Medication association and immunomodulation: An approach in fungal diseases and in particular in the treatment of paracoccidioidomycosis

Low-level LASER therapy accelerates fungal lesions cicatrization by increasing the production of Th1 and Th2 cytokines

Paracoccidioidomycosis (PCM) is a systemic mycosis with serious clinical consequences in which the use of antifungal drugs requires long-term treatment. Therefore, we studied the effect of low-level LASER therapy (LLLT) to evaluate its prospects as a complementary treatment for PCM and improve the clinical response to the disease.

OBJECTIVES

Our study focused on the resolution of lesions caused by fungal infection using a subcutaneous air pouch model of infection.

METHODS

We evaluated cell profile and cytokines, fungi viability, and the presence of fibroblasts and fibrocytes at the site of infection. Inoculation of P. brasiliensis (Pb) was performed using a subcutaneous air pouch model and the LLLT irradiation was performed on alternate days on the rear paws of mice for 10 days, after which the cells from the air pouch were collected and analyzed.

RESULTS

In animals irradiated with LLLT, the influx of cells to the air pouch was reduced, but they were more activated and produced pro-inflammatory (IL-12, IL-17 and TNF-α) and neutrophil (PMN) activating cytokines (IL-8, GM-CSF and γ-IFN). A better resolution of the infection, evidenced by the reduction in the number of viable fungi with preserved morphology in the air pouch, and an increase in the number of fibrocytes, indicating a healing profile were also observed.

CONCLUSION

LLLT decreased the influx of PMN, but those presents were highly activated, with increased fungicidal activity. LLLT irradiation also resulted in earlier cicatrization at the site of infection, leading to a better outcome of the infection. These data are favorable to the use of LLLT as a complementary therapy in PCM.

The Relationship between Diet, Gut Mycobiome, and Functional Gastrointestinal Disorders: Evidence, Doubts, and Prospects

Gut fungi are important parts of intestinal microbes. Dietary ingredients have the potential to regulate the structure of gut fungi in different directions and modulate mycobiome composition by changing dietary patterns, which have been applied to neurological disorders. Emerging pieces of evidence have revealed the regulatory functions of gut mycobiome in gastrointestinal diseases, but the relationships between gut fungi and functional gastrointestinal disorders (FGIDs) are ignored in the past. This review discusses the impact of dietary nutrients and patterns on mycobiome, and the possible ways in which gut fungi are involved in the pathogenesis of FGIDs. Besides affecting host immunity, intestinal fungi can be involved in the pathogenesis of FGIDs by endosymbiosis or bidirectional regulation with gut bacteria as well. In addition, the Mediterranean diet may be the most appropriate dietary pattern for subjects with FGIDs. A full understanding of these associations may have important implications for the pathogenesis and treatment of FGIDs.

Itraconazole and neutrophil interactions in the immune-inflammatory response of paracoccidioidomycosis using a murine air pouch infection model

Paracoccidioidomycosis (PCM) caused by Paracoccidioides brasiliensis (Pb), is a severe mycosis, prevalent in tropical countries. The presence of polymorphonuclear neutrophils (PMN) in lesions is conspicuous, indicating their central role in innate immunity through the direct killing of Pb and the production of cytokines that activate acquired immunity in the presence of itraconazole (Itra). The toxicity and direct antifungal activity of Itra on Pb in splenocyte co-cultures were evaluated in vitro. Itra showed no toxic effect but marked antifungal activity against Pb. Purified PMN were obtained by the subcutaneous (SC) injection of Pb into mice. Results showed the effect of Itra on the size of the air pouch produced, the cellular population that migrated to the infection site, protein, and mitochondrial metabolism patterns, production of ROS an NO, and the number of cytokines synthesized. Lower doses (3 and 10 mg/kg) of Itra did not affect the cellular profile but led to a lower influx of viable more active PMN, and increased production of ROS and proteins. At a dose of 50 mg/kg the PMN profile remained unchanged along with all other parameters analyzed remained unaltered. Decreases in most cytokine levels were inversely proportional to the Itra concentration. Lower Itra concentrations may elicit activation of the immune response because the combined effects of therapy and immune response are needed, while the higher dose does not require it. Itra also promotes the activation of the cytokines which elicit PMN activation and consequently the resolution of Pb18 infection in the air pouch.

Could the Lung Be a Gateway for Amphotericin B to Attack the Army of Fungi?

Fungal diseases are a significant cause of morbidity and mortality worldwide, primarily affecting immunocompromised patients. Aspergillus, Pneumocystis, and Cryptococcus are opportunistic fungi and may cause severe lung disease. They can develop mechanisms to evade the host immune system and colonize or cause lung disease. Current fungal infection treatments constitute a few classes of antifungal drugs with significant fungi resistance development. Amphotericin B (AmB) has a broad-spectrum antifungal effect with a low incidence of resistance. However, AmB is a highly lipophilic antifungal with low solubility and permeability and is unstable in light, heat, and oxygen. Due to the difficulty of achieving adequate concentrations of AmB in the lung by intravenous administration and seeking to minimize adverse effects, nebulized AmB has been used. The pulmonary pathway has advantages such as its rapid onset of action, low metabolic activity at the site of action, ability to avoid first-pass hepatic metabolism, lower risk of adverse effects, and thin thickness of the alveolar epithelium. This paper presented different strategies for pulmonary AmB delivery, detailing the potential of nanoformulation and hoping to foster research in the field. Our finds indicate that despite an optimistic scenario for the pulmonary formulation of AmB based on the encouraging results discussed here, there is still no product registration on the FDA nor any clinical trial undergoing ClinicalTrial.gov.

Brazilian Red Propolis shows antifungal and immunomodulatory activities against Paracoccidioides brasiliensis

ETHNOPHARMACOLOGICAL RELEVANCE

Paracoccidioidomycosis (PCM) is a systemic mycosis with high prevalence in South America and especially in Brazil with severe clinical consequences that need broadened therapeutic options. Propolis is a natural resin from bees used in folk medicine for centuries with the first report in the ancient history of Egypt by Eberly papyrus, in Middle-Ages used to wash the newborn's umbilical cord and World War II as antiseptic or antibiotics. Nowadays it is a natural product worldwide consumed as food and traditionally used for oral and systemic diseases as an anti-inflammatory, antimicrobial, antifungal, and other diseases. Brazilian red propolis (BRP) is a new type of propolis with a distinguished chemical profile and biological activities from propolis (green) with pharmacological properties such as antimicrobial, anti-inflammatory, antioxidant, and others.

AIM OF STUDY

Thus, the main purpose of this study was to investigate the direct in vitro and ex vivo effect of BRP on Paracoccidioides brasiliensis.

MATERIAL AND METHODS

Antifungal activity of different concentrations of BRP on a virulent P. brasiliensis isolate (Pb18) was evaluated using the microdilution technique. Also, mice splenic cells co-cultured with Pb18 were treated with BRP at different times and concentrations (only Pb18 = negative control). Mice were inoculated with Pb18 and treated with different concentrations of BRP (50-500 mg/mL) in a subcutaneous air pouch. In this later experimental model, macroscopic characteristics of the air pouch were evaluated, and cellular exudate was collected and analyzed for cellular composition, mitochondrial activity, total protein reactive oxygen specimens (ROS), and nitric oxide production, as well as the number of viable fungal cells.

RESULTS

The in vitro experiments showed remarkable direct antifungal activity of BRP, mainly with the highest concentration employed (500 mg/mL), reducing the number of viable cells to 10% of the original inoculum after 72 h incubation. The splenocytes co-cultivation assays showed that BRP had no cytotoxic effect on these cells, on the contrary, exerted a stimulatory effect. This stimulation was also observed on the PMNs at the air pouch, as verified by production of ROS and total proteins and mitochondrial activity. This activation resulted in enhanced fungicidal activity, mainly with the 500 mg/mL concentration of BRP. An anti-inflammatory effect was also detected, as verified by the smaller volume of the BRP-treated air pouch as well as by an earlier shift from neutrophils to mononuclear cells present in the infection site.

CONCLUSION

Our results strongly suggest, for the first time in the literature, that Brazilian Red propolis has four protective mechanisms in experimental paracoccidioidomycosis: activating neutrophils, exerting a direct antifungal effect, preventing fungal dissemination, and controlling excessive inflammation process.

Paracoccidioidomycosis Protective Immunity

Protective immunity against Paracoccidioides consists of a stepwise activation of numerous effector mechanisms that comprise many cellular and soluble components. At the initial phase of non-specific innate immunity, resistance against Paracoccidioides comes from phagocytic polymorphonuclear neutrophils, natural killer (NK) cells and monocytes, supplemented by soluble factors such as cytokines and complement system components. Invariant receptors (Toll-like receptors (TLRs), Dectins) which are present in cells of the immune system, detect patterns present in Paracoccidioides (but not in the host) informing the hosts cells that there is an infection in progress, and that the acquired immunity must be activated. The role of components involved in the innate immunity of paracoccidioidomycosis is herein presented. Humoral immunity, represented by specific antibodies which control the fungi in the blood and body fluids, and its role in paracoccidioidomycosis (which was previously considered controversial) is also discussed. The protective mechanisms (involving various components) of cellular immunity are also discussed, covering topics such as: lysis by activated macrophages and cytotoxic T lymphocytes, the participation of lytic products, and the role of cytokines secreted by T helper lymphocytes in increasing the efficiency of Paracoccidioides, lysis.

What is the elephant in the room when considering new therapies for fungal diseases?

The global scenario of antimicrobial resistance is alarming, and the development of new drugs has not appeared to make substantial progress. The constraints on drug discovery are due to difficulties in finding new targets for therapy, the high cost of development, and the mismatch between the time of drug introduction in a clinic and microorganism adaptation to a drug. Policies to address neglected diseases miss the broad spectrum of mycosis. Society is not aware of the actual threat represented by fungi to human health, food security, and biodiversity. The evidence discussed here is critical for warning governments to establish effective surveillance policies for fungi.HIGHLIGHTSFungal diseases are ignored even among neglected disease classifications.There are few options to treat mycoses, which is an increasing concern regarding fungal resistance to drugs, as evidenced by the spread of Candida auris.Fungal diseases represent a real threat to human health and food security.Investment in research to investigate the potential of repurposing drugs already in use could obtain results in the short term.