Assessing antibacterial efficacy of a polyhexanide hydrogel versus alginate-based wound dressing in burns

OBJECTIVE

Burn injuries pose a heightened risk of infection, which is primarily responsible for increased morbidity and mortality. Factors such as extensive skin damage and compromised immunity exacerbate this vulnerability. Pseudomonas aeruginosa and Staphylococcus aureus are frequently identified in burns, with Gram-negative Pseudomonas aeruginosa often resistant to antibacterial agents. While Flaminal, an alginate-based wound dressing (Flen Health, Belgium), aids wound healing, its antibacterial effects are limited compared with 1% silver sulfadiazine (1% SSD). In contrast, Prontosan Wound Gel X, a betaine and polyhexanide-based hydrogel (B. Braun Medical AG, Switzerland), has been shown to effectively combat various microbes and promotes wound healing.

METHOD

In this study, two research cohorts were retrospectively established (control group: patients receiving standard of care with the alginate-based wound dressing; intervention group: patients receiving the polyhexanide hydrogel wound dressing), comprising patients admitted to a burn centre between 2019 and 2022. Patients were eligible when continuous wound treatment with either of the two wound dressings was performed. Laser Doppler imaging (LDI) scans were conducted. Regions of interest (ROIs) were selected based on LDI scans and divided into healing time categories. Wound swabs were collected and the presence of Pseudomonas aeruginosa and Staphylococcus aureus was documented. Bacterial load was evaluated using a semiquantitative scale. Wound healing was recorded.

RESULTS

The control group consisted of 31 patients with 93 ROIs, while the intervention group had 67 ROIs involving 29 patients. Both groups exhibited similar proportions of healing time categories (p>0.05). The polyhexanide hydrogel dressing outperformed the alginate-based dressing in antiseptic efficacy by significantly reducing the incidence of Pseudomonas aeruginosa- and Staphylococcus aureus-positive cultures in patients' wounds. Wound healing time for conservative treatment was comparable between groups.

CONCLUSION

In this study, the polyhexanide hydrogel dressing minimised Pseudomonas aeruginosa and Staphylococcus aureus colonisation in burn wounds, demonstrating strong antibacterial properties, emphasising its potential to minimise infections in burn injuries.

Associations Between Drug Treatments and the Risk of Aneurysmal Subarachnoid Hemorrhage: a Systematic Review and Meta-analysis

There is increasing interest in drug therapy for preventing aneurysmal subarachnoid hemorrhage (aSAH). We aimed to comprehensively evaluate the association between drug use and the risk of aSAH. We searched PubMed and Scopus from the databases' inception until December 2021. Observational studies reporting the association between any drug therapy and aSAH were included. The odds ratios (ORs) for each drug used in aSAH were meta-analyzed with a random-effect model. According to the systematic review, 25 observational studies were eligible for the present study. Four therapeutic purpose-based classes (e.g., lipid-lowering agents) and 14 mechanism-based classes (e.g., statins) were meta-analyzed. Anti-hypertensive agents (OR, 0.50; 95% confidence interval [95% CI], 0.33-0.74), statins (OR, 0.55; 95% CI, 0.35-0.85), biguanides (OR, 0.57; 95% CI, 0.34-0.96), and acetylsalicylic acid (ASA) (OR, 0.62; 95% CI, 0.41-0.94) were inversely associated with the risk of aSAH. Non-ASA non-steroidal anti-inflammatory drugs (OR, 1.73; 95% CI, 1.07-2.79), selective cyclooxygenase-2 inhibitors (OR, 2.04; 95% CI, 1.24-3.35), vitamin K antagonists (OR, 1.50; 95% CI, 1.18-1.91), and dipyridamole (OR, 1.77; 95% CI, 1.23-2.54) were positively associated with the incidence of aSAH. There was also a trend toward a positive association between glucocorticoids (OR, 1.38; 95% CI, 0.97-1.94) and aSAH. The present study suggests that anti-hypertensive agents, statins, biguanides, and ASA are candidate drugs for preventing aSAH. By contrast, several drugs (e.g., anti-thrombotic drugs) may increase the risk of aSAH. Thus, the indications of these drugs in patients with intracranial aneurysms should be carefully determined.

Biguanide-anchored albumin-based nanoplatform inhibits epithelial-mesenchymal transition and reduces the stemness phenotype for metastatic cancer therapy

In clinical chemotherapy, albumin-bound paclitaxel (Abraxane) can improve the tumor targeting property and therapeutic efficacy of paclitaxel (PTX) against orthotopic malignancies. However, patients with metastatic cancer have a poor prognosis, probably due to the instability, chemoresistance, and inability of albumin-bound paclitaxel to alter the tumor microenvironment. Here we propose a new biguanide-modified albumin-based nanoplatform that encapsulates paclitaxel for the effective treatment of metastatic cancer. The PTX is encapsulated in poly (lactic-co-glycolic acid) cores coated with biguanide-modified albumin (HSA-NH). The functionalized nanoparticles (HSA-NH NPs) exhibit a remarkable stable profile with low drug release (P < 0.05 versus Abraxane), target tumor tissues, suppress epithelial-mesenchymal transition (EMT) events for anti-metastatic effects, and reduce the phenotype of cancer stem cells. As a result, HSA-NH NPs effectively prolong animal survival (55 days) by inhibiting not only primary tumor growth but also metastasis. This study provides proof of concept that the biguanide-anchored albumin-based nanoplatform encapsulating PTX is a powerful, safe, and clinically translational strategy for the treatment of metastatic cancer. STATEMENT OF SIGNIFICANCE: Albumin-bound paclitaxel (Abraxane) can increase paclitaxel's tumor targeting and therapeutic efficacy in clinical cancer treatments such as breast cancer. However, the instability, chemoresistance, and lack of tumor microenvironment modulation of albumin-bound paclitaxel may lead to poor therapeutic efficacy in metastatic cancer patients. Here we develop biguanide-anchored albumin-based nanoplatforms that encapsulate paclitaxel (HSA-NH NPs) for metastatic cancer treatment. Poly(lactic-co-glycolic acid) (PLGA) cores encapsulating paclitaxel improve the stability of HSA-NH NPs. Based on the activities of metformin, biguanide-anchored albumin adsorbed on PLGA cores improves paclitaxel efficacy, inhibits various aberrant changes during epithelial-mesenchymal transition, and reduces tumor cell stemness. The biguanide-anchored albumin-based nanoplatform encapsulating PTX can serve as a potent, safe, and clinically translational approach for metastatic cancer therapies.

Efficacy of Polyhexamethylene Biguanide in Reducing Post-Operative Infections: A Systematic Review and Meta-Analysis

Background: Post-operative infections are a substantial cause of morbidity and mortality worldwide. Polyhexamethylene biguanide (PHMB) is an antimicrobial agent that has been used in various surgical settings to prevent infections. However, the literature on its efficacy in reducing post-operative infections remains unclear. Materials and Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy of PHMB in reducing post-operative infections. The risk of bias and methodologic quality of the included studies were also assessed. Results: The systematic review included nine RCTs, and eight were included in the meta-analysis that showed that the use of PHMB was associated with a reduction in the rate of post-operative infections. The overall effect size was statistically significant, with moderate heterogeneity across the included studies (log Peto's odds ratio [OR], -0.890; 95% confidence interval [CI], -1.411 to -0.369; I2 = 41.89%). However, the diversity in the application of PHMB and the potential influence of other factors, such as adherence to infection prevention protocols and organizational-level variables, underscore the need for further primary studies. Conclusions: Polyhexamethylene biguanide appears to be a promising intervention for reducing post-operative infections. However, more high-quality, well-designed RCTs are needed to confirm these findings and to explore the most effective ways to use PHMB within specific infection prevention bundles. Future research should also aim to control for potential confounding factors to provide a more comprehensive understanding of the efficacy of PHMB in reducing post-operative infections.

Cannabinoformins: Designing Biguanide-Embedded, Orally Available, Peripherally Selective Cannabinoid-1 Receptor Antagonists for Metabolic Syndrome Disorders

We have designed orally bioavailable, non-brain-penetrant antagonists of the cannabinoid-1 receptor (CB1R) with a built-in biguanide sensor to mimic 5'-adenosine monophosphate kinase (AMPK) activation for treating obesity-associated co-morbidities. A series of 3,4-diarylpyrazolines bearing rational pharmacophoric pendants designed to limit brain penetration were synthesized and evaluated in CB1R ligand binding assays and recombinant AMPK assays. The compounds displayed high CB1R binding affinity and potent CB1R antagonist activities and acted as AMPK activators. Select compounds showed good oral exposure, with compounds 36, 38-S, and 39-S showing <5% brain penetrance, attesting to peripheral restriction. In vivo studies of 38-S revealed decreased food intake and body weight reduction in diet-induced obese mice as well as oral in vivo efficacy of 38-S in ameliorating glucose tolerance and insulin resistance. The designed "cannabinoformin" four-arm CB1R antagonists could serve as potential leads for treatment of metabolic syndrome disorders with negligible neuropsychiatric side effects.

Effectiveness of a purified type I collagen matrix plus the antimicrobial polyhexamethylene biguanide for use in cutaneous wounds: analysis of a population of three combined registries

INTRODUCTION

Chronic wounds represent a significant burden to the health care system and patients.

OBJECTIVE

This study determined the effectiveness of a wound scaffold comprised of PCMP for use in nonhealing, cutaneous wounds; this study analyzes pooled data from the population of 3 combined registries.

MATERIALS AND METHODS

A total of 3 combined registry populations were pooled from a single-center study of 41 patients, a single-center study of 86 patients, and the RESPOND Registry of 307 patients treated at 28 centers. All 434 patients received PCMP and were followed for up to 48 weeks. Male and female patients 18 years or older with wounds between 0.2 cm2 and 200 cm2 were included.

RESULTS

In total, there were 95 VLUs, 78 DFUs, 90 PIs, 73 PSWs, and 98 wounds of other etiologies analyzed. The mean baseline area, depth, and volume of all 434 wounds was 15.1 cm2, 4.9 mm, and 7.2 cm3, respectively. K-M median time to wound closure for all wounds was 19 weeks. At weeks 20, 24, 28, and 48, the frequency of wound closure for all wounds was 51%, 56%, 62%, and 72%, respectively. The median time to closure by wound type was 22 weeks for VLUs, 24 weeks for DFUs, 23 weeks for PIs, 12 weeks for PSWs, and 14 weeks for other wounds. The proportion of wounds closed were 72% (VLUs), 52% (DFUs), 63% (PIs), 95% (PSWs), and 67% (other etiologies).

CONCLUSIONS

This 434-patient PCMP cohort analysis showed 72% wound closure and median time to wound closure of 19 weeks. PCMP demonstrated effectiveness for use in multiple wound types.

Risk of Lactic Acidosis in Hospitalized Diabetic Patients Prescribed Biguanides in Japan: A Retrospective Total-Population Cohort Study

Patient data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) are used to assess the effect of biguanide administration on rates of lactic acidosis (LA) in hospitalized diabetes mellitus (DM) patients. In this retrospective cohort study (from April 2013 to March 2016), we compare DM inpatients prescribed biguanides to DM inpatients who were not prescribed biguanides to quantify the association between biguanides and incidence of LA. In total, 8,111,848 DM patient records are retrieved from the NDB. Of the 528,768 inpatients prescribed biguanides, 782 develop LA. Of the 1,967,982 inpatients not prescribed biguanides, 1310 develop LA. The rate ratio of inpatients who develop LA and are administered biguanides to those who developed LA without receiving biguanides is 1.44 (95% CI, 1.32-1.58). Incidence rates and rate ratios for both sexes are elevated in the group prescribed biguanides for patients aged 70 years and older, markedly in those 80 years and older: 40.12 and 6.31 (95% CI, 4.75-8.39), respectively, for men and 34.96 and 5.40 (95% CI, 3.91-7.46), respectively, for women. Biguanides should be used conservatively in patients older than 70 years, particularly for those with comorbidities, and with caution in patients 80 years and older.

The biguanide polyamine analog verlindamycin promotes differentiation in neuroblastoma via induction of antizyme

Deregulated polyamine biosynthesis is emerging as a common feature of neuroblastoma and drugs targeting this metabolic pathway such as DFMO are in clinical and preclinical development. The polyamine analog verlindamycin inhibits the polyamine biosynthesis pathway enzymes SMOX and PAOX, as well as the histone demethylase LSD1. Based on our previous research in acute myeloid leukemia (AML), we reasoned verlindamycin may also unblock neuroblastoma differentiation when combined with all-trans-retinoic acid (ATRA). Indeed, co-treatment with verlindamycin and ATRA strongly induced differentiation regardless of MYCN status, but in MYCN-expressing cells, protein levels were strongly diminished. This process was not transcriptionally regulated but was due to increased degradation of MYCN protein, at least in part via ubiquitin-independent, proteasome-dependent destruction. Here we report that verlindamycin effectively induces the expression of functional tumor suppressor-antizyme via ribosomal frameshifting. Consistent with previous results describing the function of antizyme, we found that verlindamycin treatment led to the selective targeting of ornithine decarboxylase (the rate-limiting enzyme for polyamine biosynthesis) as well as key oncoproteins, such as cyclin D and Aurora A kinase. Retinoid-based multimodal differentiation therapy is one of the few interventions that extends relapse-free survival in MYCN-associated high-risk neuroblastoma and these results point toward the potential use of verlindamycin in this regimen.

Current status of oral antidiabetic drug prescribing patterns based on the body mass index for Japanese type 2 diabetes mellitus patients and yearly changes in diabetologists' prescribing patterns from 2002 to 2019 (JDDM61)

AIMS/INTRODUCTION

Type 2 diabetes mellitus is caused by a relative imbalance between insulin secretion and sensitivity related to the body mass index (BMI). Seven categories of oral antidiabetic drugs (OADs) are available in Japan. It is important to assess the OAD utilization patterns based on patients' BMI levels.

MATERIALS AND METHODS

OAD prescribing patterns from 2002 to 2019 were analyzed using the data collected in the computerized diabetes care database provided by the Japan Diabetes Clinical Data Management Study Group; OAD utilization patterns in 25,751 OAD-treated type 2 diabetes mellitus patients registered in 2019 were analyzed after classifying them into five categories of BMI.

RESULTS

Comparing OAD usage between 2002 and 2019, sulfonylureas decreased from 44.5 to 23.2%, and biguanides (BGs) increased from 19.3 to 50.3%. Dipeptidyl peptidase-4 inhibitors (DPP4is) increased to 56.9% in 2019. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) increased to 23.6% in 2019. About 90% of type 2 diabetes mellitus patients had BMI < 30 kg/m2 . DPP4is were the most used OADs in 2019. When BMI exceeded 30 kg/m2 , use of BGs and sodium-glucose cotransporter 2 inhibitors increased, and use of sulfonylureas and DPP4is decreased. Although DPP4is were the most used OADs for patients with BMI <30 kg/m2 , they were the third most prescribed OADs for patients with BMI >35 kg/m2 after BGs and sodium-glucose cotransporter 2 inhibitors .

CONCLUSIONS

DPP4i usage was as high as that of BG in the analysis of Japanese type 2 diabetes mellitus patients with relatively low BMI. This was considered to be a treatment option appropriate for the pathophysiology in Japanese patients.

Wound cleansing for treating venous leg ulcers

BACKGROUND

Leg ulcers are open skin wounds that occur below the knee but above the foot. The majority of leg ulcers are venous in origin, occurring as a result of venous insufficiency, where the flow of blood through the veins is impaired; they commonly arise due to blood clots and varicose veins. Compression therapy, using bandages or stockings, is the primary treatment for venous leg ulcers. Wound cleansing can be used to remove surface contaminants, bacteria, dead tissue and excess wound fluid from the wound bed and surrounding skin, however, there is uncertainty regarding the effectiveness of cleansing and the best method or solution to use.

OBJECTIVES

To assess the effects of wound cleansing, wound cleansing solutions and wound cleansing techniques for treating venous leg ulcers.

SEARCH METHODS

In September 2019 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) comparing wound cleansing with no wound cleansing, or RCTs comparing different wound cleansing solutions, or different wound cleansing techniques.

DATA COLLECTION AND ANALYSIS

We screened studies for their appropriateness for inclusion, assessed their risk of bias using the Cochrane 'Risk of bias' tool, and used GRADE methodology to determine the certainty of evidence. Two review authors undertook these tasks independently, using predetermined criteria. We contacted study authors for missing data where possible.

MAIN RESULTS

We included four studies with a total of 254 participants. All studies included comparisons between different types of cleansing solutions, and three of these reported our primary outcomes of complete wound healing or change in ulcer size over time, or both. Two studies reported the secondary outcome, pain. One study (27 participants), which compared polyhexamethylene biguanide (PHMB) solution with saline solution for cleansing venous leg ulcers, did not report any of the review's primary or secondary outcomes. We did not identify any studies that compared cleansing with no cleansing, or that explored comparisons between different cleansing techniques. One study (61 participants) compared aqueous oxygen peroxide with sterile water. We are uncertain whether aqueous oxygen peroxide makes any difference to the number of wounds completely healed after 12 months of follow-up (risk ratio (RR) 1.88, 95% confidence interval (CI) 1.10 to 3.20). Similarly, we are uncertain whether aqueous oxygen peroxide makes any difference to change in ulcer size after eight weeks of follow-up (mean difference (MD) -1.38 cm², 95% CI -4.35 to 1.59 cm²). Finally, we are uncertain whether aqueous oxygen peroxide makes any difference to pain reduction, assessed after eight weeks of follow-up using a 0 to 100 pain rating, (MD 3.80, 95% CI -10.83 to 18.43). The evidence for these outcomes is of very low certainty (we downgraded for study limitations and imprecision; for the pain outcome we also downgraded for indirectness). Another study (40 participants) compared propyl betaine and polihexanide with a saline solution. The authors did not present the raw data in the study report so we were unable to conduct independent statistical analysis of the data. We are uncertain whether propyl betaine and polihexanide make any difference to the number of wounds completely healed, change in ulcer size over time, or wound pain reduction. The evidence is of very low certainty (we downgraded for study limitations and imprecision). The final study (126 participants) compared octenidine dihydrochloride/phenoxyethanol (OHP) with Ringer's solution. We are uncertain whether OHP makes any difference to the number of wounds healed (RR 0.96, 95% CI 0.53 to 1.72) or to the change in ulcer size over time (we were unable to conduct independent statistical analysis of available data). The evidence is of very low certainty (we downgraded for study limitations and imprecision). None of the studies reported patient preference, ease of use of the method of cleansing, cost or health-related quality of life. In one study comparing propyl betaine and polihexanide with saline solution the authors do not report any adverse events occurring. We are uncertain whether OHP makes any difference to the number of adverse events compared with Ringer's solution (RR 0.58, 95% CI 0.29 to 1.14). The evidence is of very low certainty (we downgraded for study limitations and imprecision).

AUTHORS' CONCLUSIONS

There is currently a lack of RCT evidence to guide decision making about the effectiveness of wound cleansing compared with no cleansing and the optimal approaches to cleansing of venous leg ulcers. From the four studies identified, there is insufficient evidence to demonstrate whether the use of PHMB solution compared with saline solution; aqueous oxygen peroxide compared with sterile water; propyl betaine and polihexanide compared with a saline solution; or OHP compared with Ringer's solution makes any difference in the treatment of venous leg ulcers. Evidence from three of the studies is of very low certainty, due to study limitations and imprecision. One study did not present data for the primary or secondary outcomes. Further well-designed studies that address important clinical, quality of life and economic outcomes may be important, based on the clinical and patient priority of this uncertainty.

Evidence-Based Review of Antibiofilm Agents for Wound Care

Significance: Biofilms in vivo are small densely packed aggregations of microbes that are highly resistant to host immune responses and treatment. They attach to each other and to nearby surfaces. Biofilms are difficult to study and identify in a clinical setting as their quantification necessitates the use of advanced microscopy techniques such as confocal laser scanning microscopy. Nonetheless, it is likely that biofilms contribute to the pathophysiology of chronic skin wounds. Reducing, removing, or preventing biofilms is thus a logical approach to help clinicians heal chronic wounds. Recent Advances: Wound care products have demonstrated varying degrees of efficacy in destroying biofilms in in vitro and preclinical models, as well as in some clinical studies. Critical Issues: Controlled studies exploring the beneficial role of biofilm eradication and its relationship to healing in patients with chronic wounds are limited. This review aims to discuss the mode of action and clinical significance of currently available antibiofilm products, including surfactants, dressings, and others, with a focus on levels of evidence for efficacy in disrupting biofilms and ability to improve wound healing outcomes. Future Directions: Few available products have good evidence to support antibiofilm activity and wound healing benefits. Novel therapeutic strategies are on the horizon. More high-quality clinical studies are needed. The development of noninvasive techniques to quantify biofilms will facilitate increased ease of research about biofilms in wounds and how to combat them.

Structure and State of Water in Branched N-Vinylpyrrolidone Copolymers as Carriers of a Hydrophilic Biologically Active Compound

Hydrated copolymers of N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate as a promising platform for biologically active compounds (BAC) were investigated by different physical chemical methods (dynamic light scattering, infrared spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry) and the quantum chemical modeling of water coordination by the copolymers in a solution. According to the quantum chemical simulation, one to two water molecules can coordinate on one O-atom of the lactam ring of VP units in the copolymer. Besides the usual terminal coordination, the water molecule can form bridges to bind two adjacent C=O groups of the lactam rings of VP units. In addition to the first hydration shell, the formation of a second one is also possible due to the chain addition of water molecules, and its structure depends on a mutual orientation of C=O groups. We showed that N,N-dimethylbiguanidine hydrochloride (metformin) as a frontline drug for the treatment of type 2 diabetes mellitus can be associated in aqueous solutions with free and hydrated C=O groups of the lactam rings of VP units in studied copolymers. Based on the characteristics of the H-bonds, we believe that the level of the copolymer hydration does not affect the behavior and biological activity of this drug, but the binding of metformin with the amphiphilic copolymer will delight in the penetration of a hydrophilic drug across a cell membrane to increase its bioavailability.

Efficacy of Wound Cleansers on Wound-Specific Organisms Using In Vitro and Ex Vivo Biofilm Models

Biofilms are believed to be a source of chronic inflammation in non-healing wounds.

PURPOSE

In this study, the pre-clinical anti-biofilm efficacy of several wound cleansers was examined using the Calgary minimum biofilm eradication concentration (MBEC) and ex vivo porcine dermal explant (PDE) models on Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans biofilms.

METHODS

A surfactant-based cleanser and antimicrobial-based cleansers containing ionic silver, hypochlorous acid (HOCl), sodium hypochlorite (NaOCl), and polyhexamethylene biguanide (PHMB) were tested on the MBEC model biofilms with a 10-minute application time. Select cleansers were then tested on the mature PDE biofilms with 10-minute applications followed by the application of cleanser-soaked gauze. The PDE model was further expanded to include single and daily applications of the cleansers to mimic daily and 72-hour dressing changes.

RESULTS

In the MBEC model, PHMB- and HOCl-based cleansers reduced immature MRSA, C albicans, and P aeruginosa biofilm regrowth by > 3× when compared with silver, surfactant, and saline cleansers. The major differences could be elucidated in the PDE model in which, after daily application, 1 PHMB-based cleanser showed a statistically significant reduction (3-8 CFU/mL log reduction) in all mature biofilms tested, while a NaOCl-based cleanser showed significant reduction in 2 microorganisms (3-5 CFU/mL log reduction, P aeruginosa and MRSA).The other PHMB-based cleanser showed a statistically significant 3 log CFU/mL reduction in P aeruginosa. The remaining cleansers showed no statistically significant difference from the saline control.

CONCLUSION

Results confirm that there are model-dependent differences in the outcomes of these studies, suggesting the importance of model selection for product screening. The results indicate that 1 PHMB-based cleanser was effective in reducing mature P aeruginosa, MRSA, and C albicans biofilms and that sustained antimicrobial presence was necessary to reduce or eliminate these mature biofilms.

Synergistic Effect and Antibiofilm Activity of a Skin and Wound Cleanser

INTRODUCTION

Biofilm in chronic wounds impedes the wound healing process. Each biofilm has differing characteristics requiring a multifaceted approach for removal while maintaining a surrounding environment conducive to wound healing.

OBJECTIVE

In this study, 3 of the components in a wound cleanser are tested to determine synergy in eradicating biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa in vitro.

MATERIALS AND METHODS

The 3 components assessed for synergy were ethylenediamine tetraacetic acid sodium salts (EDTA), vicinal diols (VD; ethylhexylglycerin and octane-1,2-diol), and polyhexamethylene biguanide (PHMB). Each component was assessed individually and in combination while dissolved in a base solution. The Calgary assay method was used for biofilm growth and treatment. Kull Equation analysis for synergy was conducted using viable count results.

RESULTS

Synergy is defined as the interaction of components to produce a combined effect greater than the sum of their separate effects. The base solution containing all 3 components (EDTA, VD, and PHMB) reduced biofilm viability by more than 5 logs, demonstrating statistically significant synergy. The 3 components tested individually in the base solution resulted in the following: EDTA did not reduce bacteria viability; VD reduced viability by about 1 log; and PHMB reduced P aeruginosa viability by about 2.5 logs and MRSA viability by about 4 logs. Of importance, the MRSA biofilm failed to regrow in the recovery plates after combined treatment, indicating complete elimination of the biofilm bacteria.

CONCLUSIONS

The experimental and calculated results indicate the 3 components (VD, EDTA, and PHMB) when used together act synergistically to eradicate MRSA and P aeruginosa biofilms in vitro.

Antidiabetics and antihypertensive medications use in Morocco: A pharmacoepidemiological descriptive study

Background

In Morocco, and many other African countries, there is a paucity of antihypertensive and antidiabetics use amongst the general population.

Aim

To investigate the epidemiological profile of antihypertensive and antidiabetics use and analysis their adverse reactions.

Setting

This study was conducted in the prefecture of Figuig, Morocco.

Methods

A cross-sectional descriptive study. Data was collected using semi-structured questionnaire about their pharmacological treatment and presented using descriptive statistical analysis.

Results

Sample of 244 subjects, predominantly women 58.15% (p < 0.03) composed of diabetic patients 56.96% (n = 139) and hypertensive patients 43.03% (n = 105). After adjustments, 60.24% of all patients were under monotherapy. The diabetics were being treated using the Biguanide class (26.92%), insulin (20.0%) and sulfonylureas (10.0%) while hypertensive patients were treated by Calcium Channel Blockers (27.36%), Angiotensin Converting Enzyme Inhibitors (21.05%), Angiotensin T-Blockers (16.84%), Diuretics (7.36%) and β-adrenergic receptors blockers (3.15%). In total, 23.00% of all subjects have experienced negative side-effects, mostly, reported (90.38%) to health professionals and 23.52% of them have interrupted temporarily or try to change their treatment. Gastro-intestinal problems were the most adverse reactions reported (11.11%) followed by headache, dizziness and tinnitus (6.66%) and asthenia, feeling sick and feeling of faintness (5.33%).

Conclusion

Managing diabetes and hypertension entails a lot of public challenges and requires more focus and interest, especially amongst the illiterate population in remote areas. Some of the suggested ways to help face the problem include the introduction of new innovative measures, systems of fellow-up and adverse reactions.

Repression of LKB1 by miR-17∼92 Sensitizes MYC-Dependent Lymphoma to Biguanide Treatment

Cancer cells display metabolic plasticity to survive stresses in the tumor microenvironment. Cellular adaptation to energetic stress is coordinated in part by signaling through the liver kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) pathway. Here, we demonstrate that miRNA-mediated silencing of LKB1 confers sensitivity of lymphoma cells to mitochondrial inhibition by biguanides. Using both classic (phenformin) and newly developed (IM156) biguanides, we demonstrate that elevated miR-17∼92 expression in Myc+ lymphoma cells promotes increased apoptosis to biguanide treatment in vitro and in vivo. This effect is driven by the miR-17-dependent silencing of LKB1, which reduces AMPK activation in response to complex I inhibition. Mechanistically, biguanide treatment induces metabolic stress in Myc+ lymphoma cells by inhibiting TCA cycle metabolism and mitochondrial respiration, exposing metabolic vulnerability. Finally, we demonstrate a direct correlation between miR-17∼92 expression and biguanide sensitivity in human cancer cells. Our results identify miR-17∼92 expression as a potential biomarker for biguanide sensitivity in malignancies.

Biguanide-Derived Polymeric Nanoparticles Kill MRSA Biofilm and Suppress Infection In Vivo

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of drug-resistant infections. Its propensity to develop biofilms makes it especially resistant to conventional antibiotics. We present a novel nanoparticle (NP) system made from biocompatible F-127 surfactant, tannic acid (TA), and biguanide-based polymetformin (PMET) (termed FTP NPs), which can kill MRSA biofilm bacteria effectively in vitro and in vivo and which has excellent biocompatibility. FTP NPs exhibit biofilm bactericidal activity-ability to kill bacteria both inside and outside biofilm-significantly better than many antimicrobial peptides or polymers. At low concentrations (8-32 μg/mL) in vitro, FTP NPs outperformed PMET with ∼100-fold (∼2 log₁₀) greater reduction of MRSA USA300 biofilm bacterial cell counts, which we attribute to the antifouling property of the hydrophilic poly(ethylene glycol) contributed by F-127. Further, in an in vivo murine excisional wound model, FTP NPs achieved 1.8 log₁₀ reduction of biofilm-associated MRSA USA300 bacteria, which significantly outperformed vancomycin (0.8 log₁₀ reduction). Moreover, in vitro cytotoxicity tests showed that FTP NPs have less toxicity than PMET toward mammalian cells, and in vivo intravenous injection of FTP NPs at 10 mg/kg showed no acute toxicity to mice with negligible body weight loss and no significant perturbation of blood biomarkers. These biguanide-based FTP NPs are a promising approach to therapy of MRSA infections.

Micropore Particle Technology Promotes Wound Healing, Whereas Polyhexamethylene Biguanide Causes Tissue Degeneration: A Case Report

CASE REPORT

A 72-year-old woman with a nontraumatic spinal cord injury developed eschar on her lower right back. An underlying abscess was identified, which upon surgical debridement left a large wound extending down to the hip bone. In addition, the hip suffered from chronic osteomyelitis and was exposed at the bottom of the wound. The wound was initially treated for 5 weeks with Manuka honey but deteriorated further. Next, micropore particle technology (MPPT) was used. It cleared the wound of necrotic tissue based on autolytic debridement and removed the soft tissue infection; over a 3-month period, the wound reduced 50% in volume. Treatment approach was changed to polyhexamethylene biguanide (PHMB) and was applied as a gel once every second day to the wound. After 6 days, it was observed to cause tissue degeneration, disruption of the structure of the exposed bone, and the appearance of froth coming through the hip bone. A pain syndrome developed and the use of PHMB was terminated on day 10. After a wash-out period, the use of MPPT was reinitiated. Over the following 8 months, MPPT continued to control the infectious debris coming from the hip bone and promote healing without affecting the bone or causing side effects.

CONCLUSIONS

It is generally assumed that the cytotoxic properties of antiseptics seen in cell culture experiments do not occur on wounds. The present case shows these cytotoxic properties are expressed on wounds, and they do disrupt tissues and tissue regeneration.

A Novel CGM Metric-Gradient and Combining Mean Sensor Glucose Enable to Improve the Prediction of Nocturnal Hypoglycemic Events in Patients with Diabetes

Nocturnal hypoglycemia is a serious complication of insulin-treated diabetes, and it is often asymptomatic. A novel CGM metric-gradient was proposed in this paper, and a method of combining mean sensor glucose (MSG) and gradient was presented for the prediction of nocturnal hypoglycemia. For this purpose, the data from continuous glucose monitoring (CGM) encompassing 1,921 patients with diabetes were analyzed, and a total of 302 nocturnal hypoglycemic events were recorded. The MSG and gradient values were calculated, respectively, and then combined as a new metric (i.e., MSG+gradient). In addition, the prediction was conducted by four algorithms, namely, logistic regression, support vector machine, random forest, and long short-term memory. The results revealed that the gradient of CGM showed a downward trend before hypoglycemic events happened. Additionally, the results indicated that the specificity and sensitivity based on the proposed method were better than the conventional metrics of low blood glucose index (LBGI), coefficient of variation (CV), mean absolute glucose (MAG), lability index (LI), etc., and the complex metrics of MSG+LBGI, MSG+CV, MSG+MAG, and MSG+LI, etc. Specifically, the specificity and sensitivity were greater than 96.07% and 96.03% at the prediction horizon of 15 minutes and greater than 87.79% and 90.07% at the prediction horizon of 30 minutes when the proposed method was adopted to predict nocturnal hypoglycemic events in the aforementioned four algorithms. Therefore, the proposed method of combining MSG and gradient may enable to improve the prediction of nocturnal hypoglycemic events. Future studies are warranted to confirm the validity of this metric.

Mining treatment patterns of glucose-lowering medications for type 2 diabetes in the Netherlands

RATIONALE AND OBJECTIVES

Different classes of glucose-lowering medications are used for patients with type 2 diabetes mellitus (T2DM) management. It is unclear how often these medications are prescribed in clinical practice. In this study, we aimed to describe treatment patterns of glucose-lowering medications in patients with T2DM in the Netherlands.

METHODS

We studied a cohort of 73 819 patients with T2DM, aged ≥45 years with a first prescription for oral glucose-lowering medication between 2011 and 2017. We used the NControl database with dispensing data from 800 pharmacies in the Netherlands. Prevalence of each glucose-lowering medication class during 6 years after the index date was calculated. Using SQL Server, we identified stepwise patterns of medication prescription in this population.

FINDINGS

During the study period, prevalence of biguanides (BIGU) decreased from 95.6% to 80.8% and use of sulfonylureas (SU) increased from 27.3% to 42.3%. 55.2% of all patients only received BIGUs, 19.1% of all patients started on BIGUs but switched to BIGU +SU. 13.5% of patients with T2DM initiated insulins, on average 532 days (almost 18 months) after the index date.

CONCLUSIONS

Our findings showed that in the Netherlands, medication treatment in patients with T2DM is mainly consistent with the clinical guidelines in the Netherlands during the study period.

Comparison of olanexidine versus povidone-iodine for preventing surgical site infection in gastrointestinal surgery: study protocol for a multicentre, single-blind, randomised controlled clinical trial

INTRODUCTION

The prevalence of surgical site infection (SSI) remains higher in gastrointestinal surgery than in other surgeries. Although several guidelines have indicated the efficacy of chlorhexidine and povidone-iodine in reducing the SSI rate, the optimal recommendation has still not been established. Therefore, it is necessary to determine the more effective antiseptic for surgical site preparation. Olanexidine (1.5% olanedine, Otsuka Pharmaceutical Factory, Tokushima, Japan), which is a new antiseptic in Japan, has antimicrobial activity against a wide range of bacteria, including Gram-positive and Gram-negative bacteria. Our study will contribute to determining a new antiseptic for use in gastrointestinal and other surgeries.

METHODS AND ANALYSIS

We propose a multicentre, randomised controlled clinical trial for comparing two treatments, that is, 1.5% olanexidine or 10% povidone-iodine, for surgical skin preparation to prevent SSI in clean-contaminated gastrointestinal surgeries with surgical wounds. Patients aged ≥20 years at the time of consent will be included. The primary outcome measure is the 30-day postoperative SSI rate. For the primary analysis, which is aimed at comparing the treatment effects, the adjusted risk ratio and its 95% CI will be estimated using the Mantel-Haenszel method.

ETHICS AND DISSEMINATION

The protocol was first approved by the Institutional Review Board of Keio University School of Medicine, followed by the institutional review board of each participating site. Participant recruitment began in June 2018. The final results will be published in international peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

UMIN 000031560; Pre-results.

Molluscicidal activity of polyhexamethylene biguanide hydrochloride on the early-life stages and adults of the Biomphalaria glabrata (Say, 1818)

Schistosomiasis is a disease that affects tropical and subtropical areas and is considered the second most prevalent parasitic disease in the world. One of the ways of combating this disease is the use of molluscicidal agents to eliminate or reduce the population of intermediate host snails. Polyhexamethylene biguanide hydrochloride (PHMB) is a chemical biocide commonly used as a disinfectant and antiseptic in the food industry and very successfully for the disinfection of swimming pools. The US Environmental Protection Agency (USEPA) indicated the PHMB as low environmental risk. The present study aimed to evaluate the molluscicidal activity of the PHMB in freshwater snail (Biomphalaria glabrata), intermediate host of Schistosoma mansoni. The PHMB showed high toxicity against all stages of the snail B. glabrata: embryos, new-borns and adults. The LC₅₀ estimated was 0.98 mg L^-1; 1.43 mg L^-1 and 1.49 mg L^-1, respectively, after exposure of 144 h for embryos and 96 h for new-borns and adults. PHMB did not prevent the development of embryos within the egg mass, since at all concentrations evaluated 80% of the embryos managed to develop until the hypo-stage, which is the last stage of development before hatching. However, PHMB inhibited the hatching of embryos by 100% at all concentrations above 1.6 mg L^-1. PHMB proved to be a promising substance in the fight against schistosomiasis by eliminating the intermediate host (B. glabrata). This was the first study that makes an experimental observation of the molluscicidal activity of PHMB.

Amebaborne "Attilina massiliensis" Keratitis, France

We report a case of Acanthamoeba castellani keratitis in a person who wore contact lenses. The amebae hosted an ameba-resistant bacterial symbiont, provisionally named “Attilina massiliensis,” a yet undescribed α-Proteobacterium.

Type 2 Diabetes in Neuroendocrine Tumors: Are Biguanides and Statins Part of the Solution?

CONTEXT

Biguanides and statins exert beneficial effects on various cancer types. Their precise effects and underlying molecular mechanisms are poorly understood.

MATERIALS AND METHODS

We analyzed the relationship between metabolic syndrome and histological, epidemiological, and prognosis variables in two cohorts of patients with neuroendocrine tumors (NETs): those with lung carcinoids (LCs; n = 81) and those with gastroenteropancreatic NET (GEP-NET; n = 100). Biguanide and statin antitumor effects were investigated by evaluating proliferation, migration, secretion, gene expression, and involved molecular pathways in BON1/QGP1 cell cultures.

RESULTS

Pleura invasion was higher (LCs group; P < 0.05) and tumor diameter tended to be increased (GEP-NET group) in patients with type 2 diabetes (T2DM) than in those without. Somatostatin and ghrelin systems mRNA levels differed in tumor tissue of patients with T2DM taking metformin or not. Biguanides decreased proliferation rate in BON1/QGP1 cells; the effects of statins on proliferation rate depended on the statin and cell types, and time. Specifically, only simvastatin and atorvastatin decreased proliferation in BON1 cells, whereas all statins decreased proliferation rate in QGP1 cells. Metformin and simvastatin decreased migration capacity in BON1 cells; biguanides decreased serotonin secretion in BON1 cells. Phenformin increased apoptosis in BON1/QGP1 cells; simvastatin increased apoptosis in QGP1 cells. These antitumor effects likely involved altered expression of key genes related to cancer aggressiveness.

CONCLUSION

A clear inhibitory effect of biguanides and statins was seen on NET-cell aggressiveness. Our results invite additional exploration of the potential therapeutic role of these drugs in treatment of patients with NETs.

Intracorneal injection of a detachable hybrid microneedle for sustained drug delivery

There are increasing demands for long-term and controlled corneal drug delivery to treat various ocular diseases. Although biodegradable ocular inserts or contact lenses have been developed, the invasiveness and inefficiency of the approaches still need to be improved. Microneedle (MN) technology can deliver therapeutic molecules to the eye in a minimally invasive manner. However, the current ocular MN technology is limited to either short-term corneal drug delivery or retinal drug delivery by suprachoroidal injection. For long-term and minimally invasive corneal drug delivery, we have developed a detachable biodegradable MN that can be delivered to the inside of the cornea for sustained drug release. The detachable and biodegradable MN is a hybrid MN consisting of a drug-loaded biodegradable tip and a supporting base. The hybrid MN can be applied to the cornea by impact insertion, and it leaves only the drug-loaded biodegradable tip within the corneal tissue so that it can release the drug for a certain period. By concentration-controlled molding, the dimension of drug-loaded MN tips was precisely controlled and their detachability was optimized. The detachable tip and a supporting base were assembled to form a hybrid MN by pressure-assisted transfer molding. We carefully optimized the dimension of the drug-tip, injection dwell time, and insertion depth to achieve effective intracorneal injection of the drug-tip. The detachable hybrid MN was applied to an Acanthamoeba keratitis model wherein a biodegradable drug-tip was successfully delivered to the inside of the mouse cornea in vivo. Follow-up of the MN-treated cases for 7 days confirmed the therapeutic efficacy of the detachable biodegradable MN tips. STATEMENT OF SIGNIFICANCE: For the treatment of infectious diseases in the cornea, such as keratitis, eye drops need to be applied topically every hour for a couple of days. This is extremely uncomfortable, and poor compliance to such tightly scheduled drug administration can result in permanent scar formation in the cornea. In this work, we demonstrate a simple and rapid injection of biodegradable microneedle tips in the corneal tissue wherein the tips can deliver antibacterial drugs for 4 days to treat keratitis. Unlike other patch-style microneedle technologies, this approach allows for insertion depth-controlled and highly localized injection of detachable individual microneedle tips to the diseased tissue for sustained drug delivery. This overcomes the limitations of patch-style microneedles such as short-term drug delivery and unnecessary blockage of tissue.

Mapping of biguanide transporters in human fat cells and their impact on lipolysis

AIM

To examine the cell membrane transporters involved in mediating the antilipolytic effect of biguanides in human fat cells.

MATERIALS AND METHODS

Gene expression of biguanide transporters was mapped in human subcutaneous adipose tissue and in adipocytes before and after differentiation. Those expressed in mature fat cells were knocked down by RNA interference (RNAi) and the antilipolytic effects of metformin and two novel, highly potent biguanides, NT1014 and NT1044, were examined.

RESULTS

Analysis of the transporter affinity of biguanides in HEK293 cells overexpressing individual transporters showed that NT1014 and NT1044 had >10 times higher affinity than metformin. Animal studies showed that NT1014 was >5 times more potent than metformin in lowering plasma glucose in mice. In human fat cells, the novel biguanides displayed higher AMP-activated protein kinase activation and antilipolytic efficacy than metformin. Five transporters, organic cation transporter (OCT)1 (SLC22A1), organic cation transporter novel type 1 (OCTN1; SLC22A4), OCT3 (SLC22A3), plasma membrane monoamine transporter (PMAT; SLC29A4) and multidrug and toxin extrusion transporter (MATE1; SLC47A1), were detectable in fat cells but only OCT3, PMAT and MATE1 increased during adipogenesis in vitro and were enriched in fat cells compared with other adipose cell types. Gene knockdown by RNAi showed that MATE1 and PMAT reduction attenuated the antilipolytic effect of metformin but only PMAT knockdown decreased the effect of all three biguanides.

CONCLUSIONS

While human fat cells primarily express three biguanide transporters, our data suggest that PMAT is the primary target for development of fat cell-specific antilipolytic biguanides with high sensitivity and potency.

A report of 10 patients with Acanthamoeba keratitis

CLINICAL CASES

Cases are presented of 10 patients with Acanthamoeba keratitis treated between 2008 and 2017. All were contact lens wearers. All of them received treatment with a biguanide combined with a diamidine. In 3 cases the infestation did not exceed the superficial stroma, responding to topical treatment. In 7, the infection reached the deep stroma, with 6 of these cases requiring penetrating keratoplasty (PKP), 3 of them therapeutic PKP because of perforation risk or ocular spreading. The visual acuity improved in all the cases.

CONCLUSION

The infestation depth at the time of diagnosis appears to be the main risk factor for requiring a PKP.

Effect of a New Purified Collagen Matrix With Polyhexamethylene Biguanide on Recalcitrant Wounds of Various Etiologies: A Case Series

INTRODUCTION

The management of chronic, nonhealing wounds in patients with multiple comorbidities continues to be a challenge for health care practitioners. Chronic wounds typically do not progress through the normal phases of wound healing and generally remain stagnant during the inflammatory phase, resulting in an increase in proteolytic enzymes with degradation of the extracellular matrix. Bacterial biofilm has been documented to be one of the main factors delaying wound healing, resulting in the prolongation of the inflammatory phase.

OBJECTIVE

In order to control biofilm formation, sequester proteolytic enzymes, and provide a biocompatible scaffold to support healing, the investigators utilize a purified collagen matrix containing polyhexamethylene biguanide (PCMP) in a case series of 9 wounds on 8 patients with multiple comorbidities who did not respond to previous conventional or adjuvant therapy.

MATERIALS AND METHODS

Wound etiologies included 3 pressure ulcers, 1 diabetic foot ulcer, 1 venous leg ulcer, 2 postsurgical wound dehiscences, 1 ulcer secondary to calciphylaxis, and 1 traumatic wound secondary to hematoma. The average wound size at the first PCMP application was 34.0 cm2, and the wounds were present for an average of 9.2 weeks prior to the first PCMP application.

RESULTS

Patients received an average of 5.8 PCMP applications. Of the 6 wounds that healed, average time to closure from the first PCMP application was 10 weeks. The remaining 3 wounds demonstrated improved wound appearance with 100% granulation tissue and an average area reduction during PCMP treatment of 61.4%.

CONCLUSIONS

This case series demonstrated that PCMP along with good wound care supported both wound closure and improvements in wound bed condition and area reduction on recalcitrant, nonhealing wounds of various etiologies.

Polyhexanide 0.2% in treatment of trophic foot ulcers in leprosy - preliminary study

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which affects peripheral nerves, skin and mucous membranes. The impairment of neural function as well as sensory or sensory-motor disabilities in leprosy continue to be a problem that requires careful attention in the management of patients with the aim to avoid or minimize their progression to prevent sequelae. One of the most common characteristics of these ulcers is the tendency to chronicity, with variable therapeutic response. In this article, we shall discuss the therapeutic management of thirteen trophic leprosy ulcers in eight patients using polyhexanide 0.2% products.

The prescribing trend of oral antidiabetic agents for type 2 diabetes in Taiwan: An 8-year population-based study

The purpose of this study was to evaluate the prescription trend and pattern of oral antidiabetic (OAD) medications, which are extensively used worldwide for treating type 2 diabetes, in 2 age groups.In this population-based study, data obtained from the National Health Insurance Research Database, Taiwan, were analyzed to investigate the prescription trend of all types of OAD medications during 2005 to 2012. We used descriptive statistics to demonstrate the trend of prescription patterns stratified by age (aged 65 years and above or younger than 65).Sulfonylurea (SU) was once the most commonly used drug, but the proportion of its prescription had declined gradually (76.83% in 2005 to 63.70% in 2012). Consequently, biguanide (BG) became the most commonly used drug since 2010 (64.31% in 2005 to 74.41% in 2012). In addition, the prescriptions of thiazolidinedione decreased significantly (9.20% in 2005 to 2.86% in 2012), whereas the usage of DPP-4 inhibitor increased with time (3.73% in 2009 to 19.64% in 2012). The treatment choice of SU and α-glucosidase inhibitor (AGI) was higher in elderly patients compared with the younger population (SU: 62.70% in 2012, AGI: 12.78% in 2012). Two-drug combination therapies were the prevalent treatment choices for patients with type 2 diabetes (44.77% in 2012), particularly in the elderly group; however, ≥3 drug combination therapies increased gradually during the study period, particularly in the younger group.This descriptive study presents the change in the prescription of OAD medication for different age groups during 2005 to 2012.

Metformin: historical overview

Metformin (dimethylbiguanide) has become the preferred first-line oral blood glucose-lowering agent to manage type 2 diabetes. Its history is linked to Galega officinalis (also known as goat's rue), a traditional herbal medicine in Europe, found to be rich in guanidine, which, in 1918, was shown to lower blood glucose. Guanidine derivatives, including metformin, were synthesised and some (not metformin) were used to treat diabetes in the 1920s and 1930s but were discontinued due to toxicity and the increased availability of insulin. Metformin was rediscovered in the search for antimalarial agents in the 1940s and, during clinical tests, proved useful to treat influenza when it sometimes lowered blood glucose. This property was pursued by the French physician Jean Sterne, who first reported the use of metformin to treat diabetes in 1957. However, metformin received limited attention as it was less potent than other glucose-lowering biguanides (phenformin and buformin), which were generally discontinued in the late 1970s due to high risk of lactic acidosis. Metformin's future was precarious, its reputation tarnished by association with other biguanides despite evident differences. The ability of metformin to counter insulin resistance and address adult-onset hyperglycaemia without weight gain or increased risk of hypoglycaemia gradually gathered credence in Europe, and after intensive scrutiny metformin was introduced into the USA in 1995. Long-term cardiovascular benefits of metformin were identified by the UK Prospective Diabetes Study (UKPDS) in 1998, providing a new rationale to adopt metformin as initial therapy to manage hyperglycaemia in type 2 diabetes. Sixty years after its introduction in diabetes treatment, metformin has become the most prescribed glucose-lowering medicine worldwide with the potential for further therapeutic applications.

The mechanisms of action of metformin

Metformin is a widely-used drug that results in clear benefits in relation to glucose metabolism and diabetes-related complications. The mechanisms underlying these benefits are complex and still not fully understood. Physiologically, metformin has been shown to reduce hepatic glucose production, yet not all of its effects can be explained by this mechanism and there is increasing evidence of a key role for the gut. At the molecular level the findings vary depending on the doses of metformin used and duration of treatment, with clear differences between acute and chronic administration. Metformin has been shown to act via both AMP-activated protein kinase (AMPK)-dependent and AMPK-independent mechanisms; by inhibition of mitochondrial respiration but also perhaps by inhibition of mitochondrial glycerophosphate dehydrogenase, and a mechanism involving the lysosome. In the last 10 years, we have moved from a simple picture, that metformin improves glycaemia by acting on the liver via AMPK activation, to a much more complex picture reflecting its multiple modes of action. More work is required to truly understand how this drug works in its target population: individuals with type 2 diabetes.

Metformin: clinical use in type 2 diabetes

Metformin is one of the most popular oral glucose-lowering medications, widely considered to be the optimal initial therapy for patients with type 2 diabetes mellitus. Interestingly, there still remains controversy regarding the drug's precise mechanism of action, which is thought to involve a reduction in hepatic glucose production. It is now recommended as first-line treatment in various guidelines, including that of the EASD and ADA. Its favoured status lies in its efficacy, low cost, weight neutrality and good safety profile. Other benefits have also been described, including improvements in certain lipids, inflammatory markers, and a reduction in cardiovascular events, apparently independent from the drug's glucose-lowering effect. Data have emerged questioning the previous reluctance to use this agent in those with mild to moderate chronic kidney disease. Regulations guiding its use in patients with stable, modest renal dysfunction have, as a result, become more lenient in recent years. With no long-term studies comparing it against newer glucose-lowering drugs, some of which have more robust evidence for cardioprotection, metformin's established role as 'foundation therapy' in type 2 diabetes may justifiably be challenged.

Drug-class-specific changes in the volume and cost of antidiabetic medications in Poland between 2012 and 2015

Aim

to investigate the drug-class-specific changes in the volume and cost of antidiabetic medications in Poland in 2012–2015.

Methods

This retrospective analysis was conducted based on the National Health Fund database covering an entire Polish population. The volume of antidiabetic medications is reported according to ATC/DDD methodology, costs—in current international dollars, based on purchasing power parity.

Results

During a 4-year observational period the number of patients, consumption of antidiabetic drugs and costs increased by 17%, 21% and 20%, respectively. Biguanides are the basic diabetes medication with a 39% market share. The insulin market is still dominated by human insulins, new antidiabetics (incretins, thiazolidinediones) are practically absent. Insulins had the largest share in diabetes medications expenditures (67% in 2015). The increase in antidiabetic medications costs over the analysed period of time was mainly caused by the increased use of insulin analogues.

Conclusions

The observed tendencies correspond to the evidence-based HTA recommendations. The reimbursement status, the ratio of cost to clinical outcomes and data on the long-term safety have a deciding impact on how a drug is used.

Should Side Effects Influence the Selection of Antidiabetic Therapies in Type 2 Diabetes?

PURPOSE OF REVIEW

There are currently over 40 different drugs in 12 distinct classes approved in the USA to treat patients with type 2 diabetes mellitus. This review summarizes our current knowledge about potential side effects of antidiabetic therapy and attempts to apply it to a clinical practice setting.

RECENT FINDINGS

Given the heterogeneity of both the patients and the disease, it is mathematically impossible to test every available drug combination in long-term outcome, prospective, randomized blinded fashion before a clinician decides which agent(s) to prescribe to a specific patient in a given situation. To complicate the clinician's dilemma, there is lack of available tests to predict an individual's response or propensity to side effects. Further, the data available are derived from small, short-term registration trials and typically focus on relative rather than absolute risks of any given drug and do not address the potential adverse outcomes if a patient's diabetes remains untreated. Clinicians have to personalize their choice of antidiabetic therapy based both on the specific characteristics of the patient in front of them (stage of diabetes and its complications, overall health status, socioeconomic situation, other medications present, desire to improve control of diabetes, etc.) and the current knowledge about the relative and absolute balance of benefits and risks of any individual medication in that specific patient. It has to be recognized that this requires constant re-evaluation as database of our experience with antidiabetic therapy expands.

Dacryoadenitis and extraocular muscle inflammation associated with contact lens-related Acanthamoeba keratitis: A case report and review of the literature

The present report discusses a new case of dacryoadenitis with extraocular muscle inflammation associated with Acanthamoeba keratitis (AK) in a contact lens wearer. A 41-year-old male, who has worn silicone hydrogel contact lenses on an extended basis for about 10 years, attended with the complaints of vision disturbance, hyperemia, and pain in his right eye. His history revealed that 1.5 month ago, he had been diagnosed with allergic conjunctivitis and had used steroid eye drops. Biomicroscopic examination revealed eyelid edema, chemosis, and ring infiltration, radial keratoneuritis and an epithelial defect in the cornea. Magnetic resonance imaging demonstrated enlarged lacrimal gland with edematous changes consistent with inflammation due to dacryoadenitis. There were also thickening and edema of the right superior oblique and lateral rectus muscle. The treatment protocol for AK was applied with no specific treatment for dacryoadenitis. After 4 months of the treatment, dacryoadenitis and keratitis regressed. Dacryoadenitis and extraocular muscle inflammation may accompany AK more frequently than expected and previously known. The evaluation of the lacrimal gland and extraocular muscles in presence of AK might be beneficial for understanding better the exact clinical picture and course of the keratitis.

Comparison of baseline characteristics and clinical course in Japanese patients with type 2 diabetes among whom different types of oral hypoglycemic agents were chosen by diabetes specialists as initial monotherapy (JDDM 42)

Little is known about the relationships between patient factors and the antihyperglycemic agents that have been prescribed as initial therapy by diabetes specialists for patients with type 2 diabetes. Moreover, there has been little clarification of the subsequent usage patterns and related factors that influenced the continuation or discontinuation of the drug or the addition of another drug. To provide information on these issues, we evaluated the clinical characteristics of Japanese patients with type 2 diabetes for whom different types of oral hypoglycemic agents (i.e., either sulfonylureas, biguanides, or DPP-4 inhibitors (DPP-4Is)) were chosen as initial monotherapy by diabetes specialists and evaluated subsequent usage patterns.Prescription data on 3 different antidiabetic agents from December 2009 to March 2015 from diabetes specialists' patient registries were used to identify variables at baseline related to initial prescriptions; also, the addition of another hypoglycemic drug or discontinuation of the initial therapy was evaluated 1 year after the initial prescription. Analyzed were data on 2666 patients who received initial monotherapy with either a sulfonylurea (305 patients), biguanide (951 patients), or DPP-4I (1410 patients). Patients administered sulfonylureas were older, had a lower body mass index (BMI), longer duration of diabetes, and worse glycemic control than recipients of biguanides. Use of biguanides was related to younger age, short duration of diabetes, and obesity but was negatively associated with poor glycemic control. Older age but neither obesity nor poor glycemic control was associated with DPP-4Is. In all 3 groups a high HbA1c value was related to adding another hypoglycemic agent to the initial therapy. Moreover, adding another drug to a DPP-4I was related to a younger age and higher BMI.Patients' age, duration of diabetes, obesity, and glycemic control at baseline influenced the choice of hypoglycemic agents. Selection of a biguanide differs greatly from that of a sulfonylurea or DPP-4I with regard to age and obesity.

The Dramatic Recovery of a Patient with Biguanide-associated Severe Lactic Acidosis Following Thiamine Supplementation

Biguanides are a drug of choice for the treatment of type 2 diabetes mellitus. Although they can cause lactic acidosis in susceptible patients with predisposing risk factors, the incidence of lactic acidosis is reported to be very low when they are used properly. We herein present a case of biguanide-associated severe lactic acidosis complicated with thiamine deficiency that was provoked without predisposing factors for thiamine deficiency. Diabetic patients taking biguanide may be predisposed to thiamine deficiency, even when there is no evidence of risk factors, and the high-dose administration of thiamine may be essential in the treatment of this otherwise under-recognized disorder.

[CHANGES OF LIFETIME MORPHOLOGICAL PARAMETERS OF THE RETINA ON THE BACKGROUND OF CORRECTION OF LIPID METABOLISM IN PATIENTSWITH TYPE 2 DIABETES MELLITUS]

The functional changes of retina morphological parameters of macular zone were investigated under condition of long term action of fenofibrate, 145 mg in patients with diabetes mellitus type 2. Dynamic observation of certain ophthalmologic (visual acuity, macular thickness zone) and system functional parameters (lipid fractions content in serum) in long-term use of this medical drug in 20 patients with diabetes type 2 and DMO for 8 months. In this period we revealed some positive changes in the functional state of the macular area: increase of visual acuity, decrease of macula thickness and the improvement of the lipid profile in blood serum.

The combination of dulaglutide and biguanide reduced bodyweight in Japanese patients with type 2 diabetes

The efficacy and safety of once-weekly dulaglutide 0.75 mg (dulaglutide) in Japanese patients with type 2 diabetes (T2D) were evaluated according to subgroups defined by concomitant oral hypoglycaemic agents. This exploratory analysis included data from a randomized, open-label, phase III study that compared dulaglutide with insulin glargine (glargine) (n = 361). The three subgroups were dulaglutide or glargine in combination with sulphonylurea (SU) alone, biguanide (BG) alone or SU and BG combined. There were no clinically relevant differences in glycated haemoglobin (HbA1c) changes among the three subgroups in the dulaglutide group; in the glargine group, a numerically greater reduction was observed in combination with BG alone compared to the other two groups (SU alone and SU + BG). Weight loss was observed with dulaglutide in combination with BG alone or with SU + BG. The incidence of adverse events among subgroups was significantly different in the glargine group but not in the dulaglutide group. Incidence of hypoglycaemia was highest in combination with SU for both treatments. For patients with T2D, dulaglutide added to concomitant BG may be more likely to result in weight loss than dulaglutide added to concomitant SU.

0.1% Polyhexanide-Betaine Solution as an Adjuvant in a Case-Series of Chronic Wounds

INTRODUCTION

The application of 0.1% polyhexanide-betaine gel and irrigating solution was used in place of saline during standard of care wound treatment for 70 chronic wounds of various etiologies. Our goal in this study sample was to investigate the number of days to wound closure, change in absolute wound size, and antimicrobial initiation from baseline visit, following application of polyhexanide-betaine in standard of care wound treatment. Results suggested a benefit of Prontosan® (Polyhexanide-betaine, B. Braun Medical Inc., Allentown, Pennsylvania), with very few patients being administered supplemental antibiotic treatment.

MATERIALS AND METHODS

A retrospective chart analysis evaluated 0.1% polyhexanide-betaine as an adjuvant in the management of chronic non-healing wounds. Over a two-year period at a single wound center, 0.1% polyhexanide-betaine gel and irrigating solution were applied in place of saline during standard of care wound treatment for 70 chronic wounds of various etiologies. Standard weekly wound protocols and debridement were performed. All wounds were evaluated for days to closure, change in wound dimensions, and number of patients requiring antibiotic therapy after initial consultation at the study site.

RESULTS

A case series of 49 patients presented 70 wounds for analysis. Antimicrobial therapy was initiated in five of 49 patients. Days to wound closure revealed that venous wounds showed the shortest number of days to closure (29 days) with diabetic ulcers the longest (92 days). Significant comorbid conditions and concomitant medications were present in all groups and did not appear associated with closure rates.

CONCLUSIONS

The use of 0.1% polyhexanide-betaine gel and solution in treating chronic non-healing wounds provided a moist wound healing environment facilitating closure. Of particular note was the fact that with polyhexanide-betaine, antimicrobial therapy was not initiated in nearly 90% of patients. It is theorized that the antimicrobial effect of 0.1% polyhexanide-betaine gel and solution inhibited bacterial colonization and reduced the need for antimicrobial usage. A prospective controlled and randomized study is warranted to further explore this theory.

The Effectiveness of Topical Polyhexamethylene Biguanide (PHMB) Agents for the Treatment of Chronic Wounds: A Systematic Review

INTRODUCTION

This is the first systematic review to explore the evidence on PHMB and determine how effective this topical agent is for the treatment of chronic wounds.

MATERIALS AND METHODS

PubMed, Ovid MEDLINE, CINAHL, Embase, the Cochrane library, and Scopus were searched for relevant articles published from 1946 to February 3, 2014, with no restrictions on publication status. ProQuest was searched for relevant dissertations, editorials, and conference abstracts. Non-indexed journals were searched and companies that manufacture wound care materials containing PHMB were contacted for unpublished data. Only randomized controlled trials available in English were included. Bias was assessed using the CONSORT document for all included studies. After inclusion and exclusion criteria were determined, four reviewers (ET, SK, SG, RD) independently reviewed each title and abstract of the literature search results to determine whether the paper should be included for this review. When disagreements on study inclusion emerged, reviewers resolved them through discussion.

RESULTS

Of the 1,725 articles identified in the search, 6 met inclusion criteria. Four studies reported wound healing. Two of these studies evaluated changes in wound surface area and the other two evaluated wound bed evolution with variable results. In five studies, participants randomly assigned to PHMB topical agents showed significant improvement in bacterial control compared to control groups. Five studies reported pain reduction from the use of PHMB agents.

DISCUSSION

There were a small number of eligible studies found, but the interventions, outcome measures, and outcome reporting varied greatly, making meta-analysis impossible. PHMB agents were shown to promote healing and reduce pain more effectively than control treatments.

CONCLUSION

The existing evidence shows that topical PHMB may promote healing of chronic stalled wounds, reduce bacterial burden, eliminate methicillin-resistant staphylococcus aureus (MRSA), and alleviate wound-related pain.

A randomized clinical trial of basal insulin peglispro vs NPH in insulin-naïve patients with type 2 diabetes: the IMAGINE 6 trial

AIMS

Basal insulin peglispro (BIL) has a longer duration of action than conventional insulin analogues and a hepato-preferential mechanism of action. This study assessed whether BIL was non-inferior to isophane insulin (NPH) in reducing HbA1c in insulin-naïve patients with type 2 diabetes, when added to pre-study oral anti-hyperglycaemic medications.

MATERIALS AND METHODS

This was a Phase 3, open-label, treat-to-target (TTT), randomized trial with a 2-week lead-in, 26-week treatment and a 4-week safety follow-up period. Patients were randomized to bedtime (pm) NPH, morning (am) BIL or pm BIL in a 1:1:1 ratio.

RESULTS

Six hundred and forty-one patients [NPH, n = 213; BIL, n = 428 (am, n = 213; pm, n = 215)] received study drug. BIL was non-inferior to NPH for HbA1c change from baseline at Week 26 with a between-treatment difference (95% confidence interval) of -0.37% (-0.50, -0.23%). HbA1c at baseline was 8.5%, and was lower in BIL- vs NPH-treated patients after 26 weeks of treatment (6.8% vs 7.1%; P < .001). More BIL-treated patients achieved HbA1c <7.0% and HbA1c <7.0% without nocturnal hypoglycaemia. Fasting serum glucose levels and nocturnal hypoglycaemia rates were lower in BIL-treated patients; total hypoglycaemia rates were similar. Treatment-emergent adverse events were similar between groups. Fasting triglycerides decreased from baseline in both groups and to a greater extent with NPH, but were not significantly different between groups at Week 26. Mean alanine aminotransferase (ALT) increased with BIL treatment, but there was no evidence of acute severe hepatotoxicity.

CONCLUSIONS

In this TTT study, BIL treatment showed clinically relevant improvements in glycaemic control and a significant reduction in nocturnal hypoglycaemia compared to NPH.

Pharmacology and therapeutic implications of current drugs for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a global epidemic that poses a major challenge to health-care systems. Improving metabolic control to approach normal glycaemia (where practical) greatly benefits long-term prognoses and justifies early, effective, sustained and safety-conscious intervention. Improvements in the understanding of the complex pathogenesis of T2DM have underpinned the development of glucose-lowering therapies with complementary mechanisms of action, which have expanded treatment options and facilitated individualized management strategies. Over the past decade, several new classes of glucose-lowering agents have been licensed, including glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors and sodium/glucose cotransporter 2 (SGLT2) inhibitors. These agents can be used individually or in combination with well-established treatments such as biguanides, sulfonylureas and thiazolidinediones. Although novel agents have potential advantages including low risk of hypoglycaemia and help with weight control, long-term safety has yet to be established. In this Review, we assess the pharmacokinetics, pharmacodynamics and safety profiles, including cardiovascular safety, of currently available therapies for management of hyperglycaemia in patients with T2DM within the context of disease pathogenesis and natural history. In addition, we briefly describe treatment algorithms for patients with T2DM and lessons from present therapies to inform the development of future therapies.

Negative Pressure Wound Therapy With Instillation and Dwell Time Used to Treat Infected Orthopedic Implants: A 4-patient Case Series

Infection following orthopedic implants for bone fixation or joint replacement is always serious and may require removal of the osteosynthetic material. Negative pressure wound therapy with instillation and dwell time (NPWTi-d) is an emerging therapy for the treatment of complex wounds, including infected wounds with osteosynthetic material. The purpose of this case study was to evaluate the outcomes of 4 patients (1 man, 3 women; age range 49 to 71 years) with a postoperative wound infection (POWI) following fracture repair and internal fixation. All patients were at high risk for surgical complications, including infections. Standard infection treatments (antibiotics) had been unsuccessful. Based on the available literature, a NPWTi-d protocol was developed. Following surgical debridement, wounds were instilled with polyhexanide biguanide with a set dwell time of 15 minutes, followed by continuous NPWTi-d of -125 mm Hg for 4 hours. The system was changed every 3 to 4 days until sufficient granulation tissue was evident and negative pressure without instillation could be used. Systemic antibiotics were continued in all patients. Granulation tissue was found to be sufficient in 12 to 35 days in the 4 cases, no recurrence of infection was noted, and the osteosynthesis material remained in place. No adverse events were observed. Research is needed to compare the safety and effectiveness of this adjunct treatment in the management of challenging wounds to other patient and wound management approaches.

Long-term safety and efficacy of fasiglifam (TAK-875), a G-protein-coupled receptor 40 agonist, as monotherapy and combination therapy in Japanese patients with type 2 diabetes: a 52-week open-label phase III study

This multicentre, open-label, phase III study investigated the safety and efficacy of the G-protein-coupled receptor 40 agonist fasiglifam. Japanese patients with type 2 diabetes and inadequate glycaemic control despite diet and/or exercise (n = 282), or despite diet and/or exercise plus one oral antidiabetic agent [sulphonylurea (n = 262), rapid-acting insulin secretagogue (n = 124), α-glucosidase inhibitor (n = 141), biguanide (n = 136), thiazolidinedione (n = 139) or dipeptidyl peptidase-4 inhibitor (n = 138)] were randomized to treatment with fasiglifam 25 or 50 mg once daily for 52 weeks. The primary endpoints were safety variables. The overall incidence of treatment-emergent adverse events (TEAEs) was 75.4-85.1% in the 25 mg group and 78.9-89.9% in the 50 mg group; most TEAEs were mild. Hypoglycaemia was negligible with fasiglifam monotherapy and most common with sulphonylurea combination therapy (12.4 and 9.1% for 25 and 50 mg groups, respectively). Abnormal liver-related laboratory values were uncommon. Glycated haemoglobin levels decreased from week 2 in all groups and were maintained to week 52. Although fasiglifam as monotherapy or in combination regimens was well tolerated during long-term treatment, global concerns about liver safety led to termination of its development after study completion.

Natural Products to Counteract the Epidemic of Cardiovascular and Metabolic Disorders

Natural products have always been exploited to promote health and served as a valuable source for the discovery of new drugs. In this review, the great potential of natural compounds and medicinal plants for the treatment or prevention of cardiovascular and metabolic disorders, global health problems with rising prevalence, is addressed. Special emphasis is laid on natural products for which efficacy and safety have already been proven and which are in clinical trials, as well as on plants used in traditional medicine. Potential benefits from certain dietary habits and dietary constituents, as well as common molecular targets of natural products, are also briefly discussed. A glimpse at the history of statins and biguanides, two prominent representatives of natural products (or their derivatives) in the fight against metabolic disease, is also included. The present review aims to serve as an "opening" of this special issue of Molecules, presenting key historical developments, recent advances, and future perspectives outlining the potential of natural products for prevention or therapy of cardiovascular and metabolic disease.

Case 14: Octenilin Wound Gel versus betadine/PHMB gel

Here, a clinician compares 4 weeks of treatment with Prontosan Wound Gel with a subsequent 4 weeks of octenilin Wound Gel on a complex diabetic foot ulcer prone to recurrent infection. The data show that, following the switch to octenilin, the previously static wound started to heal.

[POLYHEXAMETHYLENE BIGUANID HYDROCHLORIDE (BIGUANELLE) THERAPY OF BACTERIAL VAGINOSIS]

The aim of our study was to determine the efficacy and tolerability of local therapy with polyhexamethylene biguanid hydrochloride (BIGUANELLE) in women with anaerobic vaginal infection.

MATERIAL AND METHODS

We include in our study 23 women (18-50) with established by AMSEL criteria bacterial vaginosis. In all of the women at the beginning and at the end of the survey was performed gynecological examination and microbiological research (AMSEL). The therapeutic scheme at all women is with a single vaginal application of gynecological solution BIGUANELLE. Effectiveness of the treatment was evaluated according to clinical complaints and microbiological research (Amsel criteria: Ph 4.5 >; KOH (+); "clue cells"; specific vaginal fluorine). Tolerability of patients to treatment was assessed by questionnaire.

RESULTS

Clinical complaints of patients after the therapy decreased as follows: vaginal fluorine with 73.9%; odor--75%; pruritus--50%; discomfort--90%. Microbiological research and their evaluation by AMSEL, showed the therapeutic efficacy of the therapy in 16 (69.6%) of all (n-23) patients. At 7 (30.4%) women, the treatment remained without effect. At questionnaire answers, 73.9% patients were satisfied with the application of BIGUANELLE, 95.6% of them have implemented it easily, 95.6% of women believe that BIGUANELLE is more convenient to use in comparison with similar products which have a daily application, and none of the patients (100%) have any complaints in applying this gynecological solution.

CONCLUSIONS

BIGUANELLE showed good clinical efficacy in the treatment of bacterial vaginosis. It is easily applied and well tolerated by the patients.