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Journal of Clinical Medicine Jun 2024(1) : Dexmedetomidine is a sedative for patients receiving invasive mechanical ventilation (IMV) that previous single-site studies have found to be associated with...
Association between Dexmedetomidine Use and Mortality in Patients with COVID-19 Receiving Invasive Mechanical Ventilation: A U.S. National COVID Cohort Collaborative (N3C) Study.
(1) : Dexmedetomidine is a sedative for patients receiving invasive mechanical ventilation (IMV) that previous single-site studies have found to be associated with improved survival in patients with COVID-19. The reported clinical benefits include dampened inflammatory response, reduced respiratory depression, reduced agitation and delirium, improved preservation of responsiveness and arousability, and improved hypoxic pulmonary vasoconstriction and ventilation-perfusion ratio. Whether improved mortality is evident in large, multi-site COVID-19 data is understudied. (2) : The association between dexmedetomidine use and mortality in patients with COVID-19 receiving IMV was assessed. This retrospective multi-center cohort study utilized patient data in the United States from health systems participating in the National COVID Cohort Collaborative (N3C) from 1 January 2020 to 3 November 2022. The primary outcome was 28-day mortality rate from the initiation of IMV. Propensity score matching adjusted for differences between the group with and without dexmedetomidine use. Adjusted hazard ratios (aHRs) for 28-day mortality were calculated using multivariable Cox proportional hazards models with dexmedetomidine use as a time-varying covariate. (3) : Among the 16,357,749 patients screened, 3806 patients across 17 health systems met the study criteria. Mortality was lower with dexmedetomidine use (aHR, 0.81; 95% CI, 0.73-0.90; < 0.001). On subgroup analysis, mortality was lower with earlier dexmedetomidine use-initiated within the median of 3.5 days from the start of IMV-(aHR, 0.67; 95% CI, 0.60-0.76; < 0.001) as well as use prior to standard, widespread use of dexamethasone for patients on respiratory support (prior to 30 July 2020) (aHR, 0.54; 95% CI, 0.42-0.69; < 0.001). In a secondary model that was restricted to 576 patients across six health system sites with available PaO/FiO data, mortality was not lower with dexmedetomidine use (aHR 0.95, 95% CI, 0.72-1.25; = 0.73); however, on subgroup analysis, mortality was lower with dexmedetomidine use initiated earlier than the median dexmedetomidine start time after IMV (aHR, 0.72; 95% CI, 0.53-0.98; = 0.04) and use prior to 30 July 2020 (aHR, 0.22; 95% CI, 0.06-0.78; = 0.02). (4) : Dexmedetomidine use was associated with reduced mortality in patients with COVID-19 receiving IMV, particularly when initiated earlier, rather than later, during the course of IMV as well as use prior to the standard, widespread usage of dexamethasone during respiratory support. These particular findings might suggest that the associated mortality benefit with dexmedetomidine use is tied to immunomodulation. However, further research including a large randomized controlled trial is warranted to evaluate the potential mortality benefit of DEX use in COVID-19 and evaluate the physiologic changes influenced by DEX that may enhance survival.
PubMed: 38929961
DOI: 10.3390/jcm13123429 -
Brain Sciences Jun 2024Transcranial electrical stimulation (tES) is increasingly recognized for its potential to modulate cerebral blood flow (CBF) and evoke cerebrovascular reactivity (CVR),...
Transcranial electrical stimulation (tES) is increasingly recognized for its potential to modulate cerebral blood flow (CBF) and evoke cerebrovascular reactivity (CVR), which are crucial in conditions like mild cognitive impairment (MCI) and dementia. This study explores the impact of tES on the neurovascular unit (NVU), employing a physiological modeling approach to simulate the vascular response to electric fields generated by tES. Utilizing the FitzHugh-Nagumo model for neuroelectrical activity, we demonstrate how tES can initiate vascular responses such as vasoconstriction followed by delayed vasodilation in cerebral arterioles, potentially modulated by a combination of local metabolic demands and autonomic regulation (pivotal locus coeruleus). Here, four distinct pathways within the NVU were modeled to reflect the complex interplay between synaptic activity, astrocytic influences, perivascular potassium dynamics, and smooth muscle cell responses. Modal analysis revealed characteristic dynamics of these pathways, suggesting that oscillatory tES may finely tune the vascular tone by modulating the stiffness and elasticity of blood vessel walls, possibly by also impacting endothelial glycocalyx function. The findings underscore the therapeutic potential vis-à-vis blood-brain barrier safety of tES in modulating neurovascular coupling and cognitive function needing the precise modulation of NVU dynamics. This technology review supports the human-in-the-loop integration of tES leveraging digital health technologies for the personalized management of cerebral blood flow, offering new avenues for treating vascular cognitive disorders. Future studies should aim to optimize tES parameters using computational modeling and validate these models in clinical settings, enhancing the understanding of tES in neurovascular health.
PubMed: 38928591
DOI: 10.3390/brainsci14060591 -
Use of FRET-Sensor 'Mermaid' to Detect Subtle Changes in Membrane Potential of Primary Mouse PASMCs.Cells Jun 2024Subtle changes in the membrane potential of pulmonary arterial smooth muscle cells (PASMCs) are pivotal for controlling pulmonary vascular tone, e.g., for initiating...
Subtle changes in the membrane potential of pulmonary arterial smooth muscle cells (PASMCs) are pivotal for controlling pulmonary vascular tone, e.g., for initiating Hypoxic Pulmonary Vasoconstriction, a vital mechanism of the pulmonary circulation. In our study, we evaluated the ability of the fluorescence resonance energy transfer (FRET)-based voltage-sensor Mermaid to detect such subtle changes in membrane potential. Mouse PASMCs were isolated and transduced with Mermaid-encoding lentiviral vectors before the acceptor/donor emission ratio was assessed via live cell FRET-imaging. Mermaid's sensitivity was tested by applying specific potassium chloride (KCl) concentrations. These KCl concentrations were previously validated by patch clamp recordings to induce depolarization with predefined amplitudes that physiologically occur in PASMCs. Mermaid's emission ratio dose-dependently increased upon depolarization with KCl. However, Mermaid formed unspecific intracellular aggregates, which limited the usefulness of this voltage sensor. When analyzing the membrane rim only to circumvent these unspecific signals, Mermaid was not suitable to resolve subtle changes in the membrane potential of ≤10 mV. In summary, we found Mermaid to be a suitable alternative for reliably detecting qualitative membrane voltage changes of more than 10 mV in primary mouse PASMCs. However, one should be aware of the limitations associated with this voltage sensor.
Topics: Animals; Fluorescence Resonance Energy Transfer; Membrane Potentials; Mice; Myocytes, Smooth Muscle; Pulmonary Artery; Potassium Chloride; Mice, Inbred C57BL
PubMed: 38920698
DOI: 10.3390/cells13121070 -
ACG Case Reports Journal Jun 2024Ischemic colitis (IC) should be considered as a cause for gastrointestinal symptoms in patients with recent vigorous physical activity. Vasoconstriction driven by...
Ischemic colitis (IC) should be considered as a cause for gastrointestinal symptoms in patients with recent vigorous physical activity. Vasoconstriction driven by increased sympathetic tone during exercise is believed to mediate exercise-induced IC. In this report, a 21-year-old man with no medical history developed self-resolving, sudden-onset hematochezia and abdominal pain after playing in a collegiate soccer match for 90 minutes. Colonoscopy with biopsy showed changes consistent with IC. He improved without further treatment. In most cases, exercise-induced IC resolves completely with supportive care and correction of hypovolemia. Careful monitoring is appropriate before pursuing further evaluation.
PubMed: 38912376
DOI: 10.14309/crj.0000000000001406 -
Journal of the American Heart... Jun 2024The incidental use of statins during radiation therapy has been associated with a reduced long-term risk of developing atherosclerotic cardiovascular disease. We...
BACKGROUND
The incidental use of statins during radiation therapy has been associated with a reduced long-term risk of developing atherosclerotic cardiovascular disease. We examined whether irradiation causes chronic vascular injury and whether short-term administration of statins during and after irradiation is sufficient to prevent chronic injury compared with long-term administration.
METHODS AND RESULTS
C57Bl/6 mice were pretreated with pravastatin for 72 hours and then exposed to 12 Gy X-ray head-and-neck irradiation. Pravastatin was then administered either for an additional 24 hours or for 1 year. Carotid arteries were tested for vascular reactivity, altered gene expression, and collagen deposition 1 year after irradiation. Treatment with pravastatin for 24 hours after irradiation reduced the loss of endothelium-dependent vasorelaxation and protected against enhanced vasoconstriction. Expression of markers associated with inflammation (NFκB p65 [phospho-nuclear factor kappa B p65] and TNF-α [tumor necrosis factor alpha]) and with oxidative stress (NADPH oxidases 2 and 4) were lowered and subunits of the voltage and Ca activated K BK channel (potassium calcium-activated channel subfamily M alpha 1 and potassium calcium-activated channel subfamily M regulatory beta subunit 1) in the carotid artery were modulated. Treatment with pravastatin for 1 year after irradiation completely reversed irradiation-induced changes.
CONCLUSIONS
Short-term administration of pravastatin is sufficient to reduce chronic vascular injury at 1 year after irradiation. Long-term administration eliminates the effects of irradiation. These findings suggest that a prospective treatment strategy involving statins could be effective in patients undergoing radiation therapy. The optimal duration of treatment in humans has yet to be determined.
PubMed: 38904226
DOI: 10.1161/JAHA.123.033558 -
Microvascular Research Jun 2024Patients with Takotsubo syndrome displayed endothelial dysfunction, but underlying mechanisms have not been fully clarified. This study aimed to explore molecular...
Patients with Takotsubo syndrome displayed endothelial dysfunction, but underlying mechanisms have not been fully clarified. This study aimed to explore molecular signalling responsible for catecholamine excess induced endothelial dysfunction. Human cardiac microvascular endothelial cells were challenged by epinephrine to mimic catecholamine excess. Patch clamp, FACS, ELISA, PCR, and immunostaining were employed for the study. Epinephrine (Epi) enhanced small conductance calcium-activated potassium channel current (I) through activating α1 adrenoceptor. Phenylephrine enhanced edothelin-1 (ET-1) and reactive oxygen species (ROS) production, and the effects involved contribution of I. HO enhanced I and ET-1 production. Enhancing I caused a hyperpolarization, which increases ROS and ET-1 production. BAPTA partially reduced phenylephrine-induced enhancement of ET-1 and ROS, suggesting that α1 receptor activation can enhance ROS/ET-1 generation in both calcium-dependent and calcium-independent ways. The study demonstrates that high concentration catecholamine can activate SK1-3 channels through α1 receptor-ROS signalling and increase ET-1 production, facilitating vasoconstriction.
PubMed: 38901735
DOI: 10.1016/j.mvr.2024.104699 -
Biology of Sex Differences Jun 2024Prenatal hypoxia, a common pregnancy complication, leads to impaired cardiovascular outcomes in the adult offspring. It results in impaired vasodilation in coronary and...
BACKGROUND
Prenatal hypoxia, a common pregnancy complication, leads to impaired cardiovascular outcomes in the adult offspring. It results in impaired vasodilation in coronary and mesenteric arteries of the adult offspring, due to reduced nitric oxide (NO). Thromboxane A (TxA) is a potent vasoconstrictor increased in cardiovascular diseases, but its role in the impact of prenatal hypoxia is unknown. To prevent the risk of cardiovascular disease by prenatal hypoxia, we have tested a maternal treatment using a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ). We hypothesized that prenatal hypoxia enhances vascular TxA responses in the adult offspring, due to decreased NO modulation, and that this might be prevented by maternal nMitoQ treatment.
METHODS
Pregnant Sprague-Dawley rats received a single intravenous injection (100 µL) of vehicle (saline) or nMitoQ (125 µmol/L) on gestational day (GD)15 and were exposed to normoxia (21% O) or hypoxia (11% O) from GD15 to GD21 (term = 22 days). Coronary and mesenteric arteries were isolated from the 4-month-old female and male offspring, and vasoconstriction responses to U46619 (TxA analog) were evaluated using wire myography. In mesenteric arteries, L-NAME (pan-NO synthase (NOS) inhibitor) was used to assess NO modulation. Mesenteric artery endothelial (e)NOS, and TxA receptor expression, superoxide, and 3-nitrotyrosine levels were assessed by immunofluorescence.
RESULTS
Prenatal hypoxia resulted in increased U46619 responsiveness in coronary and mesenteric arteries of the female offspring, and to a lesser extent in the male offspring, which was prevented by nMitoQ. In females, there was a reduced impact of L-NAME in mesenteric arteries of the prenatal hypoxia saline-treated females, and reduced 3-nitrotyrosine levels. In males, L-NAME increased U46619 responses in mesenteric artery to a similar extent, but TxA receptor expression was increased by prenatal hypoxia. There were no changes in eNOS or superoxide levels.
CONCLUSIONS
Prenatal hypoxia increased TxA vasoconstrictor capacity in the adult offspring in a sex-specific manner, via reduced NO modulation in females and increased TP expression in males. Maternal placental antioxidant treatment prevented the impact of prenatal hypoxia. These findings increase our understanding of how complicated pregnancies can lead to a sex difference in the programming of cardiovascular disease in the adult offspring.
Topics: Animals; Female; Rats, Sprague-Dawley; Pregnancy; Vasoconstriction; Male; Prenatal Exposure Delayed Effects; Thromboxane A2; Sex Characteristics; Antioxidants; Nitric Oxide; Mesenteric Arteries; Rats; Hypoxia; Fetal Hypoxia; 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
PubMed: 38898532
DOI: 10.1186/s13293-024-00627-x -
Animal Models and Experimental Medicine Jun 2024Under hypoxia, exaggerated compensatory responses may lead to acute mountain sickness. The excessive vasodilatory effect of nitric oxide (NO) can lower the hypoxic...
BACKGROUND
Under hypoxia, exaggerated compensatory responses may lead to acute mountain sickness. The excessive vasodilatory effect of nitric oxide (NO) can lower the hypoxic pulmonary vasoconstriction (HPV) and peripheral blood pressure. While NO is catalyzed by various nitric oxide synthase (NOS) isoforms, the regulatory roles of these types in the hemodynamics of pulmonary and systemic circulation in living hypoxic animals remain unclear. Therefore, this study aims to investigate the regulatory effects of different NOS isoforms on pulmonary and systemic circulation in hypoxic rats by employing selective NOS inhibitors and continuously monitoring hemodynamic parameters of both pulmonary and systemic circulation.
METHODS
Forty healthy male Sprague-Dawley (SD) rats were randomly divided into four groups: Control group (N-nitro-D-arginine methyl ester, D-NAME), L-NAME group (non-selective NOS inhibitor, N-nitro-L-arginine methyl ester), AG group (inducible NOS inhibitor group, aminoguanidine), and 7-NI group (neurological NOS inhibitor, 7-nitroindazole). Hemodynamic parameters of rats were monitored for 10 min after inhibitor administration and 5 min after induction of hypoxia [15% O, 2200 m a. sl., 582 mmHg (76.5 kPa), Xining, China] using the real-time dynamic monitoring model for pulmonary and systemic circulation hemodynamics in vivo. Serum NO concentrations and blood gas analysis were measured.
RESULTS
Under normoxia, mean arterial pressure and total peripheral vascular resistance were increased, and ascending aortic blood flow and serum NO concentration were decreased in the L-NAME and AG groups. During hypoxia, pulmonary arterial pressure and pulmonary vascular resistance were significantly increased in the L-NAME and AG groups.
CONCLUSIONS
This compensatory mechanism activated by inducible NOS and endothelial NOS effectively counteracts the pulmonary hemodynamic changes induced by hypoxic stress. It plays a crucial role in alleviating hypoxia-induced pulmonary arterial hypertension.
PubMed: 38888011
DOI: 10.1002/ame2.12453 -
Journal of Pain Research 2024We aimed to assess uterine and arcuate artery Doppler indices in patients with mild primary dysmenorrhea.
PURPOSE
We aimed to assess uterine and arcuate artery Doppler indices in patients with mild primary dysmenorrhea.
PATIENTS AND METHODS
A total of 55 patients were included, consisting of women without dysmenorrhea (n=26, group A) and women with mild primary dysmenorrhea (n=29, group B). Doppler measurements of the uterine and arcuate arteries were performed in both groups on the 1st-2nd days and 21st-24th days (midluteal phase) of the menstrual cycle using transvaginal ultrasound and compared between the groups. The severity of dysmenorrhea was assessed using visual analog scale scores.
RESULTS
Doppler measurements of the uterine and arcuate arteries performed on the 1st-2nd days of the menstrual cycle and the midluteal phase were similar between the groups (p>0.05). There was a significant decrease in the intragroup measurements of uterine and arcuate arteries performed on the first day of menstruation and the luteal phase in both groups (p<0.01).
CONCLUSION
Doppler findings of the uterine and arcuate arteries did not differ between patients with and without mild primary dysmenorrhea. The etiology of primary dysmenorrhea mainly involves ischemia and vasoconstriction, but mild primary dysmenorrhea appears to be associated with a different etiology other than decreased tissue perfusion.
PubMed: 38887385
DOI: 10.2147/JPR.S456239 -
Thyroid Research Jun 2024Primary hypothyroidism (PHT) is associated with an increased risk for the development of atherosclerosis (AS) and other cardiovascular disorders. PHT induces... (Review)
Review
Primary hypothyroidism (PHT) is associated with an increased risk for the development of atherosclerosis (AS) and other cardiovascular disorders. PHT induces atherosclerosis (AS) through the induction of endothelial dysfunction, and insulin resistance (IR). PHT promotes vasoconstriction and the development of hypertension. However, patients with subclinical PHT with normal thyroid hormones (THs) are also at risk for cardiovascular complications. In subclinical PHT, increasing thyroid stimulating hormone (TSH) levels could be one of the causative factors intricate in the progression of cardiovascular complications including AS. Nevertheless, the mechanistic role of PHT in AS has not been fully clarified in relation to increased TSH. Therefore, in this review, we discuss the association between increased TSH and AS, and how increased TSH may be involved in the pathogenesis of AS. In addition, we also discuss how L-thyroxine treatment affects the development of AS.
PubMed: 38880884
DOI: 10.1186/s13044-024-00199-3