Effect of Non-Surgical Periodontal Therapy on Clinical Parameters of Periodontitis, Oral Candida spp. Count and Lactoferrin and Histatin Expression in Saliva and Gingival Crevicular Fluid of HIV-Infected Patients.

BACKGROUND: Periodontitis (PDT) has gained attention in the literature with the increase in life expectancy of people living with HIV on combined antiretroviral therapy (cART). Thus, the search for inflammatory biomarkers could be useful to understand the pathophysiology of chronic oral diseases in the cART era. OBJECTIVE: The aim of this study was to evaluate the impact of non-surgical periodontal therapy (NSPT) on clinical parameters of PDT, Candida spp. count and expression of lactoferrin (LF) and histatin (HST) in saliva and gingival crevicular fluid (GCF) of HIV-infected patients. METHODS: Bleeding index (BI), probing depth (PD), clinical attachment level (CAL), colonyforming units (CFUs) of Candida spp, and LF and HST levels were measured in saliva and GCF of both groups at three different times: baseline (before treatment), and 30 and 90 days after the NSPT. Clinical, mycological and immunoenzymatic analyses were also performed. RESULTS: Twenty-two HIV-infected patients and 25 non-HIV-infected patients with PDT participated in the study. NSPT was effective in improving periodontal clinical parameters, including ≤ 4 sites with PD ≤ 5mm and BI ≤ 10%. Significant change in oral Candida spp. count occurred neither between the two groups nor after NSPT. And the salivary and GCF levels of LF and HST were not influenced by the NSPT; by contrast, except for salivary LF, HST and LF were shown to exhibit significantly higher levels in HIV-infected than in non-HIV-infected patients. CONCLUSION: NSPT was effective in improving periodontal disease parameters in HIV-infected patients, but did not affect LF and HST expression in saliva and GCF of HIV-infected patients.

Modulation of ocular surface desiccation in a murine model by histatin-5 application.

PURPOSE: To determine the efficacy of Histatin-5 (Hst5) peptide treatment in ameliorating dry eye disease (DED) phenotype in an in-vivo mouse model of scopolamine and desiccating stress (SDS) dry eye. METHODS: SDS was induced in female C57BL/6 mice by subcutaneous injections of scopolamine hydrobromide and exposure to low relative humidity and forced air draft for five days. Mouse eyes were topically treated with synthetic Hst5 peptide or balanced salt solution (BSS) twice a day for four days. Control mice were not exposed to SDS induction and did not receive any treatments. Oregon green dextran (OGD) staining was used to evaluate corneal permeability. Histologically, staining with periodic acid schiff (PAS), immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), were used to quantify the number of goblet cells (GC), CD45+ immune cells and apoptotic cells respectively in formalin fixed paraffin embedded (FFPE) mouse whole eye sections. RESULTS: Compared to treatment with BSS, Hst5 treatment significantly lowered corneal epithelial permeability, prevented conjunctival epithelial GC loss, decreased conjunctival CD45+ immune cell infiltration and reduced conjunctival epithelial cell apoptosis. CONCLUSIONS: Hst5 peptide topical treatment significantly improves the clinical parameters observed in SDS experimental model of DED. This is the first report of the efficacy of Hst5 treatment of dry eye phenotype, and potential novel treatment for DED in the clinic. Hst5 represents a new class of efficacious therapeutic agents, demonstrating pro-epithelial and anti-inflammatory activities at the ocular surface.

Targeting and synergistic action of an antifungal peptide in an antibiotic drug-delivery system.

Amphotericin B (AmB) has been widely used against fungal infections throughout almost the entire body, including the skin, nails, oral cavity, respiratory tract, and urinary tract. However, the development of AmB-loaded nanoparticles demands a novel technique that reduces its toxicity and other associated problems. Here, we developed a pH-responsive and redox-sensitive polymer-based AmB-delivery carrier system. In particular, this system was functionalized by conjugation with the antifungal peptide histatin 5, which acts both as a targeting ligand and a synergistic antifungal molecule against Candida albicans, a major systemic fungal pathogen of humans. Our results in vitro and in vivo suggest that this drug-delivery system may serve as a novel tool to facilitate the use of antimicrobial peptides as targeting ligands to pathogenic microbes, which would open new avenues of investigation in the field of drug delivery.

Development and In Vivo Evaluation of a Novel Histatin-5 Bioadhesive Hydrogel Formulation against Oral Candidiasis.

Oral candidiasis (OC), caused by the fungal pathogen Candida albicans, is the most common opportunistic infection in HIV(+) individuals and other immunocompromised populations. The dramatic increase in resistance to common antifungals has emphasized the importance of identifying unconventional therapeutic options. Antimicrobial peptides have emerged as promising candidates for therapeutic intervention due to their broad antimicrobial properties and lack of toxicity. Histatin-5 (Hst-5) specifically has exhibited potent anticandidal activity indicating its potential as an antifungal agent. To that end, the goal of this study was to design a biocompatible hydrogel delivery system for Hst-5 application. The bioadhesive hydroxypropyl methylcellulose (HPMC) hydrogel formulation was developed for topical oral application against OC. The new formulation was evaluated in vitro for gel viscosity, Hst-5 release rate from the gel, and killing potency and, more importantly, was tested in vivo in our mouse model of OC. The findings demonstrated a controlled sustained release of Hst-5 from the polymer and rapid killing ability. Based on viable C. albicans counts recovered from tongues of treated and untreated mice, three daily applications of the formulation beginning 1 day postinfection with C. albicans were effective in protection against development of OC. Interestingly, in some cases, Hst-5 was able to clear existing lesions as well as associated tissue inflammation. These findings were confirmed by histopathology analysis of tongue tissue. Coupled with the lack of toxicity as well as anti-inflammatory and wound-healing properties of Hst-5, the findings from this study support the progression and commercial feasibility of using this compound as a novel therapeutic agent.

[Alternatives for antibiotics - antimicrobial peptides and phages].

The constant increase in the number of bacteria resistant to antibiotics poses a substantial problem for the therapy of infectious diseases of different etiologies. The growing insensitivity of pathogens on the classical methods of treatment is associated mainly with multiple mechanisms of resistance created by bacteria. Furthermore, no proper antibiotic treatment causes the appearance of resistant strains even at the last line drugs. Therefore, there are still being sought alternatives in the treatment of difficult to eradicate pathogens. The antimicrobial peptides including cathelicidins, defensins, lysozyme, lactoferrin, histatins and bacteriocins arouse huge interest as potential therapeutics. They exhibit a broad spectrum of activity against many Gram-positive and Gram-negative bacteria, but also against fungi. Moreover, they are considered much safer than antibiotics, due to the fact that they are present in all eukaryotic organisms, in which they are an essential element of the immune system. In addition, phage therapy is also strongly recommended as alternative antibacterial approach. In this review we highlight the potential uses of antimicrobial peptides and bacteriophages in the treatment of infections of various etiologies.

Histatins: salivary peptides with copper(II)- and zinc(II)-binding motifs: perspectives for biomedical applications.

Natural antimicrobial peptides represent a primordial mechanism of immunity in both vertebrate and nonvertebrate organisms. Among them, histatins belong to a family of human salivary metal-binding peptides displaying potent antibacterial, antifungal and wound-healing activities. These properties, along with the ability of histatins to inhibit collagenases and cysteine proteases, have attracted much attention for their potential use in the treatment of several oral diseases. This review critically assesses the studies carried out to date in order to provide a comprehensive and systematic vision of the information accumulated so far. In particular, the relationship between metal-binding and peptide activity is extensively analysed. The review provides important clues for developing possible therapeutic applications of histatins and their synthetic peptide analogues by creating a set of necessary resource materials to support investigators and industries interested in exploiting their unique properties.

Alternative approaches to antifungal therapies.

The expansive use of immunosuppressive medications in fields such as transplantational medicine and oncology, the higher frequency of invasive procedures in an ageing population and the HIV/AIDS pandemic have increased the frequency of systemic fungal infections. At the same time, increased resistance of pathogenic fungi to classical antifungal agents has led to sustained research efforts targeting alternative antifungal strategies. In this review, we focus on two promising approaches: cationic peptides and the targeting of fungal virulence factors. Cationic peptides are small, predominantly positively charged protein fragments that exert direct and indirect antifungal activities, one mechanism of action being the permeabilization of the fungal membrane. They include lysozyme, defensins and cathelicidins as well as novel synthetic peptides. Among fungal virulence factors, the targeting of candidal secreted aspartic proteinases seems to be a particularly promising approach.

Evidence of intact histatins in the in vivo acquired enamel pellicle.

Understanding the composition and function of the acquired enamel pellicle (AEP) has been a major goal in oral biology. The aim of this study was to test the hypothesis that intact histatins are part of the in vivo AEP and that histatins after adsorption to HA have effects on in vitro enamel demineralization. This is the first study demonstrating the presence of intact histatins in vivo in the AEP. The in vitro experiments show that all naturally occurring histatins in the AEP have the potential to provide some level of protection against acid injury.

Antimicrobial peptides in oral cancer.

There is increasing evidence that antimicrobial peptides (AMPs) are differentially regulated in cancers such as oral squamous cell carcinomas (OSCC). Data showing that AMPs influence the growth of tumor cells, exhibit direct cytotoxic activity towards cancer cells, function as a tumor suppressor gene or activate the adaptive immunity suggest that a dysregulation of AMPs may be associated with the development of cancer. There is no question that, with increasing resistance against conventional chemotherapy, novel anticancer agents are needed. It is interesting to speculate that natural AMP or synthetic derivatives can be used to develop novel strategies to fight cancer diseases and may represent a novel family of anticancer agents. However, future research is needed to employ the role of AMPs in cancer and to investigate their role as potential anticancer drugs.