A bi-functional nanofibrous composite membrane for wound healing applications.

Various wound dressings have been developed so far for wound healing, but most of them are ineffective in properly reestablishing the skin's structure, which increases infection risks and dehydration. Electrospun membranes are particularly interesting for wound dressing applications because they mimic the extracellular matrix of healthy skin. In this study, a potential wound healing platform capable of inducing synergistic antibacterial and antioxidation activities was developed by incorporating bio-active rosmarinic acid-hydroxyapatite hybrid (HAP-RA) with different contents (0.5, 1, and 1.5 wt.%) into the electrospun polyamide 6 (PA6) nanofibers. Then, polyethylene glycol (PEG) was introduced to the nanofibrous composite to improve the biocompatibility and biodegradability of the dressing. The results indicated that the hydrophilicity, water uptake, biodegradability, and mechanical properties of the obtained PA6/PEG/HAP-RA nanofibrous composite enhanced at 1 wt.% of HAP-RA. The nanofibrous composite had excellent antibacterial activity. The antioxidation potential of the samples was assessed in vitro. The MTT assay performed on the L929 cell line confirmed the positive effects of the nanofibrous scaffold on cell viability and proliferation. According to the results, the PA6/PEG/HAP-RA nanofibrous composite showed the desirable physiochemical and biological properties besides antibacterial and antioxidative capabilities, making it a promising candidate for further studies in wound healing applications.

Electrospun nylon 6/hyaluronic acid/chitosan bioactive nanofibrous composite as a potential antibacterial wound dressing.

Hyaluronic acid (HA) and chitosan (CS), as natural biomaterials, display excellent biocompatibility and stimulate the growth and proliferation of fibroblasts. Furthermore, nylon 6 (N6) is a low-cost polymer with good compatibility with human tissues and high mechanical stability. In this study, HA and CS were applied to modify N6 nanofibrous mat (N6/HA/CS) for potential wound dressing. N6/HA/CS nanofibrous composite mats were developed using a simple one-step electrospinning technique at different CS concentrations of 1, 2, and 3 wt%. The results demonstrated that incorporating HA and CS into N6 resulted in increased hydrophilicity, as well as favorable physical and mechanical properties. In addition, the minimum inhibitory concentration and (MIC) optical density techniques were used to determine the antibacterial properties of N6/HA/CS nanofibrous composite mats, and the results demonstrated that the composites could markedly inhibit the growth of Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. Because of its superior mechanical properties, substantial antimicrobial effects, and hydrophilic surface, N6/HA/CS at 2 wt% of CS (N6/HA/CS2) was chosen as the most suitable nanofibrous mat. The swelling, porosity, gel content, and in vitro degradation studies imply that N6/HA/CS2 nanofibrous composite mat has proper moisture retention and biodegradability. Furthermore, the N6/HA/CS2 nanofibrous composite mat was discovered to be nontoxic to L929 fibroblast cells and to even improve cell proliferation. Based on the findings, this research offers a simple and rapid method for creating material that could be utilized as prospective wound dressings in clinical environments.

Contemporaneous SARS-CoV-2-Neutralizing Antibodies Mediated by N-glycan Shields.

Mutations and the glycosylation of epitopes can convert immunogenic epitopes into non-immunogenic ones via natural selection or evolutionary pressure, thereby decreasing their sensitivity to neutralizing antibodies. Based on Thomas Francis's theory, memory B and T cells induced during primary infections or vaccination will freeze the new mutated epitopes specific to naïve B and T cells from the repertoire. On this basis, some researchers argue that the current vaccines derived from the previous strains of the SARS-CoV-2 virus do not increase immunity and may also prevent the immune response against new epitopes. However, evidence shows that even if the binding affinity is reduced, the previous antibodies or T cell receptors (TCRs) can still bind to this new epitope of the Beta, Gamma, and Delta variant if their concentration is high enough (from a booster injection) and neutralize the virus. This paper presents some convincing immunological reasons that may challenge this theory and argue for the continuation of universal vaccination to prevent further mutations of the SARS-CoV-2 virus. Simultaneously, the information presented can be used to develop vaccines that target novel epitopes or create new recombinant drugs that do not lose their effectiveness when the virus mutates.

The correlation between humoral immune responses and severity of clinical symptoms in COVID-19 patients.

The SARS-CoV-2 pandemic persists with global repercussions. Initial COVID-19 symptoms encompass pneumonia, fever, myalgia, and fatigue. The human immune system produces IgM and IgG antibodies in response to SARS-CoV-2. Despite previous research, a comprehensive understanding of the interplay between clinical manifestations and humoral immune responses remains elusive. This study aims to scrutinize this association. 134 COVID-19 patients were enrolled, and stratified into mild, moderate, and severe symptom groups. Serum IgM and IgG levels were assessed thrice at one-month intervals using ELISA. The findings reveal significant elevation in serum IgG levels in moderate compared to mild cases (P < 0.001). Additionally, IgG production was significantly heightened in severe cases compared to both mild (P < 0.0001) and moderate (P < 0.05) groups. IgM and IgG levels peaked initially and diminished over time. While anti-SARS-CoV-2 antibodies are expected to confer protection, the direct correlation between IgG levels and symptom severity may arise from delayed immune activation, resulting in an intense antibody response in severe cases. Given evidence linking delayed immune function with a dysregulated innate immune response, comprehensive data collection should encompass not only serum IgG and IgM, but also early measurement of type I interferons at symptom onset. This could provide a more thorough understanding of COVID-19 progression.

Development of an antibacterial and antioxidative nanofibrous membrane using curcumin-loaded halloysite nanotubes for smart wound healing: In vitro and in vivo studies.

Endowing wound dressings with drug delivery capability is a suitable strategy to transfer medicinal compounds locally to damaged skin layers. These dressings are especially useful for accelerating the healing rate in the cases of long-term treatment, and adding more functionalities to the platform. In this study, a wound dressing composed of polyamide 6, hyaluronic acid, and curcumin-loaded halloysite nanotubes (PA6/HA/HNT@Cur) was designed and fabricated for wound healing applications. The physicochemical properties of this platform were investigated through Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. Moreover, wettability, tensile strength, swelling, and in vitro degradation were assessed. The HNT@Cur was incorporated in the fibers in three concentrations and 1 wt% was found as the optimum concentration yielding desirable structural and mechanical properties. The loading efficiency of Cur on HNT was calculated to be 43 ± 1.8%, and the release profiles and kinetics of nanocomposite were investigated at physiological and acidic pH. In vitro antibacterial and antioxidation studies showed that the PA6/HA/HNT@Cur mat had strong antibacterial and antioxidation activities against gram-positive and -negative pathogens and reactive oxygen species, respectively. Desirable cell compatibility of the mat was found through MTT assay against L292 cells up to 72 h. Finally, the efficacy of the designed wound dressing was evaluated in vivo; after 14 days, the results indicated that the wound size treated with the nanocomposite mat significantly decreased compared to the control sample. This study proposed a swift and straightforward method for developing materials that might be utilized as wound dressings in clinical settings.

Control of eriocitrin release from pH-sensitive gelatin-based microgels to inhibit α-glucosidase: an experimental and computational study.

α-Glucosidase is among the intestinal epithelial enzymes that produce absorbable glucose in the final stage of glycan catabolism. It leads to an increase in blood glucose levels as a result of high glucose uptake in diabetic patients. However, inhibition of this essential biochemical process can be a useful therapeutic approach to diabetes mellitus (DM). Eriocitrin (ER) is an abundant "flavanone glycoside" in citrus fruits with rich antioxidant properties whose effects on α-Glu inhibition in the small intestine remain to be determined. Herein, pH-sensitive microgels (MGs) were designed based on cross-linked methacrylate with acrylamide (AM) and acrylic acid (AAc) (molar ratio 70 : 30 of AAc : AM) as a controlled release system for sustained delivery of ER into the small intestine. The presence of amide and acrylate in MGs and the mechanical resistance were determined using FT-IR spectroscopy, rheology, and viscoelastometry. In vitro experiments showed that MGs could protect ER against diffusion in the gastric location and adjust its release in the intestinal milieu. The intestinal α-Glu activity was inhibited by ER (IC50 value of 12.50 ± 0.73 µM) in an uncompetitive dose-dependent manner. The presence of ER altered the structure of α-Glu and reduced the hydrophobic pockets of the enzyme. Molecular docking analysis along with molecular dynamics simulation displayed that ER-α-Glu formation is directed by hydrogen binding with Asp69, Asp215, Glu411, Asp307, and Tyr347 residues. Moreover, in vivo assessment showed that rat blood glucose concentration decreased after ER administration compared with the control group. The results highlight that ER-loaded-MGs can be considered as a useful releasing strategy in treating DM via α-Glu inhibition.

Protein and polysaccharide-based asymmetric mat with tuned bilayer configuration for enhanced wound healing efficiency.

In this research we focused on the fabrication of an asymmetric bilayer membrane with core-shell/simple layer configuration providing the functions of needed hierarchically hydrophilicity and porosity, anti-infectious, tissue adhesion as well as degradation and integration with tissue, cells proliferation, and enhanced promotion of tissue regeneration. The bilayer membrane composed of collagen (Col), chitosan (CS), aloe vera (AV) and gelatin (Gel), not only simulates the features of the epidermis and dermis layer of a natural skin but also benefits from the materials necessary for the regeneration of injured skin tissue during the healing process. The results of full-thickness skin wound evaluation revealed that the fabricated asymmetric membrane could facilitate wound healing within 10 days mainly through enhancing cellular activities, enhancing collagen deposition, and promoting proliferation. Results of histopathological analysis and immunohistochemistry after 10 days of treatment, demonstrated more re-epithelialization and collagen density for the treated groups compared to the control group.

Sugarcane molasses enhances TGF-ß secretion and FOXP3 gene expression by Bifidobacterium Animalis Subsp. Lactis stimulated PBMCs of Ulcerative Colitis patients.

Ulcerative colitis (UC) is one of the inflammatory diseases of the gut with frequent bloody diarrhea leads to increased rates of anemia. Evidences indicate the immunomodulation disorders in the response to intestinal microbiota in UC. Although sugarcane molasses, rich in necessary minerals and vitamins, could be a good support nutrient but its effect on immune system of UC patients is unknown. To determine how the immune system of UC patients responds to molasses this study was planned. Bifidobacterium lactis were cultivated on MRS broth. PBMCs of 12 UC patients were separated by Ficoll-Hypaque centrifugation and co-cultured with different concentrations of UV killed bacteria and/or molasses in RPMI-1640 plus 10 % FCS. The gene expression of FoxP3 was measured by real-time PCR. TGF-ß and TNF-α were measured in supernatant of PBMCs by ELISA. Sugarcane molasses and B. lactis significantly augmented TGF-ß compared to control (p < 0.01 and p < 0.001 respectively). The secretion levels of TGF-ß by B. lactis plus molasses compared to B. lactis stimulated PBMCs was significantly higher (p < 0.05) but the level of TNF-α by PBMCs after 2/4/12 h incubation with B. lactis plus molasses compared to B. lactis alone was not changed (p > 0.2). The level of FOXP3 expression after treatment with molasses was increased significantly (p < 0.05). These data show that if sugarcane molasses added to B. lactis, not only do not increase the pro-inflammatory cytokine, TNF-α, but also augments the anti-inflammatory cytokine, TGF-ß by PBMCs. Therefore, these results pave the way for further investigation to show sugarcane molasses as a safe support to compensate the lost nutrients in UC patients.

Sumatriptan Increases Skin Flap Survival through Activation of 5-Hydroxytryptamine 1b/1d Receptors in Rats: The Mediating Role of the Nitric Oxide Pathway.

BACKGROUND: Random pattern skin flaps are applicable for reconstructing any defect in plastic surgery. However, they are difficult to apply because of necrosis. Sumatriptan, a selective 5-hydroxytryptamine 1b/1d agonist, is routinely used to offset acute migraine attacks. Recent studies have suggested that sumatriptan may induce vasodilation at lower concentrations. The authors' aim is to investigate the effect of sumatriptan on skin flap survival and the role of nitric oxide in this phenomenon. METHODS: Seventy-two male Sprague-Dawley rats were divided into eight groups. Increasing doses of sumatriptan (0.1, 0.3, and 1 mg/kg) were given intraperitoneally to three different groups after dorsal random pattern skin flaps were performed. To assess the exact role of 5-hydroxytryptamine 1b/1d receptors, GR-127935 was administered solely and with sumatriptan. N-ω-nitro-L-arginine methyl ester (L-NAME, a nonselective nitric oxide synthase inhibitor) was used to evaluate any possible involvement of nitric oxide in this study. All rats were examined 7 days later. RESULTS: The authors' results demonstrated that flap survival was increased by lower doses of sumatriptan compared to a control group for both 0.3 mg/kg (p = 0.03, mean difference = 32, SE = 8) and 0.1 mg/kg (p = 0.02, mean difference = 26, SE = 8). This protective effect was eliminated by coadministration of GR-127935 or N-ω-nitro-L-arginine methyl ester with sumatriptan. Histopathologic studies revealed a significant increase in capillary count and collagen deposition and a decreased amount of edema, inflammation, and degeneration. CONCLUSIONS: Sumatriptan in lower concentration increases skin flap survival by means of activation of 5-hydroxytryptamine 1b/1d receptors. This effect is mediated through the nitric oxide synthase pathway.

Involvement of ATP-sensitive potassium channels and the opioid system in the anticonvulsive effect of zolpidem in mice.

Zolpidem is a hypnotic medication that mainly exerts its function through activating γ-aminobutyric acid (GABA)A receptors. There is some evidence that zolpidem may have anticonvulsive effects. However, the mechanisms underlying this effect have not been elucidated yet. In the present study, we used the pentylentetrazole (PTZ)-induced generalized seizure model in mice to investigate whether zolpidem can affect seizure threshold. We also further evaluated the roles of ATP-sensitive potassium (KATP) channels as well as µ-opioid receptors in the effects of zolpidem on seizure threshold. Our data showed that zolpidem in a dose-dependent manner increased the PTZ-induced seizure threshold. The noneffective (i.e., did not significantly alter the PTZ-induced seizure threshold by itself) doses of KATP channel blocker (glibenclamide) and nonselective opioid receptor antagonist (naloxone) were able to inhibit the anticonvulsive effect of zolpidem. Additionally, noneffective doses of either KATP channel opener (cromakalim) or nonselective µ-opioid receptor agonist (morphine) in combination with a noneffective dose of zolpidem exerted a significant anticonvulsive effect on PTZ-induced seizures in mice. A combination of noneffective doses of naloxone and glibenclamide, which separately did not affect zolpidem effect on seizure threshold, inhibited the anticonvulsive effects of zolpidem. These results suggest a role for KATP channels and the opioid system, alone or in combination, in the anticonvulsive effects of zolpidem.

Rutin activates the MAPK pathway and BDNF gene expression on beta-amyloid induced neurotoxicity in rats.

Flavonoids are present in foods such as fruits and vegetables. A relationship between the consumption of flavonoid-rich foods and prevention of human disease including neurodegenerative disorders has been demonstrated. We assessed the effect of rutin (3,3',4',5,7-pentahydroxyflavone-3-rhamnoglucoside) on the mitogen-activated protein kinase (MAPK) pathway, memory retrieval and oxidative stress in rats injected with ß-amyloid (Aß), which is implicated to have an important role in Alzheimer's disease (AD). Aß was injected bilaterally in the deep frontal cortex of rat brain. Next, rutin and saline were injected (i.p.) for 3 weeks. In comparison to the control group, rutin significantly increased extracellular signal-regulated protein kinase 1 (ERK1), cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) gene expression in the hippocampus of rats. Rutin (100 mg/kg) significantly increased memory retrieval compared to the control group. Malondialdehyde (MDA) level in the hippocampus of the rutin group was significantly lower than those in the control group. The content of sulfhydryl groups in the rutin group was higher than that in the control group. The findings show a possibility that rutin may have beneficial effects against neurotoxicity of Aß on memory in rats.

Effects of rutin on oxidative stress in mice with kainic acid-induced seizure.

OBJECTIVE: Flavonoids are present in foods such as fruits and vegetables. Several studies have demonstrated a relationship between the consumption of flavonoid-rich foods and prevention of human disease, including neurodegenerative disorders. We assessed the effect of rutin (quercetin-3-O-rutinoside) on oxidative stress in kainic acid (KA)-induced seizure. METHODS: Thirty-six BALB/c mice were randomly divided into three groups. In the control group, saline (intra-peritoneal, i.p.) was administered for 7 d, and on the last day, KA (10 mg/kg, i.p.) was injected 30 min after administration of saline. In rutin groups, mice were pretreated with rutin (100 and 200 mg/kg, i.p.) for 7 d, and on the last day, KA (10 mg/kg, i.p.) was injected 30 min after administration of rutin. Subsequently, behavioural changes were observed in mice. Lipid peroxidation and oxidative stress were measured respectively in the early and late phases after KA-induced seizures. RESULTS: Seizure scores in the rutin groups were significantly lower than those in the control group (P < 0.01). Furthermore, rutin dose-dependently inhibited the number of wet-dog shakes (WDS) (P < 0.05). Malondialdehyde level in the hippocampus of the rutin groups was significantly lower than that in the hippocampus of the control group on days 1 and 21 after KA administration. In the rutin groups, the thiol levels observed on day 1 after KA administration were higher than that in the control group (P < 0.01). CONCLUSION: These results indicate that rutin has potential anticonvulsant and antioxidative activities against oxidative stress in KA-induced seizure in mice.

Effects of vitexin on scopolamine-induced memory impairment in rats.

Various synthetic derivatives of natural flavonoids are known to have neuroactive properties. The present study aimed to investigate the effects of vitexin (5, 7, 4-trihydroxyflavone-8-glucoside), a flavonoid found in such plants as tartary buckwheat sprouts, wheat leaves phenolome, Mimosa pudica Linn and Passiflora spp, on scopolamine-induced memory impairment in rats. To achieve this goal, we assessed the effects of vitexin on memory retrieval in the presence or absence of scopolamine using a step-through passive avoidance trial. In the first part of the study, vitexin (25, 50, and 100 microM) was administered intracerebroventricularly (i.c.v.) before acquisition trials. In the second part, vitexin, at the same doses, was administered before scopolamine (10 microg, i.c.v.) and before the acquisition trials. During retention tests, vitexin (100 microM) in the absence of scopolamine significantly increased the step-through latencies compared to scopolamine. In addition, vitexin (100 microM) significantly reversed the shorter step-through latencies induced by scopolamine (P < 0.05). These results indicate that vitexin has a potential role in enhancing memory retrieval. A possible mechanism is modulation of cholinergic receptors; however, other mechanisms may be involved in its effects in acute exposure.

Neuroprotective effects of vitexin, a flavonoid, on pentylenetetrazole-induced seizure in rats.

Flavonoids are important constituents of food and beverages and have several neuropharmacological activities. Many of these compounds are ligands for γ-aminobutyric acid type A receptors in the central nervous system. This study aimed to investigate the anticonvulsant effects of intracerebroventricularly administered vitexin (5, 7, 4-trihydroxyflavone-8-glucoside), a flavonoid found in plants, in rats treated with pentylenetetrazole (90 mg/kg, intraperitoneally) and to clarify the underlying mechanism. Vitexin (100 and 200 µm, i.c.v) affected minimal clonic seizures and generalized tonic-clonic seizures induced by pentylenetetrazole by increasing the seizure onset time. Pretreatment with flumazenil suppressed the anticonvulsant effects of vitexin during the onset of both the seizures. These results indicate that vitexin has anticonvulsant effects in the brain, possibly through interaction at the benzodiazepine site of the γ-aminobutyric acid type A receptor complex.