Salvianolic acids are the most abundant water-soluble compounds extracted from Radix Salvia miltiorrhiza (Danshen). In China, Danshen has been wildly used to treat cardiovascular diseases for hundreds of years. Salvianolic acids, especially salvianolic acid A (Sal A) and salvianolic acid B (Sal B), have been found to have potent anti-oxidative capabilities due to their polyphenolic structure. Recently, intracellular signaling pathways regulated by salvianolic acids in vascular endothelial cells, aortic smooth muscle cells, as well as cardiomyocytes, have been investigated both in vitro and in vivo upon various cardiovascular insults. It is discovered that the cardiovascular protection of salvianolic acids is not only because salvianolic acids act as reactive oxygen species scavengers, but also due to the reduction of leukocyte-endothelial adherence, inhibition of inflammation and metalloproteinases expression from aortic smooth muscle cells, and indirect regulation of immune function. Competitive binding of salvianolic acids to target proteins to interrupt protein-protein interactions has also been found to be a mechanism of cardiovascular protection by salvianolic acids. In this article, we review a variety of studies focusing on the above mentioned mechanisms. Besides, the target proteins of salvianolic acids are also described. These results of recent advances have shed new light to the development of novel therapeutic strategies for salvianolic acids to treat cardiovascular diseases.

Background: Diabetic retinopathy (DR), whose standard diagnosis is performed by human experts, has high prevalence and requires a more efficient screening method. Although machine learning (ML)–based automated DR diagnosis has gained attention due to recent approval of IDx-DR, performance of this tool has not been examined systematically, and the best ML technique for use in a real-world setting has not been discussed. Objective: The aim of this study was to systematically examine the overall diagnostic accuracy of ML in diagnosing DR of different categories based on color fundus photographs and to determine the state-of-the-art ML approach. Methods: Published studies in PubMed and EMBASE were searched from inception to June 2020. Studies were screened for relevant outcomes, publication types, and data sufficiency, and a total of 60 out of 2128 (2.82%) studies were retrieved after study selection. Extraction of data was performed by 2 authors according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), and the quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis of diagnostic accuracy was pooled using a bivariate random effects model. The main outcomes included diagnostic accuracy, sensitivity, and specificity of ML in diagnosing DR based on color fundus photographs, as well as the performances of different major types of ML algorithms. Results: The primary meta-analysis included 60 color fundus photograph studies (445,175 interpretations). Overall, ML demonstrated high accuracy in diagnosing DR of various categories, with a pooled area under the receiver operating characteristic (AUROC) ranging from 0.97 (95% CI 0.96-0.99) to 0.99 (95% CI 0.98-1.00). The performance of ML in detecting more-than-mild DR was robust (sensitivity 0.95; AUROC 0.97), and by subgroup analyses, we observed that robust performance of ML was not limited to benchmark data sets (sensitivity 0.92; AUROC 0.96) but could be generalized to images collected in clinical practice (sensitivity 0.97; AUROC 0.97). Neural network was the most widely used method, and the subgroup analysis revealed a pooled AUROC of 0.98 (95% CI 0.96-0.99) for studies that used neural networks to diagnose more-than-mild DR. Conclusions: This meta-analysis demonstrated high diagnostic accuracy of ML algorithms in detecting DR on color fundus photographs, suggesting that state-of-the-art, ML-based DR screening algorithms are likely ready for clinical applications. However, a significant portion of the earlier published studies had methodology flaws, such as the lack of external validation and presence of spectrum bias. The results of these studies should be interpreted with caution.

Background: Spinocerebellar ataxia (SCA) refers to a disease entity in which polyglutamine aggregates are over-produced in Purkinje cells (PCs) of the cerebellum as well as other neurons in the central nervous system, and the formation of intracellular polyglutamine aggregates result in the loss of neurons as well as deterioration of motor functions. So far there is no effective neuroprotective treatment for this debilitating disease although numerous efforts have been made. Mesenchymal stem cells (MSCs) possess multi-lineage differentiation potentials as well as immuno-modulatory properties, and are theoretically good candidates for SCA treatment. The purpose of this study is to investigate whether transplantation of human MSCs (hMSCs) can rescue cerebellar PCs and ameliorate motor function deterioration in SCA in a pre-clinical animal model. Method: Transgenic mice bearing poly-glutamine mutation in ataxin-2 gene (C57BL/6J SCA2 transgenic mice) were serially transplanted with hMSCs intravenously or intracranially before and after the onset of motor function loss. Motor function of mice was evaluated by an accelerating protocol of rotarod test every 8 weeks. Immunohistochemical stain of whole brain sections was adopted to demonstrate the neuroprotective effect of hMSC transplantation on cerebellar PCs and engraftment of hMSCs into mice brain. Results: Intravenous transplantation of hMSCs effectively improved rotarod performance of SCA2 transgenic mice and delayed the onset of motor function deterioration; while intracranial transplantation failed to achieve such neuroprotective effect. Immunohistochemistry revealed that intravenous transplantation was more effective in the preservation of the survival of cerebellar PCs and engraftment of hMSCs than intracranial injection, which was compatible to rotarod performance of transplanted mice. Conclusion: Intravenous transplantation of hMSCs can indeed delay the onset as well as improve the motor function of SCA2 transgenic mice. The results of this preclinical study strongly support further exploration of the feasibility to transplant hMSCs for SCA patients.

Introduction: Testicular torsion is a urological emergency and infertility is a common complication due to ischemic injury. Surgical reduction and orchiopexy is indicated, but to date there is no effective method for restoration of spermatogenesis. The effects of mesenchymal stem cells (MSCs) on acute tissue injury have been demonstrated, and the abilities of paracrine support, differentiation and immune-modulation may benefit to testicular torsion-induced infertility. We investigate the therapeutic efficacy and the mechanisms of MSCs in testicular torsion-induced germ cell injury when injected locally. Methods: Six to eight-week-old Sprague–Dawley rats received surgical 720 degree torsion for 3 hours, followed by detorsion on the left testis. 20 μl of phosphate-buffered saline (PBS) without or with 3 x 10⁴ MSCs from human orbital fat tissues (OFSCs) were given for 10 rats, respectively, via local injection into the left testis 30 minutes before detorsion. 20 μl of PBS injection for 6 rats with surgical exposure without torsion served as sham control. Histopathology with Johnsen’s score analysis, Western blot analysis for superoxide dismutase 2, Bax, Caspase-3, human insulin growth factor-1 and human stem cell factor, malondialdehyde (MDA) assay in testis and plasma, hormones level including testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by ELISA Kits, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and fluorescence staining for P450, Sox-9 and VASA were performed. Results: Animals were sacrificed and bilateral orchiectomy was performed 7 days after torsion-detorsion. Local injections of OFSCs prevented torsion-induced infertility judging from Johnsen's score. TUNEL assay and Western blot analysis on caspase 3 and Bax demonstrated that OFSCs prevented ischemic/reperfusion induced intrinsic apoptosis. MDA assay revealed that OFSCs significantly reduced the oxidative stress in the damaged testicular tissues. After the OFSC injection, serum testosterone secretion was increased, while the elevation of FSH triggered by testicular injury was balanced. OFSCs also produced stem cell factor in the damaged testis. Immunofluorescence staining revealed that most transplanted cells surrounded the Leydig cells. Some of transplanted cells differentiated into p450 expressing cells within 7 days. Conclusions: Local injection of allogenic MSCs before surgical detorsion is a simple, clinical friendly procedure to rescue torsion-induced infertility.

Introduction: Topical administration of eye drops is the major route for drug delivery to the cornea. Orbital fat-derived stem cells (OFSCs) possess an in vitro corneal epithelial differentiation capacity. Both the safety and immunomodulatory ability of systemic OFSC transplantation were demonstrated in our previous work. In this study, we investigated the safety, therapeutic effect, and mechanism(s) of topical OFSC administration in an extensive alkali-induced corneal wound. Methods: Corneal injury was created by contact of a piece of 0.5 N NaOH-containing filter paper on the corneal surface of a male Balb/c mouse for 30 s. The area of the filter paper covered the central 70% or 100% of the corneal surface. OFSCs (2 × 10⁵) in 5 μl phosphate-buffered saline (PBS) were given by topical administration (T) twice a day or by two intralimbal (IL) injections in the right cornea, while 5 μl of PBS in the left cornea served as the control. Results: Topical OFSCs promoted corneal re-epithelialization of both the limbal-sparing and limbal-involved corneal wounds. In the first three days, topical OFSCs significantly reduced alkali-induced corneal edema and stromal infiltration according to a histopathological examination. Immunohistochemistry and immunofluorescence staining revealed that transplanted cells were easily detectable in the corneal epithelium, limbal epithelium and stroma, but only some of transplanted cells at the limbal epithelium had differentiated into cytokeratin 3-expressing cells. OFSCs did not alter neutrophil (Ly6G) levels in the cornea, but significantly reduced macrophage (CD68) infiltration and inducible nitrous oxide synthetase (iNOS) production during acute corneal injury as quantified by a Western blot analysis. Continuous topical administration of OFSCs for seven days improved corneal transparency, and this was accompanied by diffuse stromal engraftment of transplanted cells and differentiation into p63-expressing cells at the limbal area. The therapeutic effect of the topical administration of OFSCs was superior to that of the IL injection. OFSCs from the IL injection clustered in the limbal area and central corneal epithelium, which was associated with a persistent corneal haze. Conclusions: Topical OFSC administration is a simple, non-surgical route for stem cell delivery to promote corneal tissue regeneration through ameliorating acute inflammation and corneal epithelial differentiation. The limbal area serves as a niche for OFSCs differentiating into corneal epithelial cells in the first week, while the stroma is a potential site for anti-inflammation of OFSCs. Inhibition of corneal inflammation is related to corneal transparency.

Loss of corneal epithelial cells results in visual problems. Stem cells isolated from the limbal area of the ocular surface are able to replenish lost corneal epithelial cells. However, destruction of the healthy limbus tissue is inevitable. Theoretically, orbital fat should be an excellent source to isolate stem cells for regenerating ocular tissues as the orbital connective tissues share the same embryonic origin with the ocular proper in early organogenesis. The aim of this study is to isolate stem cells from the human orbital fat and to explore their differentiation potentials into epithelial cells. It was found that spindle-shaped, fibroblast-like cells with extensive proliferation potentials could be isolated from orbital fat tissues. These orbital fat-derived stem cells (OFSCs) possessed multi-lineage differentiation potential to become osteoblasts, chondrocytes, and adipocytes. Upon mix-culture with corneal epithelial cells, OFSCs changed their morphology to round, polygonal epithelial-like cells. Loss of CD105 expression and increased expression of epithelial cell markers, including epithelial-specific antigen and zonal occludin-1, were found upon mix-culture with corneal epithelial cells. Moreover, corneal epithelial differentiation was evidenced by expression of cytokeratin −19 and cytokeratin −3 after mix-culture with corneal epithelial cells, whereas human adipose-derived stem cells from subcutaneous fat were unable to differentiate into corneal epithelial cells under the same induction condition. We further found that direct contact with corneal epithelial cells was essential for OFSCs to commit to corneal epithelial cells. Taken together, orbital fat tissues are a novel source for multi-potent stem cells that possess the potential to differentiate into corneal epithelial lineage. OFSCs are therefore a potential candidate for cell therapy and tissue engineering of corneal epithelium.