Purinergic receptors comprise a family of transmembrane receptors that are activated by extracellular nucleosides and nucleotides. The two major classes of purinergic receptors, P1 and P2, are expressed widely in the gastrointestinal tract as well as immune cells. The purinergic receptors serve a variety of functions from acting as neurotransmitters, to autocoid and paracrine signaling, to cell activation and immune response. Nucleosides and nucleotide agonist of purinergic receptors are released by many cell types in response to specific physiological signals, and their levels are increased during inflammation. In the past decade, the advent of genetic knockout mice and the development of highly potent and selective agonists and antagonists for the purinergic receptors have significantly advanced the understanding of purinergic receptor signaling in health and inflammation. In fact, agonist/antagonists of purinergic receptors are emerging as therapeutic modalities to treat intestinal inflammation. In this article, the distribution of the purinergic receptors in the gastrointestinal tract and their physiological and pathophysiological role in intestinal inflammation will be reviewed.

Plain English summaryPeople living with a condition are uniquely positioned to inform the understanding of the therapeutic context for drug development and evaluation. In 2012, the U.S. Food and Drug Administration (FDA) established the Patient-Focused Drug Development (PFDD) initiative to more systematically obtain the patient perspective on specific diseases and their currently available treatments. PFDD meetings are unique among FDA public meetings, with a format designed to engage patients and elicit their perspectives on two topic areas: (1) the most significant symptoms of their condition and the impact of the condition on daily life; and, (2) their current approaches to treatment. FDA has conducted 24 disease-specific PFDD meetings to date. The lessons learned from PFDD meetings range from experiences common across rare diseases to more disease specific experiences that matter most to patients. FDA recognizes that FDA-led PFDD meetings alone cannot address the gaps in information on the patient perspective. Patient-focused drug development is an ongoing effort and FDA looks forward to the next steps in advancing the science and the utilization of patient input throughout drug development and evaluation.AbstractThe U.S. Food and Drug Administration (FDA) has multiple mechanisms for its regulators and staff to interact with patients -- but none quite like its novel Patient-Focused Drug Development (PFDD) initiative. FDA established the PFDD initiative to more systematically obtain the patient perspective on specific diseases and their currently available treatments. Since the initiative’s inception in 2012, FDA has held 24 PFDD meetings, covering a range of disease areas and hearing directly from thousands of patients and caregivers. FDA’s PFDD meetings have also provided key stakeholders, including patient advocates, researchers, drug developers, healthcare providers, and other government officials, an opportunity to hear the patient’s voice. The lessons learned include but are not limited to specific experiences that matter most to patients, patient perspectives on meaningful treatment benefits and how patients want to be engaged in the drug development process. FDA recognizes that FDA-led PFDD meetings alone cannot address the gaps in information on the patient perspective. Further enhancing the incorporation of the patient’s voice in drug development and evaluation continues to be a priority for FDA.

The US Food and Drug Administration (FDA) understands that innovative product development is essential to addressing the unmet medical need of non-healing chronic wounds. Barriers to product development for non-healing chronic wounds may involve but are not limited to a dearth of biological models, challenges in drug delivery, challenges in clinical trial execution, and limited commercial viability. This perspective article discusses FDA's renewed focus on non-healing chronic wounds and outlines efforts to address identified barriers to product development for nonhealing chronic wounds. In collaboration with key wound healing stakeholders including academia, professional associations, patient groups, reimbursement organizations and industry, FDA intends to help advance product development for non-healing chronic wounds for the ultimate betterment of patients.

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