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.

Off-label use of immune checkpoint inhibitors for the treatment of solid tumors: analysis of a nationwide patient sample.

PURPOSE: Immune checkpoint inhibitors (ICIs) have become an indispensable part of clinical practice; however, off-label use of these agents is unknown. We aimed to define the patterns of off-label use of ICIs in a nationwide sample of patients. METHODS: The online database (Reçetem) was retrospectively searched for off-label use cases related to ICIs approved during a 6-month period. Adult patients with metastatic solid tumors were included. Ethics approval was obtained. Reasons for off-label use were recorded in eight categories and cases were assessed for adherence to current guidelines. Statistical analysis was performed with GNU PSPP version 1.5.3. RESULTS: Five hundred seventy-seven reasons for use were recorded for 538 cases related to 527 patients (67.5% male). Non-small-cell lung cancer (NSCLC) (35.9%) was the most common cancer type. Nivolumab (49%), pembrolizumab (25.5%), and atezolizumab (25%) were commonly used. The top reason for off-label use was lack of approval for the cancer type (37.1%), followed by use beyond the approved treatment line (21%). Nivolumab was more frequently used than atezolizumab and/or pembrolizumab in patients with malignant melanoma, kidney cancer, head and neck cancer, and hepatocellular carcinoma (Chi-square goodness-of-fit test, p < 0.001). The guideline adherence rate was 60.5%. CONCLUSION: Off-label use of ICIs was primarily related to (NSCLC), and most patients were treatment-naïve in contrast to the acceptance that off-label use results from exhausted treatment options. Lack of approval is a significant reason for the off-label use of ICIs.

Normalization of organ bath contraction data for tissue specimen size: does one approach fit all?

Organ bath experiments are a key technology to assess contractility of smooth muscle. Despite efforts to standardize tissue specimen sizes, they vary to a certain degree. As it appears obvious that a larger piece of tissue should develop greater force, most investigators normalize contraction data for specimen size. However, they lack agreement which parameter should be used as denominator for normalization. A pre-planned analysis of data from a recent study was used to compare denominators used for normalization, i.e., weight, length, and cross-sectional area. To increase robustness, we compared force with denominator in correlation analysis and also coefficient of variation with different denominators. This was done concomitantly with urinary bladder strips and aortic rings and with multiple contractile stimuli. Our urinary bladder data show that normalization for strip weight yielded the tightest but still only moderate correlation (e.g., r2 = 0.3582 for peak carbachol responses based on 188 strips). In aorta, correlations were even weaker (e.g., r2 = 0.0511 for plateau phenylephrine responses normalized for weight based on 200 rings). Normalization for strip size is less effective in reducing data variability than previously assumed; the normalization denominator of choice must be identified separately for each preparation.

Urinary Bladder Weight and Function in a Rat Model of Mild Hyperglycemia and Its Treatment With Dapagliflozin.

Hypertrophy and dysfunction of the urinary bladder are consistently observed in animal models of type 1 and less consistently in those of type 2 diabetes. We have tested the effects of mild hyperglycemia (n = 10 per group) in a randomized, blinded study and, in a blinded pilot study, of type 2 diabetes (n = 6 per group) and its treatment with dapagliflozin (1 mg/kg per day) on weight, contraction, and relaxation of the rat bladder. Based on a combination of high-fat diet and a low dose of streptozotocin, animals in the main study reached a mean peak blood glucose level of about 300 mg/dl, which declined to 205 mg/dl at study end. This was associated with a small, if any, increase in bladder weight. In a pooled analysis of all animals of the main and the pilot study, we detected a correlation of moderate strength between blood glucose and bladder weight (r 2 = 0.2013; P = 0.0003 for Pearson correlation coefficient). Neither the main nor the pilot study found evidence for an altered contractility (responses to carbachol or KCl) or relaxation (responses to isoprenaline, fenoterol, CL 316,243, or forskolin). Treatment with dapagliflozin in the absence of hyperglycemia increased diuresis in the main study by 43% relative to control and increased bladder weight by 15% in the pooled groups of both studies (post hoc analysis). We conclude that mild hyperglycemia has no major effects on bladder hypertrophy or function.

Beta-3 adrenoceptors: A potential therapeutic target for heart disease.

As heart failure (HF) is a growing public health problem worldwide, rapid therapeutic development is required to improve HF management. Decreased myocardial contractility in HF is associated with the persistent sympathetic activation of ß1/ß2-adrenoceptors (ß1/ß2-ARs). Although it is initially activated to compensate for a decline in myocardial contractility, it plays a pivotal role in organ damage and functional deterioration over time, resulting in the desensitization of receptors involved. The third ß-AR subtype, ß3-AR, is resistant to desensitization, and as a result, the expression of this subtype is enhanced in human failing myocardium. In addition, this upregulation and the stimulation of this subtype have been demonstrated to mediate cardioprotective effects such as antihypertrophic, antioxidant and antifibrotic effects via various signaling pathways in different cell types. However, the role of this attractive therapeutic intervention in heart diseases must be clarified through clinical trials.

Role of the ß3-adrenergic receptor subtype in catecholamine-induced myocardial remodeling.

ß3-Adrenoceptors (AR) stimulate cardiac Na+/K+ pump in healthy hearts. ß3-ARs are upregulated by persistent sympathetic hyperactivity; however, their effect on Na+/K+ ATPase activity and ventricular function in this condition is still unknown. Here, we investigate preventive effects of additional ß3-AR activation (BRL) on Na+/K+ ATPase activity and in vivo hemodynamics in a model of noradrenaline-induced hypertrophy. Rats received NA or NA plus simultaneously administered BRL in vivo infusion for 14 days; their cardiac function was investigated by left ventricular pressure-volume analysis. Moreover, fibrosis and apoptosis were also assessed histologically. NA induced an hypertrophic pattern, as detected by morphological, histological, and biochemical markers. Additional BRL exposure reversed the hypertrophic pattern and restored Na+/K+ ATPase activity. NA treatment increased systolic function and depressed diastolic function (slowed relaxation). Additional BRL treatment reversed most NA-induced hemodynamic changes. NA decreased Na+/K+ pump α2 subunit expression selectively, a change also reversed by additional BRL treatment. Increasing ß3-AR stimulation may prevent the consequences of chronic NA exposure on Na+/K+ pump and in vivo hemodynamics. ß3-AR agonism may thus represent a new therapeutic strategy for pharmacological modulation of hypertrophy under conditions of chronically enhanced sympathetic activity.

Onset of decreased heart work is correlated with increased heart rate and shortened QT interval in high-carbohydrate fed overweight rats.

Mechanical activity of the heart is adversely affected in metabolic syndrome (MetS) characterized by increased body mass and marked insulin resistance. Herein, we examined the effects of high carbohydrate intake on cardiac function abnormalities by evaluating in situ heart work, heart rate, and electrocardiograms (ECGs) in rats. MetS was induced in male Wistar rats by adding 32% sucrose to drinking water for 22-24 weeks and was confirmed by insulin resistance, increased body weight, increased blood glucose and serum insulin, and increased systolic and diastolic blood pressures in addition to significant loss of left ventricular integrity and increased connective tissue around myofibrils. Analysis of in situ ECG recordings showed a markedly shortened QT interval and decreased QRS amplitude with increased heart rate. We also observed increased oxidative stress and decreased antioxidant defense characterized by decreases in serum total thiol level and attenuated paraoxonase and arylesterase activities. Our data indicate that increased heart rate and a shortened QT interval concomitant with higher left ventricular developed pressure in response to ß-adrenoreceptor stimulation as a result of less cyclic AMP release could be regarded as a natural compensation mechanism in overweight rats with MetS. In addition to the persistent insulin resistance and obesity associated with MetS, one should consider the decreased heart work, increased heart rate, and shortened QT interval associated with high carbohydrate intake, which may have more deleterious effects on the mammalian heart.