Inhibitory effects of rosmarinic acid on pterygium epithelial cells through redox imbalance and induction of extrinsic and intrinsic apoptosis

Oxidative Stress in the Anterior Ocular Diseases: Diagnostic and Treatment

The eye is a metabolically active structure, constantly exposed to solar radiations making its structure vulnerable to the high burden of reactive oxygen species (ROS), presenting many molecular interactions. The biomolecular cascade modification is caused especially in diseases of the ocular surface, cornea, conjunctiva, uvea, and lens. In fact, the injury in the anterior segment of the eye takes its origin from the perturbation of the pro-oxidant/antioxidant balance and leads to increased oxidative damage, especially when the first line of antioxidant defence weakens with age. Furthermore, oxidative stress is related to mitochondrial dysfunction, DNA damage, lipid peroxidation, protein modification, apoptosis, and inflammation, which are involved in anterior ocular disease progression such as dry eye, keratoconus, uveitis, and cataract. The different pathologies are interconnected through various mechanisms such as inflammation, oxidative stress making the diagnostics more relevant in early stages. The end point of the molecular pathway is the release of different antioxidant biomarkers offering the potential of predictive diagnostics of the pathology. In this review, we have analysed the oxidative stress and inflammatory processes in the front of the eye to provide a better understanding of the pathomechanism, the importance of biomarkers for the diagnosis of eye diseases, and the recent treatment of anterior ocular diseases.

The role of cyclophilin A and VEGF in the pathogenesis and recurrence of pterygium

PURPOSE

Pterygium is defined as overgrowth of abnormal conjunctival tissue on the cornea. Many proinflammatory cytokines and various growth factors have been implicated in the pathogenesis of pterygium. Cyclophilin A (CyPA) is a protein that is used by cyclosporin A (CsA) as the intracellular receptor and is secreted in response to inflammatory stimuli. Vascular endothelial growth factor (VEGF) is the most important angiogenic factor. This study aimed to assessment CyPA and VEGF immunoreactivity in pterygium specimens.

MATERIAL AND METHODS

In this cross-sectional study, 32 primary pterygium samples, 25 recurrent pterygium samples and 25 normal bulbar conjunctiva samples were included. The histopathological features, CyPA and VEGF immunoreactivity of surgically excised pterygium specimens were compared with control conjunctiva specimens obtained from normal bulbar conjunctiva.

RESULTS

CyPA immunoreactivity in vascular endothelial cells, epithelial cells, and stromal cells was remarkably higher in pterygium specimens than control conjunctiva specimens (p = 0.004, p = 0.012, p = 0.001, respectively). Morever, VEGF immunoreactivity in endothelial cells was remarkably higher in pterygium specimens than control conjunctiva specimens (p < 0.001). When recurrent and primary pterygium specimens were compared, CyPA and VEGF immunoreactivity was remarkably higher in recurrent pterygium (p = 0.001, p = 0.001, respectively). Pearson correlation showed that CyPA immunoreactivity correlated with stromal vascularity, stromal inflammation, and mast cell count in pterygium specimens.

CONCLUSION

This study aimed to assess CyPA and VEGF may have a important function in the pathogenesis and recurrence of pterygium.

Anxiolytic and antidepressive potentials of rosmarinic acid: A review with a focus on antioxidant and anti-inflammatory effects

Depression and anxiety are the most prevalent neuropsychiatric disorders that have emerged as global health concerns. Anxiolytic and antidepressant drugs, such as benzodiazepines, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, and tricyclics, are the first line used in treating anxiety and depression. Although these drugs lack efficacy and have a delayed response time and numerous side effects, their widespread abuse and market continue to grow. Over time, traditional practices using natural and phytochemicals as alternative therapies to chemical drugs have emerged to treat many pathological conditions, including anxiety and depression. Recent preclinical studies have demonstrated that the phenolic compound, rosmarinic acid, is effective against several neuropsychiatric disorders, including anxiety and depression. In addition, rosmarinic acid showed various pharmacological effects, such as cardioprotective, hepatoprotective, lung protective, antioxidant, anti-inflammatory, and neuroprotective effects. However, the potentialities of the use of rosmarinic acid in the treatment of nervous system-related disorders, such as anxiety and depression, are less or not yet reviewed. Therefore, the purpose of this review was to present several preclinical and clinical studies, when available, from different databases investigating the effects of rosmarinic acid on anxiety and depression. These studies showed that rosmarinic acid produces advantageous effects on anxiety and depression through its powerful antioxidant and anti-inflammatory properties. This review will examine and discuss the possibility that the anxiolytic and anti-depressive effects of rosmarinic acid could be associated with its potent antioxidant and anti-inflammatory activities.

Pump proton inhibitors display anti-tumour potential in glioma

OBJECTIVES

Glioma is one of the most aggressive brain tumours with poor overall survival despite advanced technology in surgical resection, chemotherapy and radiation. Progression and recurrence are the hinge causes of low survival. Our aim is to explain the concrete mechanism in the proliferation and progression of tumours based on tumour microenvironment (TME). The main purpose is to illustrate the mechanism of proton pump inhibitors (PPIs) in affecting acidity, hypoxia, oxidative stress, inflammatory response and autophagy based on the TME to induce apoptosis and enhance the sensitivity of chemoradiotherapy.

FINDINGS

TME is the main medium for tumour growth and progression. Acidity, hypoxia, inflammatory response, autophagy, angiogenesis and so on are the main causes of tumour progress. PPIs, as a common clinical drug to inhibit gastric acid secretion, have the advantages of fast onset, long action time and small adverse reactions. Nowadays, several kinds of literature highlight the potential of PPIs in inhibiting tumour progression. However, long-term use of PPIs alone also has obvious side effects. Therefore, till now, how to apply PPIs to promote the effect of radio-chemotherapy and find the concrete dose and concentration of combined use are novel challenges.

CONCLUSIONS

PPIs display the potential in enhancing the sensitivity of chemoradiotherapy to defend against glioma based on TME. In the clinic, it is also necessary to explore specific concentrations and dosages in synthetic applications.

Rosmarinic Acid Intravitreal Implants: A New Therapeutic Approach for Ocular Neovascularization

Rosmarinic acid, a plant-derived compound with antiangiogenic activity, can be applied for the treatment of ocular diseases related to neovascularization, such as diabetic retinopathy, macular edema, and age-related macular degeneration. These diseases represent the leading causes of blindness worldwide if they are not properly treated. Intravitreal devices allow for localized drug delivery to the posterior segment, increasing the drug bioavailability and promoting extended release, thus, reducing side effects and enhancing the patient's compliance to the treatment. In this work, rosmarinic acid-loaded poly lactic-co-glycolic acid intraocular implants were developed with a view for the treatment of ocular neovascularization. Physical-chemical, biocompatibility, and safety studies of the implants were carried out in vitro and in vivo as well as an evaluation of the antiangiogenic activity in a chorioallantoic membrane assay. Data obtained showed that rosmarinic acid released from the implants was quantified in the vitreous for 6 weeks, while when it was in the solution formulation, after 24 h, no drug was found in the vitreous. The delivery device did not show any sign of toxicity after clinical evaluation and in electroretinographic findings. Histological analysis showed normal eye tissue. Rosmarinic acid released from implants reduced 30% of new vessel's formation. The intravitreal implant successfully allowed for the prolonged release of rosmarinic acid, was safe to rabbits eyes, and demonstrated activity in vessel reduction, thus demonstrating potential in preventing neovascularization in ophthalmic diseases.

Potential Protective and Therapeutic Roles of the Nrf2 Pathway in Ocular Diseases: An Update

Nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) is a regulator of many processes of life, and it plays an important role in antioxidant, anti-inflammatory, and antifibrotic responses and in cancer. This review is focused on the potential mechanism of Nrf2 in the occurrence and development of ocular diseases. Also, several Nrf2 inducers, including noncoding RNAs and exogenous compounds, which control the expression of Nrf2 through different pathways, are discussed in ocular disease models and ocular cells, protecting them from dysfunctional changes. Therefore, Nrf2 might be a potential target of protecting ocular cells from various stresses and preventing ocular diseases.

Protective Effects of Rosmarinic Acid against Selenite-Induced Cataract and Oxidative Damage in Rats

Cataracts are the major cause of blindness and are associated with oxidative damage of the lens. In the present study, the aim was to evaluate the protective effects of rosmarinic acid on selenite-induced cataractogenesis in Sprague-Dawley rat pups. The animals were randomly divided into five groups, each of which consisted of 10 rat pups. Group I served as normal control (vehicle administration). For testing cataract induction, animals of Groups II, III, IV, and V were administered a single subcutaneous injection of sodium selenite (2.46 mg/kg body weight) on postpartum day 12. After sodium selenite intoxication, Group II served as control selenite. From the 11th day through the 17th day, Groups III-V received rosmarinic acid intraperitoneally at doses of 5, 10, and 50 mg/kg, respectively. On postpartum day 24, the rat pups were examined for cataract formation, and the lenses were isolated for further analysis of proteins and oxidative damage indicators. Selenite caused significant (p < 0.05) cataract formation. Through the effects of selenite, the protein expressions of filensin and calpain 2 were reduced, and the calcium concentrations, the level of lipid peroxidation (TBARS), and inflammation indicators (iNOS, COX-2, and NFκB) were upregulated. Furthermore, the protein expression of the antioxidant status (Nrf2, SOD, HO-1, and NQO1), the antioxidant enzymes activities (GSH-Px, GSH-Rd, and catalase), and the GSH levels were downregulated. In contrast, treatment with rosmarinic acid could significantly (p < 0.05) ameliorate cataract formation and oxidative damage in the lens. Moreover, rosmarinic acid administration significantly increased the protein expressions of filensin, calpain 2, Nrf2, SOD, HO-1, and NQO1, the antioxidant enzymes activities, and the GSH level, in addition to reducing the calcium, lipid peroxidation, and inflammation indicators in the lens. Taken together, rosmarinic acid is a prospective anti-cataract agent that probably delays the onset and progression of cataracts induced by sodium selenite.

Induction of Apoptosis in Pterygium Cells by Antagonists of Growth Hormone-Releasing Hormone Receptors

Purpose

The aim of the study was to investigate the signaling of growth hormone-releasing hormone receptor (GHRH-R) in the pathogenesis of pterygium and determine the apoptotic effect of GHRH-R antagonist on pterygium epithelial cells (PECs).

Methods

Fourteen samples of primary pterygium of grade T3 with size of corneal invasion ≥ 4 mm were obtained for investigation by histology, immunofluorescence, electron microscopy, explant culture, and flow cytometry.

Results

We found that PECs were localized in the basal layer of the epithelium in advancing regions of the head of pterygium. These cells harbored clusters of rough endoplasmic reticulum, ribosomes, and mitochondria, which were consistent with their aggressive proliferation. Immunofluorescence studies and Western blots showed that GHRH-R and the downstream growth hormone receptor (GH-R) were intensively expressed in PECs. Their respective ligands, GHRH and GH, were also elevated in the pterygium tissues as compared to conjunctival cells. Explanted PECs were strongly immunoreactive to GHRH-R and exhibited differentiation and proliferation that led to lump formation. Treatment with GHRH-R antagonist MIA-602 induced apoptosis of PECs in a dose-dependent manner, which was accompanied by a downregulation of ERK1 and upregulation of Caspase 3 expression.

Conclusions

Our results revealed that GHRH-R signaling is involved in survival and proliferation of PECs and suggest a potential therapeutic approach for GHRH-R antagonist in the treatment of pterygium.

Rosmarinic acid exerts an antagonistic effect on vascular calcification by regulating the Nrf2 signalling pathway

Vascular calcification (VC) is a process in which calcium phosphate crystals deposit within the intima and middle membrane of the vascular wall. Rosmarinic acid (RA) is a common phenolic compound. It possesses antioxidation, anti-inflammatory, antimicrobial effects. Our experiment aims to investigate the role and molecular mechanism of RA in VC. Rats were fed high-fat feed and injected with vitamin D3 to establish a VC model. β-Glyerophosphate (β GP) was selected to stimulate rat aortic smooth muscle cells (VSMCs) in order to establish the cell calcification model. Kits were used to detect the antioxidant index and calcification index. RA significantly reduced the levels of ALP, MDA, Ca, and P but increased SOD levels. Quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis were used to detect various antioxidant-related genes and calcified genes on an mRNA and protein level. The results showed that nuclear factor red cell-2 related factors (Nrf2), haem oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase (NQO1), and osteoprotegerin (OPG) were up regulated by RA at both the mRNA and protein levels, but kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa B(NF-κB), cadherin associated protein (β-catenin) and osteogenic transcription factor (Runx2) expression at both the mRNA and protein levels was significantly inhibited. Microscopic examination showed that RA significantly decreased the content of calcified nodules and the production of reactive oxygen species (ROS). When Nrf2 is disturbed, the role of RA is significantly blocked. Our results showed that RA can improve VC by regulating the Nrf2 pathway.

Anti-fibrotic effect of rosmarinic acid on inhibition of pterygium epithelial cells

AIM

To investigate the anti-fibrosis effect of rosmarinic acid (RA) in pterygium epithelial cells (PECs) to determine if RA is a potent agent for treating pterygium.

METHODS

The PECs (1×10⁴ cells/mL) were treated with 100 µmol/L of RA for 1, 3 and 6h. After RA treatment, the cell viability was determined by staining with acridine orange/DAPI and analysis via a NucleoCounter NC-3000. The protein expression levels of type I collagen, transforming growth factor beta-1 (TGF-β1), TGF-β type II receptor (TGF-βRII), p-Smad1/5, p-Smad2, p-Smad3, and Smad4 of the cell lysates were measured by Western blot analysis.

RESULTS

The cell viability of PECs was significantly decreased after RA treatment (P<0.01). As the result, RA reduced the protein expression of type I collagen and TGF-β1 of PECs. Additionally, RA also inhibited TGF-β1/Smad signaling by decreasing the protein expressions of TGF-βRII, p-Smad1/5, p-Smad2, p-Smad3, and Smad4.

CONCLUSION

This study demonstrate that RA could inhibit fibrosis of PECs by down-regulating type I collagen expression and TGF-β1/Smad signaling. Therefore, RA is a potent therapeutic agent for the treatment of pterygium.