Metformin. A review of its pharmacological properties and therapeutic use in non-insulin-dependent diabetes mellitus

Sustained Release Studies of Metformin Hydrochloride Drug Using Conducting Polymer/Gelatin-Based Composite Hydrogels

The present work highlights the synthesis and characterization of conducting polymer (CP)-based composite hydrogels with gelatin (GL-B) for their application as drug delivery vehicles. The spectral, morphological, and rheological properties of the synthesized hydrogels were explored, and morphological studies confirmed formation of an intense interpenetrating network. Rheological measurements showed variation in the flow behavior with the type of conducting polymer. The hydrogels showed a slow drug release rate of about 10 h due to the presence of the conducting polymer. The release kinetics were fitted in various mathematical models and were best fit in first order for PNA-, POPD-, and PANI-based GL-B hydrogels, and the PVDF/GL-B hydrogel was best fit in the zero-order models. The drug release was found to follow the order: POPD/GL-B > PANI/GL-B > PVDF/GL-B.

Mito-metformin protects against mitochondrial dysfunction and dopaminergic neuronal degeneration by activating upstream PKD1 signaling in cell culture and MitoPark animal models of Parkinson's disease

Impaired mitochondrial function and biogenesis have strongly been implicated in the pathogenesis of Parkinson's disease (PD). Thus, identifying the key signaling mechanisms regulating mitochondrial biogenesis is crucial to developing new treatment strategies for PD. We previously reported that protein kinase D1 (PKD1) activation protects against neuronal cell death in PD models by regulating mitochondrial biogenesis. To further harness the translational drug discovery potential of targeting PKD1-mediated neuroprotective signaling, we synthesized mito-metformin (Mito-Met), a mitochondria-targeted analog derived from conjugating the anti-diabetic drug metformin with a triphenylphosphonium functional group, and then evaluated the preclinical efficacy of Mito-Met in cell culture and MitoPark animal models of PD. Mito-Met (100-300 nM) significantly activated PKD1 phosphorylation, as well as downstream Akt and AMPKα phosphorylation, more potently than metformin, in N27 dopaminergic neuronal cells. Furthermore, treatment with Mito-Met upregulated the mRNA and protein expression of mitochondrial transcription factor A (TFAM) implying that Mito-Met can promote mitochondrial biogenesis. Interestingly, Mito-Met significantly increased mitochondrial bioenergetics capacity in N27 dopaminergic cells. Mito-Met also reduced mitochondrial fragmentation induced by the Parkinsonian neurotoxicant MPP+ in N27 cells and protected against MPP+-induced TH-positive neurite loss in primary neurons. More importantly, Mito-Met treatment (10 mg/kg, oral gavage for 8 week) significantly improved motor deficits and reduced striatal dopamine depletion in MitoPark mice. Taken together, our results demonstrate that Mito-Met possesses profound neuroprotective effects in both in vitro and in vivo models of PD, suggesting that pharmacological activation of PKD1 signaling could be a novel neuroprotective translational strategy in PD and other related neurocognitive diseases.

Cellulose-alginate hydrogels and their nanocomposites for water remediation and biomedical applications

In the last decade, both cellulose and alginate polysaccharides have been extensively utilized for the synthesis of biocompatible hydrogels because of their alluring characteristics like low cost, biodegradability, hydrophilicity, biodegradability, ease of availability and non-toxicity. The presence of abundant hydrophilic functional groups (like carboxyl and hydroxyl) on the surface of cellulose and alginate or their derivatives makes these materials promising candidates for the preparation of hydrogels with appealing structures and characteristics, leading to growing research in water treatment and biomedical fields. These two polysaccharides are typically blended together to improve hydrogels' desired qualities (mechanical strength, adsorption properties, cellulose/alginate yield). So, keeping in view their extensive applicability, in the present review article, recent advances in the development of cellulose/nanocellulose-alginate-based hydrogels and their relevance in water treatment (adsorption of dyes, heavy metals, etc.) and biomedical field (wound healing, tissue engineering, drug delivery) has been reviewed. Further, impact of other inorganic/organic additives in cellulose/nanocellulose-alginate-based hydrogels properties like contaminants adsorption, drug delivery, tissue engineering, etc., has also been studied. Moreover, the current difficulties and future prospects of nanocellulose-alginate-based hydrogels regarding their water purification and biomedical applications are also discussed at the end.

Pharmaceutical and Recreational Drug Usage Patterns during and Post COVID-19 Determined by Wastewater-Based Epidemiology

Wastewater-based epidemiology (WBE) was applied to evaluate the consumption trends of pharmaceuticals (i.e., antibiotics, non-steroidal anti-inflammatory drugs, antiepileptics, antihypertensives, and others), as well as recreational drugs (caffeine, alcohol, and nicotine), in Latvia from December 2020 to July 2023. The time period covers both the COVID-19 pandemic and the post-pandemic periods; therefore, the impact of the implemented restrictions and the consequences of the illness in terms of the usage of pharmaceuticals thereon were investigated. Additionally, the seasonality and impact of the seasonal flu and other acute upper respiratory infections were studied. The results revealed that the pandemic impacted the consumption of alcohol, nicotine, and caffeine, as well as several pharmaceuticals, such as antihypertensives, antidepressants, psychiatric drugs, and the painkiller ibuprofen. The findings suggest that the imposed restrictions during the pandemic may have had a negative effect on the population's health and mental well-being. Distinct seasonal trends were discovered in the consumption patterns of caffeine and alcohol, where lower use was observed during the summer. The seasonal consumption trends of pharmaceuticals were discovered in the case of antibiotics, the antiasthmatic drug salbutamol, and the decongestant xylometazoline, where higher consumption occurred during colder seasons.

Effect of 5'-adenosine monophosphate-activated protein kinase agonists on insulin and glucose dynamics in experimentally induced insulin dysregulation in horses

BACKGROUND

5'-adenosine monophosphate-activated protein kinase (AMPK) agonists, particularly resveratrol (RES), have not been extensively evaluated for their effect on insulin dysregulation (ID) in horses.

OBJECTIVES

Evaluate the effects of treatment with RES (10 mg/kg PO q12h), metformin (MET; 30 mg/kg PO q12h), and aspirin (ASP; 20 mg/kg PO q24h) on experimentally induced ID.

ANIMALS

Thirty-three healthy, adult, light-breed horses.

METHODS

Unblinded, placebo-controlled, experimental trial evaluating effects of AMPK agonists (RES, MET, and ASP) on experimentally induced ID. Horses were randomly assigned to a treatment group (RES, MET/ASP, RES/ASP, RES/MET/ASP, or placebo [CON]) after induction of ID with dexamethasone (0.08 mg/kg PO q24h for 7 days). Frequently sampled insulin-modified IV glucose tolerance tests (FSIGTT) and oral sugar tests (OST) were performed at baseline, 7 days after ID, and ID plus 7 days of treatment. Minimal model and OST variables were compared between (1-way ANOVA) and within (1-way ANOVA for repeated measures) groups over time to determine effects of treatment on ID.

RESULTS

Administration of dexamethasone for 14 days resulted in significantly altered insulin and glucose dynamics (SI, DI, basal [glucose], and [insulin]) and produced clinical signs of laminitis in 5 out of 33 (15%) of horses included in the study. Combination therapy with RES, MET, and ASP did not significantly improve insulin and glucose dynamics in horses with experimentally induced ID.

CONCLUSIONS AND CLINICAL IMPORTANCE

Metabolic testing before glucocorticoid administration should be considered in horses with clinical signs of metabolic syndrome.

Targeted Inhibition of Hsp90 in Combination with Metformin Modulates Programmed Cell Death Pathways in A549 Lung Cancer Cells

The pathophysiology of lung cancer is dependent on the dysregulation in the apoptotic and autophagic pathways. The intricate link between apoptosis and autophagy through shared signaling pathways complicates our understanding of how lung cancer pathophysiology is regulated. As drug resistance is the primary reason behind treatment failure, it is crucial to understand how cancer cells may respond to different therapies and integrate crosstalk between apoptosis and autophagy in response to them, leading to cell death or survival. Thus, in this study, we have tried to evaluate the crosstalk between autophagy and apoptosis in A549 lung cancer cell line that could be modulated by employing a combination therapy of metformin (6 mM), an anti-diabetic drug, with gedunin (12 µM), an Hsp90 inhibitor, to provide insights into the development of new cancer therapeutics. Our results demonstrated that metformin and gedunin were cytotoxic to A549 lung cancer cells. Combination of metformin and gedunin generated ROS and promoted MMP loss and DNA damage. The combination further increased the expression of AMPKα1 and promoted the nuclear localization of AMPKα1/α2. The expression of Hsp90 was downregulated, further decreasing the expression of its clients, EGFR, PIK3CA, AKT1, and AKT3. Inhibition of the EGFR/PI3K/AKT pathway upregulated TP53 and inhibited autophagy. The combination was promoting nuclear localization of p53; however, some cytoplasmic signals were also detected. Further increase in the expression of caspase 9 and caspase 3 was observed. Thus, we concluded that the combination of metformin and gedunin upregulates apoptosis by inhibiting the EGFR/PI3K/AKT pathway and autophagy in A549 lung cancer cells.

Drug-microbiota interactions: an emerging priority for precision medicine

Individual variability in drug response (IVDR) can be a major cause of adverse drug reactions (ADRs) and prolonged therapy, resulting in a substantial health and economic burden. Despite extensive research in pharmacogenomics regarding the impact of individual genetic background on pharmacokinetics (PK) and pharmacodynamics (PD), genetic diversity explains only a limited proportion of IVDR. The role of gut microbiota, also known as the second genome, and its metabolites in modulating therapeutic outcomes in human diseases have been highlighted by recent studies. Consequently, the burgeoning field of pharmacomicrobiomics aims to explore the correlation between microbiota variation and IVDR or ADRs. This review presents an up-to-date overview of the intricate interactions between gut microbiota and classical therapeutic agents for human systemic diseases, including cancer, cardiovascular diseases (CVDs), endocrine diseases, and others. We summarise how microbiota, directly and indirectly, modify the absorption, distribution, metabolism, and excretion (ADME) of drugs. Conversely, drugs can also modulate the composition and function of gut microbiota, leading to changes in microbial metabolism and immune response. We also discuss the practical challenges, strategies, and opportunities in this field, emphasizing the critical need to develop an innovative approach to multi-omics, integrate various data types, including human and microbiota genomic data, as well as translate lab data into clinical practice. To sum up, pharmacomicrobiomics represents a promising avenue to address IVDR and improve patient outcomes, and further research in this field is imperative to unlock its full potential for precision medicine.

Focus on Metformin: Its Role and Safety in Pregnancy and Beyond

Metformin is used worldwide in the treatment of type 2 diabetes and has been used in the treatment of diabetes in pregnancy since the 1970s. It is highly acceptable to patients due to its ease of administration, cost and adverse effect profile. It is effective in reducing macrosomia, large-for-gestational-age infants and reduces maternal weight gain. Despite its many advantages, metformin has been associated with reductions in foetal size and has been associated with an increase in infants born small-for-gestational-age in certain cohorts. In this article, we review its efficacy, adverse effects and long-term follow-up before, during and after pregnancy for both mother and infant. We also evaluate the other forms of treatment for gestational diabetes, including oral therapies, insulin therapy and emerging treatments.

Incidence of metformin use in patients with age-related macular degeneration versus normal controls: A population-based study in Olmsted County, Minnesota

PURPOSE

The purpose of this study is to compare the use of metformin in patients with both exudative and non-exudative age-related macular degeneration (AMD) versus control populations.

DESIGN

Retrospective review of three age- and sex-matched cohorts from 1/1/2004 to 12/31/2013: patients with exudative AMD, a cohort of dry AMD patients, and a cohort of patients without AMD. The primary endpoint was the incidence of metformin use in all of the cohorts.

RESULTS

There were 1512 patients, with 504 in each of the three cohorts. There was no difference in the prevalence of diabetes between cohorts. Compared to patients with dry AMD, patients with no AMD had increased likelihood of metformin use (p = 0.0168, OR 1.66 (1.09-2.51). There was no difference in the likelihood of metformin use between exudative AMD patients and non-AMD controls.

CONCLUSIONS

There appears to be an increased incidence of metformin use in patients without AMD compared to patients with dry AMD. Metformin's current role in the treatment of anti-aging diseases makes it a plausible target for use in the treatment of AMD, particularly dry AMD.

A Novel Drug Delivery System: Hyodeoxycholic Acid-Modified Metformin Liposomes for Type 2 Diabetes Treatment

Metformin is a first-line drug for the clinical treatment of type 2 diabetes; however, it always leads to gastrointestinal tolerance, low bioavailability, short half-life, etc. Liposome acts as an excellent delivery system that could reduce drug side effects and promote bioavailability. Hyodeoxycholic acid, a cholesterol-like structure, can regulate glucose homeostasis and reduce the blood glucose levels. As an anti-diabetic active ingredient, hyodeoxycholic acid modifies liposomes to make it overcome the disadvantages of metformin as well as enhance the hypoglycemic effect. By adapting the thin-film dispersion method, three types of liposomes with different proportions of hyodeoxycholic acid and metformin were prepared (HDCA:ME-(0.5:1)-Lips, HDCA:ME-(1:1)-Lips, and HDCA:ME-(2:1)-Lips). Further, the liposomes were characterized, and the anti-type 2 diabetes activity of liposomes was evaluated. The results from this study indicated that three types of liposomes exhibited different characteristics—Excessive hyodeoxycholic acid decreased encapsulation efficiency and drug loading. In the in vivo experiments, liposomes could reduce the fasting blood glucose levels, improve glucose tolerance, regulate oxidative stress markers and protect liver tissue in type 2 diabetic mice. These results indicated that HDCA:ME-(1:1)-Lips was the most effective among the three types of liposomes prepared and showed better effects than metformin. Hyodeoxycholic acid can enhance the hypoglycemic effect of metformin and play a suitable role as an excipient in the liposome.

Pharmacokinetic and Bioequivalence Studies of 2 Metformin Glibenclamide Tablets in Healthy Chinese Subjects Under Fasting and Fed Conditions

The rational combination of oral antidiabetic agents is more likely to provide better glycemic control than monotherapy. Metformin glibenclamide tablets can be used as second-line therapy for patients with type 2 diabetes mellitus who cannot successfully control their blood glucose levels by diet and exercise plus metformin or sulfonylureas. The aim of this study was to evaluate the bioequivalence and safety of metformin hydrochloride and glibenclamide tablets (500 mg/5 mg) prepared by 2 different vendors in healthy Chinese subjects under fasting and fed conditions. This is an open-label, single-center, randomized, 2-formulation, 2-period crossover study. After screening, 40 subjects were enrolled in the fasting trial, while 40 subjects were enrolled in the fed trial. Qualified subjects were randomly assigned to receive a monotherapy dose of 500 mg/5 mg of the test or reference formulation, and after a 1-week washout period, they took the alternative formulation. Blood samples were collected from 24 blood collection sites per cycle for pharmacokinetic analysis until 36 hours after oral administration. In total, 78 subjects completed the study. Under fasting and fed conditions, the geometric mean ratios of maximum plasma concentration, area under the plasma concentration-time curve (AUC) from time 0 to time of last quantifiable drug level , and AUC from time 0 to infinity between the 2 products, as well as the corresponding 90%CIs, were all within the range of 80%-125%. It was found that exposure (AUC from time 0 to infinity) to metformin is decreased by about 25% in the fed state compared to fasting, whereas glibenclamide exposure is increased by about 30% in the fed state. No severe adverse events were observed in the study.

Regulatory network of metformin on adipogenesis determined by combining high-throughput sequencing and GEO database

Adipose differentiation and excessive lipid accumulation are the important characteristics of obesity. Metformin, as a classic hypoglycaemic drug, has been proved to reduce body weight in type 2 diabetes, the specific mechanism has not been completely clear. A few studies have explored its effect on adipogenesis in vitro, but the existing experimental results are ambiguous. 3T3-L1 preadipocytes were used to explore the effects of metformin on the morphological and physiological changes of lipid droplets during adipogenesis. A high throughput sequencing was used to examine the effects of metformin on the transcriptome of adipogenesis. Considering the inevitable errors among independent experiments, we performed integrated bioinformatics analysis to identify important genes involved in adipogenesis and reveal potential molecular mechanisms. During the process of adipogenesis, metformin visibly relieved the morphological and functional changes. In addition, metformin reverses the expression pattern of genes related to adipogenesis at the transcriptome level. Combining with integrated bioinformatics analyses to further identify the potential targeted genes regulated by metformin during adipogenesis. The present study identified novel changes in the transcriptome of metformin in the process of adipogenesis that might shed light on the underlying mechanism by which metformin impedes the progression of obesity.

Design, synthesis, and biological evaluation of new celecoxib analogs as apoptosis inducers and cyclooxygenase-2 inhibitors

Series of new celecoxib analogs were synthesized to assess their anticancer activity against the MCF-7 cell line. Four compounds, 3a, 3c, 5b, and 5c, showed 1.4-9.2-fold more potent anticancer activity than celecoxib. The antiproliferative activity of the most potent compounds, 3c, 5b, and 5c, seems to be associated well with their ability to induce apoptosis in MCF-7 cells (18-24-fold). This evidence was supported by an increase in the expression of the tumor suppressor gene p53 (4-6-fold), the elevation in the Bax/BCL-2 ratio, and a significant increase in the level of active caspase-7 (4-7-fold). Moreover, compounds 3c and 5c showed significant cyclooxygenase-2 (COX-2) inhibitory activity. They were also docked into the crystal structure of the COX-2 enzyme (PDB ID: 3LN1) to understand their mode of binding.

Intestinal Radiation Protection and Mitigation by Second-Generation Probiotic Lactobacillus-reuteri Engineered to Deliver Interleukin-22

(1) Background: The systemic administration of therapeutic agents to the intestine including cytokines, such as Interleukin-22 (IL-22), is compromised by damage to the microvasculature 24 hrs after total body irradiation (TBI). At that time, there is significant death of intestinal microvascular endothelial cells and destruction of the lamina propria, which limits drug delivery through the circulation, thus reducing the capacity of therapeutics to stabilize the numbers of Lgr5+ intestinal crypt stem cells and their progeny, and improve survival. By its direct action on intestinal stem cells and their villus regeneration capacity, IL-22 is both an ionizing irradiation protector and mitigator. (2) Methods: To improve delivery of IL-22 to the irradiated intestine, we gavaged Lactobacillus-reuteri as a platform for the second-generation probiotic Lactobacillus-reuteri-Interleukin-22 (LR-IL-22). (3) Results: There was effective radiation mitigation by gavage of LR-IL-22 at 24 h after intestinal irradiation. Multiple biomarkers of radiation damage to the intestine, immune system and bone marrow were improved by LR-IL-22 compared to the gavage of control LR or intraperitoneal injection of IL-22 protein. (4) Conclusions: Oral administration of LR-IL-22 is an effective protector and mitigator of intestinal irradiation damage.

Why Senescent Cells Are Resistant to Apoptosis: An Insight for Senolytic Development

Cellular senescence is a process that leads to a state of irreversible cell growth arrest induced by a variety of intrinsic and extrinsic stresses. Senescent cells (SnCs) accumulate with age and have been implicated in various age-related diseases in part via expressing the senescence-associated secretory phenotype. Elimination of SnCs has the potential to delay aging, treat age-related diseases and extend healthspan. However, once cells becoming senescent, they are more resistant to apoptotic stimuli. Senolytics can selectively eliminate SnCs by targeting the SnC anti-apoptotic pathways (SCAPs). They have been developed as a novel pharmacological strategy to treat various age-related diseases. However, the heterogeneity of the SnCs indicates that SnCs depend on different proteins or pathways for their survival. Thus, a better understanding of the underlying mechanisms for apoptotic resistance of SnCs will provide new molecular targets for the development of cell-specific or broad-spectrum therapeutics to clear SnCs. In this review, we discussed the latest research progresses and challenge in senolytic development, described the significance of regulation of senescence and apoptosis in aging, and systematically summarized the SCAPs involved in the apoptotic resistance in SnCs.

Korean Clinical Practice Guidelines for Adverse Reactions to Intravenous Iodinate and MRI-Gadolinium Contrast Agents: Revised Clinical Consensus and Recommendations (3rd Edition, 2022)

대한영상의학회 진료지침위원회는 기존의 2016년 진료지침을 개정하여 ‘주사용 요오드화 조영제 및 MRI용 가돌리늄 조영제 유해 반응에 대한 한국 임상진료지침: 개정된 임상적 합의 및 권고안(2022년 제3판)’을 제작하였다. 대한영상의학회와 대한천식알레르기학회, 대한신장학회에세 추천 및 승인된 전문가 위원들이 함께 참여하였고, 전문가 합의 또는 체계적 문헌 고찰을 기반으로, 조영제를 사용 시 감염관리를 위한 자동주입기 및 연결선에 대한 기술과 요요드화 조영제에 대한 급성 유해반응 및 신장 유해반응에 대한 내용들을 수정 및 추가하였다. 이에 개정된 내용을 소개하고자 한다.

The Gut Microbiome, Metformin, and Aging

Metformin has been extensively used for the treatment of type 2 diabetes, and it may also promote healthy aging. Despite its widespread use and versatility, metformin's mechanisms of action remain elusive. The gut typically harbors thousands of bacterial species, and as the concentration of metformin is much higher in the gut as compared to plasma, it is plausible that microbiome-drug-host interactions may influence the functions of metformin. Detrimental perturbations in the aging gut microbiome lead to the activation of the innate immune response concomitant with chronic low-grade inflammation. With the effectiveness of metformin in diabetes and antiaging varying among individuals, there is reason to believe that the gut microbiome plays a role in the efficacy of metformin. Metformin has been implicated in the promotion and maintenance of a healthy gut microbiome and reduces many age-related degenerative pathologies. Mechanistic understanding of metformin in the promotion of a healthy gut microbiome and aging will require a systems-level approach. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Metformin generates profound alterations in systemic and tumor immunity with associated antitumor effects

BACKGROUND

Metformin is a commonly used antidiabetic medication which has demonstrated promise as an anticancer agent alone and in combination with conventional treatment regimens. There is increasing evidence that metformin can also generate immunomodulatory effects in solid tumors and is currently being investigated as an adjunct to immune checkpoint inhibitors (ICIs). We hypothesized that metformin would generate a shift in immunity unfavorable to tumor growth and tested this hypothesis in a preclinical model of head and neck cancer.

METHODS

Using a syngeneic mouse model of human papillomavirus-associated head and neck cancer (mEER/MTEC), we tested the impact of metformin on systemic and local immunity and tumor growth velocity. We compared the effects of acute and chronic treatment regimens on immunocyte presence and activation using a combination of flow cytometry and targeted transcriptomic analysis.

RESULTS

Acute metformin exposure generated measurable shifts in systemic myeloid and T-cell populations in non-tumor-bearing mice and decreased myeloid derived suppressor cell (MDSC) levels in tumor draining lymph nodes of tumor-bearing mice. Although metformin decreased regulatory T-cell (T-reg) and MDSC levels and increased CD8+ levels in murine tumors when combined with ICIs, acute metformin exposure was insufficient to generate substantial antitumor activity. Conversely, long-term metformin treatment significantly reduced tumor growth velocity, increased the CD8+/T-reg ratio, increased tumor infiltrating lymphocyte levels and upregulated component genes of the previously validated T-cell inflamed expression profile.

CONCLUSIONS

Metformin generates complex systemic and local immune effects which vary as a function of treatment duration. Combinatorial strategies with ICIs must take into account both the complexity and variability of these effects in order to generate maximal antitumor activity in future clinical trials.

Drug Response Diversity: A Hidden Bacterium?

Interindividual heterogeneity in response to treatment is a real public health problem. It is a factor that can be responsible not only for ineffectiveness or fatal toxicity but also for hospitalization due to iatrogenic effects, thus increasing the cost of patient care. Several research teams have been interested in what may be at the origin of these phenomena, particularly at the genetic level and the basal activity of organs dedicated to the inactivation and elimination of drug molecules. Today, a new branch is being set up, explaining the enigmatic part that could not be explained before. Pharmacomicrobiomics attempts to investigate the interactions between bacteria, especially those in the gut, and drug response. In this review, we provide a state of the art on what this field has brought as new information and discuss the challenges that lie ahead to see the real application in clinical practice.

Metformin: A Potential Candidate for Targeting Aging Mechanisms

Aging is a universal phenomenon in all biological organisms, defined by the loss of reproductive capacity and a progressive decline in fitness. In humans, aging is further associated with an increased incidence of disease conditions. The current aging population has become a primary public burden of the 21^st century. Therefore, to delay the aging process and maintain fitness in the aging population, the discovery of novel anti-aging drugs remains an urgent need. In recent years, metformin, a widely used hypoglycemic drug, has attracted growing attention in the field of anti-aging research. Reportedly, numerous studies have indicated that metformin regulates aging-related pathways, possibly delaying the aging process by modulating these pathways. The elucidation of these anti-aging effects may provide insights into the age-retarding potential of metformin. The present review focuses on the predominant molecular mechanisms associated with aging, as well as the anti-aging effects of metformin.

Synthesis of drug conjugated magnetic nanocomposite with enhanced hypoglycemic effects

In the present study, a magnetic nanocomposite (magnetite Fe₃O₄ and hematite Fe₂O₃) has been successfully synthesized by the sol-gel method and coated with polyvinyl alcohol (PVA) followed by conjugation of anti-diabetic drug metformin. Detailed structural and microstructural characterization of the nanocomposite (NP) and drug conjugated nanocomposite (NP-DC) are analyzed by the Rietveld refinement of respective XRD patterns, FTIR analysis, UV-Vis spectroscopy, SEM and TEM results. SEM and TEM image analyses reveal the spherical morphology and average size of NP, PVA coated nanoparticles (NP-PVA) and NP-DC samples, indicating a suitable size to be a nanocarrier. The biocompatibility of NP and NP-DC was carried out in NIH/3T3 and J774A. 1 cells. The enhanced activity of the drug, when conjugated with nanocomposite, is confirmed after the treatment of both the pure drug and NP-DC sample on the 18 h fasted normoglycemic and hyperglycemic mice. The blood glucose level of the mice is effectively decreased with the same concentration of the pure drug and NP-DC sample. It proves the increased activity of the NP-DC sample, as only 5 wt% drug is present that shows the same efficiency as the pure drug. This study suggests excellent biocompatibility and cytocompatibility of NP and NP-DC besides the critical property as a hypoglycemic agent. It is the first time approach of conjugating metformin with a magnetic nanocomposite for a significant increment of its hypoglycemic activity, which is very important to reduce the side effect of metformin for its prolonged use.

Infertility management in women with polycystic ovary syndrome: a review

Polycystic ovary syndrome is the most common endocrine disorder in women and a major cause of anovulatory infertility. Various medical options are used, alone or in combination, to treat subfertility associated with polycystic ovary syndrome. This narrative review was conducted to provide an update and summarize the available evidence on the management of polycystic ovary syndrome related infertility. A wide literature search was performed and preferably randomized controlled trials and systematic reviews were included. Management is often centered on lifestyle changes. Pharmacological ovulation induction is the next step, with recommended use of letrozole, clomiphene citrate or gonadotropins. When it fails, assisted reproductive technologies or laparoscopic ovarian drilling are frequently advised. Combination treatment with metformin is often recommended. More recent alternative and adjunctive treatments have been suggested, like inositol, vitamin D, bariatric surgery and acupuncture, but further research is needed for recommendation.

Metformin treatment before and during IVF or ICSI in women with polycystic ovary syndrome

BACKGROUND

The use of insulin-sensitising agents, such as metformin, in women with polycystic ovary syndrome (PCOS) who are undergoing ovulation induction or in vitro fertilisation (IVF) cycles has been widely studied. Metformin reduces hyperinsulinaemia and suppresses the excessive ovarian production of androgens. It is suggested that as a consequence metformin could improve assisted reproductive techniques (ART) outcomes, such as ovarian hyperstimulation syndrome (OHSS), pregnancy, and live birth rates.

OBJECTIVES

To determine the effectiveness and safety of metformin as a co-treatment during IVF or intracytoplasmic sperm injection (ICSI) in achieving pregnancy or live birth in women with PCOS.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL via the Cochrane Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, LILACS, the trial registries for ongoing trials, and reference lists of articles (from inception to 13 February 2020).

SELECTION CRITERIA

Types of studies: randomised controlled trials (RCTs) comparing metformin treatment with placebo or no treatment in women with PCOS who underwent IVF or ICSI treatment.

TYPES OF PARTICIPANTS

women of reproductive age with anovulation due to PCOS with or without co-existing infertility factors. Types of interventions: metformin administered before and during IVF or ICSI treatment.

PRIMARY OUTCOME MEASURES

live birth rate, incidence of ovarian hyperstimulation syndrome.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies, extracted the data according to the protocol, and assessed study quality. We assessed the overall quality of the evidence using the GRADE approach.

MAIN RESULTS

This updated review includes 13 RCTs involving a total of 1132 women with PCOS undergoing IVF/ICSI treatments. We stratified the analysis by type of ovarian stimulation protocol used (long gonadotrophin-releasing hormone agonist (GnRH-agonist) or short gonadotrophin-releasing hormone antagonist (GnRH-antagonist)) to determine whether the type of stimulation used influenced the outcomes. We did not perform meta-analysis on the overall (both ovarian stimulation protocols combined) data for the outcomes of live birth and clinical pregnancy rates per woman because of substantial heterogeneity. In the long protocol GnRH-agonist subgroup, the pooled evidence showed that we are uncertain of the effect of metformin on live birth rate per woman when compared with placebo/no treatment (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.94 to 1.79; 6 RCTs; 651 women; I2 = 47%; low-quality evidence). This suggests that if the chance for live birth following placebo/no treatment is 28%, the chance following metformin would be between 27% and 51%. Only one study used short protocol GnRH-antagonist and reported live birth rate. Metformin may reduce live birth rate compared with placebo/no treatment (RR 0.48, 95% CI 0.29 to 0.79; 1 RCT; 153 women; low-quality evidence). This suggests that if the chance for live birth following placebo/no treatment is 43%, the chance following metformin would be between 13% and 34% (short GnRH-antagonist protocol). We found that metformin may reduce the incidence of OHSS (RR 0.46, 95% CI 0.29 to 0.72; 11 RCTs; 1091 women; I2 = 38%; low-quality evidence). This suggests that for a woman with a 20% risk of OHSS without metformin, the corresponding risk using metformin would be between 6% and 14%. Using long protocol GnRH-agonist stimulation, metformin may increase clinical pregnancy rate per woman compared with placebo/no treatment (RR 1.32, 95% CI 1.08 to 1.63; 10 RCTs; 915 women; I2 = 13%; low-quality evidence). Using short protocol GnRH-antagonist, we are uncertain of the effect of metformin on clinical pregnancy rate per woman compared with placebo/no treatment (RR 1.38, 95% CI 0.21 to 9.14; 2 RCTs; 177 women; I2 = 87%; very low-quality evidence). We are uncertain of the effect of metformin on miscarriage rate per woman when compared with placebo/no treatment (RR 0.86, 95% CI 0.56 to 1.32; 8 RCTs; 821 women; I2 = 0%; low-quality evidence). Metformin may result in an increase in side effects compared with placebo/no treatment (RR 3.35, 95% CI 2.34 to 4.79; 8 RCTs; 748 women; I2 = 0%; low-quality evidence). The overall quality of evidence ranged from very low to low. The main limitations were inconsistency, risk of bias, and imprecision.

AUTHORS' CONCLUSIONS

This updated review on metformin versus placebo/no treatment before or during IVF/ICSI treatment in women with PCOS found no conclusive evidence that metformin improves live birth rates. In a long GnRH-agonist protocol, we are uncertain whether metformin improves live birth rates, but metformin may increase the clinical pregnancy rate. In a short GnRH-antagonist protocol, metformin may reduce live birth rates, although we are uncertain about the effect of metformin on clinical pregnancy rate. Metformin may reduce the incidence of OHSS but may result in a higher incidence of side effects. We are uncertain of the effect of metformin on miscarriage rate per woman.

Metformin: A Prospective Alternative for the Treatment of Chronic Pain

Metformin (biguanide) is a drug widely used for the treatment of type 2 diabetes. This drug has been used for 60 years as a highly effective antihyperglycemic agent. The search for the mechanism of action of metformin has produced an enormous amount of research to explain its effects on gluconeogenesis, protein metabolism, fatty acid oxidation, oxidative stress, glucose uptake, autophagy and pain, among others. It was only up the end of the 1990s and beginning of this century that some of its mechanisms were revealed. Metformin induces its beneficial effects in diabetes through the activation of a master switch kinase named AMP-activated protein kinase (AMPK). Two upstream kinases account for the physiological activation of AMPK: liver kinase B1 and calcium/calmodulin-dependent protein kinase kinase 2. Once activated, AMPK inhibits the mechanistic target of rapamycin complex 1 (mTORC1), which in turn avoids the phosphorylation of p70 ribosomal protein S6 kinase 1 and phosphatidylinositol 3-kinase/protein kinase B signaling pathways and reduces cap-dependent translation initiation. Since metformin is a disease-modifying drug in type 2 diabetes, which reduces the mTORC1 signaling to induce its effects on neuronal plasticity, it was proposed that these mechanisms could also explain the antinociceptive effect of this drug in several models of chronic pain. These studies have highlighted the efficacy of this drug in chronic pain, such as that from neuropathy, insulin resistance, diabetic neuropathy, and fibromyalgia-type pain. Mounting evidence indicates that chronic pain may induce anxiety, depression and cognitive impairment in rodents and humans. Interestingly, metformin is able to reverse some of these consequences of pathological pain in rodents. The purpose of this review was to analyze the current evidence about the effects of metformin in chronic pain and three of its comorbidities (anxiety, depression and cognitive impairment).

A safety evaluation of current medications for adult women with the polycystic ovarian syndrome not pursuing pregnancy

INTRODUCTION

The polycystic ovary syndrome (PCOS) is a very prevalent disorder in premenopausal women. Cardiovascular risk factors cluster in these patients, raising concern about the safety of the drugs commonly used to ameliorate symptoms of androgen excess in in this population at risk of cardiovascular morbidity.

AREAS COVERED

This review summarizes the clinical efficacy and safety profiles of drugs commonly used for the management of hyperandrogenic symptoms and endometrial protection in adult women with PCOS who do not seek pregnancy.

EXPERT OPINION

Antiandrogenic drugs usually used in adult women with PCOS carry a low risk of severe side effects. In spite of the cardiovascular risk profile of women with PCOS, and that individualized risk assessment is of paramount importance, there is no solid evidence supporting that the use of combined oral contraceptives in these women increases the risk of cardiovascular or thromboembolic events compared with the general population. However, virtually all these drugs are used in an off-label fashion. Large, high-quality studies addressing the long-term safety of pharmacological treatments in women with PCOS are definitely needed.

Repaglinide and Metformin-Loaded Amberlite Resin-Based Floating Microspheres for the Effective Management of Type 2 Diabetes

BACKGROUND

Low bioavailability of anti-diabetic drugs results in the partial absorption of the drug as they are mainly absorbed from the stomach and the lower part of the GIT. Drug bioavailability of anti-diabetic drugs can be significantly increased by prolonging gastric retention time through gastro-retentive dosage form such as floating microspheres.

OBJECTIVE

The study was aimed to develop and characterize resin based floating microspheres of Repaglinide and Metformin for superior and prolonged maintenance of normoglycaemia in type-2 diabetes mellitus.

METHODS

Repaglinide and metformin were complexed with amberlite resin; later resin complexed drug was encapsulated in Ethylcellulose floating microspheres. Floating microspheres were characterized for morphology, particle size, IR spectroscopy, DSC, in vitro release and buoyancy studies. Further, floating microspheres were tested for in vivo blood glucose reduction potential in Streptozocin- induced diabetic mice.

RESULTS

Floating microspheres had a spherical shape and slightly rough surface with the entrapment efficiency in a range of 49-78% for metformin and 52-73% for repaglinide. DSC studies revealed that no chemical interaction took place between polymer and drugs. Floating microspheres showed good buoyancy behavior (P<0.05) and prolonged drug release as compared to plain drug (P<0.05). The blood glucose lowering effect of floating microspheres on Streptozocin induced diabetic rats was significantly greater (P<0.05) and prolonged (˃12h) and normoglycaemia was maintained for 6hr.

CONCLUSION

Floating microspheres containing drug resin complex were able to prolong drug release in an efficient way for a sustained period of time; as a result, profound therapeutic response was obtained.

Concurrent metformin and silibinin therapy in diabetes: assessments in zebrafish (Danio rerio) animal model

Objective

In this study, zebrafish was used as a biological model to induce type 2 diabetes mellitus through glucose. Then, the effect of metformin and silibinin combination was examined on elevated blood glucose, intestinal tissues, liver enzymes, and TNF-α, IFN-γ, INL1β genes as inflammation marker genes.

Methods

The liver enzymes (AST, ALT, and ALP) derived from fish viscera homogenate supernatants were assayed in an auto-analyzer. The expression of target genes was quantified on RNA extracted from the tails by an in-house RT-PCR method, with fine intestine tissue staining performed by hematoxylin and eosin protocol (H&E).

Result

In the glucose-free treatments, metformin and silymarin decreased the levels of AST, ALT, and ALP enzymes in the blood. The combination of these two drugs had also a significant role in reducing glucose levels. The body weight increased significantly in the control group which was affected by glucose concentration, with the lowest body weight gain observed in the metformin group. The expression of INL-1β gene was significantly enhanced in the control group and the highest IFN-γ expression was observed in both control groups with glucose (G + CTRL) and without glucose (G-CTRL) (p < 0.05). The lowest level of TNF-α gene expression was observed in the control + glucose group (G + CTRL) (p < 0.05). Diabetic state causes weak absorption whereby the fish body demands to increase absorption level by enhancing the amount of acidic goblet cells thereby acidifying the environment in the gastric tracts.

Conclusion

Collectively, this study indicated that treatment with metformin and Silibinin could improve metabolic-mediated performances by reducing the expression of inflammatory genes and blood glucose, modulating liver enzymes, and ameliorating the intestinal inflammation in type 2 diabetic zebrafish model.

Metformin Ameliorates Gestational Diabetes Mellitus-Induced Endothelial Dysfunction via Downregulation of p65 and Upregulation of Nrf2

Gestational diabetes mellitus (GDM) causes oxidative stress in mothers and infants and causes vascular endothelial dysfunction, which is a key factor for maternal and fetal cardiovascular diseases in the later stage of GDM, seriously threatening the life and health of mothers and infants. Nowadays, metformin (MET) has been discovered to improve endothelial function, but studies regarding the mechanism of MET improving endothelial cell function and alleviating endothelial function under hyperglycemia are still extremely limited. We aimed to investigate whether MET exerts its protective role against hyperglycemia-induced endothelial dysfunction through p65 and Nrf2. In our studies, applying cell migration assay and tube formation assay, we observed an obvious improvement of endothelial function under MET-treated, as characterized by that MET accelerated GDM-attenuated migration and angiogenesis of HUVECs. And ELISA assay results uncovered that Nrf2 expression level was decreased in GDM placenta, HVUECs and maternal serum comparing with normal group, however activation Nrf2 largely ameliorated tube formation under hyperglycemic condition. Furthermore, MET elevated the Nrf2 expression level and the level of nuclear Nrf2 accumulation in hyperglycemic HUVECs. Besides, preliminary evidence predicted that Nrf2 expression was modulated by transcription factor p65, which was increased in GDM peripheral blood, placenta and HUVECs, and suppression of p65 could recover GDM-induced suppression of angiogenesis. In addition, we also confirmed MET restores the GDM-induced angiogenesis impairment may via downregulation of p65 and upregulation of Nrf2. Taken together, the endothelial protective effect of MET under GDM (HG) conditions could be partly attributed to its role in downregulating p65 and upregulating Nrf2.

Targeting gut microbiota for precision medicine: Focusing on the efficacy and toxicity of drugs

Intra- and interindividual variation in drug responses is one major reason for the failure of drug therapy, drug toxicity, and even the death of patients. Precision medicine, or personalized medicine, is a field of medicine that customizes an individual's medical diagnosis and treatment based on his/her genes, microbiomes, environments, etc. Over the past decade, a large number of studies have demonstrated that gut microbiota can modify the efficacy and toxicity of drugs, and the extent of the modification varies greatly from person to person because of the variability of the gut microbiota. Personalized manipulation of gut microbiota is an important approach to rectify the abnormal drug response. In this review, we aim to improve drug efficacy and reduce drug toxicity by combining precision medicine and gut microbiota. After describing the interactions between gut microbiota and xenobiotics, we discuss (1) the effects of gut microbiota on drug efficacy and toxicity and the corresponding mechanisms, (2) the variability of gut microbiota, which leads to variation in drug responses, (3) the biomarkers used for the patient stratification and treatment decisions before the use of drugs, and (4) the methods used for the personalized manipulation of gut microbiota to improve drug outcomes. Overall, we hope to improve the drug response by incorporating the knowledge of gut microbiota into clinical practice.

Current comments on contrast media administration in patients with renal insufficiency

Contrast media administration has been associated with complications such as nephropathy, cardiovascular morbidity, and neurovascular events, particularly in patients with renal insufficiency. This association has been questioned in recent studies. This review was performed to summarize the most current evidence on contrast induced nephropathy (CIN), contributing factors, and considerations in patients with renal insufficiency. The risk of CIN was over-estimated by the previous studies, due to a lack of control groups or presence of non-randomized control groups, which led to a selection bias. However, the thresholds associated with an increased risk of CIN are controversial and require risk-benefit analysis on an individual basis. Regarding the administration of contrast media (CM) in the emergency setting, the majority of studies suggested that CM exposure does not meaningfully increase the risk of acute kidney injury in critically ill patients (including trauma patients). Several strategies have been suggested to reduce the risk of CIN, including volume expansion to increase renal blood flow, sodium bicarbonate or N-acetylcysteine administration, and use of low-osmolal contrast media in end-stage renal disease.

Pharmacokinetic Interaction between Metformin and Verapamil in Rats: Inhibition of the OCT2-Mediated Renal Excretion of Metformin by Verapamil

The incidence of hypertension in diabetic patients has been increasing and contributing to the high mortality of diabetic patients. Recently, verapamil use was found to lower fasting blood glucose levels in diabetic patients, which led to a new indication of verapamil as combination treatment with anti-diabetic agents such as metformin. As pharmacokinetic (PK) interaction can affect drug efficacy and safety in drug combination, their PK-based interaction is recommended to be evaluated in preclinical levels as well as clinical levels. In case of metformin and verapamil, organic cation transporter (OCT) 1 and 2 primarily mediate metformin distribution to the liver and its elimination into urine, whereas cytochrome P450 is responsible for the hepatic metabolism of verapamil. Verapamil is also known as a potential OCT2 inhibitor. Thus, PK interaction between metformin (30 mg/kg) and verapamil (20 mg/kg) were investigated after their simultaneous administration to rats. In our results, verapamil inhibited the OCT2-mediated renal excretion of metformin, subsequently leading to increase of the systemic exposure of metformin. In contrast, metformin did not influence the pharmacokinetic pattern of verapamil. Although the further clinical investigation is required, our finding suggests a possibility of OCT2-mediated interaction of metformin and verapamil.

The cytotoxicity of gallium maltolate in glioblastoma cells is enhanced by metformin through combined action on mitochondrial complex 1

New drugs are needed for glioblastoma, an aggressive brain tumor with a dismal prognosis. We recently reported that gallium maltolate (GaM) retards the growth of glioblastoma in a rat orthotopic brain tumor model by inhibiting mitochondrial function and iron-dependent ribonucleotide reductase (RR). However, GaM's mechanism of action at the mitochondrial level is not known. Given the interaction between gallium and iron metabolism, we hypothesized that gallium might target iron-sulfur (Fe-S) cluster-containing mitochondrial proteins. Using Extracellular Flux Analyzer technology, we confirmed that after a 24-h incubation, GaM 50 μmol/L inhibited glioblastoma cell growth by <10% but inhibited cellular oxygen consumption rate by 44% and abrogated mitochondrial reserve capacity. GaM blocked mitochondrial complex I activity and produced a 2.9-fold increase in cellular ROS. NMR spectroscopy revealed that gallium binds to IscU, the bacterial scaffold protein for Fe-S cluster assembly and stabilizes its folded state. Gallium inhibited the rate of in vitro cluster assembly catalyzed by bacterial cysteine desulfurase in a reaction mixture containing IscU, Fe (II), DTT, and L-cysteine. Metformin, a complex I inhibitor, enhanced GaM's inhibition of complex I, further increased cellular ROS levels, and synergistically enhanced GaM's cytotoxicity in glioblastoma cells in 2-D and 3-D cultures. Metformin did not affect GaM action on cellular iron uptake or transferrin receptor1 expression nor did it enhance the cytotoxicity of the RR inhibitor Didox. Our results show that GaM inhibits complex I by disrupting iron-sulfur cluster assembly and that its cytotoxicity can be synergistically enhanced by metformin through combined action on complex I.

Effect of exercise on key pharmacokinetic parameters related to metformin absorption in healthy humans: A pilot study

Exercise is widely accepted as having therapeutic effects; thus, it is important to know whether it interacts with medications. The aim of the present pilot study was to examine the effect of high-intensity interval exercise (known to have antidiabetic action) on key pharmacokinetic parameters related to absorption of metformin (the first-line medication against type 2 diabetes). Ten healthy men participated in two sessions, spaced one to two weeks apart in random, counterbalanced order. In both sessions, participants received 1000 mg of metformin orally, 1-1.5 hours after breakfast. Then, they either ran for 60 minutes at alternating intensity, starting at 40 minutes after metformin administration, and rested without food consumption over the next 3 hours or they rested without food consumption during the entire testing period. Venous blood samples were collected before and at 0.5, 2, 2.5, 3, 3.5, 4, and 4.5 hours after metformin administration for metformin determination by liquid chromatography-mass spectrometry. Capillary blood samples were also collected for lactate and glucose measurements. Data from the two sessions were compared through Wilcoxon or Student's t test, as appropriate. Maximum plasma concentration of metformin (C_max ) was higher at exercise compared to rest (P = .059). Time to reach C_max (T_max ) decreased with exercise (P = .009), and the area under the metformin concentration vs time curve was higher at exercise (P = .047). The addition of exercise to metformin administration did not cause hypoglycemia or lactic acidosis. In conclusion, our results provide the first evidence that pharmacokinetic values related to metformin absorption are affected by exercise.

Novel Metformin-Based Schiff Bases: Synthesis, Characterization, and Antibacterial Evaluation

Novel Schiff bases of metformin hydrochloride and (ortho)para-nitrobenzaldehyde were synthesized by employing two efficient environmentally friendly methods, namely, stirring and microwave-assisted methods using water as the solvent. The advantage of microwave irradiation over the other methods was represented in the reduction of reaction time and wastes, and good yields; however, water in both methods plays the role of eco-friendly solvent. The structural properties of the (ortho)para-isomer products were analyzed by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, UV-Visible (UV-Vis) spectroscopy, ¹H nuclear magnetic resonance (NMR) spectroscopy, ¹³C NMR spectroscopy, mass spectroscopy, and differential scanning calorimetry (DSC). The newly synthesized compounds were screened for their antibacterial activity against selected Gram-positive (ATCC 25923, ATCC 43300, and ATCC 29212) and Gram-negative (ATCC 25922, ATCC 27853, and ATCC 700603) bacteria using the agar well diffusion method. Compared with the standard drug streptomycin, both Schiff bases exhibited moderate bactericidal activity against the tested bacteria with higher values of ortho-nitro compared with the para-nitro isomer; however, no effect on ATCC 43300 and ATCC 27853 was observed under the experimental conditions employed.

Elucidation of N 1-methyladenosine as a Potential Surrogate Biomarker for Drug Interaction Studies Involving Renal Organic Cation Transporters

Endogenous substrates are emerging biomarkers for drug transporters, which serve as surrogate probes in drug-drug interaction (DDI) studies. In this study, the results of metabolome analysis using wild-type and Oct1/2 double knockout mice suggested that N 1-methyladenosine (m1A) was a novel organic cation transporter (OCT) 2 substrate. An in vitro transport study revealed that m1A is a substrate of mouse Oct1, Oct2, Mate1, human OCT1, OCT2, and multidrug and toxin exclusion protein (MATE) 2-K, but not human MATE1. Urinary excretion accounted for 77% of the systemic elimination of m1A in mice. The renal clearance (46.9 ± 4.9 ml/min per kilogram) of exogenously given m1A was decreased to near the glomerular filtration rates by Oct1/2 double knockout or Mate1 inhibition by pyrimethamine (16.6 ± 2.6 and 24.3 ± 0.6 ml/min per kilogram, respectively), accompanied by significantly higher plasma concentrations. In vivo inhibition of OCT2/MATE2-K by a single dose of 7-[(3R)-3-(1-aminocyclopropyl)pyrrolidin-1-yl]-1-[(1R,2S)-2-fluorocyclopropyl]-8-methoxy-4-oxoquinoline-3-carboxylic acid in cynomolgus monkeys resulted in the elevation of the area under the curve of m1A (1.72-fold) as well as metformin (2.18-fold). The plasma m1A concentration profile showed low diurnal and interindividual variation in healthy volunteers. The renal clearance of m1A in younger (21-45 year old) and older (65-79 year old) volunteers (244 ± 58 and 169 ± 22 ml/min per kilogram, respectively) was about 2-fold higher than the creatinine clearance. The renal clearances of m1A and creatinine were 31% and 17% smaller in older than in younger volunteers. Thus, m1A could be a surrogate probe for the evaluation of DDIs involving OCT2/MATE2-K. SIGNIFICANCE STATEMENT: Endogenous substrates can serve as surrogate probes for clinical drug-drug interaction studies involving drug transporters or enzymes. In this study, m1A was found to be a novel substrate of renal cationic drug transporters OCT2 and MATE2-K. N 1-methyladenosine was revealed to have some advantages compared to other OCT2/MATE substrates (creatinine and N 1-methylnicotinamide). The genetic or chemical impairment of OCT2 or MATE2-K caused a significant increase in the plasma m1A concentration in mice and cynomolgus monkeys due to the high contribution of tubular secretion to the net elimination of m1A. The plasma m1A concentration profile showed low diurnal and interindividual variation in healthy volunteers. Thus, m1A could be a better biomarker of variations in OCT2/MATE2-K activity caused by inhibitory drugs.

The influence of chromosome 4 on metabolism and spatial memory in SHR and SLA16 rat strains

The Spontaneously Hypertensive Rat (SHR) has been proposed as a good model to study the pathways related to neurodegenerative diseases and glucose intolerance. Our research group developed the SLA16 (SHR.LEW-Anxrr16) congenic strain, which is genetically identical to the SHR strain, except for a locus on chromosome 4 (DGR). We applied in silico analysis on DGR to evaluate the association of their genes with neurobiological and metabolic pathways. After, we characterized cholesterol, triglycerides, metabolism of glucose and the behavioral performance of young (2 months old) and adult (8 months old) SHR and SLA16 rats in the open field, object location and water maze tasks. Finally, naïve young rats were repeatedly treated with metformin (200 mg/kg; v.o.) and evaluated in the same tests. Bioinformatics analysis showed that DGR presents genes related to glucose metabolism, oxidative damage and neurodegenerative diseases. Young SLA16 presented higher cholesterol, triglycerides, glucose and locomotion in the open field than SHR rats. In adulthood, SLA16 rats presented high triglycerides and locomotion in the open field and impairment on spatial learning and memory. Finally, the treatment with metformin decreased the glucose tolerance curve and also improved long-term memory in SLA16 rats. These results indicate that DGR presents genes associated with metabolic pathways and neurobiological processes that may produce alterations in glucose metabolism and spatial learning/memory. Therefore, we suggest that SHR and SLA16 strains could be important for the study of genes and subsequent mechanisms that produce metabolic glucose alterations and age-related cognitive deficits.

Knowing is not half the battle: Impacts of information from the National Health Screening Program in Korea

Health screening provides information on disease risk and diagnosis, but whether this promotes health is unclear. We estimate the impacts of information provided by Korea's National Health Screening Program by applying a regression discontinuity design around different biomarker thresholds of diabetes, obesity, and hyperlipidemia risk using administrative data that includes medical claims, biomarkers, and behavioral surveys over four years after screening. Generally, we find limited responses to disease risk information alone. However, we find evidence for weight loss around the high risk threshold for diabetes, where information is combined with active prompting for a secondary examination for diagnosis and treatment.

Salidroside stimulates the Sirt1/PGC-1α axis and ameliorates diabetic nephropathy in mice

BACKGROUND

Salidroside, an active component from Traditional Chinese Medicine Rhodiola rosea L., has various pharmacological functions including anti-inflammatory, anti-cancer and anti-oxidative properties. However, whether salidroside plays a beneficial role in diabetic nephropathy is still unclear.

PURPOSE

The objective of this work was to investigate the potential roles of salidroside against diabetic nephropathy and the underlying molecular mechanisms.

METHODS

Streptozocin was given to obese mice to generate diabetic nephropathy animal model. Salidroside was administered to these mice and proteinuria, podocyte integrity, renal morphology and fibrosis, mitochondrial biogenesis were examined.

RESULTS

Our results showed that salidroside treatment greatly attenuates diabetic nephropathy as evidenced by decreased urinary albumin, blood urea nitrogen and serum creatinine. Morphological analysis indicated that salidroside improves renal structures in diabetic nephropathy. The decreases in nephrin and podocin expression were markedly reversed by salidroside. Moreover, kidney fibrosis in diabetic nephropathy mice was largely prevented by salidroside. Mechanistically, in salidroside-treated mice, the mitochondrial DNA copy and electron transport chain proteins were significantly enhanced. Meanwhile, the reduced Sirt1 and PGC-1α expression in diabetic nephropathy was almost completely counteracted in the presence of salidroside.

CONCLUSIONS

Our data showed that salidroside plays a beneficial role against diabetic nephropathy in mice, which probably via Sirt1/PGC-1α mediated mitochondrial biogenesis.

Comparative Efficacy of Antihypertensive Agents in Salt-Sensitive Hypertensive Patients: A Network Meta-Analysis

BACKGROUND

Salt-sensitive hypertension (SSH) is an intermediate inherited phenotype of essential hypertension as well as being an independent risk factor for cardiovascular disease. However, effective medications for the treatment of SSH have not been clarified. This study was to compare the efficacious of different classes of antihypertensive agents combined with salt intake on the reduction of blood pressure (BP) in patients with SSH.

METHODS

We used sources as PubMed, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), CNKI, and WANFANG database from inception to November 2016. Studies that compared the efficacy of 2 or more antihypertensive agents or placebos in adult salt-sensitive hypertensive patients were included. The outcomes included variations in mean arterial blood pressure, systolic and diastolic blood pressure.

RESULTS

Twenty-five studies were involved in this meta-analysis. A calcium channel blocker (CCB) with hydrochlorothiazide and moderate salt intake was significantly the most efficacious in comparison with placebo (standardized mean differences (SMD), 95% credibility intervals (CI): 26.66, 12.60 to 40.16), angiotensin receptor blockers (ARBs) (SMD, 95% CI: 22.94, 5.26 to 40.51), and the other interventions for patients with SSH and no concomitant diseases. For SSH patients who were obese, CCB with metformin and moderate salt intake would decrease blood pressure with 17.90 mm Hg.

CONCLUSIONS

For SSH patients with no concomitant diseases, CCB combined with hydrochlorothiazide and moderate salt intake was optimal in reducing BP, while CCB combined with metformin and moderate salt intake was the most efficacious at reducing BP in SSH patients with coexisting obesity.

Is it necessary to discontinue metformin in diabetic patients with GFR > 60 ml/min per 1.73 m2 undergoing coronary angiography: A controversy still exists?

BACKGROUND

Although metformin is not directly nephrotoxic, it has been postulated that it can impair gluconeogenesis from lactate, which may lead lactate to be accumulated under circumstances such as contrast-induced nephropathy. The present study aims to assess the role of metformin in lactate production in a group of diabetic patients with GFR > 60 ml/min per 1.73 m2undergoing coronary angiography.

METHODS

In the present randomized clinical trial, 162 metformin-treated diabetic patients were enrolled. The enlisted patients were scheduled to undergo coronary angiography at Modarres Hospital from Feb 2012 to Nov 2012. Patients were randomly allocated to continue metformin during peri-angiography period (M (+) group) or to stop the medication 24 hours prior the procedure (M (-) group). All the patients had glomerular filtration rate of >60 mL/min per 1.73 m2. Iodixanol was the only contrast media which in all patients. Metformin-associated lactic acidosis (MALA) was defined as an arterial pH <7.35 and plasma lactate concentration >5 mmol⁄L.

RESULTS

162 patients, including79 (48.7%) male and 83 (51.3%) female patients were enrolled in the study. The average of GFR was comparable in both groups (76 ml/min per 1.73 m2 in the M (+) group versus 79 ml/min per 1.73 m2 in the M (-) group, p=0.53). No significant difference was observed in the mean dose of metformin before the study between the 2 groups (2.18 tablets per day in M (+) group vs. 2.21 tablets per day in M(-) group, p=0.62).No lactic acidosis was observed in the studied groups.

CONCLUSION

In conclusion, the results of the present study indicate that metformin continuation in diabetic patients with a GFR of more than 60 ml/min per 1.73 m2 undergoing coronary angiography does not enhance the risk of MALA development.

Metformin treatment of type 2 diabetes mellitus in pregnancy: update on safety and efficacy

With the increasing prevalence of type 2 diabetes mellitus (T2DM) in women of childbearing age, prescribing antidiabetic medications in first-trimester pregnancy is becoming more common. Metformin treatment during this time is usually avoided in countries with well-resourced healthcare. This is based on historical concerns about safety to the foetus and the widespread availability of insulin. However, there is now increasing interest in the potential benefits of metformin in pregnant women with T2DM. In this commentary, the main evidence supporting metformin safety in pregnancy is summarized, with an emphasis on the first trimester. Based on a structured literature search, the recent randomized controlled trials comparing metformin and insulin are reviewed. We then show that prescribing advice for metformin in pregnancy is inconsistent and product information/package inserts (PI) are universally out of date. This causes confusion and pushes some women and their clinicians to change from metformin to insulin. The potential advantages of metformin in pregnant women with T2DM are then discussed, including oral dosing and improved acceptability, lower resource utilization and cost, decreased insulin requirements, less maternal weight gain and less risk of maternal and neonatal hypoglycaemia. The conclusion is that metformin is a cheap and efficacious antidiabetic medication for many pregnant women with T2DM, with reasonable evidence for safety. Drug information resources should be updated so that metformin can be considered more broadly in women with T2DM who present for antenatal care.