Role of Vaginal Mucosa, Host Immunity and Microbiota in Vulvovaginal Candidiasis

Phytotherapy of Vulvovaginal Candidiasis: A Narrative Review

Vulvovaginal candidiasis (VVC) is a real gynecological problem among women of reproductive age from 15 to 49. A recent analysis showed that 75% of women will have an occurrence at least once per year, while 5% are observed to have recurrent vaginal mycosis-these patients may become unwell four or more times a year. This pathology is caused in 85-90% of cases by fungi of the Candida albicans species. It represents an intractable medical problem for female patients due to pain and pruritus. Due to the observation of an increasing number of strains resistant to standard preparations and an increase in the recurrence of this pathology when using local or oral preferential therapy, such as fluconazole, an analysis was launched to develop alternative methods of treating VVC using herbs such as dill, turmeric, and berberine. An in-depth analysis of databases that include scientific articles from recent years made it possible to draw satisfactory conclusions supporting the validity of herbal therapy for the pathology in question. Although phytotherapy has not yet been approved by the Food and Drug Administration, it appears to be a promising therapeutic solution for strains that are resistant to existing treatments. There is research currently undergoing aimed at comparing classical pharmacotherapy and herbal therapy in the treatment of vaginal candidiasis for the purpose of increasing medical competence and knowledge for the care of the health and long-term comfort of gynecological patients.

Deciphering the role of female reproductive tract microbiome in reproductive health: a review

Relevant studies increasingly indicate that female reproductive health is confronted with substantial challenges. Emerging research has revealed that the microbiome interacts with the anatomy, histology, and immunity of the female reproductive tract, which are the cornerstone of maintaining female reproductive health and preventing adverse pregnancy outcomes. Currently, the precise mechanisms underlying their interaction and impact on physiological functions of the reproductive tract remain elusive, constituting a prominent area of investigation within the field of female reproductive tract microecology. From this new perspective, we explore the mechanisms of interactions between the microbiome and the anatomy, histology, and immunity of the female reproductive tract, factors that affect the composition of the microbiome in the female reproductive tract, as well as personalized medicine approaches in managing female reproductive tract health based on the microbiome. This study highlights the pivotal role of the female reproductive tract microbiome in maintaining reproductive health and influencing the occurrence of reproductive tract diseases. These findings support the exploration of innovative approaches for the prevention, monitoring and treatment of female reproductive tract diseases based on the microbiome.

Bacterial Vaginosis and Vulvovaginal Candidiasis Pathophysiologic Interrelationship

Among the infectious causes of vulvovaginal symptoms, bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) dominate. Apart from infrequent mixed infections, both are considered independent and caused by unrelated pathogenic mechanisms. Clinical experience, however, is strongly suggestive that in some populations these infections are linked with recurrent BV (RBV) serving as the dominant etiopathogenic trigger for development of recurrent VVC (RVVC) with profound clinical and therapeutic consequences. The biologic basis for this critical interrelationship is discussed and suggests that as a consequence of BV dysbiosis, and not necessarily because of antibiotics prescribed, immune defenses are compromised, neutralizing vaginal yeast tolerance. The consequent BV-induced vaginal proinflammatory environment predisposes to mixed infection or consecutive episodes of post-treatment VVC. Recurrent BV and repeated antimicrobial drug exposure also predispose to acquired fluconazole resistance in C. albicans isolates, contributing to refractory vulvovaginal candidiasis.

Bioactive-Loaded Hydrogels Based on Bacterial Nanocellulose, Chitosan, and Poloxamer for Rebalancing Vaginal Microbiota

Biocompatible drug-delivery systems for soft tissue applications are of high interest for the medical and pharmaceutical fields. The subject of this research is the development of hydrogels loaded with bioactive compounds (inulin, thyme essential oil, hydro-glycero-alcoholic extract of Vitis vinifera, Opuntia ficus-indica powder, lactic acid, citric acid) in order to support the vaginal microbiota homeostasis. The nanofibrillar phyto-hydrogel systems developed using the biocompatible polymers chitosan (CS), never-dried bacterial nanocellulose (NDBNC), and Poloxamer 407 (PX) incorporated the water-soluble bioactive components in the NDBNC hydrophilic fraction and the hydrophobic components in the hydrophobic core of the PX fraction. Two NDBNC-PX hydrogels and one NDBNC-PX-CS hydrogel were structurally and physical-chemically characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and rheology. The hydrogels were also evaluated in terms of thermo-responsive properties, mucoadhesion, biocompatibility, and prebiotic and antimicrobial effects. The mucin binding efficiency of hydrogel base systems was determined by the periodic acid/Schiff base (PAS) assay. Biocompatibility of hydrogel systems was determined by the MTT test using mouse fibroblasts. The prebiotic activity was determined using the probiotic strains Limosilactobacillus reuteri and Lactiplantibacillus plantarum subsp. plantarum. Antimicrobial activity was also assessed using relevant microbial strains, respectively, E. coli and C. albicans. TEM evidenced PX micelles of around 20 nm on NDBNC nanofibrils. The FTIR and XRD analyses revealed that the binary hydrogels are dominated by PX signals, and that the ternary hydrogel is dominated by CS, with additional particular fingerprints for the biocompounds and the hydrogel interaction with mucin. Rheology evidenced the gel transition temperatures of 18-22 °C for the binary hydrogels with thixotropic behavior and, respectively, no gel transition, with rheopectic behavior for the ternary hydrogel. The adhesion energies of the binary and ternary hydrogels were evaluated to be around 1.2 J/m2 and 9.1 J/m2, respectively. The hydrogels exhibited a high degree of biocompatibility, with the potential to support cell proliferation and also to promote the growth of lactobacilli. The hydrogel systems also presented significant antimicrobial and antibiofilm activity.

Enhancing Immunity and Modulating Vaginal Microflora Against Candidal Vaginitis Through Nanoemulsion Supplemented with Porphyra Oligosaccharide as an Intravaginal Vaccine Adjuvant

Background

Intravaginal vaccination is an encouraging approach to prevent infectious vaginitis, with nanoemulsions showing effectiveness as mucosal adjuvants.

Purpose

This study aimed to formulate a nanoemulsion incorporating Porphyra oligosaccharide (PO@NE) and assess its effectiveness as a mucosal adjuvant in intravaginal vaccines against candidal vaginitis.

Materials and Methods

PO@NE was prepared, and the stability, immunomodulatory activity and cytotoxicity were screened in vitro. Further, the preventive effect of PO@NE as adjuvants for heat-killed Candida albicans (HK-CA) vaccines was explored in a murine model of candidal vaginitis, in comparison with those supplemented with polysaccharide (PP@NE). The mice were intravaginally vaccinated with 106 HK-CA cells, suspended in 1% NE without or with either PO or PP at a final concentration of 6.5 μg/mL, in a total volume of 20 μL. This vaccination was intravaginally administered once a week for 3 weeks. One week following the final vaccination, the mice underwent an intravaginal challenge with 107 C. albicans cells. One week after the challenge, the mice were euthanized to isolate serum, spleen, vaginal washes, and vaginal tissues for analysis.

Results

PP@NE and PO@NE, with diameters approximately around 100 nm, exhibited exceptional stability at 4°C and low cytotoxicity when used at a concentration of 1% (v/v). Intravaginal vaccination with HK-CA adjuvanted with PO@NE effectively protected against candidal vaginitis evidenced by less Candida hyphae colonization, milder mucosal damage and cell infiltration. Moreover, enhanced mucosal antibody production, induction of T helper (Th)1 and Th17-related immune responses, enlarged the population of CD8+ cells, and elevated vaginal microflora diversity were observed in vaccinated mice. Interestingly, the potency was rather attenuated when PO@NE was replaced with PP@NE.

Conclusion

These findings indicate PO@NE as a HK-CA vaccine adjuvant for candidal vaginitis prevention via enhancement of both cellular and humoral immunity and modulation of vaginal microflora, emphasizing further intravaginal vaccination development.

Preparation and evaluation of Cordyceps militaris polysaccharide- and sesame oil-loaded nanoemulsion for the treatment of candidal vaginitis in mice

BACKGROUND

Candida albicans is the most prevalent fungal pathogen, affecting over 75% of women who have experienced candidal vaginitis. Given the identification of drug-resistant C. albicans strains, there is an urgent need to develop therapeutic methods for treating vaginal Candida infection. Polysaccharide is the major bioactive component of Cordyceps militaris, known to modulate immune responses and alleviate inflammation. Sesame oil is known with anti-microbial and anti-inflammatory activities.

METHODS

C. militaris polysaccharide was prepared and formulated with sesame oil to prepare emulsion and nanoemulsion, which are ideal mucosal delivery systems for both hydrophobic and hydrophilic compounds concurrently. The physical property and storage stability of these formulations were illustrated, and their effects on ameliorating vaginitis were investigated in a murine model of vaginal Candida infection.

RESULTS

C. militaris polysaccharide-containing nanoemulsion showed smaller particle size, lower polydispersity index, higher zeta-potential and better stability than emulsion. Intravaginal administration of C. militaris polysaccharide-containing nanoemulsion significantly attenuated C. militaris colonization and vaginitis. Notably, these formulations exerted distinct effects on modulating cell infiltration and splenic cytokine production. Moreover, different profile of vaginal microflora was observed among the treatment groups, revealing the potential action mechanisms of these formulations to mitigate vaginal Candida infection.

CONCLUSION

C. militaris polysaccharide- and sesame oil-containing nanoemulsion is potential to be developed as intravaginal therapeutic strategy for C. albicans-induced vaginitis.

Efficacy and mechanism of Baicao Fuyanqing suppository on mixed vaginitis based on 16S rRNA and metabolomics

Background

Mixed vaginitis is the infection of the vagina by at least two different pathogens at the same time, both of which contribute to an abnormal vaginal environment leading to signs and symptoms. Baicao Fuyanqing suppository (BCFYQ) is a Miao ethnomedicine, used to treat various vaginitis. The aim of this study was to investigate the efficacy and possible mechanism of BCFYQ in the treatment of mixed vaginitis based on 16S rRNA high-throughput sequencing and metabonomics.

Methods

Escherichia coli and Candida albicans were used to establish mixed vaginitis model in SD rats. Three groups of low, medium and high doses (0.18/0.36/0.64 g.kg-1) were established, and administered vaginally once a day for 6 consecutive days. After the last administration, vaginal pH and IL-1β, IL-2, IL-13 and IgA levels were measured, and the vaginal tissue was examined pathologically. In addition, the vaginal flora was characterised by 16S rRNA, and endogenous metabolites in the vaginal tissue were detected by UHPLC-Q-Exactive MS.

Results

Compared with the model group, BCFYQ can reduce the vaginal pH of rats, make it close to the normal group and improve the damaged vaginal epithelial tissue. The results of ELISA showed that BCFYQ decreased the levels of IL-1 β and IL-2 and increased the levels of IL-13 and IgA (P<0.05). In addition, BCFYQ may increase the abundance of vaginal flora, especially Lactobacillus. The differential metabolite enrichment pathway suggests that the therapeutic mechanism of BCFYQ is mainly related to lipid metabolism and amino acid metabolism.

Conclusion

Our research shows that BCFYQ has a good therapeutic effect on mixed vaginitis. It repairs the damaged vaginal mucosa by regulating the vaginal flora and lipid metabolism disorders to improve the local immune function of the vagina and inhibit the growth and reproduction of pathogens.

Extract of Sophorae flavescentis radix-Cnidii fructus couplet medicines treats vulvovaginal candidiasis by affecting the vaginal mucosal barrier

Aim: This study investigated the inhibition of extract of Sophorae flavescentis radix-Cnidii fructus couplet medicines (ESCC) on Candida albicans (C. albicans) in vitro and the effect of ESCC on the vaginal mucosal barrier in vivo. Materials & methods: Susceptibility testing was performed with C. albicans SC5314. A vulvovaginal candidiasis mouse model was successfully established. The plate method, Gram staining, hematoxylin and eosin staining and ELISA were used to detect relevant inflammatory indexes: IFN-γ, IL-1 and TNF-α. Quantitative real-time PCR and western blot were used to detect mucosal immune-related factors: MUC1, MUC4, DEFB1 and DEFB2. Results: ESCC was able to inhibit the proliferative activity of C. albicans, and it affected inflammation-related factors and indicators of vaginal mucosal immunity. Conclusion: ESCC showed potential value in the treatment of vulvovaginal candidiasis.

The Interplay between Candida albicans, Vaginal Mucosa, Host Immunity and Resident Microbiota in Health and Disease: An Overview and Future Perspectives

Vulvovaginal candidiasis (VVC), which is primarily caused by Candida albicans, is an infection that affects up to 75% of all reproductive-age women worldwide. Recurrent VVC (RVVC) is defined as >3 episodes per year and affects nearly 8% of women globally. At mucosal sites of the vagina, a delicate and complex balance exists between Candida spp., host immunity and local microbial communities. In fact, both immune response and microbiota composition play a central role in counteracting overgrowth of the fungus and maintaining homeostasis in the host. If this balance is perturbed, the conditions may favor C. albicans overgrowth and the yeast-to-hyphal transition, predisposing the host to VVC. To date, the factors that affect the equilibrium between Candida spp. and the host and drive the transition from C. albicans commensalism to pathogenicity are not yet fully understood. Understanding the host- and fungus-related factors that drive VVC pathogenesis is of paramount importance for the development of adequate therapeutic interventions to combat this common genital infection. This review focuses on the latest advances in the pathogenic mechanisms implicated in the onset of VVC and also discusses novel potential strategies, with a special focus on the use of probiotics and vaginal microbiota transplantation in the treatment and/or prevention of recurrent VVC.

Alterations of Vaginal Microbiota and Chlamydia trachomatis as Crucial Co-Causative Factors in Cervical Cancer Genesis Procured by HPV

Chlamydia trachomatis and human papillomavirus (HPV) are the most common pathogens found in sexually transmitted infections (STIs), and both are known to increase the risk of cervical cancer (CC) and infertility. HPV is extremely common worldwide, and scientists use it to distinguish between low-risk and high-risk genotypes. In addition, HPV transmission can occur via simple contact in the genital area. From 50 to 80% of sexually active individuals become infected with both C. trachomatis and HPV viruses during their lifetime, and up to 50% become infected with an HPV oncogenic genotype. The natural history of this coinfection is strongly conditioned by the balance between the host microbiome and immune condition and the infecting agent. Though the infection often regresses, it tends to persist throughout adult life asymptomatically and silently. The partnership between HPV and C. trachomatis is basically due to their similarities: common transmission routes, reciprocal advantages, and the same risk factors. C. trachomatis is a Gram-negative bacteria, similar to HPV, and an intracellular bacterium, which shows a unique biphasic development that helps the latter continue its steady progression into the host throughout the entire life. Indeed, depending on the individual’s immune condition, the C. trachomatis infection tends to migrate toward the upper genital tract and spread to the uterus, and the fallopian tubes open up a pathway to HPV invasion. In addition, most HPV and C. trachomatis infections related to the female genital tract are facilitated by the decay of the first line of defense in the vaginal environment, which is constituted by a healthy vaginal microbiome that is characterized by a net equilibrium of all its components. Thus, the aim of this paper was to highlight the complexity and fragility of the vaginal microenvironment and accentuate the fundamental role of all elements and systems involved, including the Lactobacillus strains (Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus crispatus) and the immune–endocrine system, in preserving it from oncogenic mutation. Therefore, age, diet, and genetic predisposition together with an unspecific, persistent low-grade inflammatory state were found to be implicated in a high frequency and severity grade of disease, potentially resulting in pre-cancerous and cancerous cervical lesions.

The Role of Host and Fungal Factors in the Commensal-to-Pathogen Transition of Candida albicans

Abstract

Purpose of Review

The fungus Candida albicans has evolved to live in close association with warm-blooded hosts and is found frequently on mucosal surfaces of healthy humans. As an opportunistic pathogen, C. albicans can also cause mucosal and disseminated infections (candidiasis). This review describes the features that differentiate the fungus in the commensal versus pathogenic state and the main factors underlying C. albicans commensal-to-pathogen transition.

Recent Findings

Adhesion, invasion, and tissue damage are critical steps in the infection process. Especially invasion and damage require transcriptional and morphological changes that differentiate C. albicans in the pathogenic from the commensal state. While the commensal-to-pathogen transition has some conserved causes and features in the oral cavity, the female urogenital tract, and the gut, site-specific differences have been identified in recent years.

Summary

This review highlights how specific factors in the different mucosal niches affect development of candidiasis. Recent evidence suggests that colonization of the gut is not only a risk factor for systemic candidiasis but might also provide beneficial effects to the host.

Vulvovaginal candidiasis and vaginal microflora interaction: Microflora changes and probiotic therapy

Vaginal microbiome is mutually beneficial to the host and has a significant impact on health and disease. Candida species, including Candida albicans, are part of the mucosal flora of most healthy women. Under suitable conditions, they can live in the vulvovaginal mucosa, resulting in symptomatic vulvovaginal candidiasis (VVC). Based on the analysis of 16S ribosomal RNA gene sequences, great progress has been made in exploring the composition and structure of vaginal bacterial community. Moreover, researchers have conducted several studies on whether vaginal microbiome will change during VVC infection. In addition, it has been reported that vaginal colonization of probiotics in vaginal microorganisms, especially Lactobacillus, can effectively reduce the risk of VVC and treat VVC. This review aims to summarize the changes of vaginal microflora during VVC infection, and further point out the possibility of using lactic acid bacteria as probiotics to treat VVC, so as to reduce the adverse consequences of VVC infection and reduce the expensive treatment cost.

Lycopene, Mesoporous Silica Nanoparticles and Their Association: A Possible Alternative against Vulvovaginal Candidiasis?

Commonly found colonizing the human microbiota, Candida albicans is a microorganism known for its ability to cause infections, mainly in the vulvovaginal region known as vulvovaginal candidiasis (VVC). This pathology is, in fact, one of the main C. albicans clinical manifestations, changing from a colonizer to a pathogen. The increase in VVC cases and limited antifungal therapy make C. albicans an increasingly frequent risk in women's lives, especially in immunocompromised patients, pregnant women and the elderly. Therefore, it is necessary to develop new therapeutic options, especially those involving natural products associated with nanotechnology, such as lycopene and mesoporous silica nanoparticles. From this perspective, this study sought to assess whether lycopene, mesoporous silica nanoparticles and their combination would be an attractive product for the treatment of this serious disease through microbiological in vitro tests and acute toxicity tests in an alternative in vivo model of Galleria mellonella. Although they did not show desirable antifungal activity for VVC therapy, the present study strongly encourages the use of mesoporous silica nanoparticles impregnated with lycopene for the treatment of other human pathologies, since the products evaluated here did not show toxicity in the in vivo test performed, being therefore, a topic to be further explored.

Novel Antifungals for the Treatment of Vulvovaginal Candidiasis: Where Are We?

Vulvovaginal candidiasis (VVC) is a common health-related issue and the second most common cause of vaginitis. Previously, azole antifungals were the mainstay of VVC treatment. Additionally, boric acid and nystatin have been used topically for management of VVC. Despite being effective and well tolerated by most patients, the use of azoles may be limited in some cases. Currently, two new antifungal agents have received US Food and Drug Administration approval for use in the management of VVC. In this article, we briefly review treatment regimens used for the management of VVC over the past decade, the newly approved agents and their possible clinical application, and future treatment considerations.