LL37/FPR2 regulates neutrophil mPTP promoting the development of neutrophil extracellular traps in diabetic retinopathy.

Diabetic retinopathy (DR) is characterized by chronic, low-grade inflammation. This state may be related to the heightened production of neutrophil extracellular traps (NETs) induced by high glucose (HG). Human cathelicidin antimicrobial peptide (LL37) is an endogenous ligand of G protein-coupled chemoattractant receptor formyl peptide receptor 2 (FPR2), expressed on neutrophils and facilitating the formation and stabilization of the structure of NETs. In this study, we detected neutrophils cultured under different conditions, the retinal tissue of diabetic mice, and fibrovascular epiretinal membranes (FVM) samples of patients with proliferative diabetic retinopathy (PDR) to explore the regulating effect of LL37/FPR2 on neutrophil in the development of NETs during the process of DR. Specifically, HG or NG with LL37 upregulates the expression of FPR2 in neutrophils, induces the opening of mitochondrial permeability transition pore (mPTP), promotes the increase of reactive oxygen species and mitochondrial ROS, and then leads to the rise of NET production, which is mainly manifested by the release of DNA reticular structure and the increased expression of NETs-related markers. The PI3K/AKT signaling pathway was activated in neutrophils, and the phosphorylation level was enhanced by FPR2 agonists in vitro. In vivo, increased expression of NETs markers was detected in the retina of diabetic mice and in FVM, vitreous fluid, and serum of PDR patients. Transgenic FPR2 deletion led to decreased NETs in the retina of diabetic mice. Furthermore, in vitro, inhibition of the LL37/FPR2/mPTP axis and PI3K/AKT signaling pathway decreased NET production induced by high glucose. These results suggested that FPR2 plays an essential role in regulating the production of NETs induced by HG, thus may be considered as one of the potential therapeutic targets.

Impaired Dynamic Cerebral Autoregulation as a Predictor for Cerebral Hyperperfusion After Carotid Endarterectomy: A Prospective Observational Study.

OBJECTIVE: Cerebral hyperperfusion syndrome (CHS) is a severe complication of carotid endarterectomy (CEA). Because cerebral hyperperfusion (CH) reduces the benefits of CEA, it is important to identify patients at high risk of developing CH. We investigated dynamic cerebral autoregulation (dCA) as a potential predictor of CH after CEA. METHODS: In a prospective observational study of 90 patients, we defined CH as a ≥100% increase in the transcranial Doppler ultrasound-derived mean flow velocity of the middle cerebral artery compared to baseline, with or without clinical manifestations. We examined dCA in the supine position and during squat-stand maneuvers using the transfer function, analyzing phase, gain, and coherence. Logistic regression analysis and receiver operating characteristic (ROC) curves were used to assess the relationships between variables and outcomes. RESULTS: Cerebral hyperperfusion (CH) occurred in 18 patients after CEA. The CH group had a lower ipsilateral phase for both body postures than the non-CH group at very low and low frequencies, respectively (both P < 0.01). Postoperative CH was independently associated with the preoperative peak systolic velocity (PSV)sten/PSVdis ratio and the ipsilateral phase in both body postures at a very low frequency. Receiver operating characteristic (ROC) curve analysis showed that the ipsilateral phase had excellent CH predictive accuracy in the supine position and squat-stand maneuvers at a very low frequency (areas under the curve: 0.809 and 0.839, respectively, both P < 0.001; cutoff values: 24.7 and 11.7, respectively). CONCLUSIONS: The lower ipsilateral phase may serve as a predictor of CH after CEA.

Comparable dynamic cerebral autoregulation and neurovascular coupling of the posterior cerebral artery between healthy men and women.

AIMS: Most studies focus on dynamic cerebral autoregulation (dCA) in the middle cerebral artery (MCA), and few studies investigated neurovascular coupling (NVC) and dCA in the posterior cerebral artery (PCA). We investigated NVC and dCA of the PCA in healthy volunteers to identify sex differences. METHODS: Thirty men and 30 age-matched women completed dCA and NCV assessments. The cerebral blood flow velocity (CBFV) and mean arterial pressure were evaluated using transcranial Doppler ultrasound and a servo-controlled plethysmograph, respectively. The dCA parameters were analyzed using transfer function analysis. The NCV was evaluated by eyes-open and eyes-closed (24 s each) periodically based on voice prompts. The eyes-open visual stimulation comprised silent reading of Beijing-related tourist information. RESULTS: The PCA gain was lower than that of the MCA in all frequency ranges (all p < 0.05). Phase was consistent across the cerebrovascular territories. The cerebrovascular conductance index (CVCi) and mean CBFV (MV) of the PCA were significantly higher during the eyes-open than eyes-closed period (CVCi: 0.50 ± 0.12 vs. 0.38 ± 0.10; MV: 42.89 ± 8.49 vs. 32.98 ± 7.25, both p < 0.001). The PCA dCA and NVC were similar between the sexes. CONCLUSION: We assessed two major mechanisms that maintain cerebral hemodynamic stability in healthy men and women. The visual stimulation-evoked CBFV of the PCA was significantly increased compared to that during rest, confirming the activation of NVC. Men and women have similar functions in PCA dCA and NCV.

Impaired Dynamic Cerebral Autoregulation in Patients With Cerebral Venous Sinus Thrombosis: Evaluation Using Transcranial Doppler and Silent Reading Stimulation.

OBJECTIVE: Cerebral venous sinus thrombosis (CVST) may impair dynamic cerebral autoregulation (dCA) of the middle cerebral artery (MCA). However, most studies have focused on dCA of the MCA; a few studies are based on the posterior cerebral artery (PCA) during silent reading and neurovascular coupling (NVC). This study explored the effects of CVST on dCA of the MCA and PCA during silent reading and NVC. METHODS: From January 2021 to August 2022, 60 CVST patients and 30 controls were enrolled in this study. Non-invasive continuous beat-to-beat blood pressure, cerebral blood flow velocity and other associated information on the MCA and PCA during silent reading were collected using a transcranial Doppler. NVC assessment was performed by opening and closing the eyes periodically based on voice prompts, and eye-opening visual stimulation was achieved by silently reading Chinese tourism materials. Visual stimulation signals can selectively activate Brodmann's areas 17, 18, and 19 of the occipital when reading silently with open eyes, prompting them to release neurotransmitters and dilate PCA. dCA was determined by transfer function analysis. RESULTS: In dCA of the PCA during silent reading, the CVST group's very low frequency phase was lower than that of the control group (p = 0.047). In NVC, the difference in the indexes of the cerebrovascular conductance and visually evoked flow response of the CVST group were lower than those of the control group (p = 0.017 and p = 0.019, respectively). CONCLUSION: Compared with the control group, dCA and NVC of the PCA during silent reading were impaired in CVST patients.

[Effects of E-selectin and their ligands on the adhesive metastasis of hepatocellular carcinoma].

OBJECTIVES: To explore the effects of E-selectin, ICAM-1 and their ligands on the adhesive metastasis of hepatocellular carcinoma (HCC), and to select possible anti-adhesion drugs for hepatocellular carcinoma metastasis. METHODS: 78 HCC patients were analyzed with the correlation of clinical features to the expression levels of E-selectin, sLeX, sLeA and CD44v6 in the tumor tissue. The adhesion between HepG2 and endothelial cell lines was examined by solid phase adhesion assay in vitro. Two kinds of drugs were accessed for their anti-adhesion ability. RESULTS: The positive rate of E-selectin in vascular endothelia cells adjacent to cancer nest is 70.51%, and which of sLeX, sLeA, CD44v6 within tumor cells is 64.10%, 69.23%, 62.90% respectively. The patients' life span is closely related with the positive expression of sLeX, sLeA, CD44v6 (P = 0.008, 0.001, 0.022). The positive expression of E-selectin, sLeX and sLeA is significantly correlated to portal vein tumor thrombus (PVTT), preoperative extrahepatic metastasis, and satellite foci, but not to the size of tumor and AFP. The level of CD44v6 expression is significantly correlated to patient's survival time. The expression levels of E-selectin and ICAM-1 are remarkably higher after ED25 and ECV304 cell lines be activated. Meanwhile the adhesive ability of HepG2 to endothelial cell is mediated. Dexamethasone, tanshinone IIA are able to block this adhesion at low concentration. CONCLUSION: The expression levels of E-selectin, sLeX, sLeA and CD44v6 are closely correlated with clinical features. E-selectin, ICAM-1 and their ligands are important molecules of hepatocellular carcinoma and endothelial cells to tumor adhesive metastasis. Dexamethasone, tanshinone II A can be hopefully used as anti-adhesion drugs.