Peroxynitrite upregulates angiogenic factors VEGF-A, BFGF, and HIF-1α in human corneal limbal epithelial cells

The effect of leucocytosis on retinopathy of prematurity

Postnatal leukocytosis reflects the general condition of inflammatory. Infection and inflammatory reaction have been proven to affect the occurrence of ROP and other visual dysfunction. Infants with a gestational age of < 28 weeks who were less than three days of age and admitted to the hospital between September 2015 and March 2021 were included in the study. Infants with a white blood cell (WBC) count ≥ 30 × 109/L were assigned to the leucocytosis group (n = 82). Gestational age- and weight-matched infants without leucocytosis were included as a control group (n = 85). The incidence and prognosis of ROP in preterm infants were compared between the groups. Receiver operating characteristic (ROC) curves were used to analyse the correlation between the WBC count and severe ROP. Compared to the infants in the control group, those in the leucocytosis group had lower 1-min Apgar scores (p < 0.001); higher C-reactive protein (p < 0.001) and procalcitonin (p < 0.001); and higher incidences of intracranial haemorrhage (p = 0.007), leukomalacia (p = 0.045), sepsis (p = 0.006), bronchopulmonary dysplasia (p = 0.017). The maternal age was higher in the leucocytosis group (p < 0.001). After adjusting for gestational age at 45 weeks, the incidence of severe ROP (p = 0.001) and the requirement for ranibizumab injections (p = 0.004) were higher in the leucocytosis group. The cut-off WBC count was determined to be 19.1 × 109/L, with a sensitivity of 88.6%, a specificity of 77.3%, and an area under the curve of 0.941 (95% confidence interval: 0.904-0.978) for the detection of severe ROP. Leucocytosis may be associated with severe ROP in premature infants.

Can Complete Blood Count Parameters Predict Retinopathy of Prematurity?

Objectives

To predict the risk of retinopathy of prematurity (ROP) development according to routine complete blood count (CBC) parameters.

Materials and Methods

The medical records and CBC results of 150 premature neonates were retrospectively evaluated. As ROP develops 1 month after birth, first month CBC profiles of neonates without ROP (non-ROP), with ROP (ROP group), and those with Type 1, Type 2, and Stage 1+2 ROP were compared. Besides known statistical methods like Student's t-test, logistic regression and classification & regression tree (C&RT) analysis were also done to identify a reliable quantitative predictive parameter.

Results

Mean gestational age and birth weight of the ROP group (n=99) and non-ROP (n=43) group were 29.39±3.43 and 32.05±2.20 weeks and 1382.44±545.30 and 1691.51±360.84 grams, respectively (p<0.001, p<0.001). Average hemoglobin (Hb) (p<0.001), hematocrit (HCT) (p<0.001), erythrocyte (p=0.005), mean corpuscular hemoglobin (MCH) (p=0.020), and MCH concentration (p=0.019) values of the ROP group were lower than those of the non-ROP group. Leukocyte was higher in the ROP group (p=0.018). Hb [odds ratio (OR)=0.668, 95% confidence interval (CI)=0.555-0.804, p<0.001], red cell distribution width (RDW) (OR=1.282, 95% CI=1.012-1.624, p=0.040), leukocyte (OR=1.157, 95% CI=1.053-1.271, p=0.002), and platelet (OR=0.997, 95% CI: 0.994-0.999, p=0.036) values differed significantly between the two groups. Platelet, MCV, and MCH parameters were found to be lower in the Type 1 ROP group compared to the Stage 1+2 ROP group (p<0.005). MCH was the most prominent predictor (cut-off: 34.43 pg) according to the results of C&RT analysis.

Conclusion

As Hb plays an important role in oxygen transport, low levels of Hb and especially MCH may cause increased vascular endothelial growth factor secretion from the hypoxic retina, thereby causing ROP. Therefore, the results of this study are encouraging regarding the use of the abovementioned CBC parameters as a simple screening test to predict ROP.

The role of nitric oxide in ocular surface physiology and pathophysiology

Nitric oxide (NO) has a wide array of biological functions including the regulation of vascular tone, neurotransmission, immunomodulation, stimulation of proinflammatory cytokine expression and antimicrobial action. These functions may depend on the type of isoform that is responsible for the synthesis of NO. NO is found in various ocular tissues playing a pivotal role in physiological mechanisms, namely regulating vascular tone in the uvea, retinal blood circulation, aqueous humor dynamics, neurotransmission and phototransduction in retinal layers. Unregulated production of NO in ocular tissues may result in production of toxic superoxide free radicals that participate in ocular diseases such as endotoxin-induced uveitis, ischemic proliferative retinopathy and neurotoxicity of optic nerve head in glaucoma. However, the role of NO on the ocular surface in mediating physiology and pathophysiological processes is not fully understood. Moreover, methods used to measure levels of NO in the biological samples of the ocular surface are not well established due to its rapid oxidation. The purpose of this review is to highlight the role of NO in the physiology and pathophysiology of ocular surface and propose suitable techniques to measure NO levels in ocular surface tissues and tears. This will improve the understanding of NO's role in ocular surface biology and the development of new NO-based therapies to treat various ocular surface diseases. Further, this review summarizes the biochemistry underpinning NO's antimicrobial action.

Peroxynitrite enhances self-renewal, proliferation and neuronal differentiation of neural stem/progenitor cells through activating HIF-1α and Wnt/β-catenin signaling pathway

Hypoxic/ischemic stimulation could mediate growth and differentiation of neural stem/progenitor cells (NSCs) into mature neurons but its underlying mechanisms are largely unclear. Peroxynitrite formation is considered as a crucial pathological process contributing to cerebral ischemia-reperfusion injury. In the present study, we tested the hypothesis that peroxynitrite at low concentration could function as redox signaling to promote the growth of NSCs under hypoxic/ischemic conditions. Increased NSCs proliferation was accompanied by peroxynitrite production in the rat brains with 1 h of ischemia plus 7 days of reperfusion in vivo. Cell sorting experiments revealed that endogenous peroxynitrite level affected the capacity of proliferation and self-renewal in NSCs in vitro. Hypoxia stimulated peroxynitrite production and promoted NSCs self-renewal, proliferation and neuronal differentiation whereas treatments of peroxynitrite decomposition catalysts (PDCs, FeTMPyP and FeTPPS) blocked the changes in NSCs self-renewal, proliferation and neuronal differentiation. Exogenous peroxynitrite treatment revealed similar effects to promote NSCs proliferation, self-renewal and neuronal differentiation. Furthermore, the neurogenesis-promoting effects of peroxynitrite were partly through activating HIF-1α correlated with enhanced Wnt/β-catenin signaling pathway. In conclusion, peroxynitrite could be a cellular redox signaling for promoting NSCs proliferation, self-renewal and neuronal differentiation and peroxynitrite production could contribute to neurogenesis in ischemic/hypoxic NSCs.

Evaluation of efficacy of anti-angiogenesis therapy for VX2 hepatic tumors in rabbits by spectral CT and CT perfusion imaging

AIM: To explore the efficacy of anti-angiogenesis therapy for VX2 hepatic tumors in rabbits by spectral computed tomography (CT) imaging and CT perfusion imaging.

METHODS: Sixty New Zealand white rabbits with implanted VX2 hepatic tumors were randomly divided into two groups (A and B), with each group containing 30 rabbits. On day 14 after tumor implantation, group B received intravenous endostatin at a dose of 3 mg/kg for 7 d. Both groups underwent spectral CT and CT perfusion scans on day 21 after tumor implantation. The animals were then sacrificed, and the expression of VEGF mRNA and FGF2 protein in the tumor rim (TR) and the normal region (NR) was detected by RT-PCR and Western blot, respectively.

RESULTS: For CT perfusion parameters, group A showed increased blood flow (BF), blood volume (BV), permeability surface (PS) and hepatic arterial fraction (HAF) and decreased mean transit time (MTT) in the TR compared with NR (P < 0.05). From days 14 to 21, BF and PS showed an increasing trend, while MTT decreased with tumor growth (P < 0.05). The standardization of iodine (NIC) during arterial phase of the TR and NR exhibited a statistically significant difference (P < 0.05). The NIC of the TR during the arterial phase was significantly higher on day 21 than on day 14. Compared with group A on day 21, BF, BV, PS and HAF decreased, and MTT increased in group B. Pearson correlation analysis showed that these parameters were positively correlated with VEGF mRNA and FGF2 protein expression.

CONCLUSION: Spectral imaging and CT perfusion imaging can provide hemodynamic information of liver lesions and quantitatively reflect the efficacy of anti-angiogenesis therapy.