Epsilon-poly-l-lysine microneedle patch loaded with amorphous doxycycline nanoparticles for synergistic treatment of skin infection.

The development of antibiotic-loaded microneedles has been hindered for years by limited excipient options, restricted drug-loading space, poor microneedle formability, and short-term drug retention. Therefore, this study proposes a dissolving microneedle fabricated from the host-defense peptide ε-poly-l-lysine (EPL) as an antibacterial adjuvant system for delivering antibiotics. EPL serves not only as a major matrix material for the microneedle tips, but also as a broad-spectrum antibacterial agent that facilitates the intracellular accumulation of the antibiotic doxycycline (DOX) by increasing bacterial cell membrane permeability. Furthermore, the formation of physically crosslinked networks of EPL affords microneedle tips with improved formability, good mechanical properties, and amorphous nanoparticles (approximately 7.2 nm) of encapsulated DOX. As a result, a high total loading content of both antimicrobials up to 2319.1 µg/patch is achieved for efficient transdermal drug delivery. In a Pseudomonas aeruginosa-induced deep cutaneous infection model, the EPL microneedles demonstrates potent and long-term effects by synergistically enhancing antibiotic activities and prolonging drug retention in infected lesions, resulting in remarkable therapeutic efficacy with 99.91 % (3.04 log) reduction in skin bacterial burden after a single administration. Overall, our study highlights the distinct advantages of EPL microneedles and their potential in clinical antibacterial practice when loaded with amorphous DOX nanoparticles.

Modulating the antibacterial effect of the existing antibiotics along with repurposing drug metformin.

Owing to the extensive prevalence of resistant bacteria to numerous antibiotic classes, antimicrobial resistance (AMR) poses a well-known hazard to world health. As an alternate approach in the field of antimicrobial drug discovery, repurposing the available medications which are also called antibiotic resistance breakers has been pursued for the treatment of infections with antimicrobial resistance pathogens. In this study, we used Haloperidol, Metformin and Hydroxychloroquine as repurposing drugs in in vitro (Antibacterial Antibiotic Sensitivity Test and Minimum Inhibitory Concentration-MIC) and in vivo (Shigellosis in Swiss albino mice) tests in combination with traditional antibiotics (Oxytetracycline, Erythromycin, Doxycycline, Gentamicin, Ampicillin, Chloramphenicol, and Penicillin) against a group of AMR resistance bacteria (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Shigella boydii). After observing the results of the conducted in vitro experiments we studied the effects of the above non antibiotic drugs in combination with the said antibiotics. As an repurposing adjuvant antibiotic drug, Metformin exhibited noteworthy activity in almost all in vitro, in vivo and in silico tests (Zone of inhibition for 30 to 43 mm for E.coli in combination with Doxycycline; MIC value decreased 50 µM to 0.781 µM with Doxycycline on S. boydii).In rodents Doxycycline and Metformin showed prominent against Shigellosis in White blood cell count (6.47 ± 0.152 thousand/mm3) and Erythrocyte sedimentation rate (10.5 ± 1.73 mm/hr). Our findings indicated that Metformin and Doxycycline combination has a crucial impact on Shigellosis. The molecular docking study was performed targeting the Acriflavine resistance protein B (AcrB) (PDB ID: 4CDI) and MexA protein (PDB ID: 6IOK) protein with Metformin (met8) drug which showed the highest binding energy with - 6.4 kcal/mol and - 5.5 kcal/mol respectively. Further, molecular dynamics simulation revealed that the docked complexes were relatively stable during the 100 ns simulation period. This study suggest Metformin and other experimented drugs can be used as adjuvants boost up antibiosis but further study is needed to find out the safety and efficacy of this non-antibiotic drug as potent antibiotic adjuvant.

Utilizing the photodynamic properties of curcumin to disrupt biofilms in Cutibacterium acnes: A promising approach for treating acne.

BACKGROUND: The treatment of acne vulgaris is often challenging due to the antibiotic resistance frequently observed in Cutibacterium acnes (C.acnes), a prevalent bacterium linked to this condition. OBJECTIVE: The objective of this research was to examine the impact of curcumin photodynamic therapy (PDT) on the survival of C.acnes and activity of biofilms produced by this microorganism. METHODS: Following the Clinical and Laboratory Standards Institute (CLSI) guidelines, we assessed the drug sensitivity of 25 clinical C.acnes strains to five antibiotics (erythromycin, clindamycin, tetracycline, doxycycline, minocycline) and curcumin by implementing the broth microdilution technique. In addition, we established C.acnes biofilms in a laboratory setting and subjected them to curcumin-PDT(curcumin combined with blue light of 180 J/cm2). Afterwards, we evaluated their viability using the XTT assay and observed them using confocal laser scanning microscopy. RESULTS: The result revealed varying resistance rates among the tested antibiotics and curcumin, with erythromycin, clindamycin, tetracycline, doxycycline, minocycline, and curcumin exhibiting resistance rates of 72 %, 44 %, 36 %, 28 %, 0 %, and 100 %, respectively. In the curcumin-PDT inhibition tests against four representative antibiotic-resistant strains, it was found that the survival rate of all strains of planktonic C. acnes was reduced, and the higher the concentration of curcumin, the lower the survival rate. Furthermore, in the biofilm inhibition tests, the vitality and three-dimensional structure of the biofilms were disrupted, and the inhibitory effect became more significant with higher concentrations of curcumin. CONCLUSION: The results emphasize the possibility of using curcumin PDT as an alternative approach for the treatment of C.acnes, especially in instances of antibiotic-resistant variations and infections related to biofilms.

Synergistic effect of doxycycline and aqueous extract of irradiated khella on structure of nanobacteria isolated from kidney stones: In vitro and in vivo studies.

Kidney stones have been associated with an increased risk of chronic kidney diseases, end-stage renal failure. This study is devoted to isolate nanobacteria from patients with active urolithiasis and investigate the in vitro and in vivo antinanobacterial activity of some antibiotics alone or in combination with extracts of irradiated herbs from certain medicinal plants. Nanobacteria were detected using scanning (SEM) and transmission (TEM) electron microscopy, protein electrophoresis (SDS-PAGE) and DNA profile. The antimicrobial susceptibility of some biofilm-producing nanobacterial isolates was evaluated. The effect of medicinal plant extracts on growth was tested. A combination treatment between the most potent extracts and antibiotics was tested on biofilm production, protein profile, release of 260 nm absorbing material, protein content, and ultrastructure of the strongest biofilm producers. In vivo study of nanobacteria and its treatment by the most potent agents was evaluated on male rats. Renal function was measured in serum; histological examination and oxidative stress parameters were determined in kidney tissues. Results showed that streptomycin, trimethoprim/sulfamethoxazole, doxycycline, and water extracts of irradiated khella at 6 kGy had antinanobacterial activity. Meanwhile, the synergistic effect of the aqueous extract of irradiated Khella and doxycycline showed higher inhibition activity on microbial growth and biofilm production. They affected dramatically the strength of its cell membrane and subsequently its ultrastructure. Moreover, these results are confirmed by ameliorations in renal function and histological alterations. It could be concluded that the combination of DO and an aqueous extract of irradiated khella has an antinephrotoxic effect against nanobacteria-induced renal toxicity.

Tetracycline antibiotics: Potential anticancer drugs.

In recent years, research on tetracycline antibiotics has gradually shifted from their antibacterial effects to anticancer effects. Doxycycline, minocycline, and tigecycline as the US Food and Drug Administration (FDA) approved tetracycline antibiotics have been the main subjects of studies. Evidence indicated that they have anticancer properties and are able to control cancer progression through different mechanisms, such as anti-proliferation, anti-metastasis, and promotion of autophagy or apoptosis. In addition, studies have shown that these three tetracycline antibiotics can be utilized in conjunction with chemotherapeutic and targeted drugs to inhibit cancer progression and improve the quality of patient survival. Therefore, doxycycline, minocycline, and tigecycline are taken as examples in this work. Their mechanisms of action in different cancers and related combination therapies are introduced. Their current roles in alleviating the suffering of patients undergoing chemotherapy when used as adjuvant drugs in clinical treatment are also described. Finally, the research gaps and potential research directions at this stage are briefly summarized.

In vitro study of nanoliposomes containing curcumin and doxycycline for enhanced antimicrobial photodynamic therapy against Aggregatibacter actinomycetemcomitans.

The excessive inappropriate use of systemic antibiotics has contributed to the emergence of antibiotic-resistant pathogens, which pose a significant risk to the success of treatment. This study has approached this problem by developing doxycycline-loaded liposome doped with curcumin (NL-Cur+Dox) for combination antibacterial therapy against Aggregatibacter actinomycetemcomitans. The characterization of formulation revealed encapsulation of both drugs in NL-Cur+Dox with an average size of 239 nm and sustained release behavior. Transmission electron microscopy analysis confirmed the vesicular-shaped nanocarriers without any aggregation or crystallization. The cytotoxic and hemolytic activities of NL-Cur+Dox were evaluated. The anti-biofilm and anti-metabolic effects of NL-Cur+Dox -mediated antimicrobial photodynamic therapy (aPDT) were examined. The data indicated that NL-Cur+Dox -mediated aPDT led to a significant reduction of biofilm (82.7%, p = 0.003) and metabolic activity (75%, p < 0.001) of A. actinomycetemcomitans compared to the control. NL-Cur+Dox had no significant cytotoxicity to human gingival fibroblast cells under selected conditions (p = 0.074). In addition, the hemolytic activity of NL-Cur+Dox were negligible (< 5%). These findings demonstrate the potential application of such potent formulations in reducing one of the main bacteria causing periodontitis where the NL-Cur+Dox could be exploited to achieve an improved phototherapeutic efficiency.

Integrated Multiomics and Synergistic Functional Network Revealed the Mechanism in the Tolerance of Different Ecotypes of Salvia miltiorrhiza Bge. to Doxycycline Pollution.

Tetracycline pollution in soil irreversibly damages the biosafety of plants by inhibiting the mitochondrial function. Some traditional Chinese medicine (TCM) plants, such as Salvia miltiorrhiza Bunge, have a strong tolerance to mitochondrial damage. We comprehensively compared the doxycycline (DOX) tolerances of two ecotypes of S. miltiorrhiza in the Sichuan and Shandong provinces and found that the Sichuan ecotype had a lower yield reduction, more stable accumulation of medicinal ingredients, higher mitochondrial integrity, and a more robust antioxidant system. The synergetic response networks under DOX pollution of both ecotypes were constructed using RNA sequencing and ultrahigh-performance liquid chromatography-tandem mass spectrometry. The differentiation of the downstream pathways of aromatic amino acids (AAAs) produced variations in the DOX tolerance of S. miltiorrhiza in different regions. The Sichuan ecotype maintained redox homeostasis and xylem development by activating salvianolic acid and indole biosynthesis, while the Shandong ecotype balanced chemical and mechanical defenses by regulating the flavonoid biosynthesis. Rosmarinic acid, a downstream AAA molecule, maintains the mitochondrial homeostasis of plant seedlings under DOX pollution by targeting the ABCG28 transporter. We also highlight the significance of downstream AAA small molecules in guiding the development of bio-based environmental pollution remediation agents.

Baicalein Resensitizes Multidrug-Resistant Gram-Negative Pathogens to Doxycycline.

As multidrug-resistant pathogens emerge and spread rapidly, novel antibiotics urgently need to be discovered. With a dwindling antibiotic pipeline, antibiotic adjuvants might be used to revitalize existing antibiotics. In recent decades, traditional Chinese medicine has occupied an essential position in adjuvants of antibiotics. This study found that baicalein potentiates doxycycline against multidrug-resistant Gram-negative pathogens. Mechanism studies have shown that baicalein causes membrane disruption by attaching to phospholipids on the Gram-negative bacterial cytoplasmic membrane and lipopolysaccharides on the outer membrane. This process facilitates the entry of doxycycline into bacteria. Through collaborative strategies, baicalein can also increase the production of reactive oxygen species and inhibit the activities of multidrug efflux pumps and biofilm formation to potentiate antibiotic efficacy. Additionally, baicalein attenuates the lipopolysaccharide-induced inflammatory response in vitro. Finally, baicalein can significantly improve doxycycline efficacy in mouse lung infection models. The present study showed that baicalein might be considered a lead compound, and it should be further optimized and developed as an adjuvant that helps combat antibiotic resistance. IMPORTANCE Doxycycline is an important broad-spectrum tetracycline antibiotic used for treating multiple human infections, but its resistance rates are recently rising globally. Thus, new agents capable of boosting the effectiveness of doxycycline need to be discovered. In this study, it was found that baicalein potentiates doxycycline against multidrug-resistant Gram-negative pathogens in vitro and in vivo. Due to its low cytotoxicity and resistance, the combination of baicalein and doxycycline provides a valuable clinical reference for selecting more effective therapeutic strategies for treating infections caused by multidrug-resistant Gram-negative clinical isolates.

Sunlight promoted self-fenton photodegradation and pathway of doxycycline: Interactive effects of nanomaterial on bean plant and its genotoxicity against Allium cepa.

Photocatalytic induction of electron/hole recombination, surface property and light response ability effectively enhance the photocatalytic activity of nanomaterial. In this work, the effective charge carrier separating Sn/Mn-ZnFe2O4-CdFe2O4-Ag3PO4 Quantum dots (M/SZFO-CFO-AP QDs) was fabricated for photocatalytic degradation of doxycycline (doxy) antibiotic. The result showed enhanced photocatalytic activity of doxy and the degradation efficiency of doxy was about 98.8% in short span of time. The calculated WH plot and urbach energy of prepared photocatalyst exhibited evidence for the prevalence of point defects and its contribution to efficient charge separation and transferability. The total organic carbon (TOC) removal was found to be 98.9%, which depicts the complete mineralization of doxy. The synergetic charge transfer of n-p-n heterojunction enables the effective removal of doxy under visible light irradiation. Further, the genotoxicity study was determined by interacting the SZFO-CFO-AP QDs with Allium Cepa. The results depict that SZFO-CFO-AP QDs show lower toxicity level and there were no trace of defective mitotic phases and micro nuclei. Further, the progression and development of bean plant was determined after treating with prepared nanomaterials and the result showed the enhanced growth in SZFO-CFO-AP QDs treated bean plant compared to the counterparts. Therefore, the prepared SZFO-CFO-AP QDs was can be used as an environmental friendly photocatalyst for effective treatment of antibiotic present in the water bodies.

Distepharinamide, a novel dimeric proaporphine alkaloid from Diploclisia glaucescens, inhibits the differentiation and proliferative expansion of CD4+Foxp3+ regulatory T cells.

BACKGROUND: CD4+Foxp3+ regulatory T cells (Tregs) represent the primary cellular mechanism of tumor immune evasion. Elimination of Treg activity by the pharmacological agent may enhance anti-tumor immune responses. However, Treg-eliminating agents, especially those with small molecules, are rarely reported. PURPOSE: To identify small molecule inhibitors of Treg cells from natural products. METHODS: Compounds from Diploclisia glaucescens were isolated by column chromatography, and structures were identified by spectroscopic evidence and quantum calculations. The tet-On system for Foxp3-GFP expression in Jurkat T cells was generated to screen Treg inhibitors based on Foxp3 expression. The effect of the compound on TNF-induced proliferative expansion of naturally occurring Tregs (nTregs) and TGF-ß-induced generation of Tregs (iTregs) from naive CD4+ Tcells was further examined. RESULTS: A novel dimeric proaporphine alkaloid, designated as distepharinamide (DSA) with a symmetric structure isolated from the stems of D. glaucescens, restrained the doxycycline (Doxy)-induced Foxp3-tGFP expression, decreased the half-life of Foxp3 mRNA as well as reduced the mRNA levels of chemokine receptors (CCR4, CCR8 and CCR10) in Jurkat T cells with inducible Foxp3-tGFP expression. In lymphocytes or purified Tregs from wild-type C57BL/6 mice or from C57BL/6-Tg(Foxp3-DTR/EGFP)23.2Spar/Mmjax mice, DSA markedly inhibited TNF-induced proliferative expansion of Tregs present in the unfractionated CD4+ T cells, accompanied by the down-regulation of TNFR2, CD25 and CTLA4 expression on Tregs. Furthermore, DSA potently inhibited TGF-ß-induced differentiation of Foxp3-expressing iTregs. Importantly, the expression of Foxp3 mRNA by both nTregs and iTregs was decreased by DSA treatment. Nevertheless, DSA at the same concentrations did not inhibit the proliferation of conventional CD4+ and CD8+ T cells stimulated by anti-CD3/CD28 antibodies. CONCLUSION: DSA, a novel dimeric proaporphine alkaloid, potently inhibited the expansion of nTregs and generation of iTregs. Therefore, DSA or its analogs may merit further investigation as novel immunotherapeutic agents.

Study Effect of Azithromycin and Doxycycline in Mucus Producing and Inflammatory Signaling Pathways of Allergic Asthma.

Asthma is a respiratory disease; involving millions of people worldwide. The main cause of asthma is allergy and immune response dysregulation. The effects of azithromycin and doxycycline as asthma-controlling drugs were evaluated in this study. Mice asthma model was produced and asthmatic mice were treated with azithromycin (75 mg/kg, orally) and doxycycline (20 mg/kg, orally). Eosinophils and neutrophils count, interleukin (IL)-4, IL-5, IL-12, IL-13, and total immunoglobulin E (IgE) levels were measured. Histological study and evaluating the genes expression of Muc5ac, Muc5b, IL-33, COX2, MYD88, and TRAF6 were performed. Azithromycin and doxycycline did not affect eosinophil and neutrophil percentage, IL-4, IL-5, IL-12, and total IgE levels, peribronchial and perivascular inflammation, goblet cell hyperplasia, and gene expression of MYD88, TRAF6, and COX2. Treatment with azithromycin significantly decreased IL-13 level, mucus secretion, and gene expression of IL-33, Muc5ac, and Muc5b; compared to the non-treated asthma group. Azithromycin administration controls mucus secretion and inflammation. Azithromycin therapy and not doxycycline might be an effective adjuvant option in asthma with reducing mucus in the airway.

Ecotoxicological effects of untreated pig manure from diets with or without growth-promoting supplements on Eisenia andrei in subtropical soils.

This study aimed to evaluate the effects of untreated pig manure from diets incorporating growth-promoting supplements (antibiotics and Zn oxide) on the survival and reproduction of Eisenia andrei earthworms. The tested manures were obtained from four different groups of pigs fed with four different diets: CS, a diet based on corn and soymeal; TR, a diet based on corn, soymeal, and ground wheat (15%); CSa, a diet based on corn and soymeal + 100 ppm of doxycycline + 50 ppm of colistin + 2500 ppm of Zn oxide; and TRa, a diet based on corn, soymeal, and ground wheat (15%) + 100 ppm of doxycycline + 50 ppm of colistin + 2500 ppm of Zn oxide. The study used two soils representative of the Southern region of Brazil (Oxisol and Entisol). In general, there were no significant differences between the different manures tested in each soil. However, there were differences in the toxicity manure on E. andrei between the soils, and the magnitude of this effect was dependent on the applied dose. In Oxisol, LC50 values were higher than 80 m3 ha-1, and EC50 varied from 9 to 27 m3 ha-1. In Entisol, the LC50 values were below the lowest dose tested (< 25 m3 ha-1), and EC50 remained around 5 m3 ha-1. It may be possible that the effects observed were attributed to an excess of nitrogen, copper, and zinc, promoted by the addition of the untreated manure and how these factors interacted with soil type.

In Situ Effects of Doxycycline on Neuromuscular Junction in Mice.

BACKGROUND: The antibacterial mechanism of doxycycline is known, but its effects on the nerve-muscle system are still not unclear. OBJECTIVE: The aim of the study was to combine molecular targets of the neuromuscular machinery using the in situ neuronal blocker effect of doxycycline, a semisynthetic second-generation tetracycline derivative, on mice neuromuscular preparations. METHODS: The effects of doxycycline were assessed on presynaptic, synaptic cleft, and postsynaptic neurotransmission, along with the muscle fiber, using the traditional myographic technique. Precisely, the effects of doxycycline were categorized into "all" or "nothing" effects depending on the concentration of doxycycline used; "all" was obtained with 4 µM doxycycline, and "nothing" was obtained with 1-3 µM doxycycline. The rationale of this study was to apply known pharmacological tools against the blocker effect of 4 µM doxycycline, such as F55-6 (Casearia sylvestris), CaCl2 (or Ca2+), atropine, neostigmine, polyethylene glycol (PEG 400), and d-Tubocurarine. The evaluation of cholinesterase enzyme activity and the diaphragm muscle histology were performed, and protocols on the neuromuscular preparation submitted to indirect or direct stimuli were complementary. RESULTS: Doxycycline does not affect cholinesterase activity nor causes damage to skeletal muscle diaphragm; it acts on ryanodine receptor, sarcolemmal membrane, and neuronal sodium channel with a postjunctional consequence due to the decreased availability of muscle nicotinic acetylcholine receptors. CONCLUSION: In conclusion, in addition to the neuronal blocker effect of doxycycline, we showed that doxycycline acts on multiple targets. It is antagonized by F55-6, a neuronal Na+-channel agonist, and Ca2+, but not by neostigmine.

Biological Profile of Two Gentiana lutea L. Metabolites Using Computational Approaches and In Vitro Tests.

Natural products have been the main source of bioactive molecules for centuries. We tested the biological profile of two metabolites extracted from Gentiana lutea L. by means of computational techniques and in vitro assays. The two molecules (loganic acid and gentiopicroside) were tested in silico using an innovative technique, named Inverse Virtual Screening (IVS), to highlight putative partners among a panel of proteins involved in inflammation and cancer events. A positive binding with cyclooxygenase-2 (COX-2), alpha-1-antichymotrypsin, and alpha-1-acid glycoprotein emerged from the computational experiments and the outcomes from the promising interaction with COX-2 were confirmed by Western blot, highlighting the reliability of IVS in the field of the natural products.

Doxycycline alleviates acute traumatic brain injury by suppressing neuroinflammation and apoptosis in a mouse model.

Traumatic brain injury (TBI) is one of the significant causes of death among young people worldwide. Doxycycline (DOX), an antibiotic with anti-inflammatory effects, has not been used as a therapeutic agent to modify the inflammatory response after the traumatic brain injury. In this study, intraperitoneal administration of DOX reduced significantly the acute inflammatory markers like IL-6 and CD3, microglial migration to the damaged area marked with Iba-1, and neuronal apoptosis assessed with TUNEL assay at 72 h after the trauma. The low dose, 10 mg/kg of DOX had a dominant anti-inflammatory effect; while the high dose, 100 mg/kg of DOX, was more effective in decreasing neuronal apoptosis. In early hours after the head trauma, use of a low dose (10 mg/kg) of DOX for decreasing the acute form of inflammation followed by a high dose (100 mg/kg) for the anti-apoptotic effects particularly in severe head traumas, would be a promising approach to alleviate the brain injury.

Effect of Inducible BMP-7 Expression on the Osteogenic Differentiation of Human Dental Pulp Stem Cells.

BMP-7 has shown inductive potential for in vitro osteogenic differentiation of mesenchymal stem cells, which are an ideal resource for regenerative medicine. Externally applied, recombinant BMP-7 was able to induce the osteogenic differentiation of DPSCs but based on our previous results with BMP-2, we aimed to study the effect of the tetracyclin-inducible BMP-7 expression on these cells. DPSC, mock, and DPSC-BMP-7 cell lines were cultured in the presence or absence of doxycycline, then alkaline phosphatase (ALP) activity, mineralization, and mRNA levels of different osteogenic marker genes were measured. In the DPSC-BMP-7 cell line, the level of BMP-7 mRNA significantly increased in the media supplemented with doxycycline, however, the expression of Runx2 and noggin genes was upregulated only after 21 days of incubation in the osteogenic medium with doxycycline. Moreover, while the examination of ALP activity showed reduced activity in the control medium containing doxycycline, the accumulation of minerals remained unchanged in the cultures. We have found that the induced BMP-7 expression failed to induce osteogenic differentiation of DPSCs. We propose three different mechanisms that may worth investigating for the engineering of expression systems that can be used for the induction of differentiation of mesenchymal stem cells.

A secondary approach with conventional medicines and supplements to recuperate current COVID-19 status.

Novel coronavirus 2019 (COVID-19) is a zoonosis that revised the global economic and societal progress since early 2020. The SARS-CoV-2 has been recognized as the responsible pathogen for COVID-19 with high infection and mortality rate potential. It has spread in 192 countries and infected about 1.5% of the world population, and still, a proper therapeutic approach is not unveiled. COVID-19 indication starts with fever to shortness of breathing, leading to ICU admission with the ventilation support in severe conditions. Besides the symptomatic mainstay clinical therapeutic approach, only Remdesivir has been approved by the FDA. Several pharmaceutical companies claimed different vaccines with exceptionally high efficacy (90-95%) against COVID-19; how long these vaccines can protect and long-term safety with the new variants are unpredictable. After the worldwide spread of the COVID-19 pandemic, numerous clinical trials with different phases are being performed to find the most appropriate solution to this condition. Some of these trials with old FDA-approved drugs showed promising results. In this review, we have precisely compiled the efforts to curb the disease and discussed the clinical findings of Ivermectin, Doxycycline, Vitamin-D, Vitamin-C, Zinc, and cannabidiol and their combinations. Additionally, the correlation of these molecules on the prophylactic and diseased ministration against COVID-19 has been explored.

Biomaterial-Based Nanocomposite for Osteogenic Repurposing of Doxycycline.

BACKGROUND: Besides its antimicrobial action, doxycycline (DX) has lately been repurposed as a small-molecule drug for osteogenic purposes. However, osteogenic DX application is impeded by its dose-dependent cytotoxicity. Further, high-dose DX impairs cell differentiation and mineralization. PURPOSE: Integrating DX into a biomaterial-based delivery system that can control its release would not only ameliorate its cytotoxic actions but also augment its osteogenic activity. In this work, we managed to engineer novel composite DX-hydroxyapatite-polycaprolactone nanoparticles (DX/HAp/PCL) to modify DX osteogenic potential. METHODS: Employing a 23-factorial design, we first optimized HApN for surface-area attributes to maximize DX loading. Composite DX/HAp/PCL were then realized using a simple emulsification technique, characterized using various in vitro methods, and evaluated for in vitro osteogenesis. RESULTS: The developed HApN exhibited a favorable crystalline structure, Ca:P elemental ratio (1.67), mesoporous nature, and large surface area. DX/HAp/PCL achieved the highest reported entrapment efficiency (94.77%±1.23%) of DX in PCL-based particles. The developed composite system achieved controlled release of the water-soluble DX over 24 days. Moreover, the novel composite nanosystem managed to significantly ameliorate DX cytotoxicity on bone-marrow stem cells, as well as enhance its overall proliferation potential. Alkaline phosphatase and mineralization assays revealed superior osteodifferentiation potential of the composite system. Quantification of gene expression demonstrated that while DX solution was able to drive bone-marrow stem cells down the osteogenic lineage into immature osteoblasts after 10-day culture, the innovative composite system allowed maturation of osteodifferentiated cells. To the best of our knowledge, this is the first work to elaborate the impact of DX on the expression of osteogenic genes: RUNX2, OSP, and BSP. Further, the osteogenicity of a DX-loaded particulate-delivery system has not been previously investigated. CONCLUSION: Our findings indicate that repurposing low-dose DX in complementary biomaterial-based nanosystems can offer a prominent osteogenic candidate for bone-regeneration purposes.

Distinct alpha-Synuclein species induced by seeding are selectively cleared by the Lysosome or the Proteasome in neuronally differentiated SH-SY5Y cells.

A major pathological feature of Parkinson's disease (PD) is the aberrant accumulation of misfolded assemblies of alpha-synuclein (α-Syn). Protein clearance appears as a regulator of the 'α-Syn burden' underlying PD pathogenesis. The picture emerging is that a combination of pathways with complementary roles, including the Proteasome System and the Autophagy-Lysosome Pathway, contributes to the intracellular degradation of α-Syn. This study addresses the mechanisms governing the degradation of α-Syn species seeded by exogenous fibrils in neuronally differentiated SH-SY5Y neuroblastoma cells with inducible expression of α-Syn. Using human α-Syn recombinant fibrils (pre-formed fibrils, PFFs), seeding and aggregation of endogenous Proteinase K (PK)-resistant α-Syn species occurs within a time frame of 6 days, and is still prominent after 12 days of PFF addition. Clearance of α-Syn assemblies in this inducible model was enhanced after switching off α-Syn expression with doxycycline. Lysosomal inhibition led to accumulation of SDS-soluble α-Syn aggregates 6 days after PFF-addition or when switching off α-Syn expression. Additionally, the autophagic enhancer, rapamycin, induced the clearance of α-Syn aggregates 13 days post-PFF addition, indicating that autophagy is the major pathway for aggregated α-Syn clearance. SDS-soluble phosphorylated α-Syn at S129 was only apparent at 7 days of incubation with a higher amount of PFFs. Proteasomal inhibition resulted in further accumulation of SDS-soluble phosphorylated α-Syn at S129, with limited PK resistance. Our data suggest that in this inducible model autophagy is mainly responsible for the degradation of fibrillar α-Syn, whereas the proteasome system is responsible, at least in part, for the selective clearance of phosphorylated α-Syn oligomers.

Influence of doxycycline administration on rat embryonic development during organogenesis.

This experiment was performed to evaluate the possible embryotoxic and teratogenic effects of doxycycline during rat development. Twenty-one female rats were used and distributed into three groups equally (seven animals/group). The low dose group received doxycycline at a dose of 5 mg/kg bw/day orally from the 6th to 14th day of gestation. The high dose group received 10 mg/kg bw/day orally for the same period, the Control group received 1 mL distilled water orally for the same period. The dams were dissected on the 20th day of gestation and their fetuses were subjected to morphological, skeletal, and histological examination. Moreover, DNA damage analysis of liver cells of pregnant rats and their fetuses or fetal skull was assessed by Comet assay. The obtained results showed a significant decrease in fetal body weight, several morphological anomalies, and severe lack of ossification on the skull bones, phalanges, and sternum bone as well as shortness in the ulna and radius bones. Histological studies of pregnant rats revealed congestion and dilatation of the central vein of the liver lobules and fatty degeneration of the hepatocytes. In addition, 20 day-fetuses showed a marked increase of necrotic hepatocytes associated with an increased average of megakaryocytes and periportal leukocytic infiltration. Moreover, doxycycline induced a significant increase in the percentage of DNA damage and tail length of examined samples. Conclusively, doxycycline caused certain fetal abnormalities, so it is advisable to avoid using this drug during pregnancy.