Author Interviews, Dermatology / 05.04.2021

MedicalResearch.com Interview with: Wolfgang Liedtke, M.D., Ph.D. Professor (tenured) of Neurology, Anesthesiology and Neurobiology
Attending Physician, Duke Neurology Clinics for Headache, Head-Pain and Trigeminal Sensory Disorders
Attending Physician, Duke Clinics for Innovative Pain Therapy at Brier Creek (Dept of Anesthesiology)
Duke University School of Medicine, Center for Translational Neuroscience
Durham NC 27710 Since April 2021 Chair of Neurology Global Development Scientific Council Regeneron Pharmaceuticals Tarrytown NY 10591MedicalResearch.com: What is the background for this study? Response: There are systemic diseases that are characterized by intense itching, yet without inflammation of the skin and not associated with allergic inflammation. For example and importantly, liver disease with non-functional secretion of bile (cholestatic liver disease, most common primary biliary cholangitis, an autoimmune disease), but also chronic end-stage renal disease (also certain lymphomas and pruritic psoriasis where the itch is whole-body, not only restricted to diseased skin).We thought that these diseases might be great starting points to better understand itch because there is no inflamed skin and no allergies. Thus, there must be some systemic factor that causes itch, and we were intent on discovering such factors, and with them, molecular mechanisms how they cause itch.For cholestatic liver disease, one of the best candidates to fit this profile has been lysophosphatidic acid (LPA), since the pioneering discoveries of Andreas Kremer, one of our co-authors.My research laboratory at Duke has been rooted in my discovery of TRPV4 ion channels 20 years ago, out of the Friedman Lab at The Rockefeller University in NYC. Over the years, with my colleague Yong Chen out of my lab, now leading his own independent research operation, we focused on the role of TRPV4 ion channels in skin. 5 years ago Yong and I published a paper that provided some evidence for TRPV4 in skin perhaps playing a role in itch.Working with phospholipids, we made the serendipitous discovery that lysophosphatidyl choline (LPC) is a more potent itch-inducing lipid molecule than LPA. Of note, LPC is the metabolic precursor of LPA. We then found that LPA does not depend on TRPV4 to elicit itch. The more robust itch evoked by LPC was significantly reduced when we knocked down TRPV4 in skin keratinocytes. Itch was NOT affected when TRPV4 was deleted from sensory nerve cells that innervate the skin.In terms of background, my long-term goal has been to elucidate how innervating peripheral nerve cell and innervated organ, such as skin, talk to one another so that the sensation that is felt is regulated or modulated, e.g how can skin influence itch or pain, how can joint cells influence pain.That became the exciting bedrock of our study, and we took it from there, 5 years of hard work with collaborations spanning the globe, and a final stretch of exhausting work during the pandemic. (more…)
Author Interviews, Dermatology, Kidney Disease / 22.06.2020

MedicalResearch.com Interview with: Gil Yosipovitch, MD, Professor Miami Itch Center Lennar Medical Foundation South Miami Clinic in Coral Gables University of Miami Health SystemMedicalResearch.com: What is the background for this study? Response: Chronic Pruritus is a common and burdensome condition in patients with end stage chronic kidney disease (CKD). It is Present at all stages of CKD, not only in patients undergoing hemodialysis (including stage 3-5 CKD). There are no approved treatments for this condition in US and Europe. CKD pruritus has significant impact on quality of life of patients with higher mortality rates due to its effect on sleep.Studies in the last 2 decades have shown that in patients with CKD pruritus there is an imbalance between endogenous mu opioids that are over expressed to Kappa Opioids that are down regulated. Difelikefalin (DFK) is a novel peripherally selective kappa opioid receptor (KOR) agonist. Study of IV DFK administration in hemodialysis patients has recently been published and showed significant anti Pruritic effect ( NEJM Fishbane et al. 382: 289-290, 2020).(more…)
Author Interviews, Dermatology, Hepatitis - Liver Disease, NEJM / 07.06.2018

MedicalResearch.com Interview with: Dr Christophe Corpechot Centre de Référence Maladie Rares: Maladies Inflammatoires des Voies Biliaires et Hépatites Auto-immunes (MIVB-H) Filière Maladies Rares: Maladies Rares du Foie de l’Adulte et de l’Enfant Hôpital Saint-Antoine (APHP) et Sorbonne Universités ParisMedicalResearch.com: What is the background for this study?Response: Primary biliary cholangitis (PBC, previously known as "primary biliary cirrhosis") is a rare, chronic, slowly progressive liver disease of unknown cause, mainly affecting women of middle age. It is characterized by serum marks of autoimmunity (specific auto-antibodies), chronic inflammation and destruction of small intra-hepatic bile ducts, and consequent bile secretion impairment (chronic cholestasis) leading to the progressive development of cirrhosis and liver failure. Ursodeoxycholic acid (UDCA) is the only first-line approved treatment for PBC. It improves the biochemical measures of cholestasis and prolongs survival without liver transplantation. However, 30% to 40% of UDCA-treated patients continue to have clinically significant abnormalities of their biochemical liver tests and those patients remain at high risk of developing end-stage liver disease complications.Recently (2016), obeticholic acid (OCA) in association with UDCA has been conditionally approved in patients with an inadequate response to UDCA. This approval (FDA, EMA) was based one the results of a 1-year randomized, double-blind, placebo-controlled trial of OCA in patients with an incomplete response or intolerance to UDCA (POISE trial). In this trial, OCA was shown to improve the biochemical features of cholestasis (alkaline phosphatase (ALP) level < 1.67 times the upper limit of the normal range and a reduction of at least 15% from baseline) but was associated with a significant increase of pruritus, a characteristic, potentially debilitating symptom of PBC. BEZURSO is the first ever placebo-controlled phase 3 trial of a fibrate (a class of drugs known to be agonists of the peroxisome proliferator-activated receptors alpha) in PBC. In this 2-year randomized double-blind trial, 100 patients with an incomplete response to UDCA were assigned to bezafibrate 400 mg/day (n=50) or placebo (n=50), all in association with continued UDCA therapy.(more…)
Author Interviews, Dermatology, Kidney Disease / 30.09.2014

MedicalResearch.com Interview wth:Mei-Ju Ko, MD, PhD Department of Dermatology, Taipei City Hospital Department of Dermatology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.Medical Research: What are the main findings of the study?Dr. Ko: In this study, not only did we find that serum levels of interleukin (IL)-31 were significantly higher in hemodialysis patients with pruritus symptoms, but we also demonstrated a positive exposure-response relationship between IL-31 levels and visual analog scale (VAS) scores of pruritus intensity. We also noted an inverse correlation between the severity of pruritus and the dialysis dose assessed by Kt/V. (more…)