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The purpose of Lunar OI (Orthostatic Intolerance) is to determine if there are differences between males and females in tolerance to and cardiovascular responses during different angles of head-up tilt simulating gravity levels less than or equal to Earth's gravity. Also, this study will determine if a gradient compression garment affects tolerance to tilting and the cardiovascular stress at different tilt angles. Males and females are being identified by biological sex. This will be a two-phased study design. In Phase I we will determine whether there are differences in the development of signs or symptoms of orthostatic intolerance between males and females when tilted head up on a table to different angles to simulate gravity levels that astronauts may experience when landing on or launching from the surface of the Moon. In Phase II, the tilt tests simulating the same gravity levels from Phase I will be repeated, but a custom-made lower-body compression garment will be worn to see if wearing the garment affects the development of orthostatic intolerance. For both study phases, before tilting, a drug will be administered to reduce the amount fluid in the blood (plasma) to levels similar to that experienced by astronauts during spaceflight.
As people get older, especially women, they often feel dizzy or even faint when they go from sitting or lying down to standing up. This happens because their blood pressure (BP) drops, which can lead to falls, heart problems, and even death in older adults. When BP changes, it affects how well the heart works and how it talks with blood vessels. However, little research has been done on how the heart and blood vessels talk during times of low BP. The crosstalk between the heart and blood vessels is important, as it allows enough blood and oxygen to reach the brain and other vital organs. Some research shows that as we get older, the crosstalk does not work as well. This can make it harder for blood to flow properly or put extra pressure on the heart and arteries. That's why we want to study how the heart and blood vessels talk during a laboratory-simulated situation of low BP in young and older men and women. In our study, participants will lie down with their lower body in a chamber that creates a vacuum around their legs. This safely mimics what happens when you stand up quickly. We can then measure heart function, the stress on arteries, and BP while your legs are in that vacuum. We'll use an ultrasound to check the heart and a finger cuff to measure BP. We'll also see if gripping something firmly can help protect from sudden drops in blood pressure. This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it. The main questions the current study aims to address are: * Does the cross-talk between the heart and vessels become more impaired with aging during laboratory-simulated conditions of low BP? * Do women have worse crosstalk between the heart and blood vessels during laboratory-simulated conditions of BP? * Does hand gripping protect against drops in BP during conditions of low BP? All participants will be asked to * Complete two laboratory conditions on two separate days with a randomized order (like flipping a coin): * Exposure to a lower body negative pressure (LBNP) chamber to safely simulate low BP (control) * Exposure to a lower body negative pressure (LBNP) while conducting hand-squeezingexercise (experimental). The investigators will examine how heart and blood vessel interactions, as well as blood pressure (BP) responses, differ in young and older adults of both sexes when exposed to a laboratory-simulated low BP condition (LBNP), both with and without hand squeezing exercise.
Orthostatic hypotension (OH) and orthostatic intolerance (OI) are common conditions where blood pressure drops when standing up, causing dizziness, fainting, or fatigue. These affect up to 30% of adults over 65 and raise risks for heart disease, stroke, kidney problems, and more. Current medications often don't fully help and can cause side effects like high blood pressure when lying down. The STANDUP study tests a new approach: using a minimally invasive procedure to open narrowed veins above the heart (supracardiac veins) that may block blood flow back to the heart. We believe fixing these blockages could improve blood pressure control and reduce symptoms. This is a 2-year study enrolling 100 adults (age 18+) with OH or OI that hasn't improved with standard treatments or is worsened by lying-down high blood pressure. What happens in the study? Participants get imaging (like X-rays and ultrasound) to check for vein narrowing. If needed, doctors use a thin tube (catheter) through a small skin puncture to inflate a tiny balloon (angioplasty) or place a small mesh tube (stent) to widen the veins. The procedure takes a few hours under local anesthesia, with monitoring for safety. Follow-up visits check symptoms, blood pressure, and quality of life at 2-4 weeks, 3 months, 6 months, 1 year, and 2 years. Who can join? Adults 18+ with diagnosed OH/OI not helped by meds. Must give informed consent. Not eligible if: Pregnant, breastfeeding, actively infected, or unable to take blood thinners. Possible benefits: Better standing tolerance, fewer symptoms, improved daily life, less need for meds, and new knowledge on vein issues in OH/OI. Risks: Rare but include bleeding, infection, stroke, vein clots, stent issues, radiation from imaging, or temporary symptom worsening. We'll monitor closely and report any problems. This single-arm trial (no placebo group) will compare before-and-after results to see if the procedure helps. No study drug costs; covered by insurance or clinic. Led by Dr. Karthikeyan Arcot at St. Francis Hospital, Roslyn, NY. Contact for details.
Observational two phase, retrospective and prospective registry study to assess the prevalence of and characterize outcomes of autonomic dysfunction (AD) in patients who undergo bariatric surgery (BS) and to better define the underlying pathophysiology of AD following BS.
This study is researching an experimental drug called REGN7544 (called "study drug"). The study is focused on participants with POTS. The aim of the study is to see how safe, tolerable, and effective the study drug is. The study is looking at several other research questions, including: * How the study drug changes heart rate and blood pressure in participants with POTS * What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the study drug less effective or could lead to side effects)
The LIFT will be conducted at Brigham and Women's Hospital (BWH) of Harvard Medical School, focusing on the effect of Pyridostigmine (Mestinon) and Low-Dose Naltrexone (LDN) in subjects aged 18-65 meeting the Canadian consensus criteria (CCC) for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) as well as having specifically Orthostatic Intolerance. This double-blind, placebo-controlled study will involve 160 participants randomized into one of four possible groups: Pyridostigmine/LDN (40), Pyridostigmine/Placebo (40), LDN/Placebo (40), Placebo/Placebo (40). The dose of Pyridostigmine will be carefully titrated from 30mg to 60mg three times a day, and the dose of LDN will be titrated from 1.5 mg to 4.5 mg once daily. The trial includes a scale-back plan, allowing participants to reduce their dosage if they experience intolerance symptoms, with adjustments made during weekly visits. This plan provides a personalized approach to medication tolerance, ensuring participant's safety and comfort throughout the trial. The time commitment for the participant is approximately three (3) months, and during this time, there will be three (3) in-person visits to BWH and four (4) virtual visits. Study procedures will include two (2) submaximum cardiopulmonary exercise tests, questionnaires (virtually completed), and blood and urine collection. We will be recruiting from the BWH Dyspnea Clinic as well as the Open Medicine Foundation (OMF) StudyME Registry and anticipate the entire trial will take two (2) years to complete. The LIFT represents a significant endeavor to improve treatment options for ME/CFS patients and contribute to the broader understanding of this debilitating condition.
Parasympathetic nervous system (PNS) is part of the body's autonomic nervous system(PNS) protects body against inflammation. Study shows that reduced PNS function activity is associated with persistent inflammation. Preliminary data from the studies shows, that post-COVID-19 POTS patients have reduced parasympathetic (PNS) function. Given that the PNS protects against inflammation, this clinical trial aims to prove that post-COVID-19 POTS is caused by reduced PNS activity, which in turn, contributes to persistent inflammation, orthostatic intolerance, and OI symptoms. The study will evaluate immune cell activation in post-COVID-19 POTS and patients with history of COVID-19 infection without sequelae and correlate this with the degree of decreased PNS activity.
Postural tachycardia syndrome (POTS) is the most common chronic cause of postural lightheadedness, and upright confusion afflicting many Americans, mostly young women. Many POTS patients hyperventilate by increasing their depth of breathing that produces tachycardia, alters blood flow and blood pooling in the body and importantly reduces brain blood flow causing "brain fog". In this proposal the investigators will demonstrate in young women that abnormal repeated brief impairment of blood pressure and brain flow just after standing sensitizes the body's oxygen sensor in POTS to respond as if it were in a low oxygen environment causing hyperventilation and its consequences. In this project the investigators will use various drugs that will help to understand the mechanisms that cause POTS in this unique subset of POTS patients who hyperventilate.