia: A cross-sectional study.

Schools have to ensure student safety and well-being. However, medical emergencies involving injuries are common, requiring teachers to provide prompt first aid before professional care arrives. This study assessed knowledge and awareness of first aid among school teachers to identify areas needing improvement. This cross-sectional study surveyed 371 teachers from the eastern region primary schools using a standardized questionnaire assessing first aid knowledge across areas like bleeding control, fractures, seizures, choking, and burns. Demographic factors were analyzed for correlations with knowledge levels. Pearson's Chi-square tests analyzed bivariate relationships comparing correct knowledge identification percentages across teacher sociodemographic. The level of statistical significance was at a P value <0.05 across tests. Only 157 teachers felt able to appropriately handle medical emergencies. Major knowledge gaps existed regarding airway obstruction and chemical injuries, with 168 unable to identify correct responses for choking first aid and 105 unsure of chemical burn management steps. Appropriate fracture management was lacking, with just 70 correctly endorsing nose pinch for nosebleeds. Cardiopulmonary resuscitation knowledge was inadequate, with 57 of teachers unaware of the basics. Teachers demonstrating higher knowledge levels overwhelmingly had prior first aid training (153, 66.5%) compared to untrained counterparts (89, 63.1%). The study revealed poor first aid knowledge among elementary school teachers for effectively managing child emergencies. Strategies enhancing delivery must address barriers around training access, knowledge attrition, and variability in baseline skills through sustainable system-wide policies applied nationally. Fulfilling schools' ethical obligations toward maintaining student safety requires urgent reforms to bolster emergency preparedness.

Engineered Mesenchymal Stromal Cell Exosomes-Loaded Microneedles Improve Corneal Healing after Chemical Injury.

Corneal alkali burns represent a prevalent ophthalmic emergency with the potential to induce blindness. The main contributing mechanisms include excessive inflammation and delayed wound healing. Existing clinical therapies have limitations, promoting the exploration of alternative methods that offer improved efficacy and reduced side effects. Adipose-derived stem cell-exosome (ADSC-Exo) has the potential to sustain immune homeostasis and facilitate tissue regeneration. Nevertheless, natural ADSC-Exo lacks disease specificity and exhibits limited bioavailability on the ocular surface. In this study, we conjugated antitumor necrosis factor-α antibodies (aT) to the surface of ADSC-Exo using matrix metalloproteinase-cleavable peptide chains to create engineered aT-Exo with synergistic effects. In both in vivo and in vitro assessments, aT-Exo demonstrated superior efficacy in mitigating corneal injuries compared to aT alone, unmodified exosomes, or aT simply mixed with exosomes. The cleavable conjugation of aT-Exo notably enhanced wound healing and alleviated inflammation more effectively. Simultaneously, we developed poly(vinyl alcohol) microneedles (MNs) for precise and sustained exosome delivery. The in vivo results showcased the superior therapeutic efficiency of MNs compared with conventional topical administration and subconjunctival injection. Therefore, the bioactive nanodrugs-loaded MNs treatment presents a promising strategy for addressing ocular surface diseases.

Progress in Research on the Role of the Thioredoxin System in Chemical Nerve Injury.

(1) Background: Various factors, such as oxidative stress, mitochondrial dysfunction, tumors, inflammation, trauma, immune disorders, and neuronal toxicity, can cause nerve damage. Chemical nerve injury, which results from exposure to toxic chemicals, has garnered increasing research attention. The thioredoxin (Trx) system, comprising Trx, Trx reductase, nicotinamide adenine dinucleotide phosphate, and Trx-interacting protein (TXNIP; endogenous Trx inhibitor), helps maintain redox homeostasis in the central nervous system. The dysregulation of this system can cause dementia, cognitive impairment, nerve conduction disorders, movement disorders, and other neurological disorders. Thus, maintaining Trx system homeostasis is crucial for preventing or treating nerve damage. (2) Objective: In this review study, we explored factors influencing the homeostasis of the Trx system and the involvement of its homeostatic imbalance in chemical nerve injury. In addition, we investigated the therapeutic potential of the Trx system-targeting active substances against chemical nerve injury. (3) Conclusions: Chemicals such as morphine, metals, and methylglyoxal interfere with the activity of TXNIP, Trx, and Trx reductase, disrupting Trx system homeostasis by affecting the phosphatidylinositol-3-kinase/protein kinase B, extracellular signal-regulated kinase, and apoptotic signaling-regulated kinase 1/p38 mitogen-activated protein kinase pathways, thereby leading to neurological disorders. Active substances such as resveratrol and lysergic acid sulfide mitigate the symptoms of chemical nerve injury by regulating the Ras/Raf1/extracellular signal-regulated kinase pathway and the miR-146a-5p/TXNIP axis. This study may guide the development of Trx-targeting modulators for treating neurological disorders and chemical nerve injuries.

In vitro model to evaluate effect of acidic pepsin on vocal fold barrier function

The pathophysiology of laryngopharyngeal reflux (LPR) and its impact on the vocal fold is not well understood, but may involve acid damage to vocal fold barrier functions. Two different components encompass vocal fold barrier function: the mucus barrier and tight junctions. Mucus retained on epithelial microprojections protects the inside of the vocal fold by neutralizing acidic damage. Tight junctions control permeability between cells.Here we developed an in vitro experimental system to evaluate acidic injury and repair of vocal fold barrier functions. We first established an in vitro model of rat vocal fold epithelium that could survive at least one week after barrier function maturation. The model enabled repeated evaluation of the course of vocal fold repair processes. Then, an injury experiment was conducted in which vocal fold cells were exposed to a 5-min treatment with acidic pepsin that injured tight junctions and cell surface microprojections.Both of them healed within one day of injury. Comparing vocal fold cells treated with acid alone with cells treated with acidic pepsin showed that acidic pepsin had a stronger effect on intercellular permeability than acid alone, whereas pepsin had little effect on microprojections.This result suggests that the proteolytic action of pepsin has a larger effect on protein-based tight junctions than on phospholipids in microprojections. This experimental system could contribute to a better understanding of vocal fold repair processes after chemical or physical injuries, as well as voice problems due to LPR pathogenesis.

Occupational Injuries among Health Care Workers in Selected Hospitals in Ogbomosho, Oyo State

Occupational injuries present significant risks to health care workers (HCWs) in Ogbomosho, Oyo State, affecting those in some of the most productive years of their lives. This descriptive cross-sectional study assesses the types and associated factors of such injuries among 312 HCWs using self-structured questionnaires. Findings indicate that a majority of HCWs experience physical, biological, and chemical injuries, strongly influenced by factors like inadequate safety training and lack of protective equipment. Statistical analysis reveals significant correlations between the occurrence of occupational injuries and factors such as the years of experience (p = 0.000) and the work environment conditions. The study underscores the need for improved safety protocols and preventive measures, including regular training and adequate provision of personal protective equipment, to mitigate these risks and enhance worker safety.

A Blast and Burn Hand Injury Caused by an Exploding Vaping Device in a Pediatric Patient: A Case Report.

In this report, we present an injury to the hand caused by an exploding vaping device. This report summarizes the burn, blast and chemical injury, and discusses best practice for treatment. This case provides a warning to healthcare professionals and the public about the potential for and the seriousness of this injury. We hope to emphasize the rising incidence of vaping among children, the injuries that may occur, and the methods for treatment.

Visual and ocular surface rehabilitation with scleral lenses in a patient with limbal stem cell deficiency due to chemical injury – A case report

Scleral lenses are widely used for therapeutic purposes. This case report aims to emphasize the advantages of utilizing scleral lenses as a nonsurgical management option and presents evidence of their effectiveness in improving UCVA from 2/60 to 6/12 and reducing the corneal neovascularization and a hazy interface in a patient with partial limbal stem cell deficiency (LSCD) secondary to chemical injury. This case report highlights the potential of the scleral lens if given with an ideal fit and close monitoring for LSCD caused by chemical injury.

Engineering Titanium-Hydroxyapatite Nanocomposite Hydrogels for Enhanced Antibacterial and Wound Healing Efficacy.

External factors often lead to predictable damage, such as chemical injuries, burns, incisions, and wounds. Bacterial resistance to antibiotics at wound sites underscores the importance of developing hydrogel composite systems with inorganic nanoparticles possessing antibacterial properties to treat infected wounds and expedite the skin regeneration process. In this study, a promising TiO2-HAp@PF-127@CBM inorganic and organic integrated hydrogel system was designed to address challenges associated with bacterial resistance and wound healing. The synthesized TiO2-hydroxyapatite (HAp) nanocomposites were coated with an FDA-approved PluronicF-127 polymer and combined with a carbomer hydrogel (CBM) to accomplish the final product. The synthesized nanoparticles exhibit enhanced biocompatibility against L929 and HUVECs and cell proliferation effects. To mitigate oxidative stress caused by TiO2-induced reactive oxygen species in dark environments for effective antibacterial effects, HAp promotes cell proliferation, expediting wound skin layer formation. CBM binds to inorganic nanoparticles, facilitating their gradual release and promoting wound healing. The reduced inflammation and enhanced tissue regeneration observed in the TiO2-HAp@PF-127@CBM group suggest a favorable environment for wound repair. These results align with prior findings highlighting the biocompatibility and wound-healing properties of titanium-HAp-based materials. The ability of the TiO2-HAp@PF-127@CBM hydrogel dressing to promote granulation tissue formation and facilitate epidermal regeneration underscores its potential for promoting antibacterial effects and wound healing applications.

Demographic Data and Trends in Use of Amniotic Membrane Transplant During the Past Decade at a Tertiary Eye Center.

In this study, we aimed to define demographic data and trends in use of amniotic membrane transplant during the past decade at a tertiary eye center. We included 272 patients who underwent amniotic membrane transplant for ocular surface pathology from January 2009 to December 2021. We retrospectively evaluated the medical data. The male-to-female ratio of patients was 41/23. Mean age of the patients was 50 ± 23.6 years (range, 1-91 years). Indications consisted of ocular surface lesion excision surgery (n = 184; 66.7%), chemical injury (n = 25; 9.1%), persistent epithelial defect (n = 23; 8.3%), keratitis (n = 22; 8%), noninfectious corneal perforation (n = 9; 3.3%), bullous keratopathy (n = 9; 3.3%), and ocular cicatricial pemphigoid (n = 4; 1.4%). Single amniotic membrane transplant was applied to 236 patients (85.5%), and multiple transplant was applied to 40 patients (14.5%). We observed repeated amniotic membrane transplant rates and amniotic membrane degradation durations that were associated with primary disease (P = .005 and P < .001, respectively). Degradation time was shorter in cases of chemical burns and keratitis than in cases after ocular surface lesion excision. Amniotic membrane transplant indication rates were statistically different between the first 6 years and the last 6 years of the 12 years of data (P = .041). The frequency of amniotic membrane transplant application in microbial keratitis has increased substantially in the past 2 years. Amniotic membrane is used as a biomaterial in various ocular surface diseases due to its anti-inflammatory, antimicrobial, and wound-healing properties. After transplant, the amniotic membrane, which is directly related to the inflam-matory processes of the primary disease, degrades gradually. There may be changes in the trend of amniotic membrane transplant, the indications of which are progressively expanding over time.

Keratin 5 basal cells are temporally regulated developmental and tissue repair progenitors in bladder urothelium.

Urothelium forms a distensible yet impermeable barrier, senses and transduces stimuli, and defends the urinary tract from mechanical, chemical, and bacterial injuries. Biochemical and genetic labeling studies support the existence of one or more progenitor populations with the capacity to rapidly regenerate the urothelium following injury, but slow turnover, a low mitotic index, and inconsistent methodologies obscure progenitor identity. The progenitor properties of basal keratin 5 urothelial cells (K5-UCs) have been previously investigated, but those studies focused on embryonic or adult bladder urothelium. Urothelium undergoes desquamation and apoptosis after birth, which requires postnatal proliferation and restoration. Therefore, we mapped the fate of bladder K5-UCs across postnatal development/maturation and following administration of cyclophosphamide to measure homeostatic and reparative progenitor capacities, respectively. In vivo studies demonstrate that basal K5-UCs are age-restricted progenitors in neonates and juveniles, but not in adult mice. Neonatal K5-UCs retain a superior progenitor capacity in vitro, forming larger and more differentiated urothelial organoids than adult K5-UCs. Accordingly, K5-UC transcriptomes are temporally distinct, with enrichment of transcripts associated with cell proliferation and differentiation in neonates. Induction of urothelial proliferation is sufficient to restore adult K5-UC progenitor capacity. Our findings advance the understanding of urothelial progenitors and support a linear model of urothelial formation and regeneration, which may have significant impact on therapeutic development or tissue engineering strategies.NEW & NOTEWORTHY Fate mapping reveals an important linear relationship, whereby bladder basal urothelial cells give rise to intermediate and superficial cells in an age-restricted manner and contribute to tissue repair. Neonatal basal cells reprise their role as superior progenitors in vitro and display distinct transcriptional signatures, which suggest progenitor function is at least partially cell intrinsic. However, the urothelium progenitor niche cannot be overlooked, since FGF7 rescues adult basal cell progenitor function.

Micro-needle mesotherapy in anti-aging prevention and skin rejuvenation - the importance of inflammation, healing and skin regeneration after the procedure

The skin serves numerous vital roles in the human body, such as protecting against physical, chemical, and mechanical injuries. Although skin aging is a natural phenomenon, it is still the subject of research by scientists seeking methods to delay the process. One of the innovative treatments in this field is micro-needle mesotherapy, referred to as collageninducing therapy. The study aimed to describe the features of the ageing skin, elucidate the alterations that occur with time, and investigate the reparative mechanisms triggered by micro-needle mesotherapy treatment. Microneedle-induced skin inflammation is a desirable process. It leads to the healing of damage and can significantly contribute to wrinkle shallowing, improved hydration and skin remodeling.

Hand Sanitizer: Stopping the Spread of Infection at a Cost.

The recent rise in hand sanitizer use due to the COVID-19 pandemic has had a beneficial impact on stopping the spread of disease, but the potential negative implications of its overuse on the body and the microbiome have yet to be thoroughly reviewed. Epidermal layers absorb hand sanitizer from direct application to the skin, making them some of the most susceptible cells to the adverse effects of overuse. The increased usage of hand sanitizer can affect the variation, quantity, and diversity of the skin microflora, leading to conditions such as eczema, atopic dermatitis, and even systemic toxicity due to colonization of the skin with pathogenic bacteria. Due to the close-knit relationship between the skin and gut, the gastrointestinal system can also incur disruptions due to the negative effects on the skin as a result of excessive hand sanitizer use, leading to gut dysbiosis. Additionally, the accidental ingestion of hand sanitizer, and its abuse or misuse, can be toxic and lead to alcohol poisoning, which is an issue most commonly seen not only in the pediatric population but also in adolescents and adults due to aberrant recreational exposure. As a vulnerable body system, the eyes can also be negatively impacted by hand sanitizer misuse leading to chemical injury, visual impairment, and even blindness. In this review, we aim to highlight the variations in hand sanitizer formulation, the benefits, and how misuse or overuse may lead to adverse effects on the skin, gut, and eyes. In particular, we review the advantages and disadvantages of alcohol-based hand sanitizers (ABHSs) and non-alcohol-based hand sanitizers (NABHSs) and how the components and chemicals used in each can contribute to organ dysbiosis and systemic damage.

Nanohydroxyapatite Coating Attenuates Fibrotic and Immune Responses to Promote Keratoprosthesis Biointegration in Advanced Ocular Surface Disorders.

Keratoprosthesis (KPro) implantation is frequently the only recourse for patients with severe corneal disease. However, problems arise due to inadequate biointegration of the KPro, particularly the PMMA optical cylinder, such as tissue detachment, tissue melting, or eye-threatening infection in the interface. Here, using the AuroKPro as a model prosthesis, a surface functionalization approach─coating the optical cylinder with nanohydroxyapatite (nHAp)─was trialed in rabbit eyes with and without a proceeding chemical injury. In chemically injured eyes, which simulated total limbal epithelial stem cell deficiency, clear benefits were conferred by the coating. The total modified Hackett-McDonald score and area of tissue apposition differences 12 weeks after implantation were 5.0 and 22.5%, respectively. Mechanical push-in tests revealed that 31.8% greater work was required to detach the tissues. These differences were less marked in uninjured eyes, which showed total score and tissue apposition differences of 2.5 and 11.5%, respectively, and a work difference of 23.5%. The improved biointegration could be contributed by the attenuated expression of fibronectin (p = 0.036), collagen 3A1 (p = 0.033), and α-smooth muscle actin (p = 0.045)─proteins typically upregulated during nonadherent fibrous capsule envelopment of bioinert material─adjacent to the optical cylinders. The coating also appeared to induce a less immunogenic milieu in the ocular surface tissue, evidenced by the markedly lower expression of tear proteins associated with immune and stimulus responses. Collectively, the level of these tear proteins in eyes with coated prostheses was 1.1 ± 13.0% of naïve eyes: substantially lower than with noncoated KPros (246.5 ± 79.3% of naïve, p = 0.038). Together, our results indicated that nHAp coating may reduce the risk of prosthesis failure in severely injured eyes, which are representative of the cohort of KPro patients.