Protective Effects of Pituitary Adenylate-Cyclase-Activating Polypeptide on Retinal Vasculature and Molecular Responses in a Rat Model of Moderate Glaucoma

Injectable Gel-PEG hydrogels as promising delivery system for intravitreal PACAP release: Novel therapeutics for unilateral common carotid artery occlusion induced retinal ischemia

Retinal ischemia is an ophthalmic emergency often caused by cardiovascular diseases, leading to irreversible vision loss and even blindness. Innovative retinal ischemia treatments are needed due to limited options. The pathological mechanisms involve retinal cell apoptosis and microglial activation. The pituitary adenylate cyclase-activating polypeptide (PACAP) is a well distributed neuropeptide found in both central nervous system and peripheral organs. Though it shows great anti-apoptosis and anti-microglia activation properties, it is rapidly cleared by intravitreal injection. Herein, we established a novel poly(ethylene glycol) (PEG) hydrogel system by cross-linking 4arm-PEG-NHS and 4arm-PEG-NH2 to load PACAP (PACAP@Gel-PEG), which exhibited great fluidity, injectability, structural recovery ability, moderate swelling ratio and drug release ability that were appropriate for drug delivery. Then the safety and effectiveness of the PACAP@Gel-PEG were evaluated in vitro in three retinal cell lines (ARPE-19, 661 W and rRMC) and in vivo using the unilateral common carotid artery occlusion (UCCAO) mice model. The CCK-8 test and live/dead staining demonstrated that PACAP@Gel-PEG exhibited excellent biocompatibility in three retinal cell lines. Furthermore, after PACAP@Gel-PEG treatment, a great anti-apoptotic effect was observed in cells treated by CoCl2. Application of PACAP@Gel-PEG greatly improved the therapeutic efficacy of PACAP in restoring retinal function, maintaining retinal integrity, and suppressing apoptosis and microglia activation in retinal tissues. Moreover, in mice, the biosafety of PACAP@Gel-PEG was confirmed by H&E staining of systemic organs. Taken together, our results demonstrated PACAP@Gel-PEG as a promising therapeutic option for retinal ischemia, providing new strategies for vision restoration.

Optimization of an Ischemic Retinopathy Mouse Model and the Consequences of Hypoxia in a Time-Dependent Manner

The retina is one of the highest metabolically active tissues with a high oxygen consumption, so insufficient blood supply leads to visual impairment. The incidence of related conditions is increasing; however, no effective treatment without side effects is available. Furthermore, the pathomechanism of these diseases is not fully understood. Our aim was to develop an optimal ischemic retinopathy mouse model to investigate the retinal damage in a time-dependent manner. Retinal ischemia was induced by bilateral common carotid artery occlusion (BCCAO) for 10, 13, 15 or 20 min, or by right permanent unilateral common carotid artery occlusion (UCCAO). Optical coherence tomography was used to follow the changes in retinal thickness 3, 7, 14, 21 and 28 days after surgery. The number of ganglion cells was evaluated in the central and peripheral regions on whole-mount retina preparations. Expression of glial fibrillary acidic protein (GFAP) was analyzed with immunohistochemistry and Western blot. Retinal degeneration and ganglion cell loss was observed in multiple groups. Our results suggest that the 20 min BCCAO is a good model to investigate the consequences of ischemia and reperfusion in the retina in a time-dependent manner, while the UCCAO causes more severe damage in a short time, so it can be used for testing new drugs.

Ocular Inflammation and Oxidative Stress as a Result of Chronic Intermittent Hypoxia: A Rat Model of Sleep Apnea

Obstructive sleep apnea (OSA) is a sleep disorder characterized by intermittent complete or partial occlusion of the airway. Despite a recognized association between OSA and glaucoma, the nature of the underlying link remains unclear. In this study, we investigated whether mild OSA induces morphological, inflammatory, and metabolic changes in the retina resembling those seen in glaucoma using a rat model of OSA known as chronic intermittent hypoxia (CIH). Rats were randomly assigned to either normoxic or CIH groups. The CIH group was exposed to periodic hypoxia during its sleep phase with oxygen reduction from 21% to 10% and reoxygenation in 6 min cycles over 8 h/day. The eyes were subsequently enucleated, and then the retinas were evaluated for retinal ganglion cell number, oxidative stress, inflammatory markers, metabolic changes, and hypoxic response modulation using immunohistochemistry, multiplex assays, and capillary electrophoresis. Statistically significant differences were observed between normoxic and CIH groups for oxidative stress and inflammation, with CIH resulting in increased HIF-1α protein levels, higher oxidative stress marker 8-OHdG, and increased TNF-α. Pyruvate dehydrogenase kinase-1 protein was significantly reduced with CIH. No significant differences were found in retinal ganglion cell number. Our findings suggest that CIH induces oxidative stress, inflammation, and upregulation of HIF-1α in the retina, akin to early-stage glaucoma.

Iron deficiency affects oxygen transport and activates HIF1 signaling pathway to regulate phenotypic transformation of VSMC in aortic dissection

BACKGROUND

Aortic dissection (AD) is a macrovascular disease which is pathologically characterized by aortic media degeneration.This experiment aims to explore how iron deficiency (ID) affects the function of vascular smooth muscle cell (VSMC) and participates in the occurrence and development of AD by regulating gene expression.

METHODS

The relationship between iron and AD was proved by Western-blot (WB) and immunostaining experiments in human and animals. Transcriptomic sequencing explored the transcription factors that were altered downstream. WB, flow cytometry and immunofluorescence were used to demonstrate whether ID affected HIF1 expression through oxygen transport. HIF1 signaling pathway and phenotypic transformation indexes were detected in cell experiments. The use of the specific HIF1 inhibitor PX478 further demonstrated that ID worked by regulating HIF1.

RESULTS

The survival period of ID mice was significantly shortened and the pathological staining results were the worst. Transcriptomic sequencing indicated that HIF1 was closely related to ID and the experimental results indicated that ID might regulate HIF1 expression by affecting oxygen balance. HIF1 activation regulates the phenotypic transformation of VSMC and participates in the occurrence and development of AD in vivo and in vitro.PX478, the inhibition of HIF1, can improve ID-induced AD exacerbation.

Silva H, P. de Carvalho R, Ventura ALM, Calaza KC, Silveira MS, Kubrusly RCC, de Melo Reis RA. The Healthy and Diseased Retina Seen through Neuron-Glia Interactions

The retina is the sensory tissue responsible for the first stages of visual processing, with a conserved anatomy and functional architecture among vertebrates. To date, retinal eye diseases, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, glaucoma, and others, affect nearly 170 million people worldwide, resulting in vision loss and blindness. To tackle retinal disorders, the developing retina has been explored as a versatile model to study intercellular signaling, as it presents a broad neurochemical repertoire that has been approached in the last decades in terms of signaling and diseases. Retina, dissociated and arranged as typical cultures, as mixed or neuron- and glia-enriched, and/or organized as neurospheres and/or as organoids, are valuable to understand both neuronal and glial compartments, which have contributed to revealing roles and mechanisms between transmitter systems as well as antioxidants, trophic factors, and extracellular matrix proteins. Overall, contributions in understanding neurogenesis, tissue development, differentiation, connectivity, plasticity, and cell death are widely described. A complete access to the genome of several vertebrates, as well as the recent transcriptome at the single cell level at different stages of development, also anticipates future advances in providing cues to target blinding diseases or retinal dysfunctions.

Antihypertensive effect and mechanism of the traditional recipe of medicine food homology (Buyang Huanwu Decoction) in China: Meta analysis and network pharmacological exploration

Background

Hypertension has become a part of the lives of many people worldwide. With the development, an increasing number of people have begun to control their hypertension through products of medicine food homology, such as Buyang Huanwu Decoction (BYHWD). However, there has been no objective review of the regulation of hypertension by BYHWD.

Methods

As of 9 October 2023, this review made a detailed search of nine databases to look for random controlled trials (RCTs) focused on the use of BYHWD for treating hypertension. This was followed by network pharmacological analysis, and molecular docking assessment using AutoDockTools to explore the mode of action.

Results

BYHWD was effective in reducing SBP (MD: 0.767; 95 % CI: 0.629, 0.905; p = 0.000), DBP (MD: 0.427; 95 % CI: 0.292, 0.561; p = 0.000), 24h SBP (MD: 0.665; 95 % CI: 0.368, 0.962; p = 0.000), 24h DBP (MD: 0.547; 95 % CI: 0.318, 0.777; p = 0.000), dSBP (MD: 0.625; 95 % CI: 0.395, 0.855; p = 0.000), dDBP (MD: 0.632; 95 % CI: 0.401, 0.862; p = 0.000), nSBP (MD: 0.859; 95 % CI: 0.340, 1.377; p = 0.001), nDBP (MD: 0.704; 95 % CI: 0.297, 1.112; p = 0.001), pv (MD: 1.311; 95 % CI: 0.363, 2.259; p = 0.007) and NIHSS (MD: 1.149; 95 % CI: 0.100, 2.199; p = 0.032), and elevating CER (OR = 2.848; 95 % CI: 1.388, 5.843; p = 0.004). However, BYHWD did not significantly reduce HCY, and there was no significant difference in the incidence of AE. In terms of the mechanism of action, the main active ingredient of BYHWD is quercetin, and the core targets are AKT1, MMP9, and others. Molecular docking also showed that quercetin mainly interacts with the amino acid residue CYS-28 of MMP2. Second, the KEGG analysis showed that BYHWD mainly act on HIF-1, Apelin, and cGMP-PKG signalling pathways, and GO analysis showed that it related to the apical part of the cell, circulatory system processes, and nuclear receptor activity. Conclusion: BYHWD can lowered blood pressure, reduced plasma viscosity, and restored neurological function with good tolerability, and had no significant effect on HCY levels. This study further demonstrated that quercetin is the main active ingredient of BYHWD that acts via the AKT1 and HIF-1 signalling pathways. These results provide new guidance for people's dietary choices by the general public.