The Role of Nutrition During the COVID-19 Pandemic: What We Know.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) (COVID-19) infection provokes serious clinical consequences, which in many situations need hospitalization of the patient in Intensive Care Unit. Additionally, SARS-COV-2 infection can indirectly cause deaths in aged individuals as well as in patients with co-morbidities. OBJECTIVE: To evaluate the effects of nutrition during the COVID-19 pandemic in both hospitalized patients and the general population. METHODS: Authors searched Medline (PubMed), Web of Science, EMBASE, Cochrane Library, Google, and Institutional websites for medical subheadings terms and free full text referred to "SARS-CoV-2", COVID-19", "nutrition", "immune system", before 31st July 2020. RESULTS: A total of 20 articles describing different nutritional interventions for patients with SARS-- CoV-2 infection focusing on the general population have been included. Of these, 6 studies are dealing with nutritional interventions for patients with SARS-CoV2 infection. The others are focalized on a potential beneficial effect exerted by a Mediterranean diet (MD), related to the supplementation of micronutrients and vitamins. CONCLUSION: A correct lifestyle, including the consumption of nutrients largely present in MD, may be beneficial for preventing or improving prognosis in the SARS-CoV-2 infection.

Taking Advantage of Plant Defense Mechanisms to Promote Human Health. Exploitation of Plant Natural Products for Preventing or Treating Human Disease: Second of Two Parts.

BACKGROUND: Plants have been regarded as essential source of food for human beings, as confirmed by archeological studies that have revealed the presence of proteins from cereals and legumes on old pottery. SPECIFIC AIMS: In this review, major health effects derived from the consumption of plant fibers, polyunsaturated fatty acids (PUFAs) and polyphenols, respectively, will be described with special emphasis on their mechanisms of action, both at cellular and molecular levels. Dietary Compounds: Fibers exhibit a prevalent prebiotic effect, acting on the intestinal microbiota with the production of protective metabolites, such as short chain fatty acids. Plant PUFAs include α-linolenic and stearidonic acids, which are the precursors of other two major PUFAs, namely, eicosapentaenoic and docosahexaenoic acids. Some clinical trials demonstrated the ability of PUFAs to lower the risk of coronary disease, while other trials did not confirm such a finding. Polyphenols are endowed with anti-oxidant and anti-inflammatory activity in view of their property to inhibit NF-κB activation, to induce the anti-inflammatory T regulatory cells and to normalize the intestinal microbiota. The beneficial effects of polyphenols on obesity/diabetes, allergic/autoimmune and inflammatory disease are elucidated. CONCLUSION: Plants are one of the major sources of healthy dietary products, whose exploitation may promote prevention of chronic disease.

Red Grape Polyphenol Oral Administration Improves Immune Response in Women Affected by Nickel-Mediated Allergic Contact Dermatitis.

BACKGROUND: Our previous findings demonstrated that in vitro supplementation of polyphenols, extracted from seeds of red grape (Nero di Troia cultivar), to peripheral lymphomonocytes from patients affected by allergic contact dermatitis (ACD) to nickel (Ni) could reduce the release of proinflammatory cytokines and nitric oxide (NO), while increasing the levels of interleukin (IL)-10, an anti-inflammatory cytokine. OBJECTIVE: To assess whether an intervention with oral administration of polyphenols leads to a reduction of peripheral biomarkers in ACD patients. METHODS: At T0, 25 patients affected by ACD to Ni were orally administered with 300 mg polyphenols prodie extracted from seeds of red grape (Nero di Troia cultivar) (NATUR-OX®) for 3 months (T1). The other 25 patients affected by ACD to Ni received placebo only for the same period of time. Serum biomarkers were analyzed at T0 and T1. In both groups, seven dropouts were recorded. RESULTS: At T1 in comparison to T0, in treated patients, values of interferon-γ, IL-4, IL-17, pentraxin 3 and NO decreased, while IL-10 levels increased when compared with T0 values. Conversely, in placebo- treated patients, no modifications of biomarkers were evaluated at T1. CONCLUSION: Present laboratory data rely on the anti-oxidant, anti-inflammatory and anti-allergic properties of polyphenols.

Platelets: Angels and Demons Dancing on the Immune Stage. Nutrition Conducts the Orchestra.

Platelets are cellular fragments derived from bone-marrow megacaryocytes and they are mostly involved in the haemostasis and coagulation. However, according to recent data, platelets are able to perform novel immune functions. In fact, they possess a receptorial armamentarium on their membrane for interacting with innate and adaptive immune cells. In addition, platelets also secrete granules which contain cytokines and chemokines for activating and recruiting even distant immune cells. The participation of platelets in inflammatory processes will also be discussed in view of their dual role in terms of triggering or resolving inflammation. Involvement of platelets in disease will be illustrated, pointing to their versatile function to either up- or down-regulate pathological mechanisms. Finally, despite the availability of some anti-platelet agents, such as aspirin, dietary manipulation of platelet function is currently investigated. In this regard, special emphasis will be placed on dietary omega-3 polyunsaturated fatty acids (PUFAs) and polyphenol effects on platelets. Platelets play a dual role in inflammatory-immune-mediated diseases either activating or deactivating immune cells. Diet based on substances, such as omega-3 PUFAs and polyphenols, may act as a modulator of platelet function, even if more clinical trials are needed to corroborate such a contention.

Taking Advantage of Plant Defense Mechanisms to Promote Human Health. The Plant Immune System. First of Two Parts.

Despite the evidence that plants do not possess sessile cells, they are able to mount a vigorous immune response against invaders or under stressful conditions. Plants are endowed with pattern recognition receptors (PPRs) which perceive damage-associated molecular patterns and microbe- associated molecular patterns or pathogen-associated molecular patterns (PAMPs), respectively. PPR activation leads to either the initiation of PAMP-triggered immunity (PTI) (early response) or the effector-triggered immunity (ETI). Both PTI and ETI contribute to plant systemic acquired resistance as an expression of immunological memory or trained immunity. PTI is initiated by activation of both receptor-like kinases and receptor-like proteins, while ETI depends on nucleotide- binding leucine-rich-repeat protein receptors for microbe recognition. Plant chloroplasts contribute to both PTI and ETI through the production of peptides, which act as hormones or phytocytokines. Salicylic acid, jasmonic acid and ethylene are the major compounds involved in plant defense. The interaction between plant receptors and/or their products and bacterial components will be discussed. Also, emphasis will be placed on plant microbiome for its contribution to plant immune response. Finally, the mutual interplay between insects and plants will also be illustrated. A better knowledge of plant immunity may pave the way for the exploitation of plant derivatives in the field of agriculture and medicine, as well.

Peripheral Immunosenescence and Central Neuroinflammation: A Dangerous Liaison - A Dietary Approach.

BACKGROUND & OBJECTIVES: In old people, both innate and adaptive immune responses are impaired, thus leading to a condition of systemic inflamm-ageing, even including the involvement of the central nervous system (CNS). AIMS: Here, main mechanisms of the immune ageing and neuro-inflammation will be discussed along with the dietary approaches for the modulation of age related diseases. DISCUSSION: Neuroinflammation is caused by the passage of inflammatory mediators through the brain blood barrier to CNS. Then, in the brain, antigenic stimulation of microglia and/or its activation by peripheral cytokines lead to a robust production of free radicals with another wave of proinflammatory cytokines which, in turn, causes massive neuronal damage. Also, infiltrating T cells [T helper (h) and T cytotoxic cells] contribute to neuronal damage. Additionally, a peripheral imbalance between inflammatory Th17 cells and anti-inflammatory T regulatory cells seems to be prevalent in the aged brain, thus leading to a proinflammatory profile. Alzheimer's disease, Parkinson's disease and multiple sclerosis will be described as typical neurodegenerative diseases. Finally, modulation of the immune response thanks to the anti-oxidant and anti-inflammatory effects exerted by dietary products and nutraceuticals in ageing will be discussed. Special emphasis will be placed on polyunsaturated fatty acids, polyphenols, micronutrients and pre-probiotics and synbiotics. CONCLUSION: Ageing is characterized by an imbalance subversion of the immune system with a condition of inflamm-ageing. Neuroinflammation and neurodegenerative diseases seem to be a central manifestation of a peripheral perturbation of the immune machinery. Dietary products and nutraceuticals may lead to a down-regulation of the oxidative and pro-inflammatory profile in ageing.

Eosinophils, a Jack of All Trades in Immunity: Therapeutic Approaches for Correcting Their Functional Disorders.

BACKGROUND AND OBJECTIVE: Eosinophils are primitive myeloid cells derived from bonemarrow precursors and require the intervention of interleukin (IL)-5 for their survival and persistence in blood and tissues. Under steady-state conditions, they contribute to immune regulation and homeostasis. Under pathological circumstances, eosinophils are involved in host protection against parasites and participate in allergy and inflammation. DISCUSSION: Mostly, in asthma, eosinophils provoke airway damage via the release of granule contents and IL-13 with mucus hypersecretion and differentiation of goblet cells. Then, tissue remodeling follows with the secretion of transforming growth factor-ß. Eosinophils are able to kill helminth larvae acting as antigen-presenting cells with the involvement of T helper (h)-2 cells and subsequent antibody response. However, they also exert pro-worm activity with the production of suppressive cytokine (IL- 10 and IL-4) and inhibition of nitric oxide. Eosinophils may play a pathogenic role in the course of chronic and autoimmune disease, e.g., inflammatory bowel disease and eosinophilic gastroenteritis, regulating Th2 responses and promoting a profibrotic effect. In atopic dermatitis, eosinophils are commonly detected and may be associated with disease severity. In cutaneous spontaneous urticaria, eosinophils participate in the formation of wheals, tissue remodeling and modifications of vascular permeability. With regard to tumor growth, it seems that IgE can exert anti-neoplastic surveillance via mast cell and eosinophil-mediated cytotoxicity, the so-called allergo-oncology. From a therapeutic point of view, monoclonal antibodies directed against IL-5 or the IL-5 receptors have been shown to be very effective in patients with severe asthma. Finally, as an alternative treatment, polyphenols for their anti-inflammatory and anti-allergic activities seem to be effective in reducing serum IgE and eosinophil count in bronchoalveolar lavage in murine asthma. CONCLUSION: Eosinophils are cells endowed with multiple functions and their modulation with monoclonal antibodies and nutraceuticals may be effective in the treatment of chronic disease.

Mast Cells as a Double-Edged Sword in Immunity: Their Function in Health and Disease. First of Two Parts.

Mast cells (MCs) have recently been re-interpreted in the context of the immune scenario in the sense that their pro-allergic role is no longer exclusive. In fact, MCs even in steady state conditions maintain homeostatic functions, producing mediators and intensively cross-talking with other immune cells. Here, emphasis will be placed on the array of receptors expressed by MCs and the variety of cytokines they produce. Then, the bulk of data discussed will provide readers with a wealth of information on the dual ability of MCs not only to defend but also to offend the host. This double attitude of MCs relies on many variables, such as their subsets, tissues of residency and type of stimuli ranging from microbes to allergens and food antigens. Finally, the relationship between MCs with basophils and eosinophils will be discussed.

Mast Cells as a Double Edged Sword in Immunity: Disorders of Mast Cell Activation and Therapeutic Management. Second of Two Parts.

Mast cells (MCs) bear many receptors that allow them to respond to a variety of exogenous and endogenous stimuli. However, MC function is dual since they can initiate pathological events or protect the host against infectious challenges. The role of MCs in disease will be analyzed in a broad sense, describing cellular and molecular mechanisms related to their involvement in auto-inflammatory diseases, asthma, autoimmune diseases and cancer. On the other hand, their protective role in the course of bacterial, fungal and parasitic infections will also be illustrated. As far as treatment of MC-derived diseases is concerned, allergen immunotherapy as well as other attempts to reduce MC-activation will be outlined according to the recent data. Finally, in agreement with current literature and our own data polyphenols have been demonstrated to attenuate type I allergic reactions and contact dermatitis in response to nickel. The use of polyphenols in these diseases will be discussed also in view of MC involvement.

Recent Advances on the Anti-Inflammatory and Antioxidant Properties of Red Grape Polyphenols: In Vitro and In Vivo Studies.

In this review, special emphasis will be placed on red grape polyphenols for their antioxidant and anti-inflammatory activities. Therefore, their capacity to inhibit major pathways responsible for activation of oxidative systems and expression and release of proinflammatory cytokines and chemokines will be discussed. Furthermore, regulation of immune cells by polyphenols will be illustrated with special reference to the activation of T regulatory cells which support a tolerogenic pathway at intestinal level. Additionally, the effects of red grape polyphenols will be analyzed in obesity, as a low-grade systemic inflammation. Also, possible modifications of inflammatory bowel disease biomarkers and clinical course have been studied upon polyphenol administration, either in animal models or in clinical trials. Moreover, the ability of polyphenols to cross the blood-brain barrier has been exploited to investigate their neuroprotective properties. In cancer, polyphenols seem to exert several beneficial effects, even if conflicting data are reported about their influence on T regulatory cells. Finally, the effects of polyphenols have been evaluated in experimental models of allergy and autoimmune diseases. Conclusively, red grape polyphenols are endowed with a great antioxidant and anti-inflammatory potential but some issues, such as polyphenol bioavailability, activity of metabolites, and interaction with microbiota, deserve deeper studies.

Effects of Polyphenol Administration to European Farmed Sea Bass (Dicentrharcus labrax L.): Special Focus on Hepatopancreas Morphology.

BACKGROUND AND OBJECTIVE: Hepatopancreas is an accessory organ associated with the liver in some fish, even including sea bass (Dicentrharcus labrax L.). Hepatopancreas contains an exocrine portion but until now its function has poorly been investigated. METHODS: Here, European farmed sea bass have been treated with a feed enriched in polyphenols extracted from seeds of red grape (Nero di Troia cultivar) at two different doses (100 and 200 mg/kg, respectively) from day 273 to day 323. In fish samples, hepatopancreas area sizes have been measured to evaluate the effects of this dietary regimen on its morphology. RESULTS: Quite interestingly, in treated fish area sizes of hepatopancreas were higher than those detected in untreated fish. Two hundred mg dose of polyphenols was more effective than that of 100 mg/kg polyphenols. Finally, hepatic polyphenol concentration was diminished in fish receiving 100 mg dose polyphenols and normalized with 200 mg dose in comparison to untreated fish. This evidence suggests the utilization of polyphenols for liver function, even including hepatopancreas development. CONCLUSION: Our data suggest an expansion of hepatopancreas induced by polyphenol administration that is also associated with less mortality in farmed fish.

Olive Leaf Extracts Act as Modulators of the Human Immune Response.

BACKGROUND: Olive tree leaves have been used in the Mediterranean area as traditional medicine in virtue of their healthy effects. Olive leaf extracts (OLEs) contain higher amounts of polyphenols than those detected in the extra virgin olive oil and fruit. Several lines of evidence support the cardioprotective, anti-oxidant and anti-inflammatory activities exerted by OLEs. METHODS: Peripheral blood mononuclear cells from twenty-five healthy donors were cultured in the presence of 3 µg of two OLE extracts, extract A (resuspended in water) and extract B (resuspended in 70% ethanol). After harvesting, cell pellets were used for cytofluorimetric phenotyping, while supernatants were assayed for cytokine release by means of ELISA. Furthermore, in the same supernatants nitric oxide (NO) content was determined. RESULTS: Both extracts, but especially extract A, increased absolute numbers of CD8+ and natural killer (NK) cells. In addition, an increased production of interferon (IFN)-γ by both extracts as an expression of T helper (h)1 activation was observed. Finally, both extracts enhanced NO release. CONCLUSION: OLEs, and mostly extract A, are able to in vitro modify healthy human immune response by increasing IFN-γ production which seems to be associated to the higher absolute numbers of CD8+ and NK cells and this may suggest a reinforcement of the anti-tumor activity. Furthermore, increased levels of NO may indicate the potential cardioprotective effects exerted by OLEs in virtue of their vasodilation dependent activity. Finally, OLEs are able to maintain the equilibrium between T regulatory cells and Th17 cells as evidenced by unmodified levels of interleukin (IL)-IL-10 and IL-17, respectively. In the light of these results, OLEs are potential therapeutic compounds for the treatment of chronic inflammatory disease, also preventing cardiovascular event outcome.

In vitro Effects of Polyphenols on the Peripheral Immune Responses in Nickel-sensitized Patients.

BACKGROUND: Nickel (Ni) is a metal largely present in the environment and prolonged exposure to it may lead to multiple pathological conditions in human subjects. Among these, the most frequent is allergic contact dermatitis. METHODS: Peripheral blood mononuclear cells isolated from 25 patients with Ni-dependent contact dermatitis were evaluated in terms of cytokine release and nitric oxide (NO) production in the presence or absence of two doses (3 and 5 µg, respectively) of polyphenols. RESULTS: Polyphenols were able to reduce the increased release of interferon-γ and interleukin (IL)-4, while maintaining the equilibrium between IL-10 and IL-17. At the same time, exaggerated release of NO was reduced by polyphenol supplementation. CONCLUSION: In view of their anti-inflammatory activities, polyphenols may represent a potential therapeutic tool to treat Ni-sensitized patients.

Corrigendum to "Immune Profile of Obese People and In Vitro Effects of Red Grape Polyphenols on Peripheral Blood Mononuclear Cells".

[This corrects the article DOI: 10.1155/2017/9210862.].

In Vitro Effects of Nickel on Healthy Non-Allergic Peripheral Blood Mononuclear Cells. The Role of Red Grape Polyphenols.

BACKGROUND: Nickel (Ni) is widely distributed in the environment and continuous exposure to this metal may lead to pathological manifestations, such as the human allergic contact dermatitis. METHODS: The in vitro effects of Ni on human healthy non allergic peripheral blood mononuclear cells (PBMCs) in the absence or presence of red grape polyphenols have been evaluated. In the culture supernatants, levels of cytokines have been determined by ELISA, while nitric oxide (NO) concentration has been evaluated by a colorimetric procedure. RESULTS: Ni per se did not affect release of interferon-γ, interleukin (IL)-4 and IL-10. Instead, this metal dramatically reduced production of IL-17 which was restored by the supplementation of polyphenols. Finally, while Ni significantly increased generation of NO, polyphenols reduced production of this compound. CONCLUSION: Taken together, all these data may indicate a preventative role of polyphenols against Ni exposure in non allergic to Ni individuals, also confirming the immunomodulating role of these natural products. The interaction Ni/polyphenols/lipopolysaccharides will also be discussed.

Immune Profile of Obese People and In Vitro Effects of Red Grape Polyphenols on Peripheral Blood Mononuclear Cells.

The in vitro ability of polyphenols, extracted from red grape, to modulate peripheral blood mononuclear cell responses has been evaluated in 20 obese (Ob) people. With regard to cytokine release in response to phorbol myristate acetate (PMA), levels of interleukin-2 (IL-2), interferon-γ (IFN-γ), IL-4, IL-10, and IL-17 were higher in the Ob than in healthy (H) subjects. Vice versa, IL-21 concentrations were detected only in H people but they were undetectable in the Ob counterpart. In general terms, levels of IL-1ß, IL-6, IL-8, and tumor necrosis factor-α were higher in Ob people when compared to H controls. On the other hand, polyphenols did not modify IFN-γ, IL-4, and IL-17 levels. However, an increase in IL-2 was observed in H individuals, whereas its levels were decreased in the Ob counterpart. Polyphenols significantly increased IL-10 release from H donors, whereas a trend to increase was observed in Ob people. In addition, polyphenols were able to significantly increase levels of H IL-21, while this was not the case in Ob people. Since IL-21 is an inducer of Th17 cells, it is likely that polyphenols may suppress the sources of this cytokine via production of IL-10. Accordingly, polyphenols decreased IL-1ß and IL-6 release in comparison to H controls.