Insights into stem cell therapy for diabetic retinopathy: a bibliometric and visual analysis

Stem cells have been confirmed to be involved in the occurrence and development of diabetic retinopathy; however, the underlying mechanisms remain unclear. In this study, we used Citespace software to visually analyze 552 articles exploring the stem cell-based treatment of diabetic retinopathy over the past 20 years, which were included in the Web of Science Core Collection. We found the following: (1) a co-citation analysis of the references cited by all 552 articles indicated 15 clusters. In cluster #0, representing the stem cell field, some highly cited landmark studies emerged between 2009-2013. For example, endothelial progenitor cells and diabetic retinopathy gradually received the full attention of scholars, in terms of their relationship and therapeutic prospects. Some researchers also verified the potential of adipose-derived stem cells to differentiate into stable retinal perivascular cells, using a variety of animal models of retinal vascular disease. All of these achievements provided references for the subsequent stem cell research. (2) An analysis of popular keywords among the 552 articles revealed that, during the past 20 years, a relative increase in basic research articles examining stem cells and endothelial progenitor cells for the treatment of diabetic retinopathy was observed. The contents of these articles primarily involved the expression of vascular endothelial growth factor, vascular regeneration, oxidative stress, and inflammatory response. (3) A burst analysis of keywords used in the 552 articles indicated that genetic and cytological research regarding the promotion of angiogenesis was an issue of concern from 2001 to 2012, including several studies addressing the expression of various growth factor genes; from 2014 to 2020, mouse models of diabetic retinopathy were recognized as mature animal models, and the most recent research has focused on macular degeneration, macular edema, neurodegeneration, and inflammatory changes in diabetic animal models. (4) Globally, the current authoritative studies have focused on basic research towards the stem cell treatment of diabetic retinopathy. Existing clinical studies are of low quality and have insufficient evidence levels, and their findings have not yet been widely accepted in clinical practice. Major challenges during stem cell transplantation remain, including stem cell heterogeneity, cell delivery, and the effective homing of stem cells to damaged tissue. However, clinical trials examining potential stem cell-based treatments of diabetic retinopathy, including the use of pluripotent stem cells, retinal pigment epithelial cells, bone marrow mesenchymal stem cells, and endothelial progenitor cells, are currently ongoing, and high-quality clinical evidence is likely to appear in the future, to promote clinical transformation.