BIVV001, a new class of factor VIII replacement for hemophilia A that is independent of von Willebrand factor in primates and mice.

Factor VIII (FVIII) replacement products enable comprehensive care in hemophilia A. Treatment goals in severe hemophilia A are expanding beyond low annualized bleed rates to include long-term outcomes associated with high sustained FVIII levels. Endogenous von Willebrand factor (VWF) stabilizes and protects FVIII from degradation and clearance, but it also subjects FVIII to a half-life ceiling of ∼15 to 19 hours. Increasing recombinant FVIII (rFVIII) half-life further is ultimately dependent upon uncoupling rFVIII from endogenous VWF. We have developed a new class of FVIII replacement, rFVIIIFc-VWF-XTEN (BIVV001), that is physically decoupled from endogenous VWF and has enhanced pharmacokinetic properties compared with all previous FVIII products. BIVV001 was bioengineered as a unique fusion protein consisting of a VWF-D'D3 domain fused to rFVIII via immunoglobulin-G1 Fc domains and 2 XTEN polypeptides (Amunix Pharmaceuticals, Inc, Mountain View, CA). Plasma FVIII half-life after BIVV001 administration in mice and monkeys was 25 to 31 hours and 33 to 34 hours, respectively, representing a three- to fourfold increase in FVIII half-life. Our results showed that multifaceted protein engineering, far beyond a few amino acid substitutions, could significantly improve rFVIII pharmacokinetic properties while maintaining hemostatic function. BIVV001 is the first rFVIII with the potential to significantly change the treatment paradigm for severe hemophilia A by providing optimal protection against all bleed types, with less frequent doses. The protein engineering methods described herein can also be applied to other complex proteins.

Reversible associations between human plasma fibronectin and fibrinogen γγ' heterodimer observed by high pressure size exclusion chromatography and dynamic light scattering.

We previously reported on a novel fibrin matrix having increased viscoelastic strength derived from human plasma fibronectin (pFN) and γγ'-fibrinogen (γγ'-FI). Here we use high pressure size exclusion chromatography (HPSEC) and dynamic light scattering (DLS) to observe interactions between the linearly extended conformation of γγ'-FI and random coiled pFN. Distinct γγ'-FI:pFN subpopulations were fractionated where each maintained unique retention times when individually reprocessed by HPSEC. The hydrodynamic sizes by HPSEC and DLS for these reprocessed subfractions were intermediate to that of pure γγ'-FI and pFN. SDS-PAGE analysis showed that the majority of these subfractions contained intact γγ'-FI and pFN. Importantly, after disruption and isolation using Gelatin Sepharose affinity chromatography, new complexes rapidly formed between pFN and γγ'-FI when mixed back together. This also occurred in analogous mixing experiments between Des-Aα γγ'-FI and pFN where both Aα-chains are reduced by about 15 kDa due to proteolysis. The reversible complexation observed using HPSEC and DLS was not observed in prior studies using SPR indicating that unrestricted freedom of motion is needed to efficiently form these compact associations. The presence of a γ' chain, but not the carboxy terminal portions of either Aα chain are needed for complexation phenomena between pFN and γγ'-FI.

Structure and control of the actin regulatory WAVE complex.

Members of the Wiskott-Aldrich syndrome protein (WASP) family control cytoskeletal dynamics by promoting actin filament nucleation with the Arp2/3 complex. The WASP relative WAVE regulates lamellipodia formation within a 400-kilodalton, hetero-pentameric WAVE regulatory complex (WRC). The WRC is inactive towards the Arp2/3 complex, but can be stimulated by the Rac GTPase, kinases and phosphatidylinositols. Here we report the 2.3-ångstrom crystal structure of the WRC and complementary mechanistic analyses. The structure shows that the activity-bearing VCA motif of WAVE is sequestered by a combination of intramolecular and intermolecular contacts within the WRC. Rac and kinases appear to destabilize a WRC element that is necessary for VCA sequestration, suggesting the way in which these signals stimulate WRC activity towards the Arp2/3 complex. The spatial proximity of the Rac binding site and the large basic surface of the WRC suggests how the GTPase and phospholipids could cooperatively recruit the complex to membranes.

Hierarchical regulation of WASP/WAVE proteins.

Members of the Wiskott-Aldrich syndrome protein (WASP) family control actin dynamics in eukaryotic cells by stimulating the actin nucleating activity of the Arp2/3 complex. The prevailing paradigm for WASP regulation invokes allosteric relief of autoinhibition by diverse upstream activators. Here we demonstrate an additional level of regulation that is superimposed upon allostery: dimerization increases the affinity of active WASP species for Arp2/3 complex by up to 180-fold, greatly enhancing actin assembly by this system. This finding explains a large and apparently disparate set of observations under a common mechanistic framework. These include WASP activation by the bacterial effector EspFu and a large number of SH3 domain proteins, the effects on WASP of membrane localization/clustering and assembly into large complexes, and cooperativity between different family members. Allostery and dimerization act in hierarchical fashion, enabling WASP/WAVE proteins to integrate different classes of inputs to produce a wide range of cellular actin responses.

The VieB auxiliary protein negatively regulates the VieSA signal transduction system in Vibrio cholerae.

BACKGROUND: Vibrio cholerae is a facultative pathogen that lives in the aquatic environment and the human host. The ability of V. cholerae to monitor environmental changes as it transitions between these diverse environments is vital to its pathogenic lifestyle. One way V. cholerae senses changing external stimuli is through the three-component signal transduction system, VieSAB, which is encoded by the vieSAB operon. The VieSAB system plays a role in the inverse regulation of biofilm and virulence genes by controlling the concentration of the secondary messenger, cyclic-di-GMP. While the sensor kinase, VieS, and the response regulator, VieA, behave similar to typical two-component phosphorelay systems, the role of the auxiliary protein, VieB, is unclear. RESULTS: Here we show that VieB binds to VieS and inhibits its autophosphorylation and phosphotransfer activity thus preventing phosphorylation of VieA. Additionally, we show that phosphorylation of the highly conserved Asp residue in the receiver domain of VieB regulates the inhibitory activity of VieB. CONCLUSION: Taken together, these data point to an inhibitory role of VieB on the VieSA phosphorelay, allowing for additional control over the signal output. Insight into the function and regulatory mechanism of the VieSAB system improves our understanding of how V. cholerae controls gene expression as it transitions between the aquatic environment and human host.

Sequence Diversity of VP4 and VP7 Genes of Human Rotavirus Strains in Saudi Arabia.

Group A rotavirus is responsible for inducing severe diarrhea in young children worldwide. Rotavirus vaccines are used to control the disease in many countries. In the current study, the sequences of human rotavirus G and P types in Saudi Arabia are reported and compared to different relevant published sequences. In addition, the VP4 and VP7 genes of the G1P[8] strains are compared to different antigenic epitopes of the rotavirus vaccines. Stool samples were collected from children under 2 years suffering from severe diarrhea. Screening of the rotavirus-positive samples was performed with rapid antigen detection kit. RNA was amplified from rotavirus-positive samples by reverse transcriptase polymerase chain reaction assay for both VP4 and VP7 genes. Direct sequencing of the VP4 and VP7 genes was conducted and the obtained sequences were compared to each other and to the rotavirus vaccines. Both G1P[8] G1P[4] genotypes were detected. Phylogenetic analysis revealed that the detected strains belong to G1 lineage 1 and 2, P[8] lineage 3, and to P[4] lineage 5. Multiple amino acid substitutions were detected between the Saudi RVA strains and the commonly used vaccines. The current findings emphasize the importance of the continuous surveillance of the circulating rotavirus strains, which is crucial for monitoring virus evolution and helping in predicting the protection level afforded by rotavirus vaccines.

Zinc oxide resveratrol nanoparticles ameliorate testicular dysfunction due to levofloxacin-induced oxidative stress in rats.

The present work is aimed to assess the protective influence of zinc oxide resveratrol nanoparticles against oxidative stress-associated testicular dysfunction. The number of 50 male albino rats were randomly separated into five groups (n = 10): Group I, control: rats gavage distilled water orally; Group II, Levofloxacin: rats that administered Levofloxacin (LFX) softened in distilled water at a dosage of 40 mg/kg-1 BW orally every other day; Group III, Zn-RSV: rats administered with Zn-RSV (zinc oxide resveratrol in distilled water at a dose 20 mg/kg-1 BW orally every other day; Group IV, (LFX + Zn-RSV): rats that were administered with Levofloxacin along with Zn-RSV nPs; Group V, Levofloxacin + Zn: rats were administered with Levofloxacin and Zno at a dose of 20 mg/kg-1 BW orally every other day as mentioned before. This study lasted for 2 months. Sera were collected to assess luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone values. Testicular tissues were utilized to evaluate levels of superoxide dismutase (SOD), nitric oxide (NO), malondialdehyde (MDA), and catalase (CAT). Semen samples were utilized to measure their quality (motility, concentration, and vitality). Histopathological and immune histochemical techniques investigated the morphological changes in the testis. Rats treated with Levofloxacin showed significantly lower levels of serum LH, testosterone, FSH, testicular enzymatic NO, catalase, SOD, BAX, and BCL-2 immune reactivity and sperm quality but significantly greater testicular malondialdehyde and caspase-3 immuno-reactivity Compared to both control and zinc oxide resveratrol treatment. Zinc oxide resveratrol nanoparticles ameliorated the harmful side effects of Levofloxacin. Improvements were more pronounced in the co-treatment (LFX + Zn-RSV) Zinc oxide resveratrol group than in the co-treatment (LFX + Zno) Zinc oxide group. Zinc oxide resveratrol nanoparticles could be a possible solution for levofloxacin oxidative stress-induced fertility problems.

A genome-wide approach to discovery of small RNAs involved in regulation of virulence in Vibrio cholerae.

Small RNAs (sRNAs) are becoming increasingly recognized as important regulators in bacteria. To investigate the contribution of sRNA mediated regulation to virulence in Vibrio cholerae, we performed high throughput sequencing of cDNA generated from sRNA transcripts isolated from a strain ectopically expressing ToxT, the major transcriptional regulator within the virulence gene regulon. We compared this data set with ToxT binding sites determined by pulldown and deep sequencing to identify sRNA promoters directly controlled by ToxT. Analysis of the resulting transcripts with ToxT binding sites in cis revealed two sRNAs within the Vibrio Pathogenicity Island. When deletions of these sRNAs were made and the resulting strains were competed against the parental strain in the infant mouse model of V. cholerae colonization, one, TarB, displayed a variable colonization phenotype dependent on its physiological state at the time of inoculation. We identified a target of TarB as the mRNA for the secreted colonization factor, TcpF. We verified negative regulation of TcpF expression by TarB and, using point mutations that disrupted interaction between TarB and tpcF mRNA, showed that loss of this negative regulation was primarily responsible for the colonization phenotype observed in the TarB deletion mutant.

Re-sleeve gastrectomy: weight loss, comorbidities and gerd evaluation in a large series with 5 years of follow-up.

INTRODUCTION: Laparoscopic sleeve gastrectomy (SG) has rapidly become one of the most commonly performed procedures in bariatric surgery. Weight regain and insufficient weight loss are the most common causes for surgical failure. Re-sleeve gastrectomy (ReSG) can represent an option when there is evidence of a dilated gastric tube. OBJECTIVES: The aim of the study is to evaluate safety, efficacy and rate of gastro-esophageal reflux disease (GERD) after ReSG in one of the largest series present in literature with long-term follow up. METHODS AND STUDY DESIGN: Retrospective study design. From February 2010 to August 2018, 102 patients underwent ReSG at our Centre. We divided patients into two groups, according to the main reason for surgical failure: insufficient weight loss or progressive weight regain. RESULTS: One hundred-two patients (78 women, 24 men) with BMI 38 ± 6 kg/m2 underwent ReSG (mean age 44 years). Rate of postoperative complications was 3.9% (4/102). After a mean follow-up of 55 months, mean BMI decreased to 30,4 kg/m2 and the mean percentage of excess weight loss (%EWL) was 51 ± 38.6. Symptoms of GERD were present in 35/102 patients (34.3%) and the need for a new operation occurred in six patients. Forty-five patients were submitted to ReSG for progressive weight regain (group A) and 57 for insufficient weight loss (group B). No differences were found in terms of postoperative BMI and %EWL. CONCLUSION: ReSG is a feasible procedure after primary SG failure in selected patients, but its efficacy in reducing the BMI under 30 kg/m2 is still unclear. In addition, over 30% of patients suffer from long-term gastro-esophageal reflux.

A cartilage-forming tumor of the mandibular angle: a case report.

BACKGROUND: Mandible can be the site of benign or malignant lesions of different origins, including odontogenic and non-odontogenic lesions. Cartilage-forming tumors have been rarely reported at this site. Chondrosarcoma is a rare malignant cartilage-producing neoplasm that is extremely rare in the mandible. The rarity of cartilage-forming tumor occurrence in the mandible can make diagnosis difficult for pathologists, as they do not expect this type of tumor at this anatomical site. Here we report a case of chondrosarcoma of mandibular angle. CASE PRESENTATION: A 70-year-old Moroccan male patient consulted a dentist for wisdom tooth pain. Wisdom tooth extraction was conducted. After 6 months, the patient reported the recurrence of pain associated with swelling in the mandibular area and paresthesia along the path of the mandibular nerve. A panoramic radiograph demonstrated a mixed radiolucent-opaque lesion involving the mandibular angle. Computed tomography showed a large osteolytic spontaneously hypointense and multilobulated lesion. A biopsy was done. Histopathological examination revealed sheets and irregular lobules of atypical cells presenting cartilaginous differentiation. Tumor cells showed severe nuclear atypia and were located within a hyaline cartilage matrix. Some foci of necrosis were noted. Osteoid deposits were not found. The patient was diagnosed with grade III chondrosarcoma and underwent a right segmental mandibulectomy with submandibular lymph node dissection. Macroscopically, the tumor was localized in the mandibular angle with extension in the mandibular body. Histopathology confirmed the previous diagnosis of grade III chondrosarcoma and did not show any lymph node metastasis. CONCLUSIONS: Owing to many histological similarities, grade III chondrosarcoma must be distinguished from chondroblastic osteosarcoma and metastatic lesions. In addition, chondroblastic osteosarcoma of the jawbones has a worse prognosis than chondrosarcoma, making the distinction between these two malignant tumors the most important concern of the pathologist when dealing with a cartilage-forming tumor at this site. Surgery with wide excision margins remains the best therapeutic approach, while the role of radiotherapy is controversial. The management of mandibular chondrosarcoma requires a multidisciplinary approach involving maxillofacial surgeons, radiologists, pathologists, and oncologists.

Hepatoprotective and renoprotective effects of silymarin against salinomycin-induced toxicity in adult rabbits.

Background and Aim: Salinomycin sodium, a licensed coccidiostat in rabbits, is used for fattening at a dose of 20-25 mg/kg. Salinomycin toxicity may arise from many risk factors (e.g., overdosage or use in non-target animal species). Silymarin extracted from milk thistle has antioxidant, anti-inflammatory, and antiviral properties. This study aimed to investigate the adverse impacts of oral administration of salinomycin for 28 consecutive days and how to reduce its risks and side effects by administering silymarin. Materials and Methods: Eighty-four male New Zealand White bucks (1.750-2.000 kg) were randomly divided into seven groups (12 each). Group one was the control. Groups two and three were administered salinomycin orally (doses of 20 and 40 mg/kg ration). Group four was administered salinomycin (20 mg/kg ration) and silymarin (6.5 mg/kg body weight [BW]). Group five received salinomycin (40 mg/kg ration) and silymarin (13 mg/kg BW). Groups six and seven were administered silymarin at doses of 6.5 and 13 mg/kg BW. Rabbits were euthanized and slaughtered on day 29 using the Halal method. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, urea, total proteins, albumin, total cholesterol, and high- and low-density lipoprotein (HDL and LDL) were analyzed in serum. Glutathione (GSH), superoxide dismutase (SOD), catalase, and malondialdehyde (MDA) were estimated in the liver. A histopathological investigation was performed on the liver and kidney. Results: The MDA activity, AST, ALT, total protein, albumin, total cholesterol, triglyceride, LDL, urea, and creatinine values were significantly elevated in groups two and three. The GSH, catalase, SOD, and HDL were significantly lower in these groups than in the control group. There were moderate pathologic changes in the liver and kidney of the third group. However, the results of the fourth and fifth groups improved more than those of the second and third groups. The results of the sixth and seventh groups were nearly the same as those of the control group. Conclusion: Salinomycin toxicity was caused by oxidative damage because of reactive oxygen species formation. Silymarin (6.5 or 13 mg/kg BW) tends to prevent and treat accidental toxicity. However, the high dose of silymarin (13 mg/kg BW) had more renal and hepatoprotective capacities.

Laparoscopic sleeve gastrectomy with Rossetti fundoplication: long-term (5-year) follow-up.

BACKGROUND: Gastroesophageal reflux disease (GERD), including erosive esophagitis, is highly prevalent in the obese population. Barrett's esophagus is the consequence of untreated GERD. Laparoscopic sleeve gastrectomy is one of the most frequently performed bariatric procedures. This study presents results after 5 years of follow-up of combined LSG and Rossetti fundoplication for the treatment of GERD, esophagitis, and Barrett's esophagus in patients with morbid obesity. OBJECTIVE: To evaluate long-term results after sleeve gastrectomy with Rossetti fundoplication. SETTING: Public university hospital in Italy. METHODS: Since January 2015, more than 450 patients with obesity underwent sleeve gastrectomy with a Rossetti fundoplication procedure as part of prospective studies underway at our center performed by 4 different expert bariatric surgeons. Currently, 127 patients have a follow-up of 5 years or more. RESULTS: Mean patient age was 42.9 ± 10.3 years, and mean body mass index was 42.4 ± 6.1 kg/m2. In total, 74.8% of patients were experiencing GERD before surgery. In 29 of 127 patients (22.8%), preoperative gastroscopy showed signs of esophagitis and/or Barrett's esophagus. In particular, 23 of 127 patients (18.1%) had grade A esophagitis, 2 of 127 (1.6%) had grade B, 2 of 127 (1.6%) had grade C, and 2 of 127 (1.6%) had Barrett's esophagus. Mean operative time was 51 ± 21 minutes. No intraoperative complications or conversions were reported. A regular postoperative course was seen in 91.3% of patients. Sixty months after surgery, more than 95% of patients did not experience any reflux symptoms. Percent total weight loss at follow-up was comparable with that with sleeve gastrectomy. Endoscopic follow-up demonstrated improvement of esophagitis lesions (including Barrett's esophagus) present in the preoperative setting. CONCLUSION: Laparoscopic sleeve gastrectomy with Rossetti fundoplication is well tolerated, feasible, and safe in patients with obesity, providing adequate weight loss results and complete resolution of clinical signs of GERD. We have recorded an improvement in esophagitis lesions present at preoperative gastroscopy and complete resolution of Barrett's esophagus within 5 years of follow-up.

The Preferential Therapeutic Potential of Chlorella vulgaris against Aflatoxin-Induced Hepatic Injury in Quail.

Aflatoxins (AFs) are the most detrimental mycotoxin, potentially hazardous to animals and humans. AFs in food threaten the health of consumers and cause liver cancer. Therefore, a safe, efficient, and friendly approach is attributed to the control of aflatoxicosis. Therefore, this study aimed to evaluate the impacts of Chlorella vulgaris (CLV) on hepatic aflatoxicosis, aflatoxin residues, and meat quality in quails. Quails were allocated into a control group; the CLV group received CLV (1 g/kg diet); the AF group received an AF-contaminated diet (50 ppb); and the AF+CLV group received both treatments. The results revealed that AF decreased the growth performance and caused a hepatic injury, exhibited as an increase in liver enzymes and disrupted lipid metabolism. In addition, AF induced oxidative stress, exhibited by a dramatic increase in the malondialdehyde (MDA) level and decreases in glutathione (GSH) level, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities. Significant up-regulation in the inflammatory cytokine (TNF-α, IL-1ß, and IL-6) mRNA expression was also documented. Moreover, aflatoxin residues were detected in the liver and meat with an elevation of fat% alongside a decrease in meat protein%. On the other hand, CLV supplementation ameliorated AF-induced oxidative stress and inflammatory condition in addition to improving the nutritional value of meat and significantly reducing AF residues. CLV mitigated AF-induced hepatic damage, decreased growth performance, and lowered meat quality via its antioxidant and nutritional constituents.

PhoB regulates both environmental and virulence gene expression in Vibrio cholerae.

Vibrio cholerae is a facultative pathogen that thrives in two nutritionally disparate environments, aquatic and human small intestine. Phosphate (P(i) ) is an essential nutrient that is limited in aquatic ecosystems and of unknown availability in the small intestine. Here, we show that the P(i) (Pho) regulon, which is controlled by the P(i)-specific transporter (Pst) and two-component system PhoBR, is required for V. cholerae survival in both environments, though for differing reasons. While induction of P(i) acquisition systems including Pst is critical for survival in the aquatic environment, regulation of virulence genes by PhoB and not P(i) transport per se is required for colonization of the small intestine. We show that PhoB regulates virulence genes by directly controlling expression of a key upstream transcriptional regulator, tcpPH. Thus, the Pho regulon includes virulence genes and represents a diverse gene set essential to pathogenic V. cholerae throughout its life cycle.

Predictors of stimulation-induced seizures during perirolandic glioma resection using intraoperative mapping techniques.

BACKGROUND: Intraoperative mapping techniques maximize safety and efficacy during perirolandic glioma resection but may induce seizures and limit the procedure. We aim to report the incidence and predictors of stimulation-induced seizures during mapping either patient is awake or under general anesthesia (GA). METHODS: Retrospective analysis of 64 patients (40 awake and 24 GA) with perirolandic glioma underwent resection using intraoperative mapping techniques between 2014 and 2019. Preoperative data, operative details, postoperative neurological status, and extent of resection (EOR) were analyzed. Predictors of intraoperative seizures were assessed. RESULTS: The mean cortical and subcortical stimulation intensities needed to evoke motor responses were significantly lower in awake cases than in GA patients (4.9 ± 0.42 vs. 8.9 ± 1.2 mA) and (8.3 ± 0.62 vs. 12.1 ± 1.1 mA), respectively (P = 0.01). Incidence of intraoperative seizures was lower but statistically non-significant in awake cases (10% vs. 12.5%) (P = 0.76). Preoperative multiple antiepileptic drugs (AEDs) (P = 0.03) and low-grade glioma (P = 0.04) were statistically significant predictors for intraoperative seizures. Mean EOR in awake cases was 92.03% and 90.05% in GA cases (P = 0.23). Postoperative deficits were permanent after 3 months only in 5% of awake patients versus 8.3% of GA group (P = 0.59). CONCLUSION: Awake craniotomy with intraoperative mapping can be done safely for perirolandic gliomas with lower but statistically nonsignificant incidence of intraoperative seizures and this could be attributed to statistically significant lower stimulation intensities required for mapping. Preoperative multiple AEDs and low-grade glioma are significant predictors for intraoperative seizures.

COVID-19 and Obesity: Is Bariatric Surgery Protective? Retrospective Analysis on 2145 Patients Undergone Bariatric-Metabolic Surgery from High Volume Center in Italy (Lombardy).

INTRODUCTION: On February 20, 2020, a severe case of pneumonia due to SARS-CoV-2 was diagnosed in northern Italy (Lombardy). Some studies have identified obesity as a risk factor for severe disease in patients with COVID-19. The purpose of this study was to investigate the incidence of SARS-CoV-2 infection and its severity in patients who have undergone bariatric surgery. MATERIAL AND METHODS: During the lockdown period (until May 2020), we contacted operated patients by phone and social networks (e.g., Facebook) to maintain constant contact with them; in addition, we gave the patients a dedicated phone number at which to call us for emergencies. We produced telemedicine and educational videos for obese and bariatric patients, and we submitted a questionnaire to patients who had undergone bariatric surgery in the past. RESULTS: A total of 2145 patients (313 male; 1832 female) replied to the questionnaire. Mean presurgical BMI: 44.5 ± 6.8 kg/m2. Mean age: 44.0 ± 10.0 year. Mean BMI after surgery: 29.3 ± 5.5 kg/m2 (p < 0.05). From February to May 2020, 8.4% of patients reported that they suffered from at least one symptom among those identified as related to SARS-CoV-2 infection. Thirteen patients (0.6%) tested positive for COVID-19. Six patients (0.3%) were admitted to the COVID Department, and 2 patients (0.1%) were admitted to the ICU. CONCLUSIONS: Although the reported rates of symptoms and fever were high, only 0.6% of patients tested positive for COVID-19. Among more than 2000 patients who underwent bariatric surgery analyzed in this study, only 0.1% needed ICU admission.

MetAP2 inhibition modifies hemoglobin S to delay polymerization and improves blood flow in sickle cell disease.

Sickle cell disease (SCD) is associated with hemolysis, vascular inflammation, and organ damage. Affected patients experience chronic painful vaso-occlusive events requiring hospitalization. Hypoxia-induced polymerization of sickle hemoglobin S (HbS) contributes to sickling of red blood cells (RBCs) and disease pathophysiology. Dilution of HbS with nonsickling hemoglobin or hemoglobin with increased oxygen affinity, such as fetal hemoglobin or HbS bound to aromatic aldehydes, is clinically beneficial in decreasing polymerization. We investigated a novel alternate approach to modify HbS and decrease polymerization by inhibiting methionine aminopeptidase 2 (MetAP2), which cleaves the initiator methionine (iMet) from Val1 of α-globin and ßS-globin. Kinetic studies with MetAP2 show that ßS-globin is a fivefold better substrate than α-globin. Knockdown of MetAP2 in human umbilical cord blood-derived erythroid progenitor 2 cells shows more extensive modification of α-globin than ß-globin, consistent with kinetic data. Treatment of human erythroid cells in vitro or Townes SCD mice in vivo with selective MetAP2 inhibitors extensively modifies both globins with N-terminal iMet and acetylated iMet. HbS modification by MetAP2 inhibition increases oxygen affinity, as measured by decreased oxygen tension at which hemoglobin is 50% saturated. Acetyl-iMet modification on ßS-globin delays HbS polymerization under hypoxia. MetAP2 inhibitor-treated Townes mice reach 50% total HbS modification, significantly increasing the affinity of RBCs for oxygen, increasing whole blood single-cell RBC oxygen saturation, and decreasing fractional flow velocity losses in blood rheology under decreased oxygen pressures. Crystal structures of modified HbS variants show stabilization of the nonpolymerizing high O2-affinity R2 state, explaining modified HbS antisickling activity. Further study of MetAP2 inhibition as a potential therapeutic target for SCD is warranted.

Nanoemulsion as a feasible and biocompatible carrier for ocular delivery of travoprost: Improved pharmacokinetic/pharmacodynamic properties.

Travoprost is a synthetic prostaglandin F2α analogue used in treatment of glaucoma. Due to its water insolubility and oily nature, novel delivery systems need to be developed to enhance its bioavailability, and sustain its release. In the current work, travoprost nanoemulsion was explored as a novel carrier prepared using low energy technique. Results showed that travoprost nanoemulsions exhibited suitable nanodroplet size, zeta potential, pH, refractive index, controlled release, as well as sufficient stability under accelerated conditions. In vivo studies delineated the enhanced absorption of travoprost nanoemulsion compared to the marketed eye drops Travatan®, as proven by the higher Cmax and AUC of the former, and its prolonged intraocular pressure reduction time. Moreover, the nanoemulsion formulation was proven safe and non-irritant to ocular surfaces. Therefore, it can be suggested that travoprost nanoemulsion is a promising ocular delivery system for glaucoma treatment.

Novel fibrin-fibronectin matrix accelerates mice skin wound healing.

Plasma fibrinogen (F1) and fibronectin (pFN) polymerize to form a fibrin clot that is both a hemostatic and provisional matrix for wound healing. About 90% of plasma F1 has a homodimeric pair of γ chains (γγF1), and 10% has a heterodimeric pair of γ and more acidic γ' chains (γγ'F1). We have synthesized a novel fibrin matrix exclusively from a 1:1 (molar ratio) complex of γγ'F1 and pFN in the presence of highly active thrombin and recombinant Factor XIII (rFXIIIa). In this matrix, the fibrin nanofibers were decorated with pFN nanoclusters (termed γγ'F1:pFN fibrin). In contrast, fibrin made from 1:1 mixture of γγF1 and pFN formed a sporadic distribution of "pFN droplets" (termed γγF1+pFN fibrin). The γγ'F1:pFN fibrin enhanced the adhesion of primary human umbilical vein endothelium cells (HUVECs) relative to the γγF1+FN fibrin. Three dimensional (3D) culturing showed that the γγ'F1:pFN complex fibrin matrix enhanced the proliferation of both HUVECs and primary human fibroblasts. HUVECs in the 3D γγ'F1:pFN fibrin exhibited a starkly enhanced vascular morphogenesis while an apoptotic growth profile was observed in the γγF1+pFN fibrin. Relative to γγF1+pFN fibrin, mouse dermal wounds that were sealed by γγ'F1:pFN fibrin exhibited accelerated and enhanced healing. This study suggests that a 3D pFN presentation on a fibrin matrix promotes wound healing.

What Open-Lung Biopsy Teaches Us about ARDS in COVID-19 Patients: Mechanisms, Pathology, and Therapeutic Implications.

Difficulties have risen while managing Acute Respiratory Distress Syndrome (ARDS) caused by COVID-19, although it meets the Berlin definition. Severe hypoxemia with near-normal compliance was noted along with coagulopathy. Understanding the precise pathophysiology of this atypical ARDS will assist researchers and physicians in improving their therapeutic approach. Previous work is limited to postmortem studies, while our report addresses patients under protective lung mechanical ventilation. An open-lung minithoracotomy was performed in 3 patients who developed ARDS related to COVID-19 and were admitted to the intensive care unit to carry out a pathological and microbiological analysis on lung tissue biopsy. Diffused alveolar damage with hyaline membranes was found, as well as plurifocal fibrin microthrombi and vascular congestion in all patients' specimens. Microbiological cultures were negative, whereas qualitative Reversed Transcriptase Polymerase Chain Reaction (RT-PCR) detected SARS-CoV-2 in the pulmonary parenchyma and pleural fluid in two patients. COVID-19 causes progressive ARDS with onset of severe hypoxemia, underlying a dual mechanism: shunt effect through diffused alveolar damage and dead space effect through thrombotic injuries in microvascular beds. It seems reasonable to manage this ventilation-perfusion ratio mismatch using a high dose of anticoagulant combined with glucocorticoids.