scholarly journals Nitric Oxide-mediated Cutaneous Microvascular Function is not Altered in Young Adults Following Mild-to-Moderate SARS CoV-2 Infection.

Author(s):  
Gabrielle A. Dillon ◽  
S. Tony Wolf ◽  
Lacy M. Alexander

Vascular dysfunction has been reported in adults who have recovered from COVID-19. To date, no studies have investigated the underlying mechanisms of persistent COVID-19-associated vascular dysfunction. PURPOSE: To quantify nitric oxide (NO)-mediated vasodilation in healthy adults who have recovered from SARS-CoV-2 infection. We hypothesized that COVID-19-recovered adults would have impaired NO-mediated vasodilation compared to adults who have not had COVID-19. METHODS: We performed a cross-sectional study including: 10 (5M/5W, 24 ± 4yrs) healthy control (HC) adults who were unvaccinated for COVID-19, 11 (4M/7W, 25 ± 6yrs) healthy vaccinated (HV) adults, and 12 (5M/7W, 22 ± 3yrs) post-COVID-19 (PC, 19 ± 14wks) adults. COVID-19 symptoms severity (survey) were assessed. A standardized 39°C local heating protocol was used to assess NO-dependent vasodilation via perfusion (intradermal microdialysis) of 15 mM NG-nitro-l-arginine methyl ester during the plateau of the heating response. Red blood cell flux was measured (laser-Doppler flowmetry) and cutaneous vascular conductance (CVC = flux/mmHg) was expressed as a percentage of maximum (28mM sodium nitroprusside + 43°C). RESULTS: The local heating plateau (HC: 61 ± 20%, HV: 60 ± 19%, PC: 67 ± 19%, p=0.80) and NO-dependent vasodilation (HC: 77 ± 9%, HV: 71 ± 7%, PC: 70 ± 10%, p=0.36) were not different among groups. Neither symptom severity (25 ± 12 AU) nor time since diagnosis correlated with the NO-dependent vasodilation (r=0.46, p=0.13; r=0.41, p=0.19, respectively). CONCLUSION: Healthy adults who have had mild-to-moderate COVID-19 do not have altered NO-mediated cutaneous microvascular function.

2011 ◽  
Vol 111 (6) ◽  
pp. 1561-1567 ◽  
Author(s):  
Jennifer J. DuPont ◽  
William B. Farquhar ◽  
Raymond R. Townsend ◽  
David G. Edwards

We sought to determine whether oxidative stress or a relative deficit of l-arginine plays a role in reducing cutaneous vasodilation in response to local heating in chronic kidney disease (CKD). Eight patients with stage 3–4 CKD and eight age- and sex-matched healthy control (HC) subjects were instrumented with four microdialysis (MD) fibers for the local delivery of 1) Ringers solution (R), 2) 20 mM ascorbic acid (AA), 3) 10 mM l-arginine (l-Arg), and 4) 10 mM NG-nitro-l-arginine methyl ester (l-NAME). Red blood cell (RBC) flux was measured via laser Doppler flowmetry. A standardized nonpainful local heating protocol (42°C) was used. Cutaneous vascular conductance (CVC) was calculated as RBC flux/MAP and all data were expressed as a percentage of the maximum CVC at each site (28 mM sodium nitroprusside, Tloc = 43°C). The plateau %CVCmax was attenuated in CKD (CKD: 76 ± 4 vs. HC: 91 ± 2%CVCmax; P < 0.05) and the NO contribution to the plateau was lower in CKD (CKD: 39 ± 7, HC: 54 ± 5; P < 0.05). The plateau %CVCmax in the CKD group was significantly greater at the AA and l-Arg sites compared with R (AA: 89 ± 2; l-Arg: 90 ± 1; R: 76 ± 4; P < 0.05) and did not differ from HC. Initial peak %CVCmax was also significantly attenuated at the R and l-Arg sites in CKD ( P < 0.05) but did not differ at the AA site. These results suggest that cutaneous microvascular function is impaired in stage 3–4 CKD and that oxidative stress and a deficit of l-arginine play a role in this impairment.


2018 ◽  
Vol 314 (2) ◽  
pp. H343-H349 ◽  
Author(s):  
Billie K. Alba ◽  
Jody L. Greaney ◽  
Sara B. Ferguson ◽  
Lacy M. Alexander

Psoriasis is an independent risk factor for cardiovascular disease; however, the underlying mechanisms are not fully understood. Deficits in conduit arterial function are evident in patients with psoriasis, but potential impairments in microcirculatory endothelial function remain unclear. We hypothesized that cutaneous microvascular dysfunction would be detectable in otherwise healthy individuals with psoriasis. Two intradermal microdialysis fibers were placed in (nonlesional) forearm skin of nine patients (3 men and 6 women, 39 ± 5 yr) with moderate (16 ± 2% of body surface area) plaque psoriasis and nine healthy (nonpsoriatic) control subjects (3 men and 6 women, 38 ± 5 yr) for local delivery of 1) lactated Ringer solution (control) and 2) 10 mM l-ascorbate (a nonspecific antioxidant). An index of skin blood flow was measured using laser-Doppler flowmetry during local heating (42°C). Nitric oxide (NO)-dependent vasodilation was directly quantified after perfusion of the nonspecific NO synthase inhibitor NG-nitro-l-arginine methyl ester (15 mM). A third fiber was perfused with increasing concentrations (10−10– 10−2M) of norepinephrine to elicit adrenoreceptor-mediated cutaneous vasoconstriction. NO-dependent vasodilation was attenuated in patients with psoriasis (57 ± 5% and 39 ± 7% maximum cutaneous vascular conductance in control subjects and adults with psoriasis, respectively, P < 0.01). l-Ascorbate did not improve NO-dependent vasodilation ( P > 0.05). There was no group difference in maximal vasoconstriction or microvascular sensitivity to norepinephrine ( P > 0.05). These data suggest that NO bioavailability is reduced in otherwise healthy individuals with psoriasis, which contributes to systemic microvascular dysfunction.NEW & NOTEWORTHY In adults with psoriasis, reduced nitric oxide bioavailability mediates impaired endothelium-dependent vasodilation, independent of increases in oxidative stress. Furthermore, the degree of psoriatic symptomology is directly related to greater reductions in nitric oxide-dependent vasodilation.


SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A169-A170
Author(s):  
Amrita Pal ◽  
Fernando Martinez ◽  
Ravi Aysola ◽  
Ronald Harper ◽  
Luke Henderson ◽  
...  

Abstract Introduction Obstructive sleep apnea (OSA) disrupts multiple aspect of autonomic regulation; it is unclear whether intervention with continuous positive airway pressure (CPAP) can correct such disruptions. One key index of autonomic regulation is baroreflex sensitivity (BRS), an index that indicates heart rate (HR) changes to blood pressure (BP) alterations, and which is a significant measure for evaluating long-term cardiovascular changes induced by OSA. BRS can be assessed from BP and HR changes during an autonomic challenge task such as handgrip (HG). In a cross-sectional study, we assessed BRS during HG in untreated OSA (OSA_un) and CPAP treated OSA (CPAP), together with healthy control (CON) participants to determine if CPAP can recover BRS. Methods We collected ECG and continuous beat-by-beat BP from 95 people: 32 newly-diagnosed OSA_un (51.5±13.9years; AHI 21.0±15.3events/hour; 20male); 31 CPAP (49.4±14.0years; 22.4±14.1events/hour in initial diagnosis; 23male); and 32 CON (44.1±13.8years; 10male). We acquired data over 7 mins, during which people performed three 30s HGs (60 s baseline, 90 s recovery, 80% maximum strength). We calculated BRS over the 7 min period using sequence analysis in AcqKnowledge 5.0 BRS, followed by group comparisons using ANOVA. We also analyzed BP, HR and their variabilities: BPV and HRV (sympathetic-vagal). Results Mean arterial BP increases during HG were similar in all groups, although baseline mean arterial BP was higher in OSA_unc and CPAP, relative to CON (p &lt; 0.05; OSA_un:mean±std, 90±11mmHg; CPAP: 88±10mmHg; CON 82±13mmHg). BRS was lower in OSA_un and CPAP, relative to CON (p &lt; 0.05; OSA_un: 13.1±7.6 ms/mmHg; CPAP: 13.7±9.0 ms/mmHg; control 18.3±11.9 ms/mmHg). Other cardiovascular measures of BPV, HR and HRV in addition to BP showed significant increases in response to HG, but these changes were similar in all 3 groups. Conclusion BRS during HG was reduced in both OSA_un and CPAP compared to CON, while HG evoked similar overall changes in BP and HR in all three groups. Although CPAP reduces sympathetic tone measured as Muscle Sympathetic Nerve Activity (MSNA), BRS appears to be unaffected by the intervention. Irreversible changes in the baroreflex network may occur with OSA that are not altered with CPAP usage. Support (if any) NR-017435, HL135562


Author(s):  
Xiaolin Ni ◽  
Qi Zhang ◽  
Xiang Li ◽  
Qianqian Pang ◽  
Yiyi Gong ◽  
...  

Abstract Context Sclerostin is an inhibitor of Wnt-β-catenin signaling to regulate bone formation. Circulating sclerostin levels were reported to be elevated in patients with X-linked hypophosphatemia (XLH), and sclerostin antibody (Scl-Ab) has been shown to increase bone mass and normalize circulating phosphate levels in Hyp mice. However, circulating sclerostin level in acquired hypophosphatemic patients with tumor-induced osteomalacia (TIO) remains rare reported. Objectives This study was designed to evaluate serum sclerostin levels in TIO patients comparing them with age-, sex- matched healthy controls and XLH patients, and analyze correlation of circulating sclerostin with BMD and laboratory parameters. Design, Setting and Participants 190 individuals including 83 adult TIO patients, 83 adult healthy controls and 24 adult XLH patients were enrolled in this cross-sectional study. Main outcome measures Serum sclerostin levels were determined in TIO patients, healthy controls and XLH patients. Results TIO patients (43 male and 40 female) aged 44.3 ± 8.7 (mean ± SD) years had lower levels of circulating sclerostin than healthy controls (94.2 ± 45.8 vs 108.4 ± 42.3 pg/mL, p = 0.01) with adjustment for age, gender, BMI and diabetes rate. Sclerostin levels were positively associated with age (r = 0.238, p = 0.030). Male patients had higher sclerostin level than female patients (104.7 ± 47.3 vs 83.0 ± 41.8 pg/mL, p = 0.014) and postmenopausal patients had higher tendency of sclerostin level than premenopausal patients (98.4 ± 48.8 vs 71.6 ± 32.3 ng/ml, p = 0.05). Sclerostin levels were positively associated with BMD of L1-4 (r = 0.255, p = 0.028), femoral neck (r = 0.242, p = 0.039) and serum calcium (r = 0.231, p = 0.043). TIO subgroup patients (n=24, 35.9 ± 7.3 years old) comparing with age-, sex-matched adult XLH patients and healthy controls revealed significant difference of sclerostin levels (XLH, TIO and healthy control were 132.0 ± 68.8, 68.4 ± 31.3 and 98.6 ± 41.1 pg/mL, respectively, p &lt; 0.001). Conclusions Circulating sclerostin levels were decreased in TIO patients but increased in XLH patients, which might be result of histological abnormality and bone mass.


Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Jordan C Patik ◽  
Joseph M Stock ◽  
Nathan T Romberger ◽  
Shannon L Lennon ◽  
William B Farquhar ◽  
...  

Impaired vascular function likely contributes to the association between dietary sodium intake and the development of cardiovascular disease. Using the cutaneous microvasculature as a model, we have previously shown that a high sodium (HS) diet blunts local heating-induced vasodilation in normotensive individuals with salt resistant (SR) blood pressure (BP). However, the effect of a HS diet on the cutaneous microvasculature in normotensive salt sensitive (SS) individuals remains unclear. Therefore, we tested the hypothesis that cutaneous microvascular function is reduced by a HS diet to a greater degree in SS compared to SR individuals. After each 7-day controlled feeding diet (low sodium (LS) = 20 mmol/day; HS = 300 mmol/day), an intradermal microdialysis fiber was inserted in the ventral forearm and perfused with Ringer’s solution. Skin blood flow (SkBF) was continuously monitored via laser Doppler flowmetry and a local heating unit was placed over the fiber and heated to 42°C until SkBF reached a stable plateau. Site-specific maximal SkBF was determined by perfusing 28mM sodium nitroprusside and heating to 43°C. Mean arterial pressure (MAP) was assessed at regular intervals on the contralateral arm and was used to calculate cutaneous vascular conductance (CVC = SkBF / MAP). Subjects wore a 24-hr ambulatory BP monitor and collected their urine on the final day of each diet. Fourteen subjects (9W / 5M, 42 ± 14 yr) whose MAP increased >5 mmHg (Δ8 ± 1 mmHg) on the HS diet were defined as SS and were compared to 14 age- (43± 14 yr) and sex-matched SR subjects (Δ1 ± 3 mmHg). SS and SR had similar MAP at baseline (88 ± 9 vs. 90 ± 8 mmHg, P = 0.88) and urinary sodium excretion was increased similarly across groups by the HS diet (Δ239 ± 104 vs. Δ220 ± 66 mmol / 24 hr, P = 0.20). Cutaneous vasodilation in response to local heating was decreased on the HS diet relative to the LS diet in both SS (Δ-9 ± 9 %CVCmax, P = 0.005) and SR (Δ-9 ± 9 %CVCmax, P=0.005); however, there was not a group x diet interaction (P = 0.99). In contrast to our hypothesis, these results suggest that the deleterious effects of high sodium diets on cutaneous microvascular function are similar in normotensive salt sensitive and salt resistant individuals.


2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Jamie Rylance ◽  
Anstead Kankwatira ◽  
David E. Nelson ◽  
Evelyn Toh ◽  
Richard B. Day ◽  
...  

PLoS ONE ◽  
2012 ◽  
Vol 7 (5) ◽  
pp. e38213 ◽  
Author(s):  
Octavio P. Luzardo ◽  
Luis Alberto Henríquez-Hernández ◽  
Pilar F. Valerón ◽  
Pedro C. Lara ◽  
Maira Almeida-González ◽  
...  

2018 ◽  
Vol 3 (2) ◽  
pp. 11
Author(s):  
Yadul Ulya ◽  
Aryadi Arsyad ◽  
Saidah Syamsuddin

Anemia saat hamil berefek buruk bagi ibu maupun janin, karena dapat mengurangi suplai oksigen pada metabolisme ibu akibat kekurangan kadar hemoglobin untuk mengikat oksigen, dan peran hemoglobin sebagai pengikat nitric oxide dapat menyebabkan vasokontriksi dan mempengaruhi pengiriman oksigen. Tujuannya untuk mengetahui perbedaan kadar nitric oxide pada ibu hamil trimester 1 dengan anemia dan tidak anemia. Desain penelitian cross sectional study dengan masing-masing 35 ibu hamil trimester 1 yang anemia dan tidak anemia dengan teknik consecutive sampling. Hasil penelitian menunjukkan rata-rata kadar nitric oxide pada ibu hamil trimester 1 yang anemia lebih tinggi (128,8μmol/L) dibandingkan yang tidak anemia (89,1μmol/L) nilai p=0,008. Ibu hamil trimester 1 yang anemia kemungkinan 3,692 kali memiliki resiko mengalami peningkatan kadar nitric oxide dibandingkan yang tidak anemia dengan cut off point 92,86μmol/L. Disimpulkan, kadar nitric oxide lebih tinggi pada ibu hamil trimester 1 yang anemia dan memiliki resiko terjadi peningkatan kadar nitric oxide pada ibu hamil trimester 1 dengan anemia sebesar 3,962 kali.


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