A biophysical framework for double-drugging kinases.

Selective orthosteric inhibition of kinases has been challenging due to the conserved active site architecture of kinases and emergence of resistance mutants. Simultaneous inhibition of distant orthosteric and allosteric sites, which we refer to as "double-drugging", has recently been shown to be effective in overcoming drug resistance. However, detailed biophysical characterization of the cooperative nature between orthosteric and allosteric modulators has not been undertaken. Here, we provide a quantitative framework for double-drugging of kinases employing isothermal titration calorimetry, Förster resonance energy transfer, coupled-enzyme assays, and X-ray crystallography. We discern positive and negative cooperativity for Aurora A kinase (AurA) and Abelson kinase (Abl) with different combinations of orthosteric and allosteric modulators. We find that a conformational equilibrium shift is the main principle governing cooperativity. Notably, for both kinases, we find a synergistic decrease of the required orthosteric and allosteric drug dosages when used in combination to inhibit kinase activities to clinically relevant inhibition levels. X-ray crystal structures of the double-drugged kinase complexes reveal the molecular principles underlying the cooperative nature of double-drugging AurA and Abl with orthosteric and allosteric inhibitors. Finally, we observe a fully closed conformation of Abl when bound to a pair of positively cooperative orthosteric and allosteric modulators, shedding light on the puzzling abnormality of previously solved closed Abl structures. Collectively, our data provide mechanistic and structural insights into rational design and evaluation of double-drugging strategies.

Geriatric Nutritional Risk Index and 30-Day Postoperative Mortality in Geriatric Burn Patients.

INTRODUCTION: The geriatric nutritional risk index (GNRI) can easily identify malnutrition-associated morbidity and mortality. We investigated the association between preoperative GNRI and 30-d mortality in geriatric burn patients who underwent surgery. METHODS: The study involved geriatric burn patients (aged ≥ 65 y) who underwent burn surgery between 2012 and 2022. The GNRI was computed using the following formula: 1.489 × serum albumin concentration (mg/L) + 41.7 × patient body weight/ideal body weight. Patients were dichotomized into the high GNRI (≥ 82) and low GNRI (< 82) groups. GNRI was evaluated as an independent predictor of 30-d postoperative mortality. The study also evaluated the association between GNRI and sepsis, the need for continuous renal replacement therapy (CRRT), major adverse cardiac events (MACE), and pneumonia. RESULTS: Out of 270 patients, 128 (47.4%) had low GNRI (< 82). Multivariate Cox regression analysis revealed that low GNRI was significantly associated with 30-d postoperative mortality (hazard ratio: 1.874, 95% confidence interval [CI]: 1.146-3.066, P = 0.001). Kaplan-Meier analysis revealed that the 30-day mortality rate differed significantly between the low and high GNRI groups (log-rank test, P < 0.001). The 30-d postoperative mortality (hazard ratio: 2.677, 95% CI: 1.536-4.667, P < 0.001) and the incidence of sepsis (odds ratio [OR]: 2.137, 95% CI: 1.307-3.494, P = 0.004), need for CRRT (OR: 1.919, 95% CI: 1.101-3.344, P = 0.025), MACE (OR: 1.680, 95% CI: 1.018-2.773, P = 0.043), and pneumonia (OR: 1.678, 95% CI: 1.019-2.764, P = 0.044), were significantly higher in the low GNRI group than in the high GNRI group. CONCLUSIONS: Preoperative low GNRI was associated with increased 30-d postoperative mortality, sepsis, need for CRRT, MACE, and pneumonia in geriatric burn patients.

Effects of Pulsed Radiofrequency Duration in Patients With Chronic Lumbosacral Radicular Pain: A Randomized Double-Blind Study.

OBJECTIVES: We hypothesized that the duration of pulsed radiofrequency (PRF) application may affect the effectiveness of PRF in patients with chronic lumbosacral radicular pain (LRP). MATERIALS AND METHODS: In this prospective, double-blind, randomized study, 68 patients were randomly allocated to two groups: a 6-minute group, in which PRF was applied at 42 °C for 2 minutes followed by a 2-minute pause, repeated three times; and a 12-minute group, with a continuous application at 42 °C for 12 minutes. The total application time in each group was equal. After PRF, 2 to 3 mL of 1% lidocaine with 5 mg of dexamethasone was injected. The primary outcome was the intensity of leg pain measured using a numerical rating scale (NRS) three months after the procedure. The secondary outcomes were intensities of leg and back pain, the Oswestry Disability Index (ODI), the Medication Quantification Scale III (MQS), the Global Perceived Effect of Satisfaction (GPES), and the incidence of adverse events during follow-up. Primary and secondary outcomes were analyzed using a linear mixed-effect model in the modified intention-to-treat population. RESULTS: Each group comprised 34 patients. Three patients in each group did not receive the allocated intervention owing to alleviation of pain. The estimated NRS mean of leg pain at three months was 4.0 (95% CI, 3.2-4.9) and 4.5 (95% CI, 3.6-5.4) in the 6- and 12-minute groups, respectively, with no significant difference between groups (estimated mean difference, -0.5; 95% CI, -1.8 to 0.8; p = 0.436). Regarding the intensities of leg and back pain, ODI, MQS, and GPES, there was no significant difference between the two groups except for GPES at six months. No adverse events were observed in the groups. CONCLUSIONS: Among patients with chronic LRP, a prolonged PRF application of 12 minutes, compared with 6 minutes, caused no significant difference in leg pain intensity. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number under the Clinical Trial Registry of Korea for the study is KCT0003850; https://cris.nih.go.kr.

Effectiveness of the Cooled Radiofrequency Ablation of Genicular Nerves in Patients with Chronic Knee Pain Due to Osteoarthritis: A Double-Blind, Randomized, Controlled Study.

Background: Increasing evidence supporting the clinical effectiveness of cooled radiofrequency ablation (RFA) therapy for genicular nerves in patients with chronic knee osteoarthritis (OA) exists. However, no study has been conducted to eliminate the potential influence of a placebo effect associated with this procedure. Therefore, we evaluated the efficacy of cooled RFA compared with a sham procedure in patients with painful knees due to OA. Methods: In this double-blind, randomized, controlled study, participants were randomly assigned to receive cooled RFA of the knee (cooled RFA group, n = 20) or a sham procedure (sham group, n = 20). The primary outcome was the proportion of successful responders at the three-month follow-up. The secondary outcomes were successful responders at one and six months; pain intensity of the knee; functional status; medication; and satisfaction at one, three, and six months after the procedures. Results: For the primary outcome, the successful responder rate was significantly higher in the cooled RFA group (76.5%) than in the sham group (33.3%) (p = 0.018). For the secondary outcome, more successful responders were observed in the cooled RFA group than in the sham group at one and six months after the procedure (p = 0.041 and 0.007, respectively). The decreased knee pain intensity was maintained throughout the six-month follow-up period in the cooled RFA group. No differences were observed in functional status, medication change, or satisfaction in both groups. Conclusions: The cooled RFA of genicular nerves offers significant pain relief and surpasses the effects attributable to a placebo.

Impact of Chart-Derived Frailty Index on 1-Year Mortality After Radical Cystectomy in 1004 Patients with Bladder Cancer.

BACKGROUND: Radical cystectomy is a major urological procedure with high morbidity and mortality. The chart-derived frailty index (CFI), a measure of preoperative frailty, can be calculated by using demographic and routine laboratory variables. We assessed the impact of CFI on 1-year mortality after radical cystectomy. METHODS: This retrospective study included patients with bladder cancer who underwent radical cystectomy between 2007 and 2021. The CFI was calculated as the sum of the presence of the following parameters: age > 70 years, body mass index < 18.5 kg/m2, hematocrit < 35%, albumin < 3.4 g/dL, and creatinine > 2.0 mg/dL. Patients were divided into those with low (0-2) and high (3-5) CFI. The 1-year, all-cause and cancer-specific mortalities after radical cystectomy were evaluated. RESULTS: Of the 1004 patients, 914 (91.0%) had a low CFI and 90 (9.0%) had a high CFI. The 1-year, all-cause mortality in the low and high CFI groups was 12.0% and 27.8%, respectively (P < 0.001). Multivariate Cox regression analysis revealed that high CFI (P < 0.001), tumor stage (P = 0.003), and red blood cell transfusion amount (P < 0.001) were significantly associated with 1-year, all-cause mortality after radical cystectomy. Kaplan-Meier survival analysis demonstrated significantly different 1-year, all-cause and cancer-specific mortalities after radical cystectomy between patients with a high CFI and those with a low CFI (log-rank test, both P < 0.001). CONCLUSIONS: High CFI is associated with higher 1-year mortality after radical cystectomy, suggesting that the CFI can effectively predict mortality after radical cystectomy.

Gene expression profiling of nasal inflammation induced by diesel particles using an in vivo system.

Korean diesel particulate matter 20 (KDP20) is a pollutant comprising a complex mixture of carbon and chemical irritants. Although particulate matter and nasal inflammation are strongly associated, the underlying molecular mechanism based on systematic transcriptome analysis remains unknown. In this study, genome-wide gene expression profiles of mouse nasal tissues were determined following exposure to KDP20 for 5 and 10 days and compared with those of the control (n = 4/group). We identified 758 significant differentially expressed genes (DEGs) and classified them as 5-day-specific, 10-day-specific, and common among groups based on their expression patterns. The terms "regulation of alpha-beta T cell differentiation," "macrophage differentiation," and "cell adhesion mediated by integrin" were significantly enriched in each group. Receiver operating characteristic analysis revealed six genes as potential predictive biomarkers. The differential expression of these six genes was validated using quantitative RT-PCR (n = 3/group). Furthermore, a possible mechanism for nasal inflammation was suggested through the binding analysis between metal ions and genes. The genes identified in this study may play important roles in regulating the mechanism of nasal inflammation induced by diesel particles, especially immune cell regulation, and may function as markers for diesel particle-induced nasal inflammation.

Allosteric modulation of a human protein kinase with monobodies.

Despite being the subject of intense effort and scrutiny, kinases have proven to be consistently challenging targets in inhibitor drug design. A key obstacle has been promiscuity and consequent adverse effects of drugs targeting the ATP binding site. Here we introduce an approach to controlling kinase activity by using monobodies that bind to the highly specific regulatory allosteric pocket of the oncoprotein Aurora A (AurA) kinase, thereby offering the potential for more specific kinase modulators. Strikingly, we identify a series of highly specific monobodies acting either as strong kinase inhibitors or activators via differential recognition of structural motifs in the allosteric pocket. X-ray crystal structures comparing AurA bound to activating vs inhibiting monobodies reveal the atomistic mechanism underlying allosteric modulation. The results reveal 3 major advantages of targeting allosteric vs orthosteric sites: extreme selectivity, ability to inhibit as well as activate, and avoidance of competing with ATP that is present at high concentrations in the cells. We envision that exploiting allosteric networks for inhibition or activation will provide a general, powerful pathway toward rational drug design.

Factors associated with Successful Responses to Ganglion Impar Block: A Retrospective Study.

Background: The ganglion impar (ganglion of Walther) block has been used to manage coccygeal and perineal (perianal and genital) pain due to both benign and malignant causes. However, the factors associated with successful responses to ganglion impar block are unknown. Therefore, in the present study, we aimed to identify the independent factors associated with successful responses to ganglion impar block in patients with chronic pain in coccygeal and perineal regions. Methods: From January 2008 to December 2017, we performed a retrospective review of 106 patients who underwent ganglion impar block. Patients were considered successful responders if they reported a decrease of more than 50% or 4 points on the 11-point (0 = no pain and 10 = worst possible pain) numerical rating scale 1 month after the procedure, while others were considered non-responders. Logistic regression analysis was performed to identify factors independently associated with successful responses at 1 month after the procedure. Results: Multivariable logistic regression analysis showed that cancer-related causes were significantly associated with successful responses at 1 month after ganglion impar block (odds ratio = 2.60, 95% confidence interval = 1.05 to 6.43, P = 0.038). Conclusion: Ganglion impar block may be more effective in cancer-related pain than pain due to benign causes.

Damage to Olfactory Organs of Adult Zebrafish Induced by Diesel Particulate Matter.

Particulate matter (PM) is an environmental hazard that is associated with various human health risks. The olfactory system is directly exposed to PM; therefore, the influence of PM exposure on olfactory function must be investigated. In this study, we propose a zebrafish olfactory model to evaluate the effects of exposure to diesel particulate matter (DPM), which was labeled Korean diesel particulate matter (KDP20). KDP20 comprises heavy metals and polycyclic aromatic hydrocarbons (PAHs). KDP20 exposed olfactory organs exhibited reduced cilia and damaged epithelium. Olfactory dysfunction was confirmed using an odor-mediated behavior test. Furthermore, the olfactory damage was analyzed using Alcian blue and anti-calretinin staining. KDP20 exposed olfactory organs exhibited histological damages, such as increased goblet cells, decreased cell density, and calretinin level. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed that PAHs exposure related genes (AHR2 and CYP1A) were upregulated. Reactive oxidation stress (ROS) (CAT) and inflammation (IL-1B) related genes were upregulated. Furthermore, olfactory sensory neuron (OSN) related genes (OMP and S100) were downregulated. In conclusion, KDP20 exposure induced dysfunction of the olfactory system. Additionally, the zebrafish olfactory system exhibited a regenerative capacity with recovery conditions. Thus, this model may be used in future investigating PM-related diseases.

New application for assessment of dry eye syndrome induced by particulate matter exposure.

Dry eye syndrome (DES) is a multifactorial condition characterized by insufficient tear lubrication and eye irritation. Air pollutants, including particulate matter (PM), are an emerging threat to human health causing DES and other diseases. However, the pathogenic mechanisms of DES induced by PM exposure remain to be fully elucidated. Recent studies have attempted to create DES animal model using PM exposure. In this study, we explored a novel in vivo exposure model of DES, utilizing an inhalation device (aerosol exposure system) to reproduce the natural exposure to atmospheric PM. Rats were exposed to urban PM (UPM) using this aerosol system for 5 h per day over 5 days. Tear volume in UPM-exposed rats decreased significantly, whereas corneal irregularity and lissamine green staining significantly increased following UPM exposure. Additional effects observed following UPM exposure included apoptosis in the corneal epithelium and a decrease in the number of goblet cells in the conjunctiva. UPM also affected the stability of the tear film by disrupting its mucin-4 layer. In conclusion, aerosol exposure systems have proven effective as assessment tools for DES caused by PM.

Anti-angiogenic effect of EGHB010, a standardized herbal formula of Paeoniae radix and Glycyrrhizae radix.

EGHB010 is a standardized herbal formula of the rhizome mixture of Paeonia lactiflora Pallas and Glycyrrhiza uralensis Fisch. Neovascularization in the retina is a common pathophysiology of diabetic retinal microvasculopathy and exudative macular degeneration. In this study, we evaluated the inhibitory effects of EGHB010 on abnormal retinal angiogenesis in a hyperoxia-induced neovascular retinopathy model. Vascular endothelial growth factor (VEGF)-mediated vascular tube formation was assayed in human umbilical vascular endothelial cells (HUVECs). Experimental angiogenesis in the retinas was induced by exposing C57BL/6 pups to hyperoxic environment (75% oxygen) on postnatal day 7 (P7) and then returning them to normal oxygen pressure on P12. EGHB010 (50 and 100 mg/kg/day) was administered intraperitoneally for 5 days (P12 - P16). Retinal flat mounts were prepared to measure the extent of retinal neovascularization on P17. The incubation of HUVECs with EGHB010 (1-25 µg/mL) resulted in the inhibition of VEGF-mediated tube formation in a dose-dependent manner. EGHB010 at doses of 50 and 100 mg/kg/day inhibited the formation of retinal neovascular tufts by 31.15±2.28% and 59.83±2.92%, respectively. Together, our results indicate that EGHB010 is a potent anti-angiogenic agent and may have potential for the control of abnormal retinal vessel growth in patients with ischemic retinopathy.

Apricot Kernel Extract and Amygdalin Inhibit Urban Particulate Matter-Induced Keratoconjunctivitis Sicca.

Exposure to particulate matter is a risk factor for various ocular surface diseases, including keratoconjunctivitis sicca (KCS). In this study, we investigated the protective effects of apricot kernel extract (AKE) and its bioactive compound, amygdalin, on KCS induced by exposure to urban particulate matter (UPM). In the in vivo experiments, eye drops containing 0.5 mg/mL AKE (AKE-0.5) or 1 mg/mL AKE (AKE-1) were administered directly into the eyes of female rats after UPM exposure. Additionally, the effect of AKE and amygdalin on matrix metalloproteinases (MMPs) activity and the expressions of inflammatory factors, including tumor necrosis factor (TNF)-α and interleukin (IL)-6, was investigated in conjunctival epithelial cells in vitro. Topical administration of AKE-1 attenuated UPM exposure-induced reduction of tear secretion. Both AKE-0.5 and AKE-1 inhibited UPM exposure-induced corneal epithelial damage and irregularity. AKE also protected against UPM exposure-induced disruption of the mucin-4 layer on the ocular surface. In addition, AKE and amygdalin prevented UPM-induced activation of MMPs and upregulation of TNF-α and IL-6 in conjunctival epithelial cells. Therefore, AKE may have protective effects against UPM exposure-induced KCS via the inhibition of MMPs and inflammation. The pharmacological activities of AKE may be in part due to its bioactive compound, amygdalin.

A review of analytical procedures for the simultaneous determination of medically important veterinary antibiotics in environmental water: Sample preparation, liquid chromatography, and mass spectrometry.

Medically important (MI) antibiotics are defined by the United States Food and Drug Administration as drugs containing certain active antimicrobial ingredients that are used for the treatment of human diseases or enteric pathogens causing food-borne diseases. The presence of MI antibiotic residues in environmental water is a major concern for both aquatic ecosystems and public health, particularly because of their potential to contribute to the development of antimicrobial-resistant microorganisms. In this article, we present a review of global trends in the sales of veterinary MI antibiotics and the analytical methodologies used for the simultaneous determination of antibiotic residues in environmental water. According to recently published government reports, sales volumes have increased steadily, despite many countries having adopted strategies for reducing the consumption of antibiotics. Global attention needs to be directed urgently at establishing new management strategies for reducing the use of MI antimicrobial products in the livestock industry. The development of standardized analytical methods for the detection of multiple residues is required to monitor and understand the fate of antibiotics in the environment. Simultaneous analyses of antibiotics have mostly been conducted using high-performance liquid chromatography-tandem mass spectrometry with a solid-phase extraction (SPE) pretreatment step. Currently, on-line SPE protocols are used for the rapid and sensitive detection of antibiotics in water samples. On-line detection protocols must be established for the monitoring and screening of unknown metabolites and transformation products of antibiotics in environmental water.

Aster koraiensis extract prevents diabetes-induced retinal vascular dysfunction in spontaneously diabetic Torii rats.

BACKGROUND: Aster koraiensis extract (AKE) is a standard dietary herbal supplement. The aim of this study is to investigate the inhibitory effects of AKE on diabetes-induced retinal vascular dysfunction in Spontaneously Diabetic Torii (SDT) rats. METHODS: AKE (50 and 100 mg/kg body weight/day) was administered for 16 weeks. The effects of orally administered AKE on blood glucose levels, retinal vascular leakage, apoptosis, and accumulation of advanced glycation end products (AGEs) in the retina were evaluated. RESULTS: SDT rats exhibited hyperglycemia and retinal vascular leakage, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was clearly detected apoptosis in the retinal microvasculature. Immunofluorescence staining revealed the accumulation of AGEs in the retinal vasculature of the SDT rats. However, oral administration of AKE for 16 weeks blocked diabetes-induced blood-retinal barrier (BRB) breakdown and the loss of occludin, which is an important tight junction protein. Apoptosis of retinal vascular cells and AGE accumulation were significantly inhibited after AKE treatment. CONCLUSION: These results indicate that, as a dietary herbal supplement, AKE may have beneficial effects on patients with diabetic retinopathy.

GS-E3D, a new pectin lyase-modified red ginseng extract, inhibited diabetes-related renal dysfunction in streptozotocin-induced diabetic rats.

BACKGROUND: GS-E3D is a newly developed pectin lyase-modified red ginseng extract. The purpose of this study was to investigate the therapeutic effects of GS-E3D on diabetes-related renal dysfunction in streptozotocin-induced diabetic rats. METHOD: GS-E3D (25, 50, and 100 mg/kg body weight per day) was administered for 6 weeks. The levels of blood glucose and hemoglobin A1c, and of urinary albumin, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and advanced glycation end-products (AGEs) were determined. Kidney histopathology, renal accumulation of AGEs, and expression of α-smooth muscle actin (α-SMA) were also examined. RESULTS: Administration of GS-E3D for 6 weeks reduced urinary levels of albumin, 8-OHdG, and AGEs in diabetic rats. Mesangial expansion, renal accumulation of AGEs, and enhanced α-SMA expression were significantly inhibited by GS-E3D treatment. Oral administration of GS-E3D dose-dependently improved all symptoms of diabetic nephropathy by inhibiting renal accumulation of AGEs and oxidative stress. CONCLUSION: The results of this study indicate that the use of GS-E3D as a food supplement may provide effective treatment of diabetes-induced renal dysfunction.

Gemigliptin, a dipeptidyl peptidase-4 inhibitor, inhibits retinal pericyte injury in db/db mice and retinal neovascularization in mice with ischemic retinopathy.

Retinal pericyte loss and neovascularization are characteristic features of diabetic retinopathy. Gemigliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, has shown robust blood-glucose lowering effects in type 2 diabetic patients, but its effects on diabetic retinopathy have not yet been reported. We evaluated the efficacy of gemigliptin on retinal vascular leakage in db/db mice, which is an animal model for type 2 diabetes, and neovascularization in oxygen-induced retinopathy (OIR) mice, which is an animal model for ischemic proliferative retinopathy. Gemigliptin (100mg/kg/day) was orally administered to the db/db mice for 12weeks. C57BL/6 mice on postnatal day 7 (P7) were exposed to 75% hyperoxia for 5days, followed by exposure to room air from P12 to P17 to induce OIR. Gemigliptin (50mg/kg/day) was intraperitoneally injected daily from P12 to P17. Retinal neovascularization was analyzed in flat-mounted retinas on P17. We determined the efficacy and possible mechanism of gemigliptin on high glucose-induced apoptosis of primary human retinal pericytes. The oral administration of gemigliptin for 4months significantly ameliorated retinal pericyte apoptosis and vascular leakage in the db/db mice. Gemigliptin also ameliorated retinal neovascularization in the OIR mice. Gemigliptin attenuated the overexpression of plasminogen activator inhibitor-1 (PAI-1) in the retinas of diabetic and OIR mice. Gemigliptin and PAI-1 siRNA significantly inhibited pericyte apoptosis by inhibiting the overexpression of PAI-1, which is induced by high glucose. Our results suggest that gemigliptin has potent anti-angiogenic and anti-apoptotic activities via suppressing DPP-4 and PAI-1, and the results support the direct retinoprotective action of gemigliptin.

Cnidium officinale extract and butylidenephthalide inhibits retinal neovascularization in vitro and in vivo.

BACKGROUND: Retinal neovascularization, which is the pathological growth of new blood vessels, is associated with retinopathy of prematurity, neovascular age-related macular degeneration, diabetic retinopathy and retinal vein occlusion. In this study, we evaluated the effect of an extract of Cnidium officinale Makino (COE) and its bioactive compound, butylidenephthalide (BP), on the migration and tube formation of human umbilical vein endothelial cells (HUVECs), and on retinal pathogenic neovascularization in the oxygen-induced retinopathy (OIR) mouse model. METHOD: The HUVECs were incubated with COE and BP (0.1-10 µg/ml). The mice were exposed to 75 % oxygen for 5 days starting on the 7(th) postnatal day (P7-P12). Then, the mice were returned to room air and intraperitoneally injected with COE (100 mg/kg) and BP (5 mg/kg) once per day for 5 days (P12-P16). On P17, we measured retinal neovascularization and analyzed the angiogenesis-related proteins expression using protein arrays. RESULTS: COE and BP inhibit the HUVECs migration and the tube formation in a dose-dependent manner. In addition, COE significantly decreased retinal neovascularization in the OIR mice. COE reduced the expression levels of AREG, ANG, DLL4, Endostatin, IGFBP-2 and VEGF. Additionally, BP also inhibited the retinal neovascularization and down-regulated the expression of AREG, ANG, DLL4 and VEGF. CONCLUSION: These results suggest that COE and BP exerts antiangiogenic effects on retinal neovascularization by inhibiting the expression of AREG, ANG, DLL4 and VEGF, indicating that antiangiogenic activities of COE may be in part due to its bioactive compound, BP.

HL-217, a new topical anti-angiogenic agent, inhibits retinal vascular leakage and pathogenic subretinal neovascularization in Vldlr⁻/⁻ mice.

HL-217 is a new synthetic angiogenesis inhibitor. Platelet derived growth factor (PDGF) is a vasoactive factor and has been implicated in proliferative retinopathies. In this study, we examined the mechanism of action and efficacy of topical application of HL-217 on subretinal neovascularization in very low-density lipoprotein receptor knockout (Vldlr(-/-)) mice. In three-week-old male Vldlr(-/-) mice, HL-217 (1.5 or 3mg/ml) was administered twice per day for 4 weeks by topical eye drop instillation. Neovascular areas were then measured. We used a protein array to evaluate the expression levels of angiogenic factors. The inhibitory effect of HL-217 on the PDGF-BB/PDGFRß interaction was evaluated in vitro. The neovascular area in the Vldlr(-/-) mice was significantly reduced by HL-217. Additionally, HL-217 decreased the expression levels of PDGF-BB protein and VEGF mRNA. Moreover, HL-217 dose-dependently inhibited the PDGF-BB/PDGFRß interaction (IC50=38.9 ± 0.7 µM). These results suggest that HL-217 is a potent inhibitor of PDGF-BB. HL-217, when applied topically, is an effective inhibitor of subretinal neovascularization due to its ability to inhibit the pro-angiogenic effects of PDGF-BB.