Prevention of recurrent respiratory infections : Inter-society Consensus.

Recurrent respiratory infections (RRIs) are a common clinical condition in children, in fact about 25% of children under 1 year and 6% of children during the first 6 years of life have RRIs. In most cases, infections occur with mild clinical manifestations and the frequency of episodes tends to decrease over time with a complete resolution by 12 years of age. However, RRIs significantly reduce child and family quality of life and lead to significant medical and social costs.Despite the importance of this condition, there is currently no agreed definition of the term RRIs in the literature, especially concerning the frequency and type of infectious episodes to be considered. The aim of this consensus document is to propose an updated definition and provide recommendations with the intent of guiding the physician in the complex process of diagnosis, management and prevention of RRIs.

Dietary and Protective Factors to Halt or Mitigate Progression of Autoimmunity, COVID-19 and Its Associated Metabolic Diseases.

COVID-19 is without any doubt the worst pandemic we have faced since the H1N1 virus outbreak. Even if vaccination against SARS-CoV-2 infection is becoming increasingly available, a more feasible approach for COVID-19 prevention and therapy is still needed. Evidence of a pathological link between metabolic diseases and severe forms of COVID-19 has stimulated critical reflection and new considerations. In particular, an abnormal immune response observed in certain patients with SARS-CoV-2 infection suggested possible common predisposing risk factors with autoimmune diseases such as Type 1 Diabetes (T1D). Correct supplementation with dietary factors may be key to preventing and counteracting both the underlying metabolic impairment and the complications of COVID-19. A set of agents may inhibit the cytokine storm and hypercoagulability that characterize severe COVID-19 infection: vitamin D3, omega-3 polyunsaturated fatty acids, polyphenols like pterostilbene, polydatin and honokiol, which can activate anti-inflammatory and antioxidant sirtuins pathways, quercetin, vitamin C, zinc, melatonin, lactoferrin and glutathione. These agents could be highly beneficial for subjects who have altered immune responses. In this review, we discuss the antiviral and metabolic effects of these dietary factors and propose their combination for potential applications in the prevention and treatment of COVID-19. Rigorous studies will be fundamental for validating preventive and therapeutic protocols that could be of assistance to mitigate disease progression following SARS-CoV-2 infection.

Experimental Data Based Machine Learning Classification Models with Predictive Ability to Select in Vitro Active Antiviral and Non-Toxic Essential Oils.

In the last decade essential oils have attracted scientists with a constant increase rate of more than 7% as witnessed by almost 5000 articles. Among the prominent studies essential oils are investigated as antibacterial agents alone or in combination with known drugs. Minor studies involved essential oil inspection as potential anticancer and antiviral natural remedies. In line with the authors previous reports the investigation of an in-house library of extracted essential oils as a potential blocker of HSV-1 infection is reported herein. A subset of essential oils was experimentally tested in an in vitro model of HSV-1 infection and the determined IC50s and CC50s values were used in conjunction with the results obtained by gas-chromatography/mass spectrometry chemical analysis to derive machine learning based classification models trained with the partial least square discriminant analysis algorithm. The internally validated models were thus applied on untested essential oils to assess their effective predictive ability in selecting both active and low toxic samples. Five essential oils were selected among a list of 52 and readily assayed for IC50 and CC50 determination. Interestingly, four out of the five selected samples, compared with the potencies of the training set, returned to be highly active and endowed with low toxicity. In particular, sample CJM1 from Calaminta nepeta was the most potent tested essential oil with the highest selectivity index (IC50 = 0.063 mg/mL, SI > 47.5). In conclusion, it was herein demonstrated how multidisciplinary applications involving machine learning could represent a valuable tool in predicting the bioactivity of complex mixtures and in the near future to enable the design of blended essential oil possibly endowed with higher potency and lower toxicity.

Antiviral and Antioxidant Activity of a Hydroalcoholic Extract from Humulus lupulus L.

A hydroalcoholic extract from female inflorescences of Humulus lupulus L. (HOP extract) was evaluated for its anti-influenza activity. The ability of the extract to interfere with different phases of viral replication was assessed, as well as its effect on the intracellular redox state, being unbalanced versus the oxidative state in infected cells. The radical scavenging power, inhibition of lipoperoxidation, and ferric reducing activity were assayed as antioxidant mechanisms. A phytochemical characterization of the extract was also performed. We found that HOP extract significantly inhibited replication of various viral strains, at different time from infection. Viral replication was partly inhibited when virus was incubated with extract before infection, suggesting a direct effect on the virions. Since HOP extract was able to restore the reducing conditions of infected cells, by increasing glutathione content, its antiviral activity might be also due to an interference with redox-sensitive pathways required for viral replication. Accordingly, the extract exerted radical scavenging and reducing effects and inhibited lipoperoxidation and the tBOOH-induced cytotoxicity. At phytochemical analysis, different phenolics were identified, which altogether might contribute to HOP antiviral effect. In conclusion, our results highlighted anti-influenza and antioxidant properties of HOP extract, which encourage further in vivo studies to evaluate its possible application.

A Polyphenol Rich Extract from Solanum melongena L. DR2 Peel Exhibits Antioxidant Properties and Anti-Herpes Simplex Virus Type 1 Activity In Vitro.

DR2B and DR2C extracts, obtained by ethanolic maceration of peel from commercially and physiologically ripe aubergine berries, were studied for the antioxidative cytoprotective properties and anti-HSV-1 activity, in line with the evidence that several antioxidants can impair viral replication by maintaining reducing conditions in host cells. The antioxidative cytoprotective effects against tBOOH-induced damage were assessed in Caco2 cells, while antiviral activity was studied in Vero cells; polyphenolic fingerprints were characterized by integrated phytochemical methods. Results highlighted different compositions of the extracts, with chlorogenic acid and delphinidin-3-rutinoside as the major constituents; other peculiar phytochemicals were also identified. Both samples reduced reactive oxygen species (ROS) production and exhibited scavenging and chelating properties. DR2C partly counteracted the tBOOH-induced cytotoxicity, with a remarkable lowering of lactate metabolism under both normoxia and hypoxia; interestingly, it increased intracellular GSH levels. Furthermore, DR2C inhibited the HSV-1 replication when added for 24 h after viral adsorption, as also confirmed by the reduction of many viral proteins' expression. Since DR2C was able to reduce NOX4 expression during HSV-1 infection, its antiviral activity may be correlated to its antioxidant properties. Although further studies are needed to better characterize DR2C activity, the results suggest this extract as a promising new anti-HSV-1 agent.

Historical review on thymosin α1 in oncology: preclinical and clinical experiences.

INTRODUCTION: Thymosin α1 (Tα1) is a naturally occurring polypeptide that regulates immune cell development and function, and is also capable of interacting with multiple target cells with relevant biological effects. The rationale of Tα1 use in cancer treatment stems from the consideration that tumor progression is favored by a failure of the immune response and in turn induces immune suppression. This paper will review the historical background of Tα1 use in oncology, aiming to highlight the importance of Tα1 as an immunotherapeutic tool to be used in combination with chemotherapy, a concept that is not yet fully established in clinic. AREAS COVERED: The efficacy and safety of combining Tα1 with chemotherapy and cytokines were first evaluated in murine tumor models, providing essential information about effects, mechanisms of action, doses and treatment protocols. The therapeutic potential of the chemo-immunotherapy protocol on metastatic melanoma and lung cancer has been confirmed in controlled clinical trials. Critical for the efficacy of the chemo-immunotherapy protocol is the dual action of Tα1 on immune effector and tumor cells. EXPERT OPINION: On the basis of the preclinical and clinical results available, the use of the chemo-immunotherapy protocol, in which the role of Tα1 is central, is strongly recommended.

Evaluation of anti-Candida activity of Vitis vinifera L. seed extracts obtained from wine and table cultivars.

For the first time, grape seed extracts (GSEs), obtained from wine and table cultivars of Vitis vinifera L., cultured in experimental fields of Lazio and Puglia regions of Italy and grown in different agronomic conditions, have been tested on 43 Candida species strains. We demonstrated a significant correlation between the content of the flavan-3-ols in GSEs extracts, with a polymerization degree ≥ 4, and anti-Candida activity. Moreover, we demonstrated that GSEs, obtained from plants cultured with reduced irrigation, showed a content of polymeric flavan-3-ols >250 mg/g with geometric mean MIC values between 5.7 and 20.2 mg/L against Candida albicans reference strains. GSE, showing 573 mg/g of polymeric flavan-3-ols, has been tested in an experimental murine model of vaginal candidiasis by using noninvasive in vivo imaging technique. The results pointed out a significant inhibition of Candida albicans load 5 days after challenge. These findings indicate that GSEs with high content of polymeric flavan-3-ols can be used in mucosal infection as vaginal candidiasis.

In vitro inhibition of herpes simplex virus type 1 replication by Mentha suaveolens essential oil and its main component piperitenone oxide.

Several essential oils exert in vitro activity against bacteria and viruses and, among these latter, herpes simplex virus type 1 (HSV-1) is known to develop resistance to commonly used antiviral agents. Thus, the effects of the essential oil derived from Mentha suaveolens (EOMS) and its active principle piperitenone oxide (PEO) were tested in in vitro experimental model of infection with HSV-1. The 50% inhibitory concentration (IC50) was determined at 5.1µg/ml and 1.4µg/ml for EOMS and PEO, respectively. Australian tea tree oil (TTO) was used as control, revealing an IC50 of 13.2µg/ml. Moreover, a synergistic action against HSV-1 was observed when each oil was added in combination with acyclovir. In order to find out the mechanism of action, EOMS, PEO and TTO were added to the cells at different times during the virus life-cycle. Results obtained by yield reduction assay indicated that the antiviral activity of both compounds was principally due to an effect after viral adsorption. Indeed, no reduction of virus yield was observed when cells were treated during viral adsorption or pre-treated before viral infection. In particular, PEO exerted a strong inhibitory effect by interfering with a late step of HSV-1 life-cycle. HSV-1 infection is known to induce a pro-oxidative state with depletion of the main intracellular antioxidant glutathione and this redox change in the cell is important for viral replication. Interestingly, the treatment with PEO corrected this deficit, thus suggesting that the compound could interfere with some redox-sensitive cellular pathways exploited for viral replication. Overall our data suggest that both EOMS and PEO could be considered good candidates for novel anti-HSV-1 strategies, and need further exploration to better characterize the targets underlying their inhibition.

Bioassay-guided fractionation of extracts from Hypericum perforatum in vitro roots treated with carboxymethylchitosans and determination of antifungal activity against human fungal pathogens.

The aim of this study was to individuate, by bioassay-guided fractionation, promising antifungal fractions and/or constituents from Hypericum perforatum subsp. angustifolium in vitro roots. Treatments with chitosan, O-carboxymethylchitosan (CMC) and its derivatives were used to improve xanthone production in the roots. The bioassay-guided fractionation of CMC-treated roots led to the individuation of an ethyl acetate fraction, containing the highest amount of xanthones (6.8%) and showing the best antifungal activity with minimal inhibitory concentration (MIC) values of 53.82, 14.18, and 36.52 µg/ml, against Candida spp., Cryptococcus neoformans and dermatophytes, respectively. From this fraction the prenylated xanthone, biyouxanthone D has been isolated and represented the 44.59% of all xanthones detected. For the first time in the present paper biyouxanthone D has been found in H. perforatum roots and tested against C. neoformans, dermatophytes, and Candida species. The xanthone showed the greatest antifungal activity against C. neoformans and dermatophytes, with MIC values of 20.16, 22.63 µg/ml. In conclusion, the results obtained in the present study demonstrated that CMC-treated Hpa in vitro root extracts represent a tool for the obtainment of promising candidates for further pharmacological and clinical studies.

A three-step culture system to increase the xanthone production and antifungal activity of Hypericum perforatum subsp. angustifolium in vitro roots.

Hypericum perforatum is a well-known medicinal plant. Among all secondary metabolites produced by this species, xanthones are very interesting for their antifungal activity. In the present study, with the aim to improve xanthone production and antifungal activity of H. perforatum subsp. angustifolium (sin. Fröhlich) Borkh in vitro roots, a new methodology consisting of a three-step culture system, has been developed. Regenerated roots of H. perforatum were cultured in a three-step culture system: in the first step, to increase biomass, the roots were cultured in half-strength liquid Murashige and Skoog (MS) medium supplemented with 1 mg L(-1) indole butyric acid (IBA) and 1.5% sucrose. In the second and third steps, to stimulate secondary metabolism, the roots were cultured with 1.1 mg L(-1) 2,4-dichlorophenoxyacetic acid (2,4-D), 0.215 mg L(-1) kinetin (KIN), and 0.186 mg L(-1) 1-naphthalenacetic acid (NAA). In the third step, some of the roots were treated with chitosan. Xanthone production increased 2.7 times following the three-step method. The mean minimal inhibitory concentration (MIC) values were of 36.9, 26.7, and 65 µg mL(-1), against Candida species, Cryptococcus neoformans and dermatophytes, respectively. A positive correlation between xanthone accumulation and antifungal activity has been shown.

Modulation of Th1/Th2 immune responses to HIV-1 Tat by new pro-GSH molecules.

We have previously demonstrated that in Ova-immunized mice the increase in intra-macrophage thiol pool induced by pro-GSH molecules modulates the Th1/Th2 balance in favour of a Th1-type immune response. We show now that the same molecules can support a Th1-type over Th2-type immunity against Tat, which is an early HIV-1 regulatory protein and a Th1 polarizing immunomodulator that is increasingly considered in new anti-HIV vaccination strategies. Our results indicate that Tat-immunized mice pre-treated with the C4 (n-butanoyl) derivative of reduced glutathione (GSH-C4) or a pro-drug of N-acetylcysteine (NAC) and beta-mercaptoethylamine (MEA) (I-152), have decreased levels of anti-Tat IgG1 as well as increased levels of anti-Tat IgG2a and IgG2b isotypes suggesting a Th1-type response. Moreover, Th1-(IFN-γ and IL-2) Ag-specific cellular responses were detected by ELISPOT assay in splenocytes of the same animals as well as an increase of IL-12 levels in the plasma. These findings suggest that the Th1 immune response to HIV-1 Tat could be further polarized by these molecules. These results together with those previously reported suggest that pro-GSH molecules could be used to modulate the immune response towards different antigens and may be further exploited for inducing specific Th1 immune responses against other HIV antigens as well as other intracellular pathogens in new Tat-based vaccination protocols.

Root cultures of Hypericum perforatum subsp. angustifolium elicited with chitosan and production of xanthone-rich extracts with antifungal activity.

Hypericum perforatum is a well-known medicinal plant which contains a wide variety of metabolites, including xanthones, which have a wide range of biological properties, including antifungal activity. In the present study, we evaluated the capability of roots regenerated from calli of H. perforatum subsp. angustifolium to produce xanthones. Root biomass was positively correlated with the indole-3-butyric acid concentration, whereas a concentration of 1 mg l(-1) was the most suitable for the development of roots. High auxin concentrations also inhibited xanthone accumulation. Xanthones were produced in large amounts, with a very stable trend throughout the culture period. When the roots were treated with chitosan, the xanthone content dramatically increased, peaking after 7 days. Chitosan also induced a release of these metabolites into the culture. The maximum accumulation (14.26 ± 0.62 mg g(-1) dry weight [DW]) and release (2.64 ± 0.13 mg g(-1) DW) of xanthones were recorded 7 days after treatment. The most represented xanthones were isolated, purified, and spectroscopically characterized. Antifungal activity of the total root extracts was tested against a broad panel of human fungal pathogen strains (30 Candida species, 12 Cryptococcus neoformans, and 16 dermatophytes); this activity significantly increased when using chitosan. Extracts obtained after 7 days of chitosan treatment showed high antifungal activity (mean minimum inhibitory concentration of 83.4, 39.1, and 114 µg ml(-1) against Candida spp., C. neoformans, and dermatophytes, respectively). Our results suggest that root cultures can be considered as a potential tool for large-scale production of extracts with stable quantities of xanthones.

Localisation of Bgl2p upon antifungal drug treatment in Candida albicans.

Several proteins are covalently bound to the cell wall glucan (glucan-associated proteins (GAPs)) in Candida albicans and different drugs may cause their modulation. Proteomic analysis is a suitable approach to study differential GAP patterns between control and drug-treated cells. Since antimycotics induce variation in GAP content, we investigated the effect of a sublethal dose of micafungin and observed a clear increase in Bgl2p, an enzyme with glucanosyltransferase activity, with respect to a general decrease in cell wall protein content. Immunoelectron microscopy using mouse antiserum confirmed this increase of Bgl2p on the outer cell wall but also revealed a dramatic increase in the immature Bgl2p isoform in the cytoplasm of drug-treated cells. Since this increased expression of Bgl2p is clearly dependent upon micafungin treatment, this enzyme appears to be one of the survival strategies of C. albicans and thus could be considered the molecular basis of antifungal resistance and also as a potential valuable candidate for future vaccine development.