Statin therapy and decreased incidence of positive Candida cultures among patients with type 2 diabetes mellitus undergoing gastrointestinal surgery

Spectrum of activity and mechanisms of azole-bisphosphonate synergy in pathogenic Candida

Candidiasis places a significant burden on human health and can range from common superficial vulvovaginal and oral infections to invasive diseases with high mortality. The most common Candida species implicated in human disease is Candida albicans, but other species like Candida glabrata are emerging. The use of azole antifungals for treatment is limited by increasing rates of resistance. This study explores repositioning bisphosphonates, which are traditionally used for osteoporosis, as antifungal synergists that can improve and revitalize the use of azoles. Risedronate, alendronate, and zoledronate (ZOL) were tested against isolates from six different species of Candida, and ZOL produced moderate antifungal activity and strong synergy with azoles like fluconazole (FLC), particularly in C. glabrata. FLC:ZOL combinations had increased fungicidal and antibiofilm activity compared to either drug alone, and the combination prevented the development of antifungal resistance. Mechanistic investigations demonstrated that the synergy was mediated by the depletion of squalene, resulting in the inhibition of ergosterol biosynthesis and a compromised membrane structure. In C. glabrata, synergy compromised the function of membrane-bound multidrug transporters and caused an accumulation of reactive oxygen species, which may account for its acute sensitivity to FLC:ZOL. The efficacy of FLC:ZOL in vivo was confirmed in a Galleria mellonella infection model, where combinations improved the survival of larvae infected with C. albicans and C. glabrata to a greater extent than monotherapy with FLC or ZOL, and at reduced dosages. These findings demonstrate that bisphosphonates and azoles are a promising new combination therapy for the treatment of topical candidiasis.

IMPORTANCE

Candida is a common and often very serious opportunistic fungal pathogen. Invasive candidiasis is a prevalent cause of nosocomial infections with a high mortality rate, and mucocutaneous infections significantly impact the quality of life of millions of patients a year. These infections pose substantial clinical challenges, particularly as the currently available antifungal treatment options are limited in efficacy and often toxic. Azoles are a mainstay of antifungal therapy and work by targeting the biosynthesis of ergosterol. However, there are rising rates of acquired azole resistance in various Candida species, and some species are considered intrinsically resistant to most azoles. Our research demonstrates the promising therapeutic potential of synergistically enhancing azoles with non-toxic, FDA-approved bisphosphonates. Repurposing bisphosphonates as antifungal synergists can bypass much of the drug development pipeline and accelerate the translation of azole-bisphosphonate combination therapy.

Topical statins as antifungals: a review

Cutaneous fungal infections affect millions around the world. However, severe, multi-resistant fungal infections are increasingly being reported over the past years. As a result of the high rate of resistance which urged for drug repurposing, statins were studied and found to have multiple pleiotropic effects, especially when combined with other already-existing drugs. An example of this is the synergism found between several typical antifungals and statins, such as antifungals Imidazole and Triazole with a wide range of statins shown in this review. The main mechanisms in which they exert an antifungal effect are ergosterol inhibition, protein prenylation, mitochondrial disruption, and morphogenesis/mating inhibition. This article discusses multiple in vitro studies that have proven the antifungal effect of systemic statins against many fungal species, whether used alone or in combination with other typical antifungals. However, as a result of the high rate of drug-drug interactions and the well-known side effects of systemic statins, topical statins have become of increasing interest. Furthermore, patients with dyslipidemia treated with systemic statins who have a new topical fungal infection could benefit from the antifungal effect of their statin. However, it is still not indicated to initiate systemic statins in patients with topical mycotic infections if they do not have another indication for statin use, which raises the interest in using topical statins for fungal infections. This article also tackles the different formulations that have been studied to enhance topical statins' efficacy, as well as the effect of different topical statins on distinct dermatologic fungal diseases.

Whole transcriptome analysis of schinifoline treatment in Caenorhabditis elegans infected with Candida albicans

Candida albicans is an opportunistic fungal human pathogen that has been causing an increasing number of deaths each year. Due to the widespread use of broad-spectrum antibiotics and immunosuppressants, C. albicans resistance to these therapies has increased. Thus, natural plant inhibitors are being investigated for treating C. albicans infections. Schinifoline is a 4-quinolinone alkaloid with antibacterial, insecticidal, antitumor, and other biological activities. Here, we explored the effects of schinifoline on C. albicans in C. elegans and extracted RNA from uninfected C. elegans, C. elegans infected with C. albicans, and C. elegans infected with C. albicans and treated with 100 mg/l schinifoline. Our results showed that there were significant differences among the three groups. The GO and KEGG pathway analysis suggested that the pathogenicity of C. albicans to C. elegans was caused by abnormal protein function. Schinifoline regulates lysosomal pathway related genes that accelerate the metabolism and degradation of abnormal proteins, thereby inhibiting the negative effects of C. albicans in vivo. These findings advance our understanding of the molecular mechanisms underlying schinifoline inhibition of C. albicans.

Exposure of Aspergillus fumigatus to Atorvastatin Leads to Altered Membrane Permeability and Induction of an Oxidative Stress Response

Aspergillus fumigatus is a serious cause of disease in immune-deficient patients and in those with pulmonary malfunction (e.g., cystic fibrosis (CF), asthma). Atorvastatin is a member of the statin drug family, which are the main therapeutic agents used to decrease high serum cholesterol levels by inhibiting (HMG-CoA) reductase enzyme. The aim of the work presented here was to analyse the antifungal activity of atorvastatin and assess its effect on the virulence of A. fumigatus. Atorvastatin demonstrated strong antifungal activity and reduced the growth and viability of A. fumigatus. Exposure of A. fumigatus to atorvastatin led to a reduction in ergosterol content and increased membrane permeability, as evidenced by the release of protein, amino acids and gliotoxin. Proteomic analysis revealed an increased abundance of proteins associated with an oxidative stress response, such as the glutathione s-transferase family protein (+8.43-fold), heat shock protein Hsp30/Hsp42 (+2.02-fold) and 5-demethoxyubiquinone hydroxylase, mitochondrial (+1.73-fold), as well as secondary metabolites such as isocyanide synthase A icsA (+8.52-fold) and non-ribosomal peptide synthetase fmpE (+3.06-fold). The results presented here indicate that atorvastatin has strong antifungal properties and may have potential application in the treatment of A. fumigatus infections alone or in combination with existing antifungal agents.

Repurposing of drugs approved for cardiovascular diseases: Opportunity or mirage?

Drug repurposing is a promising way in drug discovery to identify new therapeutic uses -different from the original medical indication- for existing drugs. It has many advantages over traditional approaches to de novo drug discovery, since it can significantly reduce healthcare costs and development timeline. In this review, we discuss the possible repurposing of drugs approved for cardiovascular diseases, such as β-blockers, angiotensin converting enzyme inhibitors (ACE-Is), angiotensin II receptor blockers (ARBs), statins, aspirin, cardiac glycosides and low-molecular-weight heparins (LMWHs). Indeed, numerous experimental and epidemiological studies have reported promising anti-cancer activities for these drugs. It is worth mentioning, however, that the results of these studies are often controversial and very few data were obtained by controlled prospective clinical trials. Therefore, no final conclusion has yet been reached in this area and no final recommendations can be made. Moreover, β-blockers, ARBs and statins showed promising results in randomised controlled trials (RCTs) where pathological conditions other than cancer were considered. The results obtained have led or may lead to new indications for these drugs. For each drug or class of drugs, the potential molecular mechanisms of action justifying repurposing, results obtained in vitro and in animal models and data from epidemiological and randomized studies are described.

Repurposing of Existing Statin Drugs for Treatment of Microbial Infections: How Much Promising?

Today's microbial infections' resistance to approved drugs, the emergence of new infectious diseases and lack of vaccines, create a huge threat to human health. Thus, there is an urgent need to create novel antimicrobial agents, but the high cost and prolonged timeline of novel drug discovery and development is the major barrier to make new drugs. Therefore, there is a need for specific cost effective approaches in order to identify new drugs for the treatment of various microbial infections. Drug repurposition is an alternative technique to find existing clinically approved drugs for other indications. This approach may enhance the portfolio of Pharmaceutical companies by reducing the time and money required for the development of new chemical entity. In literature, various studies have reported some encouraging results regarding the antimicrobial use of existing statin drugs. Further, some clinical studies have also shown the protective effect of statin drugs in reduction of the morbidity and mortality due to many infectious diseases but complete understanding is still lacking. Thus, there is a need for better understanding of the use of statin drugs, especially in the context of antimicrobial effects. In this review, we try to summarize the use of statin drugs in various infectious diseases and their proposed antimicrobial mechanism of action. Further, current challenges and future perspectives of repurposition of statin drugs as antimicrobial agents have also been discussed.

Antifungal effects of statins

Fungal infections are estimated to be responsible for 1.5 million deaths annually. Global anti-microbial resistance is also observed for fungal pathogens, and scientists are looking for new antifungal agents to address this challenge. One potential strategy is to evaluate currently available drugs for their possible antifungal activity. One of the suggested drug classes are statins, which are commonly used to decrease plasma cholesterol and reduce cardiovascular risk associated with low density lipoprotein cholesterol (LDL-c). Statins are postulated to possess pleiotropic effects beyond cholesterol lowering; improving endothelial function, modulating inflammation, and potentially exerting anti-microbial effects. In this study, we reviewed in-vitro and in-vivo studies, as well as clinical reports pertaining to the antifungal efficacy of statins. In addition, we have addressed various modulators of statin anti-fungal activity and the potential mechanisms responsible for their anti-fungal effects. In general, statins do possess anti-fungal activity, targeting a broad spectrum of fungal organisms including human opportunistic pathogens such as Candida spp. and Zygomycetes, Dermatophytes, alimentary toxigenic species such as Aspergillus spp., and fungi found in device implants such as Saccharomyces cerevisiae. Statins have been shown to augment a number of antifungal drug classes, for example, the azoles and polyenes. Synthetic statins are generally considered more potent than the first generation of fungal metabolites. Fluvastatin is considered the most effective statin with the broadest and most potent fungal inhibitory activity, including fungicidal and/or fungistatic properties. This has been demonstrated with plasma concentrations that can easily be achieved in a clinical setting. Additionally, statins can potentiate the efficacy of available antifungal drugs in a synergistic fashion. Although only a limited number of animal and human studies have been reported to date, observational cohort studies have confirmed that patients using statins have a reduced risk of candidemia-related complications. Further studies are warranted to confirm our findings and expand current knowledge of the anti-fungal effects of statins.

Assessment of the in vitro and in vivo activity of atorvastatin against Candida albicans

Aim. The aim of this work was to characterize the response of Candida albicans to atorvastatin, and to assess its in vivo antifungal capability.Methodology. The effect of atorvastatin on the growth and viability of C. albicans was assessed. The ability of the statin to alter cell permeability was quantified by measuring amino acid and protein leakage. The response of C. albicans to atorvastatin was assessed using label-free quantitative proteomics. The in vivo antifungal activity of atorvastatin was assessed using Galleria mellonella larvae infected with C. albicans.Results. Atorvastatin inhibited the growth of C. albicans. The atorvastatin-treated cells showed lower ergosterol levels than the controls, demonstrated increased calcofluor staining and released elevated quantities of amino acids and protein. Larvae infected with C. albicans showed a survival rate of 18.1±4.2 % at 144 h. In contrast, larvae administered atorvastatin (9.09 mg kg^-1) displayed a survival rate of 60.2±6.4 % (P<0.05). Label-free quantitative proteomics identified 1575 proteins with 2 or more peptides and 465 proteins were differentially abundant (P<0.05). There was an increase in the abundance of enzymes with oxidoreductase and hydrolase activity in atorvastatin-treated cells, and squalene monooxygenase (4.52-fold increase) and lanosterol synthase (2.84-fold increase) were increased in abundance. Proteins such as small heat shock protein 21 (-6.33-fold) and glutathione peroxidase (-2.05-fold) were reduced in abundance.Conclusion. The results presented here indicate that atorvastatin inhibits the growth of C. albicans and is capable of increasing the survival of G. mellonella larvae infected with C. albicans.

Antifungal drugs: New insights in research & development

The need for better antifungal therapy is commonly accepted in view of the high mortality rates associated with systemic infections, the low number of available antifungal classes, their associated toxicity and the increasing number of infections caused by strains with natural or acquired resistance. The urgency to expand the range of therapeutic options for the treatment of fungal infections has led researchers in recent decades to seek alternative antifungal targets when compared to the conventional ones currently used. Although new potential targets are reported, translating the discoveries from bench to bedside is a long process and most of these drugs fail to reach the patients. In this review, we discuss the development of antifungal drugs focusing on the approach of drug repurposing and the search for novel drugs for classical targets, the most recently described gene targets for drug development, the possibilities of immunotherapy using antibodies, cytokines, therapeutic vaccines and antimicrobial peptides.

Effect of Candida albicans on Intestinal Ischemia-reperfusion Injury in Rats

Background:

Inflammation is supposed to play a key role in the pathophysiological processes of intestinal ischemia-reperfusion injury (IIRI), and Candida albicans in human gut commonly elevates inflammatory cytokines in intestinal mucosa. This study aimed to explore the effect of C. albicans on IIRI.

Methods:

Fifty female Wistar rats were divided into five groups according to the status of C. albicans infection and IIRI operation: group blank and sham; group blank and IIRI; group cefoperazone plus IIRI; group C. albicans plus cefoperazone and IIRI (CCI); and group C. albicans plus cefoperazone and sham. The levels of inflammatory factors tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and diamine oxidase (DAO) measured by enzyme-linked immunosorbent assay were used to evaluate the inflammation reactivity as well as the integrity of small intestine. Histological scores were used to assess the mucosal damage, and the C. albicans blood translocation was detected to judge the permeability of intestinal mucosal barrier.

Results:

The levels of inflammatory factors TNF-α, IL-6, and IL-1β in serum and intestine were higher in rats undergone both C. albicans infection and IIRI operation compared with rats in other groups. The levels of DAO (serum: 44.13 ± 4.30 pg/ml, intestine: 346.21 ± 37.03 pg/g) and Chiu scores (3.41 ± 1.09) which reflected intestinal mucosal disruption were highest in group CCI after the operation. The number of C. albicans translocated into blood was most in group CCI ([33.80 ± 6.60] ×10² colony forming unit (CFU)/ml).

Conclusion:

Intestinal C. albicans infection worsened the IIRI-induced disruption of intestinal mucosal barrier and facilitated the subsequent C. albicans translocation and dissemination.

Association between statins and infections among patients with diabetes: a cohort and prescription sequence symmetry analysis

Purpose

A previous meta‐analysis of randomized trials did not confirm findings from observational studies that suggested that statins reduce the risk of infection. However, animal experiments indicate that statins may be more effective in reducing the risk and/or the severity of infection among patients with diabetes. Hence, we evaluated the effect of statins on antibiotic prescriptions (a proxy for infections) among patients with drug‐treated type 2 diabetes using two confounding‐reducing observational designs.

Methods

We conducted a prescription sequence symmetry analysis and a cohort study using the IADB.nl pharmacy prescription database. For the prescription sequence symmetry analysis, a sequence ratio was calculated. The matched cohort study, comparing the time to first antibiotic prescription between periods that statins are initiated and non‐use periods, was analyzed using stratified Cox regression.

Results

Prescription sequence symmetry analysis of 4684 patients with drug‐treated type 2 diabetes resulted in an adjusted sequence ratio of 0.86 (95% confidence interval [CI]: 0.81 to 0.91). Corresponding figures for the cohort analysis comparing 9852 statin‐initiation with 4928 non‐use periods showed similar results (adjusted hazard ratio: 0.88, 95%CI: 0.83 to 0.95).

Conclusions

These findings suggest that statins are associated with a reduced risk of infections among patients with drug‐treated type 2 diabetes. © 2016 The Authors. Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

Atorvastatin Reduces the Survival of Candida albicans-Infected BALB/c Mice

Several antimicrobial and immunosuppressive effects have been attributed to the statins class of antihyperlipidemia drugs. Several studies have also indicated clinical benefits for the use of statins during the management of infections and sepsis. To assess whether the immunosuppressive effects of statins outweigh their antimicrobial effects during a fungal infection BALB/c mice were administered Candida albicans via intraperitoneal injection. These mice received either a co-injection of atorvastatin along with the infection, were treated with one injection of atorvastatin per day for 5 days prior to infection, or were infected and then treated with one injection of atorvastatin for 5 days afterward. Groups that received C. albicans without being treated with atorvastatin were included as controls along with a group that only received phosphate-buffered saline. Mouse survival was then monitored; additionally, serum IFN-γ and IL-4 levels were determined by enzyme linked immunosorbent assay to assess pro-inflammatory and pro-humoral responses, respectively. Atorvastatin administration was capable of altering mouse survival rate with the lowest rate (11.1%) being observed in the group treated for 5 days prior to infection with atorvastatin compared to mice infected but not treated with atorvastatin (44.4%). IFN-γ and IL-4 levels were depressed in all C. albicans-infected groups treated with atorvastatin. The possibility that statin administration may suppress or modulate particular components of the immune system during an infection in man should be further explored in large randomized controlled trials.

Simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species

The antifungal activity of some statins against different fungal species has been reported. Thus, at the first moment, the in vitro antifungal activity of simvastatin, atorvastatin and pravastatin was tested against Candida spp. and Cryptococcus spp. Then, in a second approach, considering that the best results were obtained for simvastatin, this drug was evaluated in combination with antifungal drugs against planktonic growth and tested against biofilms of Candida spp. and Cryptococcus spp. Drug susceptibility testing was performed using the microdilution broth method, as described by the Clinical and Laboratory Standards Institute. The interaction between simvastatin and antifungals against planktonic cells was analyzed by calculating the fractional inhibitory concentration index. Regarding biofilm susceptibility, simvastatin was tested against growing biofilm and mature biofilm of one strain of each tested yeast species. Simvastatin showed inhibitory effect against Candida spp. and Cryptococcus spp. with minimum inhibitory concentration values ranging from 15.6 to 1000 mg L⁻¹ and from 62.5 to 1000 mg L⁻¹, respectively. The combination of simvastatin with itraconazole and fluconazole showed synergism against Candida spp. and Cryptococcus spp., while the combination of simvastatin with amphotericin B was synergistic only against Cryptococcus spp. Concerning the biofilm assays, simvastatin was able to inhibit both growing biofilm and mature biofilm of Candida spp. and Cryptococcus spp. The present study showed that simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species.

The role of Candida albicans SPT20 in filamentation, biofilm formation and pathogenesis

Candida albicans is a ubiquitous fungus, which can cause very serious and sometimes life-threatening infections in susceptible patients. We used Caenorhabditis elegans as a model host to screen a library of C. albicans mutants for decreased virulence and identified SPT20 as important for virulence. The transcription co-activator SPT20 was identified originally as a suppressor of Ty and solo δ insertion mutations, which can cause transcription defects in Saccharomyces cerevisiae. It is resistant to the toxicity caused by overexpression of GAL4-VP16. We constructed a C. albicans spt20Δ/Δ mutant and found the spt20Δ/Δ strain was significantly less virulent than the wild-type strain SC5314 in C. elegans (p < 0.0001), Galleria mellonella (p < 0.01) and mice (p < 0.001). Morphologically, spt20Δ/Δ mutant cells demonstrated a “snow-flake” shape and clustered together; prolonged culture times resulted in increased size of the cluster. The clustered morphology was associated with defects in nuclei distribution, as the nuclei were not observed in many cellular compartments. In addition, the C. albicans spt20Δ/Δ mutant resulted in defects in hyphae and biofilm formation (compared to the wild-type strain, p < 0.05), and sensitivity to cell wall and osmotic stressors, and to antifungal agents. Thus our study demonstrated a role of C. albicans SPT20 in overall morphology and distribution of nuclear material, which may cause the defects in filamentation and biofilm formation directly when this gene is deleted.

The effect of statin therapy on the incidence of infections: a retrospective cohort analysis

BACKGROUND

Statins have been postulated to prevent infection through immunomodulatory effects.

OBJECTIVES

To compare the incidence of infections in statin users to that in nonusers within the same health care system.

METHODS

This was a retrospective cohort study of patients enrolled as Tricare Prime or Plus in the San Antonio military multimarket. Statin users were patients who received a statin for at least 3 months between October 1, 2004 and September 30, 2005. Nonusers were patients who did not receive a statin within the study period (October 1, 2003-September 30, 2009). Inpatient and outpatient International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes were used to determine the incidence of infections during the follow-up period (October 1, 2005-September 30, 2009) via multivariable regression analysis and time to infection via Cox regression analysis.

RESULTS

Of 45,247 patients who met the study criteria, 12,981 (29%) were statin users and 32,266 were nonusers. After adjustments for age, gender, Charlson Comorbidity Score, tobacco use, alcohol abuse/dependence, health care utilization and use of specific medication classes, statin use was associated with an increased incidence of common infections (odds ratio [OR]: 1.13; 95% confidence interval [CI]: 1.06-1.19) but not influenza or fungal infections (OR: 1.06, 95% CI: 0.80-1.39; OR: 0.97; 95% CI: 0.91-1.04, respectively). Time-to-first infection was similar in statin users and nonusers in all infection categories examined.

CONCLUSIONS

Statin use was associated with an increased incidence of common infections but not influenza or fungal infections. This study does not support a protective role of statins in infection prevention; however, the influence of potential confounders cannot be excluded.

Statin use and postoperative atrial fibrillation after major noncardiac surgery

BACKGROUND

Although statin lipid-lowering medications likely reduce perioperative ischemic complications, few data exist to describe statins' effects on risk for and outcomes of atrial fibrillation following noncardiac surgery.

OBJECTIVE

To examine the association between treatment with statin medications and clinically significant postoperative atrial fibrillation (POAF) following major noncardiac surgery.

METHODS

A retrospective cohort study of patients aged 18 years or older who underwent major noncardiac surgery between January 1, 2008, and December 31, 2008. Cases of clinically significant POAF were selected by using a combination of International Classification of Diseases-9 codes and clinical variables. We defined statin users as those whose pharmacy data included a charge for a statin drug on the day of surgery, the day after surgery, or both.

RESULTS

Of 370,447 patients, 10,957 (3.0%) developed clinically significant POAF; overall, 79,871 (21.6%) received a perioperative statin. Patients receiving statins were generally older (68.8 vs 61.1 years; P <.001) and more likely to be receiving a beta-blocker (50.3% vs 21.6%; P < .001). Statin use was associated with a lower unadjusted rate of POAF (2.6% vs 3.0%; P < .001). After adjustment for patient risk factors and surgery type, odds for POAF remained significantly lower among statin-treated patients (adjusted odds ratio = 0.79; 95% confidence interval = 0.71-0.87; P < .001). Statin use was not associated with differences in cost, length of stay, or mortality among patients who developed POAF.

CONCLUSION

Treatment with statin agents appears to be associated with a lower risk for clinically significant POAF following major noncardiac surgery.