ABSTRACT
Metal-organic frameworks (MOFs) have attracted significant research interest in biomimetic catalysis. However, the modulation of the activity of MOFs by precisely tuning the coordination of metal nodes is still a significant challenge. Inspired by metalloenzymes with well-defined coordination structures, a series of MOFs containing halogen-coordinated copper nodes (Cu-X MOFs, X = Cl, Br, I) are employed to elucidate their structure-activity relationship. Intriguingly, experimental and theoretical results strongly support that precisely tuning the coordination of halogen atoms directly regulates the enzyme-like activities of Cu-X MOFs by influencing the spatial configuration and electronic structure of the Cu active center. The optimal Cu-Cl MOF exhibits excellent superoxide dismutase-like activity with a specific activity one order of magnitude higher than the reported Cu-based nanozymes. More importantly, by performing enzyme-mimicking catalysis, the Cu-Cl MOF nanozyme can significantly scavenge reactive oxygen species and alleviate oxidative stress, thus effectively relieving ocular chemical burns. Mechanistically, the antioxidant and antiapoptotic properties of Cu-Cl MOF are achieved by regulating the NRF2 and JNK or P38 MAPK pathways. Our work provides a novel way to refine MOF nanozymes by directly engineering the coordination microenvironment and, more significantly, demonstrating their potential therapeutic effect in ophthalmic disease.
ABSTRACT
Objetivo: Las quemaduras oculares químicas con compromiso extenso de limbo (mayor del 50%) tienen mal pronóstico visual con manejo médico como única alternativa terapéutica; por lo que el propósito de este trabajo es evaluar el tratamiento temprano con el implante de membrana amniótica en cuanto a resultados anatómicos y funcionales en estos pacientes. Metodología: Estudio retrospectivo tipo serie de casos. Se presentan los resultados visuales en 9 ojos de 6 pacientes tratados en la Clínica de Oftalmología de Cali y el Hospital Universitario del Valle con quemadura ocular química grave a los que se les realizó implante precoz de membrana amniótica adjunto al manejo oftalmológico convencional. Resultados: Todos los pacientes tuvieron mejoría de la agudeza visual. El 87% de ellos lograron una agudeza visual mejor corregida (AVMC) de 20/30 o mejor. Ningún paciente desarrolló simbléfaron ni requirió trasplante heterólogo de córnea. Conclusiones: Los resultados presentados sugieren que el implante de membrana amniótica precoz adicional a la terapia médica, puede ser el manejo de elección en la fase aguda de quemaduras químicas extensas de superficie ocular (compromiso mayor del 50% de limbo), ya que mejora el pronóstico visual con respecto a la terapia médica como único manejo.
Purpose: Ocular chemical burns with extensive limbus involvement (greater than 50%) have poor visual prognosis with medical management as the only therapeutic alternative; So the purpose of this work is to evaluate if early treatment with amniotic membrane implant improves the anatomical and functional results in these patients. Methods: Retrospective study of a cases series. We present the visual results in 9 eyes of 6 patients treated at the Cali Ophthalmology Clinic and the Valle´s University Hospital with severe chemical ocular burns who underwent early amniotic membrane implantation added to conventional ophthalmologic management. Results: All patients had improvement of visual acuity. 87% of patients achieved a better corrected visual acuity (BCVA) of 20/30 or better. No patient developed simblefaron or required heterologous corneal transplantation. Conclusions: The results presented suggest that amniotic membrane implantation in addition to medical therapy could be the management of choice in the acute phase of extensive ocular surface chemical burns (involvement greater than 50% of limbo), since it improves the visual prognosis with respect to medical therapy as sole management.
