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Marynissen H, Janssen C, Bamps D, de Hoon J. Vascular read-out for TRP channel functionality on distal peripheral nerve endings in healthy men. Microvasc Res 2024; 152:104654. [PMID: 38215901 DOI: 10.1016/j.mvr.2024.104654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/23/2023] [Accepted: 01/04/2024] [Indexed: 01/14/2024]
Abstract
BACKGROUND Quantification of the vasodilation after topical application of capsaicin or cinnamaldehyde is often implemented to indirectly assess Transient Receptor Potential (TRP) Vanilloid 1 (TRPV1) or Ankyrin 1 (TRPA1) functionality respectively. This method has been well-established on the human forearm. However, to enable TRP functionality assessments in distal peripheral neuropathy, the vascular response upon TRP activation on dorsal finger skin was characterized. METHODS Two doses of cinnamaldehyde (3 % and 10 % v/v) and capsaicin (300 μg and 1000 μg) were topically applied (20 μL) on the skin of the mid three proximal phalanges in 17 healthy men. The dose-response, and inter-hand and inter-period reproducibility of the dermal blood flow (DBF) increase was assessed using Laser Speckle Contrast Imaging (LSCI) during 60 min post-application. Linear mixed models explored dose-driven differences, whereas the intra-class correlation coefficient (ICC) estimated the reproducibility of the vascular response. RESULTS Both doses of cinnamaldehyde and capsaicin induced a robust, dose-dependent increase in DBF. The vascular response to cinnamaldehyde 10 % on finger skin, expressed as area under the curve, correlated well over time (ICC = 0.66) and excellently between hands (ICC = 0.87). Similarly, the response to capsaicin 1000 μg correlated moderately over time (ICC = 0.50) and well between hands (ICC = 0.73). CONCLUSION The vascular response upon topical cinnamaldehyde and capsaicin application on finger skin is an alternative approach for measurements on forearm skin. Thereby, it is a promising vascular read-out to investigate the pathophysiology, and TRP involvement in particular, of specific peripheral neuropathic pain syndromes.
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Affiliation(s)
- Heleen Marynissen
- Center for Clinical Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| | - Charlien Janssen
- Center for Clinical Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Dorien Bamps
- Center for Clinical Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Jan de Hoon
- Center for Clinical Pharmacology, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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Nicoletti T, Bink A, Helmchen B, Briel N, Frontzek K, Vlad B, Gaspert A, Boudriot E, Jung HH, Reuss AM, Weller M, Hortobágyi T. Neurologic involvement in cystinosis: Focus on brain lesions and new evidence of four-repeat (4R-) Tau immunoreactivity. J Neurol Sci 2024; 456:122841. [PMID: 38101161 DOI: 10.1016/j.jns.2023.122841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/10/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023]
Abstract
Nephropathic cystinosis is a rare autosomal recessive storage disorder caused by CTNS gene mutations, leading to autophagy-lysosomal pathway impairment and cystine crystals accumulation. Neurologic involvement is highly variable and includes both neurodevelopmental and neurodegenerative disturbances, as well as focal neurologic deficits. By presenting longitudinal data of a 28-year-old patient with a large infratentorial lesion, we summarized the pathology, clinical and imaging features of neurological involvement in cystinosis patients. Brain damage in form of cystinosis-related cerebral lesions occurs in advanced disease phases and is characterized by the accumulation of cystine crystals, subsequent inflammation with vasculitis-like features, necrosis, and calcification. Epilepsy is a frequent comorbidity in affected individuals. Steroids might play a role in the symptomatic treatment of "stroke-like" episodes due to edematous-inflammatory lesions, but probably do not change the overall prognosis. Lifelong compliance to depleting therapy with cysteamine still represents the main therapeutic option. However, consequences of CTNS gene defects are not restricted to cystine accumulation. New evidence of four-repeat (4R-) Tau immunoreactivity suggests concurrent progressive neurodegeneration in cystinosis patients, highlighting the need of innovative therapeutic strategies, and shedding light on the crosstalk between proteinopathies and autophagy-lysosomal system defects. Eventually, emerging easily accessible biomarkers such as serum neurofilament light chains (NfL) might detect subclinical neurologic involvement in cystinosis patients.
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Affiliation(s)
- Tommaso Nicoletti
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland.
| | - Andrea Bink
- Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland; Department of Neuroradiology, University Hospital Zurich, Switzerland
| | - Birgit Helmchen
- Department of Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Nils Briel
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland; Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Karl Frontzek
- Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland; Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Benjamin Vlad
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland
| | - Ariana Gaspert
- Department of Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Elisabeth Boudriot
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland
| | - Hans Heinrich Jung
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland
| | - Anna Maria Reuss
- Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
| | - Michael Weller
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Switzerland
| | - Tibor Hortobágyi
- Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland
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3
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Li T, Chung MK. Striving toward hyperthermia-free analgesia: lessons from loss-of-function mutations of human TRPV1. J Clin Invest 2023; 133:167338. [PMID: 36719371 PMCID: PMC9888373 DOI: 10.1172/jci167338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transient receptor potential vanilloid 1 (TRPV1), a receptor for capsaicin and noxious heat, has been one of the most compelling targets for analgesics. However, systemic inhibition of TRPV1 is an impractical approach as a pain killer, since systemic antagonism induces hyperthermia. Two articles in this issue of the JCI report phenotypes from separate, rare missense mutations of human TRPV1. He, Zambelli, and colleagues investigated TRPV1K710N, which showed reduced functionality, while Katz, Zaguri, and co-authors reported on TRPV1N331K, which led to a complete functional knockout. The findings provide insights that will improve our understanding of the endogenous functions of TRPV1 in humans and may facilitate a rational TRPV1-targeting approach to achieve hyperthermia-free analgesia.
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4
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Katz B, Zaguri R, Edvardson S, Maayan C, Elpeleg O, Lev S, Davidson E, Peters M, Kfir-Erenfeld S, Berger E, Ghazalin S, Binshtok AM, Minke B. Nociception and pain in humans lacking a functional TRPV1 channel. J Clin Invest 2023; 133:153558. [PMID: 36454632 PMCID: PMC9888381 DOI: 10.1172/jci153558] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUNDChronic pain is a debilitating illness with currently limited therapy, in part due to difficulties in translating treatments derived from animal models to patients. The transient receptor potential vanilloid 1 (TRPV1) channel is associated with noxious heat detection and inflammatory pain, and reports of adverse effects in human trials have hindered extensive efforts in the clinical development of TRPV1 antagonists as novel pain relievers.METHODSWe examined 2 affected individuals (A1 and A2) carrying a homozygous missense mutation in TRPV1, rendering the channel nonfunctional. Biochemical and functional assays were used to analyze the mutant channel. To identify possible phenotypes of the affected individuals, we performed psychophysical and medical examinations.RESULTSWe demonstrated that diverse TRPV1 activators, acting at different sites of the channel protein, were unable to open the cloned mutant channel. This finding was not a consequence of impairment in the expression, cellular trafficking, or assembly of protein subunits. The affected individuals were insensitive to application of capsaicin to the mouth and skin and did not demonstrate aversive behavior toward capsaicin. Furthermore, quantitative sensory testing of A1 revealed an elevated heat-pain threshold but also, surprisingly, an elevated cold-pain threshold and extensive neurogenic inflammatory, flare, and pain responses following application of the TRPA1 channel activator mustard oil.CONCLUSIONOur study provides direct evidence in humans for pain-related functional changes linked to TRPV1, which is a prime target in the development of pain relievers.FUNDINGSupported by the Israel Science Foundation (368/19); Teva's National Network of Excellence in Neuroscience grant (no. 0394886) and Teva's National Network of Excellence in Neuroscience postdoctoral fellowship.
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Affiliation(s)
- Ben Katz
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Rachel Zaguri
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Simon Edvardson
- Pediatric Neurology Unit, Pediatric Department, Hadassah University Hospital, Mount Scopus, Jerusalem, Israel
| | - Channa Maayan
- Pediatric Neurology Unit, Pediatric Department, Hadassah University Hospital, Mount Scopus, Jerusalem, Israel
| | | | - Shaya Lev
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Elyad Davidson
- Pain Relief Unit, Department of Anesthesiology and Critical Care Medicine, and
| | - Maximilian Peters
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Shlomit Kfir-Erenfeld
- Department of Bone Marrow Transplantation and Cancer Immunology, Hadassah University Hospital, Ein Kerem, Jerusalem, Israel
| | - Esther Berger
- Department of Pathology, E. Wolfson Medical Center, Holon, Israel
| | - Shifa Ghazalin
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Alexander M. Binshtok
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
| | - Baruch Minke
- Department of Medical Neurobiology, Faculty of Medicine and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University, Jerusalem, Israel
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Emma F, Hoff WV, Hohenfellner K, Topaloglu R, Greco M, Ariceta G, Bettini C, Bockenhauer D, Veys K, Pape L, Hulton S, Collin S, Ozaltin F, Servais A, Deschênes G, Novo R, Bertholet-Thomas A, Oh J, Cornelissen E, Janssen M, Haffner D, Ravà L, Antignac C, Devuyst O, Niaudet P, Levtchenko E. An international cohort study spanning five decades assessed outcomes of nephropathic cystinosis. Kidney Int 2021; 100:1112-1123. [PMID: 34237326 DOI: 10.1016/j.kint.2021.06.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/27/2021] [Accepted: 06/07/2021] [Indexed: 11/18/2022]
Abstract
Nephropathic cystinosis is a rare disease secondary to recessive mutations of the CTNS gene encoding the lysosomal cystine transporter cystinosin, causing accumulation of cystine in multiple organs. Over the years, the disease has evolved from being a fatal condition during early childhood into a treatable condition, with patients surviving into adulthood. Data on cystinosis are limited by the rarity of the disease. Here, we have investigated factors associated with kidney and growth outcome in a very large cohort of 453 patients born between 1964 and 2016 and followed in Belgium, Germany, Austria, France, Italy, Spain, The Netherlands, Turkey and United Kingdom. From the 1970s to the 1990s, the median increase in kidney survival was 9.1 years. During these years, cysteamine, a cystine-depleting agent, was introduced for the treatment of cystinosis. Significant risk factors associated with early progression to end-stage kidney disease assessed by Cox proportional multivariable analysis included delayed initiation of cysteamine therapy and higher mean leucocyte cystine levels. No significant effect on kidney function was observed for gender, pathogenic variant of the CTNS gene, and the prescription of indomethacin or renin angiotensin system blockers. Significantly improved linear growth was associated with early use of cysteamine and lower leukocyte cystine levels. Thus, our study provides strong evidence in favor of early diagnosis and optimization of cystine depletion therapy in nephropathic cystinosis.
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Affiliation(s)
- Francesco Emma
- Department of Pediatric Subspecialties, Division of Nephrology, Bambino Gesù Children's Hospital-IRCCS, Rome, Italy.
| | - William Van't Hoff
- Renal Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Katharina Hohenfellner
- Department of Pediatric Nephrology, Children's Hospital RoMed Clinics Rosenheim, Rosenheim, Germany
| | - Rezan Topaloglu
- Department of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Marcella Greco
- Department of Pediatric Subspecialties, Division of Nephrology, Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
| | - Gema Ariceta
- Division of Pediatric Nephrology, Hospital Universitari Vall d' Hebron, Barcelona, Spain
| | - Chiara Bettini
- Department of Pediatric Subspecialties, Division of Nephrology, Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
| | - Detlef Bockenhauer
- Renal Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK; Department of Renal Medicine, University College London, London, UK
| | - Koenraad Veys
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | - Lars Pape
- Department of Pediatrics II, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Sally Hulton
- Department of Paediatric Nephrology, Birmingham Women's and Children's Hospital NHS Trust, Birmingham, UK
| | - Suzanne Collin
- Renal Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey; Nephrogenetic Laboratory, Hacettepe University School of Medicine, Ankara, Turkey
| | - Aude Servais
- Paris Descartes University, Imagine Institute, Inserm U1163, Paris, France; Adult Nephrology and Transplantation, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Georges Deschênes
- Department of Pediatric Nephrology, Robert Debré Hospital, University of Paris, Paris, France
| | - Robert Novo
- Department of Paediatric Nephrology, University Hospital of Lille, Lille, France
| | | | - Jun Oh
- Department of Pediatric Nephrology, Pediatric Hepatology and Pediatric Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Elisabeth Cornelissen
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, the Netherlands
| | - Mirian Janssen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Lucilla Ravà
- Clinical Pathways and Epidemiology Unit, Medical Direction, Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
| | - Corinne Antignac
- Paris Descartes University, Imagine Institute, Laboratory of Hereditary Kidney Diseases, INSERM UMR 1163, Paris, France; Department of Genetics, AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| | - Olivier Devuyst
- Division of Nephrology, Cliniques Universitaires Saint-Luc, UCLouvain, Brussels, Belgium; Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Patrick Niaudet
- Pediatric Nephrology, Hôpital Necker-Enfants Malades, Paris University, Paris, France
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
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Modality-specific facilitation of noninjurious sharp mechanical pain by topical capsaicin. Pain 2021; 162:275-286. [PMID: 32701656 DOI: 10.1097/j.pain.0000000000002020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We had previously shown that a "blunt blade" stimulator can mimic the noninjurious strain phase of incisional pain, but not its sustained duration. Here, we tested whether acute sensitization of the skin with topical capsaicin can add the sustained phase to this noninvasive surrogate model of intraoperative pain. Altogether, 110 healthy volunteers (55 male and 55 female; 26 ± 5 years) participated in several experiments using the "blunt blade" (0.25 × 4 mm) on normal skin (n = 36) and on skin pretreated by a high-concentration capsaicin patch (8%, Qutenza; n = 36). These data were compared with an experimental incision (n = 40) using quantitative and qualitative pain ratings by numerical rating scale and SES Pain Perception Scale descriptors. Capsaicin sensitization increased blade-induced pain magnitude and duration significantly (both P < 0.05), but it failed to fully match the sustained duration of incisional pain. In normal skin, the SES pattern of pain qualities elicited by the blade matched incision in pain magnitude and pattern of pain descriptors. In capsaicin-treated skin, the blade acquired a significant facilitation only of the perceived heat pain component (P < 0.001), but not of mechanical pain components. Thus, capsaicin morphed the descriptor pattern of the blade to become more capsaicin-like, which is probably explained best by peripheral sensitization of the TRPV1 receptor. Quantitative sensory testing in capsaicin-sensitized skin revealed hyperalgesia to heat and pressure stimuli, and loss of cold and cold pain sensitivity. These findings support our hypothesis that the blade models the early tissue-strain-related mechanical pain phase of surgical incisions.
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Adult complications of nephropathic cystinosis: a systematic review. Pediatr Nephrol 2021; 36:223-236. [PMID: 32016627 DOI: 10.1007/s00467-020-04487-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 01/13/2023]
Abstract
While nephropathic cystinosis is classically thought of as a childhood disease, with improved treatments, patients are more commonly living into adulthood. We performed a systematic review of the literature available on what complications this population faces as it ages. Nearly every organ system is affected in cystinosis, either from the disease itself or from sequelae of kidney transplantation. While cysteamine is known to delay the onset of end-stage kidney disease, its effects on other complications of cystinosis are less well determined. More common adult-onset complications include myopathy, diabetes, and hypothyroidism. Some less common complications, such as neurologic dysfunction, can still have a profound impact on those with cystinosis. Areas for further research in this area include additional study of the impact of cysteamine on the nonrenal manifestations of cystinosis, as well as possible avenues for new and novel treatments.
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8
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Next generation sequencing as second-tier test in high-throughput newborn screening for nephropathic cystinosis. Eur J Hum Genet 2019; 28:193-201. [PMID: 31570786 DOI: 10.1038/s41431-019-0521-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 09/11/2019] [Accepted: 09/17/2019] [Indexed: 01/20/2023] Open
Abstract
Nephropathic cystinosis is a rare autosomal recessive lysosomal storage disorder, which causes loss of renal proximal tubular function and progressive loss of glomerular function, finally leading to end stage renal failure at school age. In the course of the disease most patients will need kidney transplantation if treatment has not been started before clinical manifestation. With an effective treatment available, a newborn screening assay is highly demanded. Since newborns with cystinosis usually do not show symptoms within the first months of life and no biochemical markers are easily detectable, a DNA-based method seems to be an obvious tool for early diagnosis. Screening was performed using high-throughput nucleic acid extraction followed by 384-well qPCR and melting analysis for the three most frequent variants (57 kb deletion NC_000017.11:g.3600934_3658165del (GRCh38); c.18_21del GACT; c.926dupG) responsible for the defective lysosomal membrane protein cystinosin (CTNS). To increase sensitivity, all heterozygous samples identified in qPCR assay were verified and screened for additional variants by applying next generation sequencing. From January 2018 to July 2019 nearly 292,000 newborns were successfully screened. We identified two newborns with a homozygous 57 kb deletion and a second one with heterozygous 57 kb deletion and a G>C substitution at position c.-512 on the second allele. Cystinosis is an example for diseases caused by a limited number of high prevalence and a high number of low prevalence variants. We have shown that qPCR combined with NGS can be used as a high throughput, cost effective tool in newborn screening for such diseases.
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Autonomic Nervous System Dysregulation in Monozygous Twins With Nephropathic Cystinosis. Kidney Int Rep 2018; 3:1489-1496. [PMID: 30450477 PMCID: PMC6224624 DOI: 10.1016/j.ekir.2018.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
PURPOSE OF REVIEW Over the past few decades, cystinosis, a rare lysosomal storage disorder, has evolved into a treatable metabolic disease. The increasing understanding of its pathophysiology has made cystinosis a prototype disease, delivering new insights into several fundamental biochemical and cellular processes. RECENT FINDINGS In this review, we aim to provide an overview of the latest advances in the pathogenetic, clinical, and therapeutic aspects of cystinosis. SUMMARY The development of alternative therapeutic monitoring strategies and new systemic and ocular cysteamine formulations might improve outcome of cystinosis patients in the near future. With the dawn of stem cell based therapy and new emerging gene-editing technologies, novel tools have become available in the search for a cure for cystinosis.
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Chung MK, Campbell JN. Use of Capsaicin to Treat Pain: Mechanistic and Therapeutic Considerations. Pharmaceuticals (Basel) 2016; 9:ph9040066. [PMID: 27809268 PMCID: PMC5198041 DOI: 10.3390/ph9040066] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/31/2022] Open
Abstract
Capsaicin is the pungent ingredient of chili peppers and is approved as a topical treatment of neuropathic pain. The analgesia lasts for several months after a single treatment. Capsaicin selectively activates TRPV1, a Ca2+-permeable cationic ion channel that is enriched in the terminals of certain nociceptors. Activation is followed by a prolonged decreased response to noxious stimuli. Interest also exists in the use of injectable capsaicin as a treatment for focal pain conditions, such as arthritis and other musculoskeletal conditions. Recently injection of capsaicin showed therapeutic efficacy in patients with Morton’s neuroma, a painful foot condition associated with compression of one of the digital nerves. The relief of pain was associated with no change in tactile sensibility. Though injection evokes short term pain, the brief systemic exposure and potential to establish long term analgesia without other sensory changes creates an attractive clinical profile. Short-term and long-term effects arise from both functional and structural changes in nociceptive terminals. In this review, we discuss how local administration of capsaicin may induce ablation of nociceptive terminals and the clinical implications.
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Affiliation(s)
- Man-Kyo Chung
- Department of Neural and Pain Sciences, University of Maryland, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, Baltimore, MD 21201, USA.
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