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Garami A, Shimansky YP, Rumbus Z, Vizin RCL, Farkas N, Hegyi J, Szakacs Z, Solymar M, Csenkey A, Chiche DA, Kapil R, Kyle DJ, Van Horn WD, Hegyi P, Romanovsky AA. Hyperthermia induced by transient receptor potential vanilloid-1 (TRPV1) antagonists in human clinical trials: Insights from mathematical modeling and meta-analysis. Pharmacol Ther 2020; 208:107474. [PMID: 31926897 DOI: 10.1016/j.pharmthera.2020.107474] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/23/2019] [Indexed: 02/06/2023]
Abstract
Antagonists of the transient receptor potential vanilloid-1 (TRPV1) channel alter body temperature (Tb) in laboratory animals and humans: most cause hyperthermia; some produce hypothermia; and yet others have no effect. TRPV1 can be activated by capsaicin (CAP), protons (low pH), and heat. First-generation (polymodal) TRPV1 antagonists potently block all three TRPV1 activation modes. Second-generation (mode-selective) TRPV1 antagonists potently block channel activation by CAP, but exert different effects (e.g., potentiation, no effect, or low-potency inhibition) in the proton mode, heat mode, or both. Based on our earlier studies in rats, only one mode of TRPV1 activation - by protons - is involved in thermoregulatory responses to TRPV1 antagonists. In rats, compounds that potently block, potentiate, or have no effect on proton activation cause hyperthermia, hypothermia, or no effect on Tb, respectively. A Tb response occurs when a TRPV1 antagonist blocks (in case of hyperthermia) or potentiates (hypothermia) the tonic TRPV1 activation by protons somewhere in the trunk, perhaps in muscles, and - via the acido-antithermogenic and acido-antivasoconstrictor reflexes - modulates thermogenesis and skin vasoconstriction. In this work, we used a mathematical model to analyze Tb data from human clinical trials of TRPV1 antagonists. The analysis suggests that, in humans, the hyperthermic effect depends on the antagonist's potency to block TRPV1 activation not only by protons, but also by heat, while the CAP activation mode is uninvolved. Whereas in rats TRPV1 drives thermoeffectors by mediating pH signals from the trunk, but not Tb signals, our analysis suggests that TRPV1 mediates both pH and thermal signals driving thermoregulation in humans. Hence, in humans (but not in rats), TRPV1 is likely to serve as a thermosensor of the thermoregulation system. We also conducted a meta-analysis of Tb data from human trials and found that polymodal TRPV1 antagonists (ABT-102, AZD1386, and V116517) increase Tb, whereas the mode-selective blocker NEO6860 does not. Several strategies of harnessing the thermoregulatory effects of TRPV1 antagonists in humans are discussed.
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Affiliation(s)
- Andras Garami
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary.
| | - Yury P Shimansky
- Department of Neurobiology, Barrow Neurological Institute, Dignity Health, Phoenix, AZ, USA
| | - Zoltan Rumbus
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Robson C L Vizin
- Thermoregulation and Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Dignity Health, Phoenix, AZ, USA
| | - Nelli Farkas
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Judit Hegyi
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Zsolt Szakacs
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary
| | - Margit Solymar
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Alexandra Csenkey
- Department of Thermophysiology, Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
| | | | | | | | - Wade D Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Peter Hegyi
- Institute for Translational Medicine, Medical School and Szentagothai Research Centre, University of Pecs, Pecs, Hungary; Department of Translational Medicine, First Department of Medicine, Medical School, University of Pecs, Pecs, Hungary
| | - Andrej A Romanovsky
- Thermoregulation and Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Dignity Health, Phoenix, AZ, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ, USA; Zharko Pharma Inc., Olympia, WA, USA.
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Sattler EC, Maier T, Hoffmann VS, Hegyi J, Ruzicka T, Berking C. Noninvasive in vivo detection and quantification of Demodex mites by confocal laser scanning microscopy. Br J Dermatol 2013; 167:1042-7. [PMID: 22716072 DOI: 10.1111/j.1365-2133.2012.11096.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In many Demodex-associated skin diseases Demodex mites are present in abundance and seem to be at least partially pathogenic. So far all diagnostic approaches such as scraping or standardized superficial skin biopsy are (semi-)invasive and may cause discomfort to the patient. OBJECTIVES To see whether confocal laser scanning microscopy (CLSM) - a noninvasive method for the visualization of superficial skin layers - is able to detect and quantify D. folliculorum in facial skin of patients with rosacea. METHODS Twenty-five patients (34-72 years of age) with facial rosacea and 25 age- and sex-matched normal controls were examined by CLSM. Mosaics of 8 × 8 mm and 5 × 5 mm were created by scanning horizontal layers of lesional skin and quantification of mites per follicle and per area as well as follicles per area was performed. RESULTS In all patients D. folliculorum could be detected by CLSM and presented as roundish or lengthy cone-shaped structures. CLSM allowed the quantification of Demodex mites and revealed significant differences (P < 0·0001): the mean number of mites was 165·4 per 8 × 8 mm area and 94·2 per 5 × 5 mm area in the patients compared with 34·7 and 22·4, respectively, in the controls. The corresponding mean number of mites per follicle was 0·7 and 0·8, respectively, in the patients and 0·1 and 0·2, respectively, in the controls. CONCLUSIONS With the help of CLSM it is possible to detect, image and quantify Demodex mites noninvasively in facial skin of patients with rosacea.
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Affiliation(s)
- E C Sattler
- Department of Dermatology and Allergology, Ludwig-Maximilian University Munich, Frauenlobstr. 9-11, 80337 Munich, Germany.
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