The loss of microglia activities facilitates glaucoma progression in association with CYP1B1 gene mutation (p.Gly61Glu)

A bibliometric analysis of the application of stem cells in glaucoma research from 1999 to 2022

Background: Glaucoma, a neurodegenerative disease of the retina, is the leading cause of irreversible blindness. Stem cells have therapeutic potential for glaucoma. However, few bibliometric studies have been published in this field. Concerning a visual map, this article aims to characterize the research context, cooperation relationship, hotspots, and trends concerning the application of stem cells in glaucoma research. Methods: Publications focusing on stem cell research and glaucoma were retrieved from the Web of Science Core Collection. VOSviewer, CiteSpace, Microsoft Excel, and Scimago Graphica were used to map the contributions of countries or regions, authors, organizations, and journals. Journal Impact Factor data were obtained from the Web of Science Core Collection. We analyzed the tendencies, hotspots, and knowledge networks using VOSviewer, and CiteSpace. Results: We analyzed 518 articles published from 1999 through 2022. In the first decade, the number of articles in this field increased slowly, and there was a marked acceleration in publication frequency after 2010. The United States, China, and England were the main contributors. Yiqin Du was the most prolific author, and among the top 10 prolific writers, Keith R. Martin's work was cited most frequently. Investigative Ophthalmology and Visual Science, Experimental Eye Research, and Cornea published the most articles in this domain. The three most commonly co-cited journals were Investigative Ophthalmology and Visual Science, Experimental Eye Research, and Proceedings of the National Academy of Sciences of the United States of America. The Central South University, the University of Pittsburgh, and the National Institutes of Health National Eye Institute were highly prolific institutions in this research area. Our keywords analysis with VOSviewer suggested directions of future research and yielded the following recent key themes, extracellular vesicles, exosomes, mitochondria, growth factors, oxidative stress, and ocular diseases. Four co-cited references had a citation burst duration until 2022. Conclusion: With improvements in overall quality of life and demographic transitions toward population aging, research and clinical focus on eye care has increased, with glaucoma as a key area of emphasis. This study added to our understanding of the global landscape and Frontier hotspots in this field.

Polymorphisms in CYP1B1 gene and the risk of suffering Primary Open-Angle Glaucoma: Systematic review and meta-analysis

PURPOSE

It had been reported that mutations in CYP1B1 gene probably play an important role in the pathogenesis of primary open angle glaucoma (POAG) but the existing genetic association studies show contradictory results. Thus, the objective of our study was to perform a systematic review and meta-analysis to characterize more precisely the potential association between given polymorphisms in CYP1B1 gene and the risk of suffering POAG.

METHODS

A systematic review of studies that related the risk of carrying CYP1B1 gene polymorphisms with POAG development was conducted. We selected 19 case-control studies including 3855 POAG patients and 4125 control subjects in our meta-analyses. A random effects model was used. Sensitivity analysis and assessment of bias were also included.

RESULTS

The prevalence of CYP1B1 gene polymorphisms were significantly more frequent among POAG patients compared to all controls (OR = 2.91, 95% CI = 1.37 - 6.21; P = 0.006). Moreover, their prevalence was significantly higher in juvenile-onset patients than in adult-onset ones (OR = 2.27, 95% CI = 1.20-4.28; P = 0.001).

CONCLUSION

The results of this meta-analysis uphold that being a carrier of polymorphic genetic variants in CYP1B1 gene would increase the risk of POAG, especially the juvenile onset.

Genetics in primary congenital glaucoma: Implications in disease management and counseling

Primary congenital glaucoma is an important cause of visual impairment in children. It can develop both pre- and postnatally. Angle surgery is the first line treatment modality. If the disease remains untreated or if the diagnosis is delayed, it can lead to irreversible visual loss and blindness. The genetics of primary congenital glaucoma are complex and not yet entirely understood. At present multiple disease-causing genes have been identified. CYP1B1 is the most well known gene causing autosomal recessive congenital glaucoma. Other genes have been found to play a role through recessive, dominant or polygenic mechanisms. Here we provide an overview of the known genes and mechanisms described in patients with PCG. Furthermore, we provide a practical counseling and follow-up guideline for relatives of a proband.

Prenatal diagnosis of primary congenital glaucoma and histopathological features in a fetal globe with cytochrome p4501B1 mutations

BACKGROUND/OBJECTIVES

This study aims to report the developmental and histopathological features of ocular tissues from an electively aborted human fetus with mutations in cytochrome p4501B1, and thus predisposed to primary congenital glaucoma in comparison to an age-matched healthy fetal globe.

SUBJECTS/METHODS

Both eyes of two 17-week gestational aged fetuses, the first with CYP1B1 mutations and the second as healthy control fetus, were studied. Hematoxylin and eosin, Periodic acid-Schiff, Gomori's trichrome, and Verhoeff-Van Gieson staining protocols in addition to immunohistochemistry staining using anti-cytochrome p4501B1, anti-fibrillin-1, and anti-4-hydroxy-2-nonenal antibodies, as primary antibodies, were performed to assess the effect of the mutations on tissue development, cytochrome p4501B1 protein expression, extracellular matrix structure, and oxidative stress in the developing fetus eye. Quantitative analyses were performed using ImageJ software. Student's t-test was used for statistical analysis and P-values <0.05 were considered as significant.

RESULTS

Delayed development in ocular tissues, decreased expression of cytochrome p4501B1 protein, irregular extracellular matrix structure, and increased oxidative stress biomarker were evident in the ocular tissues of the fetus with cytochrome p4501B1 mutations as compared to a normal globe from an age-matched fetus.

CONCLUSION

To the best of our knowledge, this is the first report of prenatal diagnosis of primary congenital glaucoma. We also describe histopathological changes in the primary congenital glaucoma-affected globes revealing the effect of cytochrome p4501B1 deficiency on ocular tissues during early fetal development contributing to the glaucoma phenotype.