Significantly reduced cytochrome P450 3A4 expression and activity in liver from humans with diabetes mellitus

Development of a Physiologically Based Pharmacokinetic Population Model for Diabetic Patients and its Application to Understand Disease-drug-drug Interactions

INTRODUCTION

The activity changes of cytochrome P450 (CYP450) enzymes, along with the complicated medication scenarios in diabetes mellitus (DM) patients, result in the unanticipated pharmacokinetics (PK), pharmacodynamics (PD), and drug-drug interactions (DDIs). Physiologically based pharmacokinetic (PBPK) modeling has been a useful tool for assessing the influence of disease status on CYP enzymes and the resulting DDIs. This work aims to develop a novel diabetic PBPK population model to facilitate the prediction of PK and DDI in DM patients.

METHODS

First, mathematical functions were constructed to describe the demographic and non-CYP physiological characteristics specific to DM, which were then incorporated into the PBPK model to quantify the net changes in CYP enzyme activities by comparing the PK of CYP probe drugs in DM versus non-DM subjects.

RESULTS

The results show that the enzyme activity is reduced by 32.3% for CYP3A4/5, 39.1% for CYP2C19, and 27% for CYP2B6, while CYP2C9 activity is enhanced by 38% under DM condition. Finally, the diabetic PBPK model was developed through integrating the DM-specific CYP activities and other parameters and was further used to perform PK simulations under 12 drug combination scenarios, among which 3 combinations were predicted to result in significant PK changes in DM, which may cause DDI risks in DM patients.

CONCLUSIONS

The PBPK modeling applied herein provides a quantitative tool to assess the impact of disease factors on relevant enzyme pathways and potential disease-drug-drug-interactions (DDDIs), which may be useful for dosing regimen optimization and minimizing the DDI risks associated with the treatment of DM.

Investigation of the Expression of CYP3A4 in Diabetic Rats in Xenobiotic Metabolism

Objectives

This study investigated the impact of a high-fat diet streptozotocin (STZ)-induced diabetes and dapagliflozin treatment on hepatic protein expression of CYP3A4.

Materials and Methods

In our study, 34 male Sprague-Dawley rats were randomly divided into four groups: Control, high-fat diet and STZ-induced diabetes, dapagliflozin-treated control, and dapagliflozin-treated diabetes. In the microsomes obtained from the livers of these rats, the protein expression levels of CYP3A4 were determined by Western blotting.

Results

Hepatic CYP3A4 protein expression levels in the control group treated with dapagliflozin were significantly decreased compared with those in the control group. In addition, hepatic CYP3A4 protein expression levels were decreased in dapagliflozin-treated diabetic Sprague-Dawley rats compared with those in both control and diabetic group rats, but the difference between the groups was not statistically significant.

Conclusion

According to these two results, the use of dapagliflozin inhibited hepatic CYP3A4 protein expression.

Immunosuppression for older liver transplant recipients

Older liver transplant recipients have a lower risk of acute rejection than younger patients (9% for patients aged ≥65 years versus 23% for those aged 18-34 years) and are more vulnerable to immunosuppression-related complications. The number of liver transplant recipients ≥65 years has risen to 22% in Europe and the US, but limited information is available on the optimal immunosuppressive regimen for these patients. In this review, we discuss the appropriate management of immunosuppressive agents in older adults to minimize adverse events while avoiding acute rejection. The way the body processes drugs greatly depends on age. In the case of calcineurin inhibitor drugs, aging reduces hepatic metabolism, leading to changes in their pharmacokinetics. Corticosteroids also show decreased clearance as the patient ages. In severe cases of hypoalbuminemia, dose adjustment of mycophenolate acid derivatives may be necessary. However, the pharmacokinetic profiles of the mammalian target of rapamycin inhibitors, basiliximab, and rabbit anti-thymocyte globulin remain unaffected by age. Furthermore, age-related frailty may impact drug metabolism and require tailored interventions and closer follow-up. Although there is limited research, elderly liver transplant recipients require less immunosuppression with double or triple-agent regimens, lower exposure to calcineurin inhibitors, and a shorter course of corticosteroids. The usage of mammalian target of rapamycin inhibitors in older transplant populations has not been specifically investigated, and thus their usage should align with indications for younger patient groups.

Tacrolimus and Diabetes in Kidney Transplantation: The Impact of Cyp3a5 Gene Polymorphism

BACKGROUND

To explore the correlation between single nucleotide polymorphisms (SNPs) of CYP3A4 rs2740574 and CYP3A5 rs776746 and post-transplant diabetes mellitus (PTDM) in Chinese renal allograft recipients treated with tacrolimus.

METHODS

A total of 244 patients treated with tacrolimus were included in this study, wherein DNA sequencing was detected through fluorescence in situ hybridization, and SNP genotyping was performed.

RESULTS

Among the 244 patients, 44 (18%) developed PTDM. The PTDM group exhibited higher preoperative body mass index and fasting plasma glucose levels, with higher creatinine values one year after surgery. The CYP3A4 rs2740574 genotype was found to be unique in its homozygous AA form. For CYP3A5 rs776746, the genotypes were distributed as follows: 28 (11.5%) cases with AA, 101 (41.4%) cases with AG, and 115 (47.1%) cases with GG, respectively (P = .042). The AA genotype showed a statistically significant difference from both AG and GG genotypes. Furthermore, the A allele of CYP3A5 rs776746 was found to be associated with an increased risk for PTDM development.

CONCLUSIONS

The occurrence of tacrolimus-related PTDM is associated with body mass index, fasting plasma glucose levels, and CYP3A5 genotype before renal transplantation. Post-transplant diabetes mellitus is correlated with unfavorable long-term renal graft function, whereas the expression of the CYP3A5 rs776746 gene is linked to an elevated risk of PTDM.

Novel mediators regulating angiogenesis in diabetic foot ulcer healing

A non-healing diabetic foot ulcer (DFU) is a debilitating clinical problem amounting to socioeconomic and psychosocial burdens. DFUs increase morbidity due to prolonged treatment and mortality in the case of non-treatable ulcers resulting in gangrene and septicemia. The overall amputation rate of the lower extremity with DFU ranges from 3.34% to 42.83%. Wound debridement, antibiotics, applying growth factors, negative pressure wound therapy, hyperbaric oxygen therapy, topical oxygen, and skin grafts are common therapies for DFU. However, recurrence and nonhealing ulcers are still major issues. Chronicity of inflammation, hypoxic environment, poor angiogenesis, and decreased formation of the extracellular matrix (ECM) are common impediments leading to nonhealing patterns of DFUs. Angiogenesis is crucial for wound healing since proper vessel formation facilitates nutrients, oxygen, and immune cells to the ulcer tissue to help in clearing out debris and facilitate healing. However, poor angiogenesis due to decreased expression of angiogenic mediators and matrix formation results in nonhealing and ultimately amputation. Multiple proangiogenic mediators and vascular endothelial growth factor (VEGF) therapy exist to enhance angiogenesis, but the results are not satisfactory. Thus, there is a need to investigate novel pro-angiogenic mediators that can either alone or in combination enhance the angiogenesis and healing of DFUs. In this article, we critically reviewed the existing pro-angiogenic mediators followed by potentially novel factors that might play a regulatory role in promoting angiogenesis and wound healing in DFUs.

Pregnane X receptor gene variant rs7643645 and total mortality in subjects with nonalcoholic fatty liver disease

Pregnane X receptor (PXR) gene variants rs7643645 and rs2461823 are reported to associate with clinically and histologically more severe liver injury in nonalcoholic fatty liver disease (NAFLD). It is known that the more progressive the NAFLD, the higher the hepatic and extra-hepatic mortality and morbidity. Thus, we investigated the total mortality in Finnish middle-aged ultrasonographically verified NAFLD patients with PXR rs7643645 AA/AG ( n  = 217) or GG ( n  = 27) variants and rs2461823 CC/CT ( n  = 215) or TT ( n  = 27) variants. In up to 30 years of follow-up, PXR rs7643645 GG subjects were at an increased risk of total mortality compared with AA/AG subjects, 1.676 (1.014-2.772), P  = 0.044. The statistically significant difference prevailed after multiple adjustments for potentially confounding factors, RR, 2.024 (1.191-3.440), P  = 0.009. In the subjects without NAFLD ( n  = 731), the mortality risk was not associated with rs7643645 variants, 1.051 (0.708-1.560; P  = 0.804). There was no difference in the total mortality between the PXR rs2461823 variant subgroups, 1.141 (0.663-1.962; P  = 0.634). As the rs7643645 G variant disrupts a putative hepatocyte nuclear factor 4α binding site located in the PXR gene promoter and is associated with lower hepatic expression of PXR and its target genes, our result suggests that genetic disruption of xenobiotic metabolism increases mortality in subjects with NAFLD. Further studies are needed to confirm the results of the present study.

Impact of type 2 diabetes on in vivo activities and protein expressions of cytochrome P450 in patients with obesity

Previous studies have not accounted for the close link between type 2 diabetes mellitus (T2DM) and obesity when investigating the impact of T2DM on cytochrome P450 (CYP) activities. The aim was to investigate the effect of T2DM on in vivo activities and protein expressions of CYP2C19, CYP3A, CYP1A2, and CYP2C9 in patients with obesity. A total of 99 patients from the COCKTAIL study (NCT02386917) were included in this cross-sectional analysis; 29 with T2DM and obesity (T2DM-obesity), 53 with obesity without T2DM (obesity), and 17 controls without T2DM and obesity (controls). CYP activities were assessed after the administration of a cocktail of probe drugs including omeprazole (CYP2C19), midazolam (CYP3A), caffeine (CYP1A2), and losartan (CYP2C9). Jejunal and liver biopsies were also obtained to determine protein concentrations of the respective CYPs. CYP2C19 activity and jejunal CYP2C19 concentration were 63% (-0.39 [95% CI: -0.82, -0.09]) and 40% (-0.09 fmol/μg protein [95% CI: -0.18, -0.003]) lower in T2DM-obesity compared with the obesity group, respectively. By contrast, there were no differences in the in vivo activities and protein concentrations of CYP3A, CYP1A2, and CYP2C9. Multivariable regression analyses also indicated that T2DM was associated with interindividual variability in CYP2C19 activity, but not CYP3A, CYP1A2, and CYP2C9 activities. The findings indicate that T2DM has a significant downregulating impact on CYP2C19 activity, but not on CYP3A, CYP1A2, and CYP2C9 activities and protein concentrations in patients with obesity. Hence, the effect of T2DM seems to be isoform-specific.

The Role of CYP3A in Health and Disease

CYP3A is an enzyme subfamily in the cytochrome P450 (CYP) superfamily and includes isoforms CYP3A4, CYP3A5, CYP3A7, and CYP3A43. CYP3A enzymes are indiscriminate toward substrates and are unique in that these enzymes metabolize both endogenous compounds and diverse xenobiotics (including drugs); almost the only common characteristic of these compounds is lipophilicity and a relatively large molecular weight. CYP3A enzymes are widely expressed in human organs and tissues, and consequences of these enzymes' activities play a major role both in normal regulation of physiological levels of endogenous compounds and in various pathological conditions. This review addresses these aspects of regulation of CYP3A enzymes under physiological conditions and their involvement in the initiation and progression of diseases.

Simultaneous absolute protein quantification of seven cytochrome P450 isoforms in rat liver microsomes by LC-MS/MS-based isotope internal standard method

The cytochrome P450 (CYP) enzymes play a pivotal role in drug metabolism. LC-MS/MS-based targeting technology has been applied to the analysis of CYP enzymes, promoting drug development and drug-drug interaction studies. Rat is one of the most commonly used models for drug metabolism assessment, but LC-MS/MS assay quantifying the abundance of CYP enzymes in rats is rarely reported. Herein, an accurate and stable LC-MS/MS based method was developed and validated for the simultaneous quantification of seven major rat CYP isoforms (CYP1A2, 2B1, 2C6, 2C11, 2D1, 2E1, and 3A1) in liver microsomes. The careful optimization of trypsin digestion and chromatography combined with isotope-labeled peptide as internal standard improved the efficiency and accuracy of the analysis. Highly specific surrogate peptides were obtained by a procedure including trypsin digestion for six hours and separated on a Hypersil Gold C18 column (100 × 2.1 mm, 3 μm) using gradient elution for 15 min with a mobile phase of water containing 0.1% formic acid and acetonitrile. In the method validation, linearity, matrix effect, recovery, stability, accuracy, and precision all meet the requirements. Subsequently, this method was applied to detect seven enzymes in rat liver microsomes from four different sources, and the correlation between the abundance and activity of CYP enzymes was further analyzed. The high-throughput detection method provided in this study will provide support for pertinent pharmaceutical research based on rat models.

Cucumis melo var. momordica as a potent antidiabetic, antioxidant and possible anticovid alternative: Investigation through experimental and computational methods

Diabetes mellitus is a typical life threatening of disease, which generate due to the dysfunction of β cells of pancreas. In 2014, WHO stated that 422 million people were infected with DM. The current pattern of management of diabetes included synthetic or plant based oral hypoglycemic drugs and insulin but drug resentence is become a very big issues in antidiabetic therapy. Thus, it's very earnest to discover now medication for this disease. Now the days, it is well acknowledged that diabetic patients are more prone towards covid and related complications. Thus, medical practitioners reformed the methodology of prescribing medication for covid infected antidiabetic therapy and encouraging the medication contains dual pharmacological properties. It is also well know that polyphenols specifically hold a significant role in oxidative stress and reduced the severity of many inflammatory diseases. Cucumis melo has rich history as ethano-pharmacological use in Indian subcontinent. The fruit and seed is well known for the treatment of various diseases due to the presence of phenolics. Therefore, in this study, the combined mixture of flower and seeds were used for the extraction of polyphenolic rich extract and tested for antidiabetic activity through the antioxidant and in vivo experiments. The antioxidant potential measurement exhibited that the selected plant  has the significant competence to down-regulate oxidative stress (DPPH scavenging IC 50 at 60.7 ±1.05 µg/mL, ABTS IC 50 at 62.15 ± 0.50 µg/mL). Furthermore, the major polyphenolic phyto-compounds derived from the Cucumis melo were used for in silico anticovid activity, docking, and complementarity studies. The anticovid activity prognosis reflected that selected phyto-compounds amentoflavone and vanillic acid have optimal possibility to interact with 3C-like protease and through this moderate anticovid activity can be exhibit. The docking experiments established that the selected compounds have propensity to interact with protein tyrosine phosphatase 1B, 11β-Hydroxysteroid dehydrogenase, superoxide dismutase, glutathione peroxidase, and catalase β-glucuronidase receptor. In vivo experiments showed that 500 mg/kg, Cucumis melo ominously amplified body weight, plasma insulin, high-density lipoprotein levels, and biochemical markers. Furthermore, extract significantly downregulate the blood glucose, total cholesterol, triglycerides, low-density lipoprotein, and very low-density lipoprotein.

Comparison of pharmacokinetic parameters of ranolazine between diabetic and non-diabetic rats

OBJECTIVES

Diabetes mellitus (DM) affects the pharmacokinetics of drugs. Ranolazine is an antianginal drug that is prescribed in DM patients with angina. We decided to evaluate the effect of DM on the pharmacokinetics of ranolazine and its major metabolite CVT-2738 in rats.

MATERIALS AND METHODS

Male rats were divided into two groups: DM (induced by 55 mg/kg Streptozotocin (STZ)) and non-DM. All animals were treated with 80 mg/kg of ranolazine for 7 continuous days. The blood samples were collected immediately at 0 (prior to dosing), 1, 2, 3, 4, 8, and 12 hr after administration of the 7th dose of ranolazine. Serum ranolazine and CVT-2738 concentrations were determined using the high-performance liquid chromatography (HPLC) method. Pharmacokinetic parameters were calculated using a non-compartmental model and compared between the two groups.

RESULTS

The peak serum concentration (Cmax) and area under the curve (AUC) of ranolazine significantly decreased in DM compared with non-DM rats. DM rats showed significantly higher volumes of distribution (Vd) and clearance (CL) of ranolazine than non-DM rats. DM did not affect Ke, Tmax, and T1/2 of ranolazine. The concentration of metabolite was lower than the HPLC limit of detection (LOD).

CONCLUSION

It was found that streptozotocin-induced DM increased Vd and CL of ranolazine, thereby decreasing the AUC of the drug. Therefore, dosage adjustment may be necessary for DM patients, which requires further clinical studies.

Choroideremia: molecular mechanisms and therapies

Choroideremia (CHM) is a monogenic X-linked chorioretinal dystrophy affecting the photoreceptors, retinal pigment epithelium (RPE), and choroid; it is caused by mutations involving the CHM gene. CHM is characterized by night blindness in early childhood, progressing to peripheral visual field loss and eventually to complete blindness from middle age. CHM encodes the ubiquitously expressed Rab escort protein 1 (REP1), which is responsible for prenylation of Rab proteins and is essential for intracellular trafficking of vesicles. In this review we explore the role of REP1 in the retina and its newly discovered systemic manifestations, and discuss the therapeutic strategies for tackling this disease, including the outcomes from recent clinical trials.

Genetic association tests in family samples for multi-category phenotypes

BACKGROUND

Advancements in statistical methods and sequencing technology have led to numerous novel discoveries in human genetics in the past two decades. Among phenotypes of interest, most attention has been given to studying genetic associations with continuous or binary traits. Efficient statistical methods have been proposed and are available for both types of traits under different study designs. However, for multinomial categorical traits in related samples, there is a lack of efficient statistical methods and software.

RESULTS

We propose an efficient score test to analyze a multinomial trait in family samples, in the context of genome-wide association/sequencing studies. An alternative Wald statistic is also proposed. We also extend the methodology to be applicable to ordinal traits. We performed extensive simulation studies to evaluate the type-I error of the score test, Wald test compared to the multinomial logistic regression for unrelated samples, under different allele frequency and study designs. We also evaluate the power of these methods. Results show that both the score and Wald tests have a well-controlled type-I error rate, but the multinomial logistic regression has an inflated type-I error rate when applied to family samples. We illustrated the application of the score test with an application to the Framingham Heart Study to uncover genetic variants associated with diabesity, a multi-category phenotype.

CONCLUSION

Both proposed tests have correct type-I error rate and similar power. However, because the Wald statistics rely on computer-intensive estimation, it is less efficient than the score test in terms of applications to large-scale genetic association studies. We provide computer implementation for both multinomial and ordinal traits.

In silico network pharmacology and in vivo analysis of berberine-related mechanisms against type 2 diabetes mellitus and its complications

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine (BBR), extracted from the traditional medicinal plant Coptis chinensis Franch., has been widely used for the treatment of type 2 diabetes mellitus (T2DM) and its complications.

AIM OF THE STUDY

To determine the potential pharmacological mechanisms underlying BBR therapeutic effect on T2DM and its complications by in silico network pharmacology and experimental in vivo validation.

MATERIALS AND METHODS

A predictive network depicting the relationship between BBR and T2DM was designed based on information collected from several databases, namely STITCH, CHEMBL, PharmMapper, TTD, Drugbank, and PharmGKB. Identified overlapping targets related to both BBR and T2DM were crossed with information on biological processes (BPs) and molecular/signaling pathways using the DAVID platform and Cytoscape software. Three candidate targets identified with the BBR-T2DM network (RXRA, KCNQ1 and NR3C1) were evaluated in the C57BL/6J mouse model of T2DM. The mice were treated with BBR or metformin for 10 weeks. Weight, fasting blood glucose (FBG), oral glucose tolerance, and expression levels of the three targets were evaluated.

RESULTS

A total of 31 targets of BBR that were also related to T2DM were identified, of which 14 had already been reported in previous studies. Furthermore, these 31 overlapping targets were enriched in 21 related BPs and 18 pathways involved in T2DM treatment. The identified BP-target-pathway network revealed the underlying mechanisms of BBR antidiabetic activity were mediated by core targets such as RXRA, KCNQ1, and NR3C1. In vivo experiments further confirmed that treatment with BBR significantly reduced weight and FBG and alleviated insulin resistance in T2DM mice. Moreover, BBR treatment promoted RXRA expression, whereas it reduced KCNQ1 and NR3C1 expression in the liver.

CONCLUSION

Using network pharmacology and a T2DM mouse model, this study revealed that BBR can effectively prevent T2DM symptoms through vital targets and multiple signaling pathways. Network pharmacology provides an efficient, time-saving approach for therapeutic research and the development of new drugs.

Stachyose inhibits vancomycin-resistant Enterococcus colonization and affects gut microbiota in mice

Vancomycin-resistant Enterococcus (VRE) caused nosocomial infections are rising globally. Multiple measures have been investigated to address this issue, altering gut microbiota through dietary intervention represents one of such effort. Stachyose can promote probiotic growth, which makes it a good candidate for potentially inhibiting VRE infection. This study aimed to determine whether stachyose inhibits VRE colonization and investigated the involvement of gut microbiota this effect of stachyose. In VRE-infection experiment, 6-week old female C57/6 J mice pre-treated with vancomycin were infected with 2 × 10⁸ CFU VRE via gavage. These mice then received oral administration of stachyose or PBS as control for 7days. Two groups of uninfected mice were also received daily gavage of stachyose or PBS for 7 days to observe the impact of stachyose treatment on normal mice. Fresh fecal and colon samples were collected, then VRE colonization, gut microbiota and gene expression were respectively assessed using cultivation, 16s rRNA sequencing and RNA-sequencing in two parallel experiment, respectively. In VRE-infected mice, stachyose treatment significantly reduced VRE colonization on days 9 and 10 post-infection. Stachyose treatment increased the relative abundance of Porphyromonadaceae, Parabacteroides, and Parabacteroides distasonis compared to the PBS-treated infection mice (P < 0.01). Uninfected mice treated with stachyose showed a significant increase in Lactobacillaceae and Lactobacillus compared to the PBS-treated uninfected mice(P < 0.05). RNA-sequencing results showed that stachyose treatment in VRE-infected mice increased expression of genes involved in TNF and IL-17 signaling pathways. Stachyose treatment also up-regulated Hsd17b14, Cyp3a44, Arg1, and down-regulated Pnliprp2, Ces1c, Pla2g4c genes involving in metabolic pathway in uninfected mice. In conclusion, stachyose supplementation can effectively inhibit VRE colonization and probably altering composition of the microbiome, which can in turn result in changes in expression of genes. Stachyose may also benefit health by increasing the abundance of Lactobacillus and expression of genes involving in metabolic pathway in normal mice.

Silybin Restored CYP3A Expression through the Sirtuin 2/Nuclear Factor κ-B Pathway in Mouse Nonalcoholic Fatty Liver Disease

Silybin is widely used as a hepatoprotective agent in various liver disease therapies and has been previously identified as a CYP3A inhibitor. However, little is known about the effect of silybin on CYP3A and the regulatory mechanism during high-fat-diet (HFD)-induced liver inflammation. In our study, we found that silybin restored CYP3A expression and activity that were decreased by HFD and conditioned medium (CM) from palmitate-treated Kupffer cells. Moreover, silybin suppressed liver inflammation in HFD-fed mice and inhibited nuclear factor κ-B translocation into the nucleus through elevation of SIRT2 expression and promotion of p65 deacetylation. This effect was confirmed by overexpression of SIRT2, which suppressed p65 nuclear translocation and restored CYP3A transcription affected by CM. The hepatic NAD⁺ concentration markedly decreased in HFD-fed mice and CM-treated hepatocytes/HepG2 cells but increased after silybin treatment. Supplementing nicotinamide mononucleotide as an NAD⁺ donor inhibited p65 acetylation, decreased p65 nuclear translocation, and restored cyp3a transcription in both HepG2 cells and mouse hepatocytes. These results suggest that silybin regulates metabolic enzymes during liver inflammation by a mechanism related to the increase in NAD⁺ and SIRT2 levels. In addition, silybin enhanced the intracellular NAD⁺ concentration by decreasing poly-ADP ribosyl polymerase-1 expression. In summary, silybin increased NAD⁺ concentration, promoted SIRT2 expression, and lowered p65 acetylation both in vivo and in vitro, which supported the recovery of CYP3A expression. These findings indicate that the NAD⁺/SIRT2 pathway plays an important role in CYP3A regulation during nonalcoholic fatty liver disease. SIGNIFICANCE STATEMENT: This research revealed the differential regulation of CYP3A by silybin under physiological and fatty liver pathological conditions. In the treatment of nonalcoholic fatty liver disease, silybin restored, not inhibited, CYP3A expression and activity through the NAD⁺/ sirtuin 2 pathway in accordance with its anti-inflammatory effect.

Diabetes mellitus aggravates ranolazine-induced ECG changes in rats

PURPOSE

Diabetes mellitus (DM) is known to affect the pharmacokinetics of drugs. In this study, we evaluated the effect of DM on the liver content of CYP 3A2 enzyme. We also explored the ECG changes after administration of ranolazine in non-DM and DM rats.

METHODS

First phase: 24 male Wistar rats were separated into 4 groups. The control group (n = 6) received normal saline and the DM groups (n = 18) were treated with a single dose (55 mg/kg) of streptozocin (STZ; i.p. injection), then were held for 10, 20, and 30 days, respectively. After study duration for each group, the liver CYP 3A2 protein content was determined using western blotting. Second phase: 48 male Wistar rats were classified into two groups of non-DM and DM; and each group was divided into 4 subgroups (n: 6). Experimental groups received oral doses of 20, 40, and 80 mg/kg ranolazine. DM and non-DM control groups received normal saline. Treatment lasted for 28 days, and then the ECG was recorded.

RESULTS

Experimental DM induced by STZ caused a significant decrement in liver CYP3A2 protein content of rats on days 10 and 20 (P < 0.01), and 30 (P < 0.05) compared to the control animals. Significant increases in QT and corrected QT (QTc) intervals (P < 0.01), and bradycardia (P < 0.01) without any significant effect on PR and QRS intervals were observed in DM in comparison with non-DM groups after ranolazine treatment.

CONCLUSIONS

In summary, DM induction in animals resulted in CYP 3A2 inhibition and the prolongation of QT and QTc interval as well as bradycardia after ranolazine treatment.

Streptozotocin-Induced Hyperglycemia Affects the Pharmacokinetics of Koumine and its Anti-Allodynic Action in a Rat Model of Diabetic Neuropathic Pain

Koumine (KM), the most abundant alkaloid in Gelsemium elegans, has anti-neuropathic, anti-inflammatory, and analgesic activities; thus, it has the potential to be developed as a broad-spectrum analgesic drug. However, factors determining the relationship between analgesic efficacy and the corresponding plasma KM concentration are largely unclear. The pharmacokinetics and pharmacodynamics of KM and their optimization in the context of neuropathic pain have not been reported. We investigated the pharmacokinetics and pharmacodynamics of KM after oral administration in a streptozotocin-induced rat model of diabetic neuropathic pain (DNP) using a population approach. A first-order absorption and elimination pharmacokinetics model best described the plasma KM concentration. This pharmacokinetic model was then linked to a linear pharmacodynamic model with an effect compartment based on the measurement of the mechanical withdrawal threshold. KM was rapidly absorbed (time to maximum plasma concentration: 0.14–0.36 h) with similar values in both DNP and naïve rats, suggesting that DNP did not influence the KM absorption rate. However, the area under the curve (AUC_0–∞) of KM in DNP rats was over 3-fold higher than that in naïve rats. The systemic clearance rate and volume of KM distribution were significantly lower in DNP rats than in naïve rats. Blood glucose value prior to KM treatment was a significant covariate for the systemic clearance rate of KM and baseline value of the threshold. Our results suggest that streptozotocin-induced hyperglycemia is an independent factor for decreased KM elimination and its anti-allodynic effects in a DNP rat model. To the best of our knowledge, this is the first study to investigate the role of DNP in the pharmacokinetics and pharmacokinetics-pharmacodynamics of KM in streptozotocin-induced diabetic rats.

Chronic Inflammatory Status Observed in Patients with Type 2 Diabetes Induces Modulation of Cytochrome P450 Expression and Activity

Diabetes mellitus is a metabolic disease that causes a hyperglycemic status which leads, over time, to serious damage to the heart, blood vessels, eyes, kidneys and nerves. The most frequent form of diabetes is type 2 diabetes mellitus (T2DM) which is often part of a metabolic syndrome (hyperglycaemia, hypertension, hypercholesterolemia, abdominal obesity) that usually requires the use of several medications from different drug classes to bring each of these conditions under control. T2DM is associated with an increase in inflammatory markers such as interleukin-6 (IL-6) and the tumor necrosis factor alpha (TNF-α). Higher levels of IL-6 and TNF-α are associated with a downregulation of several drug metabolizing enzymes, especially the cytochrome P450 (P450) isoforms CYP3As and CYP2C19. A decrease in these P450 isoenzymes may lead to unexpected rise in plasma levels of substrates of these enzymes. It could also give rise to a mismatch between the genotypes determined for these enzymes, the predicted phenotypes based on these genotypes and the phenotypes observed clinically. This phenomenon is described as phenoconversion. Phenoconversion typically results from either a disease (such as T2DM) or concomitant administration of medications inducing or inhibiting (including competitive or non-competitive inhibition) a P450 isoenzyme used by other substrates for their elimination. Phenoconversion could have a significant impact on drug effects and genotypic-focused clinical outcomes. As the aging population is exposed to polypharmacy along with inflammatory comorbidities, consideration of phenoconversion related to drug metabolizing enzymes is of importance when applying pharmacogenomic results and establishing personalized and more precise drug regimens.

Tissue-Specific Proteomics Analysis of Anti-COVID-19 Nucleoside and Nucleotide Prodrug-Activating Enzymes Provides Insights into the Optimization of Prodrug Design and Pharmacotherapy Strategy

Nucleoside and nucleotide analogs are an essential class of antivirals for COVID-19 treatment. Several nucleoside/nucleotide analogs have shown promising effects against SARS-CoV-2 in vitro; however, their in vivo efficacy is limited. Nucleoside/nucleotide analogs are often formed as ester prodrugs to improve pharmacokinetics (PK) performance. After entering cells, the prodrugs undergo several enzymatic metabolism steps to form the active metabolite triphosphate nucleoside (TP-Nuc); prodrug activation is therefore associated with the abundance and catalytic activity of the corresponding activating enzymes. Having the activation of nucleoside/nucleotide prodrugs occur at the target site of action, such as the lung, is critical for anti-SARS-CoV-2 efficacy. Herein, we conducted an absolute quantitative proteomics study to determine the expression of relevant activating enzymes in human organs related to the PK and antiviral efficacy of nucleoside/nucleotide prodrugs, including the lung, liver, intestine, and kidney. The protein levels of prodrug-activating enzymes differed significantly among the tissues. Using catalytic activity values reported previously for individual enzymes, we calculated prodrug activation profiles in these tissues. The prodrugs evaluated in this study include nine McGuigan phosphoramidate prodrugs, two cyclic monophosphate prodrugs, two l-valyl ester prodrugs, and one octanoate prodrug. Our analysis showed that most orally administered nucleoside/nucleotide prodrugs were primarily activated in the liver, suggesting that parenteral delivery routes such as inhalation and intravenous infusion could be better options when these antiviral prodrugs are used to treat COVID-19. The results also indicated that the l-valyl ester prodrug design can plausibly improve drug bioavailability and enhance effects against SARS-CoV-2 intestinal infections. This study further revealed that an octanoate prodrug could provide a long-acting antiviral effect targeting SARS-CoV-2 infections in the lung. Finally, our molecular docking analysis suggested several prodrug forms of favipiravir and GS-441524 that are likely to exhibit favorable PK features over existing prodrug forms. In sum, this study revealed the activation mechanisms of various nucleoside/nucleotide prodrugs relevant to COVID-19 treatment in different organs and shed light on the development of more effective anti-COVID-19 prodrugs.

Characterization of one anastomosis gastric bypass and impact of biliary and common limbs on bile acid and postprandial glucose metabolism in a minipig model

The alimentary limb has been proposed to be a key driver of the weight-loss-independent metabolic improvements that occur upon bariatric surgery. However, the one anastomosis gastric bypass (OAGB) procedure, consisting of one long biliary limb and a short common limb, induces similar beneficial metabolic effects compared to Roux-en-Y Gastric Bypass (RYGB) in humans, despite the lack of an alimentary limb. The aim of this study was to assess the role of the length of biliary and common limbs in the weight loss and metabolic effects that occur upon OAGB. OAGB and sham surgery, with or without modifications of the length of either the biliary limb or the common limb, were performed in Gottingen minipigs. Weight loss, metabolic changes, and the effects on plasma and intestinal bile acids (BAs) were assessed 15 days after surgery. OAGB significantly decreased body weight, improved glucose homeostasis, increased postprandial GLP-1 and fasting plasma BAs, and qualitatively changed the intestinal BA species composition. Resection of the biliary limb prevented the body weight loss effects of OAGB and attenuated the postprandial GLP-1 increase. Improvements in glucose homeostasis along with changes in plasma and intestinal BAs occurred after OAGB regardless of the biliary limb length. Resection of only the common limb reproduced the glucose homeostasis effects and the changes in intestinal BAs. Our results suggest that the changes in glucose metabolism and BAs after OAGB are mainly mediated by the length of the common limb, whereas the length of the biliary limb contributes to body weight loss.NEW & NOTEWORTHY Common limb mediates postprandial glucose metabolism change after gastric bypass whereas biliary limb contributes to weight loss.

Safety of epidural steroids: a review

Spine disease is one of the most common musculoskeletal diseases, especially in an aging society. An epidural steroid injection (ESI) is a highly effective treatment that can be used to bridge the gap between physical therapy and surgery. Recently, it has been increasingly used clinically. The purpose of this article is to review the complications of corticosteroids administered epidurally. Common complications include: hypothalamic-pituitary-adrenal (HPA) axis suppression, adrenal insufficiency, iatrogenic Cushing's syndrome, hyperglycemia, osteoporosis, and immunological or infectious diseases. Other less common complications include psychiatric problems and ocular ailments. However, the incidence of complications related to epidural steroids is not high, and most of them are not serious. The use of nonparticulate steroids is recommended to minimize the complications associated with epidural steroids. The appropriate interval and dosage of ESI are disputed. We recommend that the selection of appropriate ESI protocol should be based on the suppression of HPA axis, which reflects the systemic absorption of the corticosteroid.

Population pharmacokinetics of gabapentin in patients with neuropathic pain: Lack of effect of diabetes or glycaemic control

AIMS

Gabapentin (GBP) is widely used to treat neuropathic pain, including diabetic neuropathic pain. Our objective was to evaluate the role of diabetes and glycaemic control on GBP population pharmacokinetics.

METHODS

A clinical trial was conducted in patients with neuropathic pain (n = 29) due to type 2 diabetes (n = 19) or lumbar/cervical disc herniation (n = 10). All participants were treated with a single oral dose GBP. Blood was sampled up to 24 hours after GBP administration. Data were analysed with a population approach using the stochastic approximation expectation maximization algorithm. Weight, body mass index, sex, biomarkers of renal function and diabetes, and genotypes for the main genetic polymorphisms of SLC22A2 (rs316019) and SLC22A4 (rs1050152), the genes encoding the transporters for organic cations OCT2 and OCTN1, were tested as potential covariates.

RESULTS

GBP drug disposition was described by a 1-compartment model with lag-time, first-order absorption and linear elimination. The total clearance was dependent on estimated glomerular filtration rate. Population estimates (between-subject variability in percentage) for lag time, first-order absorption rate, apparent volume of distribution and total clearance were 0.316 h (10.6%), 1.12 h^-1 (10.7%), 140 L (7.7%) and 14.7 L/h (6.97%), respectively. No significant association was observed with hyperglycaemia, glycated haemoglobin, diabetes diagnosis, age, sex, weight, body mass index, SLC22A2 or SLC22A4 genotypes.

CONCLUSION

This population pharmacokinetics model accurately estimated GBP concentrations in patients with neuropathic pain, using estimated glomerular filtrationrate as a covariate for total clearance. The distribution and excretion processes of GBP were not affected by hyperglycaemia or diabetes.

Characterization of Differential Tissue Abundance of Major Non-CYP Enzymes in Human

The availability of assays that predict the contribution of cytochrome P450 (CYP) metabolism allows for the design of new chemical entities (NCEs) with minimal oxidative metabolism. These NCEs are often substrates of non-CYP drug-metabolizing enzymes (DMEs), such as UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), carboxylesterases (CESs), and aldehyde oxidase (AO). Nearly 30% of clinically approved drugs are metabolized by non-CYP enzymes. However, knowledge about the differential hepatic versus extrahepatic abundance of non-CYP DMEs is limited. In this study, we detected and quantified the protein abundance of eighteen non-CYP DMEs (AO, CES1 and 2, ten UGTs, and five SULTs) across five different human tissues. AO was most abundantly expressed in the liver and to a lesser extent in the kidney; however, it was not detected in the intestine, heart, or lung. CESs were ubiquitously expressed with CES1 being predominant in the liver, while CES2 was enriched in the small intestine. Consistent with the literature, UGT1A4, UGT2B4, and UGT2B15 demonstrated liver-specific expression, whereas UGT1A10 expression was specific to the intestine. UGT1A1 and UGT1A3 were expressed in both the liver and intestine; UGT1A9 was expressed in the liver and kidney; and UGT2B17 levels were significantly higher in the intestine than in the liver. All five SULTs were detected in the liver and intestine, and SULT1A1 and 1A3 were detected in the lung. Kidney abundance was the most variable among the studied tissues, and overall, high interindividual variability (>15-fold) was observed for UGT2B17, CES2 (intestine), SULT1A1 (liver), UGT1A9, UGT2B7, and CES1 (kidney). These differential tissue abundance data can be integrated into physiologically based pharmacokinetic (PBPK) models for the prediction of non-CYP drug metabolism and toxicity in hepatic and extrahepatic tissues.

Inflammation is a major regulator of drug metabolizing enzymes and transporters: Consequences for the personalization of drug treatment

Inflammation is an evolutionary process that allows survival against acute infection or injury. Inflammation is also a pathophysiological condition shared by numerous chronic diseases. In addition, inflammation modulates important drug-metabolizing enzymes and transporters (DMETs), thus contributing to intra- and interindividual variability of drug exposure. A better knowledge of the impact of inflammation on drug metabolism and its related clinical consequences would help to personalize drug treatment. Here, we summarize the kinetics of inflammatory mediators and the underlying transcriptional and post-transcriptional mechanisms by which they contribute to the inhibition of important DMETs. We also present an updated overview of the effect of inflammation on the pharmacokinetic parameters of most of the drugs that are DMET substrates, for which therapeutic drug monitoring is recommended. Furthermore, we provide opinions on how to integrate the inflammatory status into pharmacogenetics, therapeutic drug monitoring, and population pharmacokinetic strategies to improve the personalization of drug treatment for each patient.

Population pharmacokinetic analysis of bisoprolol in type 2 diabetic patients with hypertension

PURPOSE

Given that it has been reported that type 2 diabetes mellitus may affect the pharmacokinetics of a large number of drugs and that there are still no published population pharmacokinetic (PopPK) analyses in routinely treated patients with hypertension and type 2 diabetes mellitus as comorbid condition, the aim of this study was to determine PK variability of bisoprolol in 70 Serbian patients using the PopPK approach.

METHODS

PopPK analysis was conducted using a nonlinear mixed effects model (NONMEM), version 7.3.0 (Icon Development Solutions). In our patients, a total daily dose of bisoprolol ranged from 1.25 to 10 mg. The drug was administrated orally as a single daily dose or in two divided doses per day.

RESULTS

A wide range of the drug concentrations were noted (1-103 ng/mL) in the population consisted of the adult patients with type 2 diabetes mellitus. From a total of 21 separately assessed covariates, our results indicated that only creatinine clearance could have a potential impact on the variability of the clearance of bisoprolol.

CONCLUSION

Routine assessment of renal function should be carried out before the initiation of treatment with bisoprolol in order to individualize the dose and to prevent possible accumulation and adverse drug reactions.

Imbalance of Drug Transporter-CYP450s Interplay by Diabetes and Its Clinical Significance

The pharmacokinetics of a drug is dependent upon the coordinate work of influx transporters, enzymes and efflux transporters (i.e., transporter-enzyme interplay). The transporter-enzyme interplay may occur in liver, kidney and intestine. The influx transporters involving drug transport are organic anion transporting polypeptides (OATPs), peptide transporters (PepTs), organic anion transporters (OATs), monocarboxylate transporters (MCTs) and organic cation transporters (OCTs). The efflux transporters are P-glycoprotein (P-gp), multidrug/toxin extrusions (MATEs), multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). The enzymes related to drug metabolism are mainly cytochrome P450 enzymes (CYP450s) and UDP-glucuronosyltransferases (UGTs). Accumulating evidence has demonstrated that diabetes alters the expression and functions of CYP450s and transporters in a different manner, disordering the transporter-enzyme interplay, in turn affecting the pharmacokinetics of some drugs. We aimed to focus on (1) the imbalance of transporter-CYP450 interplay in the liver, intestine and kidney due to altered expressions of influx transporters (OATPs, OCTs, OATs, PepTs and MCT6), efflux transporters (P-gp, BCRP and MRP2) and CYP450s (CYP3As, CYP1A2, CYP2E1 and CYP2Cs) under diabetic status; (2) the net contributions of these alterations in the expression and functions of transporters and CYP450s to drug disposition, therapeutic efficacy and drug toxicity; (3) application of a physiologically-based pharmacokinetic model in transporter-enzyme interplay.

Evaluating the effect of type 2 diabetes mellitus on CYP450 enzymes and P-gp activities, before and after glycemic control: A protocol for a case-control pharmacokinetic study

Cytochrome P450s (CYP450) family is one of the most critical factors in the metabolism process. Hence, the present study aims to characterize the activity of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, and P-glycoprotein (P-gp) pump in patients with type 2 diabetes (T2DM). This characterization was performed before and after good glycemic control versus non-diabetic subjects following the administration of a substrate probe drug cocktail. This single-center clinical study proposes the characterization of T2DM impacts on major CYP450 drug-metabolizing enzyme and P-glycoprotein (P-gp) activities. The main propose of the present study is evaluating any alternation in major CYP450 enzymes and P-gp activities in patients with T2DM, before (A1C>7%) and after (A1C≤7%) good glycemic control along with comparing the activities versus non-diabetic subjects. The phenotypes will be assessed following the oral administration of a drug cocktail containing caffeine (CYP1A2), bupropion (CYP2B6), flurbiprofen (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A4/5), and fexofenadine (P-gp) as probe substrates. Furthermore, the influence of variables such as glycemia, genetic polymorphisms, and inflammation on the metabolism process will be evaluated. The first patient has entered the study in Dec 2018.

Bile acids associate with glucose metabolism, but do not predict conversion from impaired fasting glucose to diabetes

OBJECTIVE

Bile acids (BAs) are signaling molecules controlling lipid and glucose metabolism. Since BA alterations are associated with obesity and insulin resistance, plasma BAs have been considered candidates to predict type 2 diabetes (T2D) risk. We aimed to determine (1) the association of BAs with glucose homeostasis parameters and (2) their predictive association with the risk of conversion from prediabetes to new-onset diabetes (NOD) in a prospective cohort study.

DESIGN

205 patients with impaired fasting glucose (IFG) were followed each year during 5 years in the IT-DIAB cohort study. Twenty-one BA species and 7α-hydroxy-4-cholesten-3-one (C4), a marker of BA synthesis, were quantified by LC/MS-MS in plasma from fasted patients at baseline. Correlations between plasma BA species and metabolic parameters at baseline were assessed by Spearman's coefficients and the association between BAs and NOD was determined using Cox proportional-hazards models.

RESULTS

Among the analyzed BA species, total hyocholic acid (HCA) and the total HCA/total chenodeoxycholic acid (CDCA) ratio, reflecting hepatic BA 6α-hydroxylation activity, negatively correlated with BMI and HOMA-IR. The total HCA/total CDCA ratio also correlated negatively with HbA_1C. Conversion from IFG to NOD occurred in 33.7% of the participants during the follow-up. Plasma BA species were not independently associated with the conversion to NOD after adjustment with classical T2D risk factors.

CONCLUSIONS

Fasting plasma BAs are not useful clinical biomarkers for predicting NOD in patients with IFG. However, an unexpected association between 6α-hydroxylated BAs and glucose parameters was found, suggesting a role for this specific BA pathway in metabolic homeostasis. IT-DIAB study registry number: NCT01218061.

The oxidation and hypoglycaemic effect of sorafenib in streptozotocin-induced diabetic rats

Background

Diabetes reduces the activity of CYP3A4 and may increase the exposure for the drugs metabolized by the isoenzyme. Sorafenib is a multi-targeted tyrosine kinase inhibitor (TKI), used for the treatment of advanced renal cell carcinoma, hepatocellular carcinoma and radioactive iodine resistant thyroid carcinoma. The TKI undergoes CYP3A4-dependent oxidative transformation, which may be influenced by hyperglycaemia. The aim of the study was to compare the oxidation for sorafenib between healthy and streptozotocin-induced diabetic rats. Additionally, the effect of sorafenib on glucose levels was investigated.

Methods

The rats were assigned to the groups: streptozotocin-induced diabetic (DG, n = 8) or healthy (HG, n = 8). The rats received sorafenib orally as a single dose of 100 mg/kg. The plasma concentrations of sorafenib and its metabolite N-oxide were measured with the validated high-performance liquid chromatography with ultraviolet detection.

Results

The difference between groups in C_max and AUC_0−t values for sorafenib were significant (p = 0.0004, p = 0.0104), and similarly for the metabolite (p = 0.0008, p = 0.0011). Greater exposure for the parent drug and analysed metabolite was achieved in diabetic group. However, the C_max, AUC_0−t, and AUC_0−∞ ratios between the metabolite and sorafenib were similar in both groups. The significant reduction of glycaemia was observed only in the diabetic animals.

Conclusion

The findings of the study provide evidence that diabetes significantly influence on the exposition for sorafenib and its metabolite, but similar ratios N-oxide/sorafenib for AUC and C_max in healthy and diabetic animals suggest that oxidation of the TKI is rather unchanged. Additionally, sorafenib-associated hypoglycaemia was confirmed in diabetic animals.

Long-term expression of glomerular genes in diabetic nephropathy

Background

Although diabetic nephropathy (DN) is the most common cause for end-stage renal disease in western societies, its pathogenesis still remains largely unclear. A different gene pattern of diabetic and healthy kidney cells is one of the probable explanations. Numerous signalling pathways have emerged as important pathophysiological mechanisms for diabetes-induced renal injury.

Methods

Glomerular cells, as podocytes or mesangial cells, are predominantly involved in the development of diabetic renal lesions. While many gene assays concerning DN are performed with whole kidney or renal cortex tissue, we isolated glomeruli from black and tan, brachyuric (BTBR) obese/obese (ob/ob) and wildtype mice at four different timepoints (4, 8, 16 and 24 weeks) and performed an mRNA microarray to identify differentially expressed genes (DEGs). In contrast to many other diabetic mouse models, these homozygous ob/ob leptin-deficient mice develop not only a severe type 2 diabetes, but also diabetic kidney injury with all the clinical and especially histologic features defining human DN. By functional enrichment analysis we were able to investigate biological processes and pathways enriched by the DEGs at different disease stages. Altered expression of nine randomly selected genes was confirmed by quantitative polymerase chain reaction from glomerular RNA.

Results

Ob/ob type 2 diabetic mice showed up- and downregulation of genes primarily involved in metabolic processes and pathways, including glucose, lipid, fatty acid, retinol and amino acid metabolism. Members of the CYP4A and ApoB family were found among the top abundant genes. But more interestingly, altered gene loci showed enrichment for processes and pathways linked to angioneogenesis, complement cascades, semaphorin pathways, oxidation and reduction processes and renin secretion.

Conclusion

The gene profile of BTBR ob/ob type 2 diabetic mice we conducted in this study can help to identify new key players in molecular pathogenesis of diabetic kidney injury.

DT-678 inhibits platelet activation with lower tendency for bleeding compared to existing P2Y12 antagonists

The novel clopidogrel conjugate, DT-678, is an effective inhibitor of platelets and thrombosis in preclinical studies. However, a comparison of the bleeding risk with DT-678 and currently approved P2Y12 antagonists has yet to be determined. The objective of this study was to evaluate the bleeding tendency of animals treated with clopidogrel, ticagrelor, and DT-678. Ninety-one New Zealand white rabbits were randomized to one of 13 treatment groups (n = 7). Platelet activation was assessed by flow cytometry and light transmission aggregometry before and after the administration of various doses of DT-678, clopidogrel, and ticagrelor. Tongue template bleeding times were also measured before and after drug treatment. Treatment with P2Y12 receptor antagonists caused a dose-dependent reduction in markers of platelet activation (P-selectin and integrin αIIbβ3) and aggregation in response to adenosine diphosphate stimulation. At the same doses required for platelet inhibition, clopidogrel and ticagrelor significantly prolonged bleeding times, while DT-678 did not. DT-678 and the FDA-approved P2Y12 antagonists clopidogrel and ticagrelor are effective inhibitors of platelet activation and aggregation. However, unlike clopidogrel and ticagrelor, DT-678 did not prolong bleeding times at equally effective antiplatelet doses. The results suggest a more favorable benefit/risk ratio for DT-678 and potential utility as part of a dual antiplatelet therapy regimen.

A Brief Overview of the Antitumoral Actions of Leelamine

For the last couple of decades, natural products, either applied singly or in conjunction with other cancer therapies including chemotherapy and radiotherapy, have allowed us to combat different types of human cancers through the inhibition of their initiation and progression. The principal sources of these useful compounds are isolated from plants that were described in traditional medicines for their curative potential. Leelamine, derived from the bark of pine trees, was previously reported as having a weak agonistic effect on cannabinoid receptors and limited inhibitory effects on pyruvate dehydrogenase kinases (PDKs). It has been reported to possess a strong lysosomotropic property; this feature enables its assembly inside the acidic compartments within a cell, such as lysosomes, which may eventually hinder endocytosis. In this review, we briefly highlight the varied antineoplastic actions of leelamine that have found implications in pharmacological research, and the numerous intracellular targets affected by this agent that can effectively negate the oncogenic process.

Modulation of CYP450 Activities in Patients With Type 2 Diabetes

We conducted a comprehensive in vivo study evaluating the influence of type 2 diabetes (T2D) on major cytochrome P450 (CYP450) activities. These activities were assessed in 38 T2D and 35 non-T2D subjects after a single oral administration of a cocktail of probe drugs: 100 mg caffeine (CYP1A2), 100 mg bupropion (CYP2B6), 250 mg tolbutamide (CYP2C9), 20 mg omeprazole (CYP2C19), 30 mg dextromethorphan (CYP2D6), 2 mg midazolam (CYP3As), and 250 mg chlorzoxazone (alone; CYP2E1). Mean metabolic activity for CYP2C19, CYP2B6, and CYP3A was decreased in subjects with T2D by about 46%, 45%, and 38% (P < 0.01), respectively. CYP1A2 and CYP2C9 activities seemed slightly increased in subjects with diabetes, and no difference was observed for CYP2D6 or CYP2E1 activities. Several covariables, such as inflammatory markers (interleukin (IL)-1ß, IL-6, gamma interferon, and tumor necrosis factor alpha), genotypes, and diabetes-related and demographic-related factors were considered in our analyses. Our results indicate that low chronic inflammatory status associated with T2D modulates CYP450 activities in an isoform-specific manner.

A Pilot Study towards the Impact of Type 2 Diabetes on the Expression and Activities of Drug Metabolizing Enzymes and Transporters in Human Duodenum

To characterize effects of type 2 diabetes (T2D) on mRNA expression levels for 10 Cytochromes P450 (CYP450s), two carboxylesterases, and three drug transporters (ABCB1, ABCG2, SLCO2B1) in human duodenal biopsies. To compare drug metabolizing enzyme activities of four CYP450 isoenzymes in duodenal biopsies from patients with or without T2D. mRNA levels were quantified (RT-qPCR) in human duodenal biopsies obtained from patients with (n = 20) or without (n = 16) T2D undergoing a scheduled gastro-intestinal endoscopy. CYP450 activities were determined following incubation of biopsy homogenates with probe substrates for CYP2B6 (bupropion), CYP2C9 (tolbutamide), CYP2J2 (ebastine), and CYP3A4/5 (midazolam). Covariables related to inflammation, T2D, demographic, and genetics were investigated. T2D had no major effects on mRNA levels of all enzymes and transporters assessed. Formation rates of metabolites (pmoles mg protein⁻¹ min⁻¹) determined by LC-MS/MS for CYP2C9 (0.48 ± 0.26 vs. 0.41 ± 0.12), CYP2J2 (2.16 ± 1.70 vs. 1.69 ± 0.93), and CYP3A (5.25 ± 3.72 vs. 5.02 ± 4.76) were not different between biopsies obtained from individuals with or without T2D (p > 0.05). No CYP2B6 specific activity was measured. TNF-α levels were higher in T2D patients but did not correlate with any changes in mRNA expression levels for drug metabolizing enzymes or transporters in the duodenum. T2D did not modulate expression or activity of tested drug metabolizing enzymes and transporters in the human duodenum. Previously reported changes in drug oral clearances in patients with T2D could be due to a tissue-specific disease modulation occurring in the liver and/or in other parts of the intestines.

The utility of a system dynamics approach for understanding cumulative health risk from exposure to environmental hazards

The potential of system dynamics modeling to advance our understanding of cumulative risk in the service of optimal health is discussed. The focus is on exploring system dynamics modeling as a systems science methodology that can provide a framework for examining the complexity of real-world social and environmental exposures among populations-particularly those exposed to multiple disparate sources of risk. The discussion also examines how system dynamics modeling can engage a diverse body of key stakeholders throughout the modeling process, promoting the collective assessment of assumptions and systematic gathering of critical data. Though not a panacea, system dynamics modeling provides a promising methodology to complement traditional research methods in understanding cumulative health effects from exposure to multiple environmental and social stressors.

Systemic Absorption and Side Effects of Locally Injected Glucocorticoids

Local glucocorticoid injections are often used to treat joint, soft tissue, or spinal pain, but the systemic side effects associated with these injections are poorly understood and not well recognized. There are significant known risks to systemic administration of glucocorticoids. However, there are no guidelines that address issues of systemic absorption, overall systemic risks, or other side effects of locally injected glucocorticoids. For this review, a literature search was performed, and the available evidence on systemic absorption and clinical side effects of intra-articular and epidural glucocorticoids was synthesized. The goal was to improve clinical understanding of risks associated with these injections. Existing data suggest there is significant individual variability in the amount of systemic absorption and clinical effects of locally injected glucocorticoids. However, it is clear that both intra-articular and epidural injections can have systemic effects for weeks and that complications may be associated with their use, including Cushing syndrome, loss of bone density, infection, and hyperglycemia. The concurrent use of oral steroids, the number of injections, and the type and dose of glucocorticoids used all are important considerations in estimating risks. The total dose calculation of cumulative glucocorticoid exposure should include all local injections. Caution should be exercised when local glucocorticoid injections are used in higher risk patients, such as postmenopausal women, people with diabetes, and those considering surgery in the near term. Better provider awareness of possible systemic risks should improve decision making and informed consent with patients when considering intra-articular and epidural steroid injections for painful conditions. LEVEL OF EVIDENCE: IV.

Evaluation of the impact of waterpipe tobacco smoke exposure on the activity and expression of rat hepatic CYP450: a pharmacokinetic study

Waterpipe smoke contains many toxic constituents that can alter drug pharmacokinetics. This study assessed the effect of waterpipe smoke exposure on the activity and expression of CYP450 enzymes in rats. Animals (n = 10/group) were exposed to either waterpipe smoke or side-stream cigarette smoke for 1 h/day (6 days/week) for 31 days, or fresh air (control). An intragastric cocktail solution containing three probe drugs, phenacetin, chlorzoxazone and testosterone was administered to assess the activity of CYP1A2, CYP2E1 and CYP3A, respectively. Serum concentrations were determined using LC-MS/MS and the pharmacokinetic parameters were calculated. The mRNA expression of hepatic enzymes was also quantified. Waterpipe and cigarette smoke exposure did not significantly alter the pharmacokinetics of phenacetin, chlorzoxazone and testosterone. For example, the clearance and drug exposure values were comparable among groups for all probe drugs. Additionally, there was no significant effect of waterpipe and cigarette smoke on mRNA expression of hepatic CYP1A2, CYP2E1 and CYP3A2. The results demonstrate that waterpipe smoke exposure had no effect on the functional expression of three key CYP450 isoforms in rats. Future research is required with longer exposure periods to waterpipe smoke. Such work serves to enhance current understanding of effect of waterpipe smoke exposure on pharmacokinetics.

Review article: drug-induced liver injury in the context of nonalcoholic fatty liver disease - a physiopathological and clinical integrated view

BACKGROUND

Nonalcoholic fatty disease (NAFLD) is the most common liver disease, since it is strongly associated with obesity and metabolic syndrome pandemics. NAFLD may affect drug disposal and has common pathophysiological mechanisms with drug-induced liver injury (DILI); this may predispose to hepatoxicity induced by certain drugs that share these pathophysiological mechanisms. In addition, drugs may trigger fatty liver and inflammation per se by mimicking NAFLD pathophysiological mechanisms.

AIMS

To provide a comprehensive update on (a) potential mechanisms whereby certain drugs can be more hepatotoxic in NAFLD patients, (b) the steatogenic effects of drugs, and (c) the mechanism involved in drug-induced steatohepatitis (DISH).

METHODS

A language- and date-unrestricted Medline literature search was conducted to identify pertinent basic and clinical studies on the topic.

RESULTS

Drugs can induce macrovesicular steatosis by mimicking NAFLD pathogenic factors, including insulin resistance and imbalance between fat gain and loss. Other forms of hepatic fat accumulation exist, such as microvesicular steatosis and phospholipidosis, and are mostly associated with acute mitochondrial dysfunction and defective lipophagy, respectively. Drug-induced mitochondrial dysfunction is also commonly involved in DISH. Patients with pre-existing NAFLD may be at higher risk of DILI induced by certain drugs, and polypharmacy in obese individuals to treat their comorbidities may be a contributing factor.

CONCLUSIONS

The relationship between DILI and NAFLD may be reciprocal: drugs can cause NAFLD by acting as steatogenic factors, and pre-existing NAFLD could be a predisposing condition for certain drugs to cause DILI. Polypharmacy associated with obesity might potentiate the association between this condition and DILI.

Cytochrome P450: Polymorphisms and Roles in Cancer, Diabetes and Atherosclerosis

Cytochromes P450s (CYPs) constitute a superfamily of enzymes that catalyze the metabolism of drugs and other substances. Endogenous substrates of CYPs include eicosanoids, estradiol, arachidonic acids, cholesterol, vitamin D and neurotransmitters. Exogenous substrates of CYPs include the polycyclic aromatic hydrocarbons and about 80% of currently used drugs. Some isoforms can activate procarcinogens to ultimate carcinogens. Genetic polymorphisms of CYPs may affect the enzyme catalytic activity and have been reported among different populations to be associated with various diseases and adverse drug reactions. With regard of drug metabolism, phenotypes for CYP polymorphism range from ultrarapid to poor metabolizers. In this review, we discuss some of the most clinically important CYPs isoforms (CYP2D6, CYP2A6, CYP2C19, CYP2C9, CYP1B1 and CYP1A2) with respect to gene polymorphisms and drug metabolism. Moreover, we review the role of CYPs in renal, lung, breast and prostate cancers and also discuss their significance for atherosclerosis and type 2 diabetes mellitus.

Chronic hyperglycemia mediated physiological alteration and metabolic distortion leads to organ dysfunction, infection, cancer progression and other pathophysiological consequences: An update on glucose toxicity

Chronic exposure of glucose rich environment creates several physiological and pathophysiological changes. There are several pathways by which hyperglycemia exacerbate its toxic effect on cells, tissues and organ systems. Hyperglycemia can induce oxidative stress, upsurge polyol pathway, activate protein kinase C (PKC), enhance hexosamine biosynthetic pathway (HBP), promote the formation of advanced glycation end-products (AGEs) and finally alters gene expressions. Prolonged hyperglycemic condition leads to severe diabetic condition by damaging the pancreatic β-cell and inducing insulin resistance. Numerous complications have been associated with diabetes, thus it has become a major health issue in the 21st century and has received serious attention. Dysregulation in the cardiovascular and reproductive systems along with nephropathy, retinopathy, neuropathy, diabetic foot ulcer may arise in the advanced stages of diabetes. High glucose level also encourages proliferation of cancer cells, development of osteoarthritis and potentiates a suitable environment for infections. This review culminates how elevated glucose level carries out its toxicity in cells, metabolic distortion along with organ dysfunction and elucidates the complications associated with chronic hyperglycemia.

Nonalcoholic Fatty Liver Disease and Diabetes Are Associated with Decreased CYP3A4 Protein Expression and Activity in Human Liver

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease in the Western population. We investigated the association of nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus on CYP3A4 activity in human liver tissue from brain dead donors ( n = 74). Histopathologically graded livers were grouped into normal ( n = 24), nonalcoholic fatty liver (NAFL, n = 26), and nonalcoholic steatohepatitis (NASH, n = 24) categories. The rate of conversion of midazolam to its 1-hydroxy metabolite was used to assess in vitro CYP3A4 activity in human liver microsomes (HLM). A proteomics approach was utilized to quantify the protein expression of CYP3A4 and related enzymes. Moreover, a physiologically based pharmacokinetic (PBPK) model was developed to allow prediction of midazolam concentration in NAFL and NASH livers. CYP3A4 activity in NAFL and NASH was 1.9- and 3.1-fold ( p < 0.05) lower than normal donors, respectively. Intrinsic clearance (CLint) was 2.7- ( p < 0.05) and 4.1-fold ( p < 0.01) lower in donors with NAFL and NASH, respectively. CYP3A4 protein expression was significantly lower in NAFL and NASH donors ( p < 0.05) and accounted for significant midazolam hydroxylation variability in a multiple linear regression analysis (β = 0.869, r² = 0.762, P < 0.01). Diabetes was also associated with decreased CYP3A4 activity and protein expression. Both midazolam CLint and CYP3A4 protein abundance decreased significantly with increase in hepatic fat accumulation. Age and gender did not exhibit any significant association with the observed alterations. Predicted midazolam exposure was 1.7- and 2.3-fold higher for NAFL and NASH, respectively, which may result in a longer period of sedation in these disease-states. Data suggests that NAFLD and diabetes are associated with the decreased hepatic CYP3A4 activity. Thus, further evaluation of clinical consequences of these findings on the efficacy and safety of CYP3A4 substrates is warranted.

High fat diet induced obesity is mitigated in Cyp3a-null female mice

Recent studies indicate a role for the constitutive androstane receptor (CAR), pregnane X-receptor (PXR), and hepatic xenobiotic detoxifying CYPs in fatty liver disease or obesity. Therefore, we examined whether Cyp3a-null mice show increased obesity and fatty liver disease following 8-weeks of exposure to a 60% high-fat diet (HFD). Surprisingly, HFD-fed Cyp3a-null females fed a HFD gained 50% less weight than wild-type (WT; B6) females fed a HFD. In contrast, Cyp3a-null males gained more weight than WT males, primarily during the first few weeks of HFD-treatment. Cyp3a-null females also recovered faster than WT females from a glucose tolerance test; males showed no difference in glucose tolerance between the groups. Serum concentrations of the anti-obesity hormone, adiponectin are 60% higher and β-hydroxybutyrate levels are nearly 50% lower in Cyp3a-null females than WT females, in agreement with reduced weight gain, faster glucose response, and reduced ketogenesis. In contrast, Cyp3a-null males have higher liver triglyceride concentrations and lipidomic analysis indicates an increase in phosphatidylinositol, phosphatidylserine and sphingomyelin. None of these changes were observed in females. Last, Pxr, Cyp2b, and IL-6 expression increased in Cyp3a-null females following HFD-treatment. Cyp2b and Fatp1 increased, while Pxr, Cpt1a, Srebp1 and Fasn decreased in Cyp3a-null males following a HFD, indicating compensatory biochemical responses in male (and to a lesser extent) female mice fed a HFD. In conclusion, lack of Cyp3a has a positive effect on acclimation to a HFD in females as it improves weight gain, glucose response and ketosis.