The future of deprescribing research: seizing opportunities and learning from the past Michael A. Steinman, MDUniversity of California, San Francisco and the San Francisco VA Medical CenterWord count: 1549References: 10Funding: This work was supported by the National Institute on Aging (grants R24AG064025 and K24AG049057)Disclosures: Dr. Steinman receives royalties from UpToDate and honoraria from the American Geriatrics Society. This manuscript is based on a lecture given at the First International Conference on Deprescribing (ICOD), Kolding, Denmark, September 2022.

The present study evaluates the influence of type 2 diabetes (T2D) on important CYP450 isoforms and P-glycoprotein (P-gp) transporter activities before and 3 months after intensifying treatment regimen of 40 patients. Results have been compared with 21 non-T2D healthy participants (control group). CYPs and P-gp activities were assessed after administration of Geneva cocktail. Mean metabolic ratios (MR) for CYP2B6 (1.81±0.93 vs. 2.68±0.87), CYP2C19 (0.420 ± 0.360 vs. 0.687 ± 0.558), and CYP3A4/5 (0.487 ± 0.226 vs. 0.633 ± 0.254) significantly decreased in T2D subjects compared to control group (p<0.05). CYP2C9 (0.089±0.037 vs. 0.069±0.017) activities slightly increased in diabetic subjects and no difference was observed for CYP1A2 (0.154±0.085 vs. 0.136±0.065), CYP2D6 (1.17 ± 0.56 vs. 1.24 ± 0.83) and P-gp activities in comparison with control group. Three months after intensifying treatment regimen, MRs of CYP2C9 (0.080 ± 0.030) and CYP3A4/5 (0.592 ± 0.268) have shown a significant improvement and were not statistically different compared to control group (P>0.05). Several covariables such as inflammatory markers (IL-1β and IL-6), genotypes, diabetes- 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.

Dementia is an umbrella term for a broad group of age-associated neurodegenerative diseases. It is estimated that dementia affects 50 million people worldwide and that Alzheimer’s disease (AD) is responsible for up to 75% of cases. Small extracellular senile plaques composed of filamentous aggregates of amyloid β (Aβ) protein tend to bind to neuronal receptors, affecting cholinergic, serotonergic, dopaminergic, and noradrenergic neurotransmission, leading to neuroinflammation, among other pathophysiologic processes, and subsequent neuronal death, followed by dementia. The amyloid cascade hypothesis points to a pathological process in the cleavage of the amyloid precursor protein (APP), resulting in pathological Aβ. There is a close relationship between the pathologies that lead to dementia and depression. It is estimated that depression is prevalent in up to 90% of individuals diagnosed with Parkinson’s disease, with varying severity, and in 20 to 30% of cases of Alzheimer’s disease. The hypothalamic pituitary adrenal (HPA) axis is the great intermediary between the pathophysiological mechanisms in neurodegenerative diseases and depression. This review discusses the role of Aβ protein in the pathophysiological mechanisms of dementia and depression, considering the HPA axis, neuroinflammation, oxidative stress, signaling pathways, and neurotransmission.

Transient receptor potential vanilloid type-1 (TRPV1) channels play key roles in chronic pain conditions and are modulated by different inflammatory mediators to elicit heat sensitisation. Bradykinin is a 9-amino acid peptide chain that promotes inflammation. The aim of present study is to investigate how bradykinin and prostaglandin receptors (EP3 and EP4) modulate the sensitisation of TRPV1-mediated responses. Calcium imaging studies of rat dorsal root ganglion (DRG) neurons were employed to investigate the desensitizing responses of TRPV1 ion channels by capsaicin, and the re-sensitization of TRPV1 by bradykinin, then to explore the role EP3 and EP4 receptors in mediating these bradykinin-dependent effects. Immunocytochemistry was used to study the co-expression and distribution of EP4, TRPV1, COX-1 and B2 in rat DRG neurons. Desensitization was seen upon repeated capsaicin application, we show that bradykinin-mediated sensitization of capsaicin-evoked calcium responses in rat DRG neurons occurs is dependent on COX-1 activity, and utilises a pathway that invovles EP4 but not EP3 receptors. The present study provides evidence for a novel signalling pathway through which bradykinin can regulate the TRPV1 ion channel function via the EP4 but not EP3 receptors and provides the anatomical basis for this regulation

The objective of this study was to develop a population pharmacokinetic-pharmacodynamic model of subcutaneously administered bupivacaine in a novel extended release microparticle formulation for postoperative pain management. Bupivacaine was administered subcutaneously in the lower leg to 28 healthy male subjects in doses from 150 to 600 mg in a phase 1 randomized, placebo-controlled, double-blind, dose-ascending study with two different compositions of microparticle formulations called LIQ865. Population pharmacokinetic-pharmacodynamic models were fitted to plasma concentration-effect-time data using non-linear mixed-effects modeling. The pharmacokinetics were best described by a two-compartment model with biphasic absorption as two parallel absorption processes: a fast, zero-order process and a slower, first-order process with two transit compartments. The slow absorption process was found to be dose-dependent and rate-limiting for bupivacaine clearance at higher doses. Bupivacaine clearance and the transit rate constant describing the slow absorption process both decreased with increasing doses following a power function with a shared covariate effect of dose on the two parameters. The pharmacokinetic-pharmacodynamic relationship between plasma concentrations and effect was best described by a linear function. This model gives new insight into the pharmacokinetics and pharmacodynamics of microparticle formulations of bupivacaine, and the biphasic absorption seen for several local anesthetics.

Alzheimer’s disease (AD) is a neurodegenerative disorder that primarily manifests itself by progressive memory loss and cognitive decline, thus significantly affecting memory functions and quality of life. The canonical amyloid-β hypothesis, while significant, has faced setbacks, highlighting the need to adopt a broader perspective considering the intricate interplay of diverse pathological pathways for effective AD treatments. Sex differences in AD offer valuable insights into a better understanding of its pathophysiology. Fluctuation of the levels of ovarian sex hormones during perimenopause is associated with changes in glucose metabolism, as a possible window of opportunity to further understand the roles of sex steroid hormones and their associated receptors in the pathophysiology of AD. We review these dimensions, emphasizing the potential of estrogen receptors (ER) to reveal mitochondrial functions in the search for further research and therapeutic strategies for AD pharmacotherapy. Understanding and addressing the intricate interactions of mitochondrial dysfunction and estrogen receptors potentially pave the way for more effective approaches to AD therapy.