Ascorbic Acid Infusion Research Articles

Innovative process for improving functional and sensory quality of black garlic

Black garlic (BG) is an aged product high in brown melanoidin pigment and functional quality, however, the long aging process limits its commercial production. The present investigation was undertaken to develop an innovative process for improving the functional quality of BG as well as shortening the aging duration. Peeled garlic was subjected to two pre-treatment steps viz. Freeze-thaw (FT) and blanching (BL) followed by ascorbic acid (AA) infusion and effects were monitored during aging. Non-enzymatic browning, the main visible indicator of MR was significantly (p < 0.05) high in FT garlic due to high infused AA content. The pre-treated garlic showed significantly (p< 0.05) high fructose content (6-7-fold) over the control on the 6th day of aging. The treatment also enhanced the total phenolic content (2.5–3.0-fold) and antioxidant activity (14-fold) while reducing the processing time from 18 to 12 days. The soluble solid content (58.7 °B) and Fast index (fluorescent of advanced Maillard reaction products and soluble tryptophan) was maximum (305.2) in FT garlic on the 12th day. FTIR confirmed a strong peak at 1515 cm−1 depicting the dark nature of the BG subjected to FT. The innovative short process saved 50% of energy in production and was 43% more economical compared to its control counterpart. Overall sensory quality of FT garlic in terms of color, flavour and texture was on par with control except BL sample which showed high stickiness and low score values. Overall results suggest that FT treatment followed by infusion of ascorbic acid accelerated the Maillard reaction (MR), and improved the functional quality of BG.

The Effect of Ascorbic Acid on Hepatic Ischaemia-Reperfusion Injury in Wistar Rats: An Experimental Study.

Liver ischaemia-reperfusion (IR) during hepatic surgeries can lead to liver cell death via oxidative stress and the activation of immune cells, the release of cytokines, and damage-associated molecular patterns. Ascorbic acid has been shown to confer potential protective effects against IR injury, mainly due to its antioxidant properties. This study evaluated the effect of ascorbic acid infusion at different time points during hepatic IR in rats. Thirty-six male Wistar rats were divided into control and experimental groups that received the same total ascorbic acid dose at three different infusion times: before ischaemia, before reperfusion, or before both ischaemia and reperfusion. All of the animals experienced hepatic IR injury. We measured the hepatic enzymes, cytokines, and portal blood flow. Animals receiving ascorbic acid before both ischaemia and reperfusion had lower liver enzyme levels, reduced inflammation, and better portal venous flow than other animals. Divided doses of ascorbic acid before IR may be beneficial for reducing liver injury associated with IR.

Sodium Loading Does Not Induce Oxidative Stress-Mediated Reductions in Vascular Function in Young Adults

Short-term, high sodium diets decrease dilation responses in conduit arteries and the microvasculature when compared to low sodium diets (e.g., 7000 vs. 500 mg/day). Supraphysiological antioxidant treatment mitigates these effects supporting a role for oxidative stress in sodium-induced vascular impairments. It is unclear whether these effects are present when high sodium conditions are compared to the sodium level of a typical American diet (~3400 mg/day). Therefore, we tested the hypotheses that sodium added to the habitual diet of young adults would reduce flow mediated dilation (FMD) and post-ischemic reactive hyperemia (RH) and that an acute infusion of the antioxidant ascorbic acid (AA) would attenuate the vascular consequences of excess sodium. Methods: Young adults (6M / 8F; age: 26 ± 4 y; BMI: 23.6 ± 2.5 kg/m2) were studied following 10 days of sodium loading (SL) via table salt-filled capsules (3900 mg sodium/day) and 10 days of placebo capsules in addition to their normal diet, in random order. Total sodium intake was estimated via 24-hour urinary sodium content on day 10. On day 11, brachial artery diameter and blood velocity were continuously measured via duplex ultrasound at baseline and after 5 min of forearm ischemia. FMD, the post-ischemic change in brachial artery diameter relative to baseline diameter, provided an index of conduit artery endothelial function. The total RH in the 2 min following ischemia was measured for an index of microvascular function. Within each condition, testing was performed before (pre-AA) and after (post-AA) a 20 min intravenous infusion of 0.06 g of AA/kg lean body mass. Results: Urinary sodium content was increased by SL compared to the placebo (285 ± 94 vs. 160 ± 75 mmol/24 h, p&lt;0.001) indicating approximate sodium intakes of 6600 and 3700 mg/day, respectively. Mean arterial pressure did not differ across conditions pre-AA (SL: 77 ± 7; placebo: 75 ± 5 mmHg, P=0.40) or post-AA (SL: 79 ± 8; placebo: 76 ± 5 mmHg, P=0.17). Brachial artery FMD was not different across time or condition (SL pre-AA: 8.7 ± 3.6, post-AA: 8.8 ± 4.2% vs. placebo pre-AA: 8.8 ± 3.2, post-AA: 8.1 ± 3.5%, time x condition interaction P=0.48). RH was similar following SL and placebo (condition effect: P=0.38) but was reduced in both conditions post AA (SL: Δ-45 ± 44 ml, P=0.01; placebo: Δ-72 ± 59ml, p&lt;0.001). Conclusion: Contrary to our hypothesis, 10 days of sodium loading did not decrease FMD or post- ischemic RH in young adults compared to their habitual diet. Likewise, acute antioxidant treatment did not augment FMD in either condition and paradoxically decreased total RH independent of sodium intake. These data suggest that a short-term increase in dietary sodium intake in healthy young adults does not elicit oxidative stress-induced reductions in vascular function. NIH 5R01HL104106 and 5P20GM113125; AHA 20POST35080171. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ascorbic Acid Infusion Improves Cerebrovascular Reactivity in Middle-Aged and Older Adults

Aging is associated with reductions in cerebrovascular reactivity (CVR) and cerebrovascular conductance (CVC), which may contribute to the development of neurodegenerative disease and stroke. In the peripheral vasculature, increased oxidative stress is linked to vascular dysfunction and is ameliorated following infusion of the antioxidant ascorbic acid (AA). However, oxidative stress’ effect on cerebrovascular function in humans is not entirely understood. PURPOSE: To determine whether oxidative stress reduces CVR and CVC in middle-aged and older adults (MA/O). We hypothesized that AA infusion would increase CVR and CVC in MA/O but not young adults (YA). METHODS: Young (18-29 years) and middle-aged and older (55-79 years) adults were recruited for two identical experimental visits. Each visit consisted of the same measures performed both before and after the infusion of either AA or saline (SAL). Middle cerebral artery blood velocity (MCAv) was recorded using a transcranial Doppler ultrasound probe. CVR was tested using a hypercapnia protocol that was achieved with a computer-based gas blender that increased the subjects’ end-tidal partial pressure of carbon dioxide (PETCO2) 9 mmHg above baseline for a 3-minute period. CVR was defined as the percent change in MCAv during hypercapnia divided by the absolute change in PETCO2. CVC was defined as the percent of CVR normalized for the changes in mean arterial blood pressure. Two-way ANOVAs were used to assess the effects of AA and SAL on CVR and CVC. Fisher’s LSD tests were used to assess main and interaction effects when necessary. RESULTS: 8 YA (25 + 2 years) and 14 MA/O (65 + 6 years) completed the experimental visits. There was a significant main effect of condition (pre/post) on CVR following SAL infusion (p = 0.016), and a significant age x condition interaction effect on CVR following AA infusion (p = 0.016). There were no significant main or interaction effects on CVC following SAL infusion, but there was a significant age x condition interaction effect on CVC following AA infusion (p = 0.012). Post hoc testing indicated that the difference in CVR following SAL infusion was due to an increase in YA (3.0 + 0.5 %/mmHg pre vs. 3.8 + 1.1 %/mmHg post, p = 0.047), whereas the difference in CVR following AA infusion was due to an increase in MA/O (3.3 + 1.7 %/mmHg pre vs. 4.1 + 1.9 %/mmHg post, p = 0.006). The difference in CVC was indicated to be due to both lower baseline CVC in MA/O (2.3 + 0.4 %/mmHg YA pre vs. 1.3 + 1.1 %/mmHg MA/O pre, p = 0.019) and an increase in CVC in MA/O following AA infusion (1.3 + 1.1 %/mmHg pre vs. 2.0 + 0.5 %/mmHg post, p = 0.047). CONCLUSION: Our main finding is that AA infusion restores CVR and CVC in MA/O, but not YA. This finding suggests that age-related increases in oxidative stress may impair cerebrovascular function. Supported by NIH Grant P20 GM113125. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Antioxidant-induced modulation of sympathetic transduction to arterial blood pressure in humans

Purpose: Excess plasma free fatty acids (FAA) promote oxidative stress and an increase in peripheral resistance. Therefore, we tested the hypothesis that excess FAA limits sympathetic control of arterial blood pressure (BP) and that sympathetic control would be restored during co-administration of ascorbic acid, which is an antioxidant with vasodilatory properties. Methods: A 20% IV fat emulsion (Intralipid) was administered for 2 hours to 5 lean, healthy adults with and without co-infusion of ascorbic acid (separate visits) in a double-blinded, crossover study design. Sympathetic control of BP was examined by determining the BP response to individual bursts of muscle sympathetic nerve activity (MSNA) (microneurography). Briefly, beat-to-beat mean arterial pressure (MAP) was measured continuously (finger cuff) and signal-averaged over 15 cardiac cycles following each detected burst of MSNA over a 10-min resting period. Results: In contrast to our hypothesis, no change was observed in sympathetic transduction during lipid infusion (1.5 ± 0.4 vs. 1.4 ± 3 mmHg, P=0.75). However, co-infusion of ascorbic acid significantly increased sympathetic transduction compared with baseline (1.5 ± 0.4 vs. 2.0 ± 3 mmHg, P=0.04), in addition to reducing peripheral resistance (0.73 ± 0.11 vs. 0.53 ± 12 mmHg·min·mL−1, P=0.07). MSNA and MAP were not significantly changed during the 2-hr infusions. Conclusions: These preliminary findings suggest that excess FAA do not modulate sympathetic transduction in lean, healthy adults. However, ascorbic acid infusion reduces peripheral resistance and increases sympathetic transduction, demonstrating an inverse relation between peripheral resistance and sympathetic transduction in healthy adults. Funding and support: R01HL159370-01 (S.W.H.). This work was also supported by a CTSA grant from NCATS awarded to the University of Kansas for Frontiers: University of Kansas Clinical and Translational Science Institute (# UL1TR002366) The contents are solely the responsibility of the authors and do not necessarily represent the offcial views of the NIH or NCATS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ascorbic acid prevents stress-induced hypercoagulability in overweight and obese individuals

Ascorbic acid (AA) may contribute to restoring hemostatic balance after mental stress (MS) in overweight/obese adults. We aimed to determine the effects of AA administration on hemostatic responses to MS in overweight/obese men. Fourteen overweight/obesity men (27 ± 7 years; BMI: 29.7 ± 2.6 kg m−2) performed the Stroop color-word stress task for 5 min after non-simultaneous infusion of placebo (PL, 0.9% NaCl) and AA (3 g). Blood was collected at baseline, during MS, and 60 min after MS to measure: activated partial thromboplastin time, prothrombin time, and fibrinogen concentration, by coagulometer; platelet-derived microvesicles (PMV, mv/μL), by flow cytometry; nitrite (μM), by chemiluminescence. In PL session, MS led to decreases in PTs (stress, p = 0.03; 60 min, p < 0.001), PT-INR (stress, p < 0.001; 60 min, p < 0.01), aPTTs (60 min, p = 0.03), aPTT ratio (60 min, p = 0.04) and fibrinogen (60 min, p = 0.04), while increased PT activity (60 min, p = 0.01) when compared to baseline. Furthermore, AA increased PTs (60 min, p < 0.001), PT-INR (60 min, p = 0.03) and decreased PT activity (60 min, p < 0.001) and fibrinogen (stress, p = 0.04) when compared to PL. Nitrite was increased in response to stress during AA session (p < 0.001 vs PL). There was no difference in PMV. Ascorbic acid prevented the impaired hemostatic profile and improved nitrite response to stress in the overweight and obese adults.

Oxidative stress-related impairment of endothelial function in uncomplicated obesity

Purpose: Visceral obesity is associated with vascular oxidative stress and development of hypertension. Therefore, we tested the hypothesis that suppression of vascular oxidative stress in adults with visceral obesity would improve endothelium-dependent dilation. Methods: IV infusion of a water-soluble antioxidant (ascorbic acid) was performed in 15 middle-age obese adults (3 men/12 women) without diabetes or hypertension in a placebo-controlled, double-blinded, crossover study design. Ascorbic acid was infused at 0.06g/kg fat free mass in 100 ml saline at 5 mL/min over 20 min (bolus) followed by a drip infusion at 0.02 g/kg fat-free mass in 30 ml saline at 0.5 mL/min over 60 min. Endothelium-dependent dilation was assessed via brachial artery flow-mediated dilation (FMD) and expressed as % increase in diameter from baseline before forearm occlusion. Results: Android fat distribution in the visceral cavity (VAT%) was 39 ± 10% and body mass index (BMI) was 37 ± 6 kg/m2. IV infusion significantly increased plasma ascorbic acid concentrations (Baseline: 42 ± 2 vs. Bolus: 66 ± 6 vs. End: 62 ± 4 μmol/L, P&lt;0.001). Compared with baseline, bolus infusion of ascorbic acid significantly increased FMD (Baseline: 5.8 ± 2.5 vs. Bolus: 9.0 ± 4.0 vs. End: 8.0 ± 4.2 %, P=0.01), which remained after statistically adjusting for the stimulus (shear rate area under the curve) via analysis of covariance (P=0.04). No significant change in FMD was observed following placebo (saline) during a separate study visit (Baseline: 8.0 ± 4.4 vs. Bolus: 8.3 ± 3.9 vs. End: 8.6 ± 2.9 %, P=0.86). Conclusions: These preliminary findings suggest that acute elevations in plasma ascorbic acid concentrations improve endothelium-dependent dilation in middle-aged adults with visceral obesity. Future studies should target mechanisms by which mediators of oxidative stress in obesity (e.g., hyperlipidemia, hyperinsulinemia) inhibit nitric oxide-mediated vasodilation. Funding and support: R01HL159370-01 (S.W.H.). This work was also supported by a CTSA grant from NCATS awarded to the University of Kansas for Frontiers: University of Kansas Clinical and Translational Science Institute (# UL1TR002366). The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or CTSA. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Corneal endothelial cells and acoustic cavitation in phacoemulsification.

Postoperative complications of phacoemulsification, such as corneal edema caused by human corneal endothelial cell (CEC) injury, are still a matter of concern. Although several factors are known to cause CEC damage, the influence of ultrasound on the formation of free radicals during surgery should be considered. Ultrasound in aqueous humor induces cavitation and promotes the formation of hydroxyl radicals or reactive oxygen species (ROS). ROS-induced apoptosis and autophagy in phacoemulsification have been suggested to significantly promote CEC injury. CEC cannot regenerate after injury, and measures must be taken to prevent the loss of CEC after phacoemulsification or other CEC injuries. Antioxidants can reduce the oxidative stress injury of CEC during phacoemulsification. Evidence from rabbit eye studies shows that ascorbic acid infusion during operation or local application of ascorbic acid during phacoemulsification has a protective effect by scavenging free radicals or reducing oxidative stress. Both in experiments and clinical practice, hydrogen dissolved in the irrigating solution can also prevent CEC damage during phacoemulsification surgery. Astaxanthin (AST) can inhibit oxidative damage, thereby protecting different cells from most pathological conditions, such as myocardial cells, luteinized granulosa cells of the ovary, umbilical vascular endothelial cells, and human retina pigment epithelium cell line (ARPE-19). However, existing research has not focused on the application of AST to prevent oxidative stress during phacoemulsification, and the related mechanisms need to be studied. The Rho related helical coil kinase inhibitor Y-27632 can inhibit CEC apoptosis after phacoemulsification. Rigorous experiments are required to confirm whether its effect is realized through improving the ROS clearance ability of CEC.

Mental stress induces endothelial dysfunction by AT1R-mediated redox imbalance in overweight/obese men

The main goal of this study was to determine whether oxidative imbalance mediated by AT1 receptor (AT1R) is responsible for deleterious endothelial responses to mental stress (MS) in overweight/obese class I men. Fifteen overweight/obese men (27±7 years old; 29.8±2.6 kg/m2) participated in three randomized experimental sessions with oral administration of the AT1R blocker olmesartan (40 mg; AT1R blockade) or ascorbic acid (AA; 3g) infusion or placebo [both intravenously (0.9% NaCl) and orally]. After two hours, endothelial function was determined by flow-mediated dilation (FMD) before (baseline), 30 min (30MS), and 60 min (60MS) after a five-minute acute MS session (Stroop Color Word Test). Blood was collected before (baseline), during MS, and 60 min after MS for redox homeostasis profiling: lipid peroxidation (TBARS; thiobarbituric acid reactive species), protein carbonylation, and catalase activity by colorimetry and superoxide dismutase (SOD) activity by an ELISA kit. At the placebo session, FMD significantly decreased 30MS (P=0.05). When compared to baseline, TBARS (P<0.02), protein carbonylation (P<0.01), catalase (P<0.01), and SOD (P<0.01) increased during the placebo session. During AT1R blockade, FMD increased 30 min after MS (P=0.01 vs baseline; P<0.01 vs placebo), while AA infusion increased FMD only 60 min after MS. No differences were observed during MS with the AT1R blockade and AA regarding TBARS, protein carbonylation, catalase, and SOD. AT1R-mediated redox imbalances played an important role in endothelial dysfunction to mental stress.

Novel isochoric impregnation to develop high-quality and nutritionally fortified plant materials (apples and sweet potatoes).

Isochoric impregnation was explored as a novel pressure-assisted infusion technique to fortify plant materials with bioactive compounds. Apple and potato cylinders were impregnated with a sucrose solution containing 4% ascorbic acid (AA) while freezing under isochoric conditions. Isochoric impregnation resulted in greater infusion of AA compared to infusion at atmospheric pressure, which demonstrated the feasibility of this impregnation technology. Processing temperatures (-3°C and -5°C) and processing times (1, 3, and 5h) significantly affected the AA infusion. The AA content values ranged from 446 to 516mg/100g for apples and 322 to 831mg/100g for sweet potatoes under isochoric conditions. For both plant materials, isochoric impregnation at -3°C did not cause major changes in texture and microstructure of the biological tissues. These results indicated that isochoric impregnation of solid foods could be a feasible technology for infusion of bioactive compounds without significantly altering their matrix. PRACTICAL APPLICATION: The findings of this study showed that the use of isochoric impregnation as a fortification technique is a promising way to develop fresh-like and value-added products with improved nutrition during preservation at subfreezing temperatures.

Intravenous Ascorbic Acid and Lung Function in Severely Ill COVID-19 Patients.

Current evidence suggests that ascorbic acid improves the host’s immune system and, therefore, may play a role in reducing the severity of infectious diseases. Coronavirus disease 2019 (COVID-19) is a potentially life-threatening viral infection that mainly infects the lungs. The objective of this review was to synthesize the existing findings from studies related to the effect of intravenous ascorbic acid on lung function in COVID-19 patients. For this review, PubMed, Cochrane, SCOPUS, EMBASE, Clinical Trial Registry, and Google Scholar databases were searched from December 2019 to May 2022. There was a total of six studies that investigated the large dose of ascorbic acid infusion intravenously on lung function in severely ill subjects with COVID-19. Out of six, three studies found that high-dose intravenous ascorbic acid improved lung function markers, and three studies found null results. Infusions of 12 g/d and 24 g/d of intravenous ascorbic acid had shown a significant improvement in lung function markers in two clinical trials. Studies that administered 8 g/d, 2 g/d, and 50 mg/kg/d of intravenous ascorbic acid found no influence on mechanical ventilation need and other lung function markers in critically ill subjects with COVID-19. Overall, the effect of intravenous ascorbic acid on the lung function of subjects with COVID yielded equivocal findings. More double-blinded, randomized, clinical studies with a larger sample size are required to confirm the effect of ascorbic acid in ameliorating the lung pathologies associated with COVID infection.

Assessment of ultrasound-assisted vacuum impregnation as a method for modifying cranberries’ quality

Combined vacuum impregnation and ultrasound was proposed as an alternative method to improve the infusion of ascorbic acid in berry fruit. The effect of ultrasound application at different stages of impregnation – vacuum, relaxation, and both stages – on the qualitative characteristics of impregnated cranberries was investigated. The quality assessment was based on porosity, color, antioxidant capacity, anthocyanin, polyphenol and structure compound content. Ultrasound-assisted vacuum impregnation contributed to higher ascorbic acid content, smaller relative color difference, and greater antioxidant properties. It was found that the degree of impregnation varies considerably and depends on the stage of using ultrasound. Due to more favorable quality attributes, the conclusion was reached that ultrasound should be applied during the relaxation stage of vacuum impregnation.

Blueberries Improve Endothelial Function in Postmenopausal Women With Above-Normal Blood Pressure via Reductions in Oxidative Stress

ObjectivesResearch suggests blueberries and their (poly)phenols may improve endothelial dysfunction, a major risk factor for cardiovascular disease (CVD). The objective of this study was to investigate the impact of consuming 22 g/day for 12 weeks of freeze-dried highbush blueberry powder on endothelial function and other measures of cardiovascular health, oxidative stress, and circulating (poly)phenol metabolites in postmenopausal women with above-normal blood pressure.MethodsWe performed a randomized, double-blind, placebo-controlled, parallel-arm trial in estrogen-deficient postmenopausal women aged 45–65 years with elevated blood pressure or stage 1-HTN. Endothelial function was assessed as brachial artery flow-mediated dilation (FMD) and normalized to individual shear rate area under the curve (FMD/SRAUC) to control for inter-individual variability in reactive hyperemia-induced shear stress. To assess whether improvements in FMD were mediated by reduced oxidative stress, FMD was assessed before and after intravenous infusion of a supra-physiologic dose of ascorbic acid. Blood pressure, arterial stiffness, and plasma (poly)phenol metabolites were also assessed.ResultsA total of 43 women completed the trial (n = 32 for endothelial function). Compliance in the Blueberry and Placebo groups were 93% and 91%, respectively. Mean total plasma (poly)phenol metabolite concentrations were increased at 4 (250,053 nmol/L, P < 0.05) and 8 (303,053 nmol/L, P < 0.05) weeks in the Blueberry group compared to baseline (125,798 nmol/L) with a strong trend at 12 weeks (227,971 nmol/L, P < 0.05), and no changes in Placebo. Blood pressure and arterial stiffness were unchanged with both treatments. At 12 weeks, FMD/SRAUC was increased by 96% from baseline (P < 0.05) in the Blueberry group but unchanged in Placebo, and changes in FMD/SRAUC from baseline to 12 weeks were higher (P < 0.05) than Placebo. The response in FMD/SRAUC to ascorbic acid infusion was lower (P < 0.05) at 12 weeks compared to baseline in the Blueberry group but not Placebo.ConclusionsThese findings suggest blueberries improve endothelial function, and is mediated, in part, by reduced oxidative stress in postmenopausal women with above-normal blood pressure, a high-risk population for developing CVD.Funding SourcesUS Highbush Blueberry Council and USDA National Institute of Food and Agriculture.

Consumption of a High‐fiber Diet Improves Systolic Blood Pressure and Vascular Endothelial Function and May Reduce Oxidative Stress in Middle‐aged to Older Adults

Aging is the primary risk factor for the development of cardiovascular diseases (CVD), largely due to increases in systolic blood pressure (SBP) and oxidative stress‐related impairments in vascular endothelial function. Higher intake of dietary fiber is associated with reduced CVD risk. In healthy late middle‐aged to older (MA/O) adults, limited evidence indicates high‐fiber diet interventions improve SBP, but whether a high‐fiber diet improves endothelial function with aging is unknown.PurposeWe tested the hypothesis that a high‐fiber diet would, in addition to reducing SBP, improve endothelial function and reduce oxidative stress in healthy MA/O adults.MethodsWe performed a controlled feeding study in which 14 MA/O adults (8F/6M; age: 69 ± 5 years) consumed an isocaloric high‐fiber diet (30‐35 g/day) for 7 days. Diets also contained 60% total carbohydrates, 15% protein, 25% fat, and 12‐15% sugar. Baseline (pre) measures were performed under habitual diet conditions (26 ± 6 g fiber/day). On days 0 (pre) and 7 (post) of the diet, endothelial cells were collected via venous endovascular biopsy, and endothelial function was assessed by brachial artery flow‐mediated dilation (FMD) following 20 minutes of intravenous infusion of saline (volume control) or the antioxidant ascorbic acid (0.06 g/kg fat‐free mass in 100 mL saline at 5 mL/min; N=12), to determine whether any improvements in endothelial functional following the high‐fiber diet were due to reduced oxidative stress.ResultsConsumption of a high‐fiber diet reduced SBP (pre vs. post: 120 ± 3 vs. 116 ± 3 mmHg, p&lt;0.01) and improved endothelial function by ~30% (pre vs. post: 4.1 ± 0.5 vs. 5.3 ± 0.7 %, p=0.03). Abundance of nitrotyrosine (NT), a marker of oxidative stress, in endothelial cells from a subset of subjects (N=6) was lower after the high‐fiber diet (pre vs. post: 0.43 ± 0.16 vs. 0.29 ± 0.12 A.U., p=0.08). At baseline, infusion of ascorbic acid increased FMD by 2.2 ± 0.7 %Δ units (p=0.01 vs. saline), indicating tonic suppression of endothelial function by oxidative stress under habitual diet conditions. Ascorbic acid still increased FMD post‐high‐fiber diet but to a lesser extent (+1.2 ± 0.6 %Δ units, p=0.06 vs. saline), and differences in FMD pre vs. post high‐fiber diet were abolished by ascorbic acid (6.3 ± 0.9 vs. 6.6 ± 0.9 %, p=0.68). These data suggest that the high‐fiber diet improved FMD in part by reducing oxidative stress.ConclusionsHigh‐fiber diet consumption improves SBP in healthy MA/O adults with normal baseline levels and induces clinically significant improvements in FMD possibly via reductions in vascular oxidative stress and tonic oxidative stress‐related suppression of endothelial function. These results suggest that a high‐fiber diet may reduce CVD risk, at least in part, by mitigating increases in SBP and oxidative stress‐related impairments in endothelial function with aging.

Role of ascorbic acid infusion in critically ill patients with transfusion-related acute lung injury.

In critically ill patients, transfusion-related acute lung injury (TRALI) remains the leading cause of transfusion-related fatalities in critical care settings and is associated with inflammation and oxidative stress state. Recent research raised the potential efficacy of high-dose intravenous ascorbic acid (VC) in critically ill patients. The aim of this trial was to investigate the effect of high-dose intravenous VC as a targeted therapy for TRALI in terms of serum proinflammatory (interleukin [IL]-8, IL-1β, C-reactive protein), anti-inflammatory (IL-10), oxidative stress (superoxide dismutase, malondialdehyde) markers, and plasma VC levels. Secondary outcomes were oxygenation (PaO2 /FiO2 ratio), vasopressor use, duration of mechanical ventilation, ICU length of stay, 7-day mortality and 28-day mortality. Eighty critically ill patients with TRALI (n = 80) were randomized to receive 2.5 g/6h intravenous vitamin C for 96 hours (ASTRALI group) or placebo. Patients were followed up to measure the outcomes initially (T0) and at the end of treatment (T96). When compared to the control group, the ASTRALI group at T96 showed significantly higher median of IL-10 (31.6± 25.8 vs 17.7± 12.0pg/mL, P <.0001) levels and superoxide dismutase (12 876 ± 4627 U/L vs 5895 ± 6632 U/L, P <.0001) activities, and lower median C-reactive protein (76 ± 50 vs 89 ± 56 mg/L, P =.033), IL-8 (11.8±7.3 vs 35.5± 19.8pg/mL, P <.0001) and malondialdehyde (0.197 ±0.034 vs 0.234 ±0.074 μM/L, P =.002) levels. High-dose ascorbic acid was associated with significantly reduced oxidative stress, reduced pro-inflammatory markers except IL-1β, elevated anti-inflammatory marker and elevated plasma VC levels.

Ascorbic Acid to Prevent Postpolypectomy Bleeding in the Colon: A Randomized Controlled Trial.

It has been reported that vitamin C replacement can quickly reverse nonspecific bleeding in surgical patients with normal coagulation parameters. We evaluated the effect of intravenous ascorbic acid administration for prevention of postpolypectomy bleeding in large polyps of the colon. Patients with large polyps with heads larger than 10 mm, stalk diameter larger than 5 mm, and a length larger than 10 mm were included in this randomized controlled clinical trial. In the study group, the first 500 mg intravenous dose of vitamin C diluted in normal saline was administered 2h before colonoscopic resection of polyps and the second and third similar doses were administered on days 2 and 3 of polypectomy, respectively. The control group received normal saline in a similar fashion. The resection of polyps was performed in snare and cut-blend mode. Early and late postoperative bleeding were compared between the two groups. A total of 153 polyps were resected by endoscopic polypectomy. Early bleeding was observed in 7.2% of the patients, which was significantly lower in the vitamin C group (2.6% vs 11.8%, P =0.03). Late bleeding was observed in 6.5% of the patients with a trend lower in the vitamin C group (2.6% vs 10.5%, P =0.057). The proportion of postprocedural bleeding was significantly higher in the vitamin C group (5% vs 20%, P =0.007). Hazard ratios of early and postprocedural bleeding were 78% and 76% lower in the vitamin C group compared to the control group (P <0.05). Intravenous ascorbic acid infusion could reduce postpolypectomy bleeding.

Reactive oxygen species play a modulatory role in the hyperventilatory response to poikilocapnic hyperoxia in humans

The proposed mechanism for the increased ventilation in response to hyperoxia includes a reduced brain CO2 -[H+ ] washout-induced central chemoreceptor stimulation that results from a decrease in cerebral perfusion and the weakening of the CO2 affinity for haemoglobin. Nonetheless, hyperoxia also results in excessive brain reactive oxygen species (ROS) formation/accumulation, which hypothetically increases central respiratory drive and causes hyperventilation. We then quantified ventilation, cerebral perfusion/metabolism, arterial/internal jugular vein blood gases and oxidant/antioxidant biomarkers in response to hyperoxia during intravenous infusion of saline or ascorbic acid to determine whether excessive ROS production/accumulation contributes to the hyperoxia-induced hyperventilation in humans. Ascorbic acid infusion augmented the antioxidant defence levels, blunted ROS production/accumulation and minimized both the reduction in cerebral perfusion and the increase in ventilation observed during saline infusion. Hyperoxic hyperventilation seems to be mediated by central chemoreceptor stimulation provoked by the interaction between an excessive ROS production/accumulation and reduced brain CO2 -[H+ ] washout. The hypothetical mechanism for the increase in ventilation ( ) in response to hyperoxia (HX) includes central chemoreceptor stimulation via reduced CO2 -[H+ ] washout. Nonetheless, hyperoxia disturbs redox homeostasis and raises the hypothesis that excessive brain reactive oxygen species (ROS) production/accumulation may increase the sensitivity to CO2 or even solely activate the central chemoreceptors, resulting in hyperventilation. To determine the mechanism behind the HX-evoked increase in , 10 healthy men (24±4 years) underwent 10min trials of HX under saline and ascorbic acid infusion. , arterial and right internal right jugular vein (ijv) partial pressure for oxygen (PO2 ) and CO2 (PCO2 ), pH, oxidant (8-isoprostane) and antioxidant (ascorbic acid) markers, as well as cerebral blood flow (CBF) (Duplex ultrasonography), were quantified at each hyperoxic trial. HX evoked an increase in arterial partial pressure for oxygen, followed by a hyperventilatory response, a reduction in CBF, an increase in arterial 8-isoprostane, and unchanged PijvCO2 and ijv pH. Intravenous ascorbic acid infusion augmented the arterial antioxidant marker, blunted the increase in arterial 8-isoprostane and attenuated both the reduction in CBF and the HX-induced hyperventilation. Although ascorbic acid infusion resulted in a slight increase in PijvCO2 and a substantial decrease in ijv pH, when compared with the saline bout, HX evoked a similar reduction and a paired increase in the trans-cerebral exchanges for PCO2 and pH, respectively. These findings indicate that the poikilocapnic hyperoxic hyperventilation is likely mediated via the interaction of the acidic brain interstitial fluid and an increase in central chemoreceptor sensitivity to CO2 , which, in turn, seems to be evoked by the excessive ROS production/accumulation.

Ascorbic Acid Prevents Vascular Endothelial Dysfunction Induced by Electronic Hookah (Waterpipe) Vaping.

BackgroundElectronic hookah (e‐hookah) vaping has increased in popularity among youth, who endorse unsubstantiated claims that flavored aerosol is detoxified as it passes through water. However, e‐hookahs deliver nicotine by creating an aerosol of fine and ultrafine particles and other oxidants that may reduce the bioavailability of nitric oxide and impair endothelial function secondary to formation of oxygen‐derived free radicals.Methods and ResultsWe examined the acute effects of e‐hookah vaping on endothelial function, and the extent to which increased oxidative stress contributes to the vaping‐induced vascular impairment. Twenty‐six healthy young adult habitual hookah smokers were invited to vape a 30‐minute e‐hookah session to evaluate the impact on endothelial function measured by brachial artery flow‐mediated dilation (FMD). To test for oxidative stress mediation, plasma total antioxidant capacity levels were measured and the effect of e‐hookah vaping on FMD was examined before and after intravenous infusion of the antioxidant ascorbic acid (n=11). Plasma nicotine and exhaled carbon monoxide levels were measured before and after the vaping session. Measurements were performed before and after sham‐vaping control experiments (n=10). E‐hookah vaping, which increased plasma nicotine (+4.93±0.92 ng/mL, P<0.001; mean±SE) with no changes in exhaled carbon monoxide (−0.15±0.17 ppm; P=0.479), increased mean arterial pressure (11±1 mm Hg, P<0.001) and acutely decreased FMD from 5.79±0.58% to 4.39±0.46% (P<0.001). Ascorbic acid infusion, which increased plasma total antioxidant capacity 5‐fold, increased FMD at baseline (5.98±0.66% versus 9.46±0.87%, P<0.001), and prevented the acute FMD impairment by e‐hookah vaping (9.46±0.87% versus 8.74±0.84%, P=0.002). All parameters were unchanged during sham studies.ConclusionsE‐hookah vaping has adverse effects on vascular function, likely mediated by oxidative stress, which overtime could accelerate development and progression of cardiovascular disease.RegistrationURL: https://ClinicalTrials.gov. Unique identifier: NCT03690427.

Safety and Tolerability of Intra-Venous Ascorbic Acid in Allogeneic Hematopoietic Cell Transplant Recipients: A Matched Historical Control Study

Intravenous (IV) ascorbic acid (AA) improves organ function and reduces inflammation in sepsis, an inflammatory state similar to the post-hematopoietic cell transplant (HCT) milieu. This salutary effect is mediated by antioxidant activity as well transcriptional modulation by AA. HCT recipients are deficient in AA, therefore we evaluated the safety and efficacy of patients receiving parenteral AA after myeloablative conditioning for allogeneic HCT compared to similarly treated historical controls who did not receive AA. Methods: Patients with hematologic malignancies, AML (48% of patients), ALL (28%), and CML+MDS (25%) were enrolled in an IRB approved prospective phase 2 clinical trial (NCT03613727). IV AA 50 mg/kg/d divided in 3 doses was given on days 1-14 after HCT, followed by oral AA 500 mg bid from day 15 until 6 months post HCT (FDA-IND 138924). Conditioning regimens utilized included; fludarabine &amp; melphalan (45%), cyclophosphamide with either busulfan (30%) or total body irradiation (25%). GVHD prophylaxis included calcineurin inhibitors and methotrexate or cellcept along with anti-thymocyte globulin (ATG). Primary endpoint was reduction in TRM at 1 year. Propensity score matching was used for matching study patients with similarly treated historical controls, matching for diagnosis, conditioning regimen, and CIBMTR disease risk category for comparison of clinical outcomes. Cox-proportional hazard models were used to estimate adjusted hazard ratios (AHR) between the time-to-event outcomes and study group, adjusted for patient age, donor type, stem cell source, diagnosis, conditioning regimen, and CIBMTR disease risk. Results of an interim analysis following a period of COVID 19 mandated suspension of study accrual are reported. Results: As of March 2020, 40 patients have received IV AA: these include HLA-matched related donor (MRD; n=11), and either 10/10 or 9/10 HLA- matched unrelated donor (MUD; n=22 &amp; 7 respectively) recipients. Graft source was either peripheral blood (n=38) or bone marrow (n=2); 88% patients had CIBMTR high risk disease. Median age was 55 years; males (19). All patients enrolled were deficient in AA at day 0, median AA level 0.3 mg/dL (range: 0.1-0.5); post AA infusion level was normal at 1.6 (1.2-5.7) on day 14. Median neutrophil and platelet recovery was by 12 days (range: 9-15 &amp; 8-21 days respectively) with sustained donor engraftment. Median absolute CD3+ cell count at day 30 was 330 cells/microL. With a median follow up of 220 days in AA recipients, no statistically significant difference was observed in transplant related mortality between propensity matched historical controls and study patients (AHR 0.6, 95% CI: 0.2-1.5; p-value = 0.27); univariate survival analysis is depicted in Figure 1. Relapse was also similar (AHR 1.2, 95% CI: 0.3-4.5; p-value = 0.82), and despite a larger number of HLA mismatched unrelated donor recipients, acute GVHD (Grade II-IV) rates were similar in the two groups for both grade II-IV (AHR 0.8, 95% CI: 0.7-1.7; p-value = 0.65) and grade III-IV disease (AHR 0.6, 95% CI: 0.2-1.6; p-value = 0.32). Chronic GVHD rates were also similar (AHR 0.4, 95% CI: 0.1-2.7; p-value = 0.74). There are no attributable grade 3 - 4 toxicities from AA; CMV and EBV reactivation rates were not different in the two groups. Conclusions: In patients undergoing myeloablative allogeneic HCT the administration of IV ascorbic acid is safe and does not negatively impact myeloid engraftment or immune reconstitution. In this interim analysis, transplant related mortality, relapse and GVHD are not increased in IV AA recipients compared to historical controls. Thus, given its safety and tolerability, and possible salutary impact on survival and relapse in these high-risk patients, we posit the feasibility of a randomized phase 3 trial with IV AA in the post-transplant setting to determine its effect on relapse and TRM. Disclosures No relevant conflicts of interest to declare.

High dose ascorbic acid treatment in COVID-19 patients raised some problems in clinical chemistry testing

Abstract Objective COVID-19 pandemia still continues to threaten the whole world. High dose ascorbic acid (AA) infusion is a choice of treatment and its efficiency is still being investigated. AA interferes with many clinical chemistry tests. However, data about the interference of high concentrations of AA is not sufficient. In this study, we aimed to investigate the interference of AA at high concentrations on commonly used chemistry assays. Materials and Methods Serum samples at AA concentrations of 200, 150, 100, 75, 50, 25, 10, 5, 2 and 0 mg/dL were prepared by using the stock solution of 15000 mg/dL AA. Each sample was analyzed by using the most common 30 chemistry tests (Abbott Architect C8000, Illinois, USA) and a POCT glucometer (STANDARD GlucoNavii, Gyeonggi-do, Republic of Korea). Results Creatinine, sodium and glucose (POCT) tests were found to be positively interfered by increasing AA concentrations; while direct bilirubin, lipase, UIBC, triglyceride, total cholesterol, HDL/LDL cholesterol tests were negatively interfered. Absolute interference (%) increased as the AA concentration increased. Conclusion This is the largest and first study to investigate the interference of high dose AA, which is used in severe COVID-19 patients nowadays. Manufacturers and clinicians should be aware of the possibility of aberrant results due to high dose AA infusion. Clinicians should not forget to consult a laboratory specialist, since he is the only person to monitor the reactions in all assays, and know the technical subjects like interferences, assay method specifications. This issue is very important for correct decision-making and interpretation of the data-mining studies accurately and efficiently.