Canadian tertiary care pediatric massive hemorrhage protocols: a survey and comprehensive national review

PURPOSE

Hemorrhage is the leading cause of pediatric death in trauma and cardiac arrest during surgery. Adult studies report improved patient outcomes using massive hemorrhage protocols (MHPs). Little is known about pediatric MHP adoption in Canada.

METHODS

After waived research ethics approval, we conducted a survey of Canadian pediatric tertiary care hospitals to study MHP activations. Transfusion medicine directors provided hospital/patient demographic and MHP activation data. The authors extracted pediatric-specific MHP data from requested policy/procedure documents according to seven predefined MHP domains based on the literature. We also surveyed educational and audit tools. The analysis only included MHPs with pediatric-specific content.

RESULTS

The survey included 18 sites (100% response rate). Only 13/18 hospitals had pediatric-specific MHP content: eight were dedicated pediatric hospitals, two were combined pediatric/obstetrical hospitals, and three were combined pediatric/adult hospitals. Trauma was the most common indication for MHP activation (54%), typically based on a specific blood volume anticipated/transfused over time (10/13 sites). Transport container content was variable. Plasma and platelets were usually not in the first container. There was little emphasis on balanced plasma/platelet to red-blood-cell ratios, and most sites (12/13) rapidly incorporated laboratory-guided goal-directed transfusion. Transfusion thresholds were consistent with recent guidelines. All protocols used tranexamic acid and eight sites used an audit tool.

DISCUSSION/CONCLUSION

Pediatric MHP content was highly variable. Activation demographics suggest underuse in nontrauma settings. Our findings highlight the need for a consensus definition for pediatric massive hemorrhage, a validated pediatric MHP activation tool, and prospective assessment of blood component ratios. A national pediatric MHP activation repository would allow for quality improvement metrics.

Ochratoxin A challenges the intestinal epithelial cell integrity: results obtained in model experiments with Caco-2 cells

Contamination of human and animal diets with different mycotoxins have gained significant attention over the past decade. The intestinal barrier is the first site of exposure and a primary target for nutritional contaminants and hazardous substances including mycotoxins. In this study, the potential impact of ochratoxin A (OTA) on intestinal barrier integrity was highlighted using a human intestinal Caco-2 cell line. Cell viability following OTA exposure was determined by lactate dehydrogenase release and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover, markers of barrier integrity, such as transepithelial electrical resistance (TEER) as well as the permeability of Lucifer Yellow (LY) and fluorescein isothiocyanate (FITC)-dextran, were assessed. Furthermore, the protein expression of different tight junction (TJ) proteins, as main constituents of barrier integrity, was evaluated by Western blot. Results show that OTA reduces TEER values in a concentration- and time-dependent manner and increase the permeability of LY through the intestinal epithelial layer, while the cell viability did not change significantly. However, the damage was not severe enough to change the permeability to larger molecules, such as FITC-dextran. OTA exposure down-regulated the expression of TJ proteins claudin-1, -3 and -4 and up-regulated the expression of zona occludens 1. The observation that OTA can disrupt the epithelial barrier is of clinical importance as it may lead to an increased passage of luminal antigens into the systemic circulation.

Greater energy demand of exercise during pregnancy does not impact mechanical efficiency

Pregnant women are recommended to engage in 150 min of moderate-intensity physical activity per week to reduce pregnancy complications. Many women struggle to remain physically active throughout pregnancy, and there is no consensus about whether women adopt a less efficient movement pattern as they progress through pregnancy and experience gestational weight gain. This study assessed the change in energy expenditure and mechanical efficiency in pregnant women (PREG; n = 10) when performing a walking treadmill task in early, mid, and late pregnancy and also compared with an age- and body mass index-matched, nonpregnant (CON; n = 10) group. On average, the PREG group gained within the Institute of Medicine's gestational weight gain guidelines (11.6 ± 3.6 kg) and were all inactive (measured using accelerometry), except for 1 participant, by the third trimester, as per the 2019 Canadian physical activity guidelines for pregnant women. Energy expended to complete the walking task increased throughout pregnancy and was higher than the controls (111.5 ± 24.6 kcal) in mid and late pregnancy (139.0 ± 22.2 kcal, p = 0.02, and 147.3 ± 24.6 kcal, p = 0.005, respectively), but not early pregnancy (129.9 ± 18.9 kcal, p = 0.08). Walking mechanical efficiency was similar within pregnant women at each time point and compared to nonpregnant controls. Our findings add to the growing body of evidence demonstrating that pregnant women can safely perform physical activity by showing that walking mechanical efficiency is unchanged at low to moderate intensities. Novelty Energy demand during exercise increases proportionally to weight gain across pregnancy trimesters. However, mechanical efficiency remains unchanged during low- to moderate-intensity walking.

Breast Cancer Cell Apoptosis is Synergistically Induced by Curcumin, Trastuzumab, and Glutathione Peroxidase-1 but Robustly Inhibited by Glial Cell Line-Derived Neurotrophic Factor

We hypothesized that synergy between curcumin (CURC), trastuzumab (TZMB), and glutathione peroxidase-1 (GPX-1) accelerates breast cancer (BC) cell apoptosis which is inhibited by glial cell line-derived neurotrophic factor (GDNF). We measured survival of BC cell lines treated or cotreated with CURC and TZMB, and then with GDNF, before measuring expression levels of growth and apoptosis genes. These experiments were also repeated on SKBR3 cells transiently expressing GPX-1. CURC+TZMB cotreatment induced BC cell apoptosis more significantly than single treatment. GDNF highly inhibited CURC+TZMB toxicity and restored survival. Ectopic overexpression of GPX-1 per se induced SKBR3 cell death that was accelerated upon CURC+TZMB cotreatment. This substantial death induction was inhibited by GDNF more robustly than in single-treated cells. All these changes correlated with changes in expression levels of key molecules and were further confirmed by flow cytometry and correlation analysis. Our data indicate apoptotic induction is jointly shaped in BC cells by CURC, TZMB, and GPX-1 which correlates directly with their tripartite synergism and inversely with GDNF progrowth effects. In light of the active presence of GDNF in tumor microenvironment and necessity to overcome drug resistance, our findings can help in designing combined therapeutic strategies with implications for challenging TZMB resistance in BC.

Effect of P2 receptor blockade on cutaneous vasodilation during rest and exercise in the heat in young men

We assessed the role of purinergic P2 receptors in the regulation of cutaneous vasodilation in young adults at rest and during intermittent moderate-intensity exercise in the heat (35 °C). P2 receptor blockade augmented resting cutaneous vasodilation but had no influence during and following exercise. This increase was partly diminished by nitric oxide synthase inhibition. These results suggest a functional role of P2 receptors in the regulation of cutaneous vascular tone during ambient heat exposure at rest.

No effect of ascorbate on cutaneous vasodilation and sweating in older men and those with type 2 diabetes exercising in the heat

Aging and chronic disease such as type 2 diabetes (T2D) are associated with impairments in the body's ability to dissipate heat. To reduce the risk of heat‐related injuries in these heat vulnerable individuals, it is necessary to identify interventions that can attenuate this impairment. We evaluated the hypothesis that intradermal administration of ascorbate improves cutaneous vasodilation and sweating in older adults via nitric oxide synthase (NOS)‐dependent mechanisms during exercise in the heat and whether these improvements, if any, are greater in individuals with T2D. Older males with (n = 12, 61 ± 9 years) and without (n = 12, 64 ± 7 years) T2D performed two 30‐min bouts of cycling at a fixed rate of metabolic heat production of 500 W (~70% peak oxygen uptake) in the heat (35°C); each followed by a 20‐ and 40‐min recovery, respectively. Cutaneous vascular conductance (CVC) and sweat rate were measured at four intradermal microdialysis sites treated with either (1) lactated Ringer (Control), (2) 10 mmol/L ascorbate (an antioxidant), (3) 10 mmol/L _L‐NAME (non‐selective NOS inhibitor), or (4) a combination of ascorbate + _L‐NAME. In both groups, ascorbate did not modulate CVC or sweating during exercise relative to Control (all P > 0.05). In comparison to Control, _L‐NAME alone or combined with ascorbate attenuated CVC during exercise (all P ≤ 0.05) but had no influence on sweating (all P > 0.05). We show that in both healthy and T2D older adults, intradermal administration of ascorbate does not improve cutaneous vasodilation and sweating during exercise in the heat. However, NOS plays an important role in mediating cutaneous vasodilation.

The mycotoxin deoxynivalenol facilitates allergic sensitization to whey in mice

Intestinal epithelial stress or damage may contribute to allergic sensitization against certain food antigens. Hence, the present study investigated whether impairment of intestinal barrier integrity by the mycotoxin deoxynivalenol (DON) contributes to the development of whey-induced food allergy in a murine model. C3H/HeOuJ mice, orally exposed to DON plus whey once a week for 5 consecutive weeks, showed whey-specific IgG1 and IgE in serum and an acute allergic skin response upon intradermal whey challenge, although early initiating mechanisms of sensitization in the intestine appeared to be different compared with the widely used mucosal adjuvant cholera toxin (CT). Notably, DON exposure modulated tight-junction mRNA and protein levels, and caused an early increase in IL-33, whereas CT exposure affected intestinal γδ T cells. On the other hand, both DON- and CT-sensitized mice induced a time-dependent increase in the soluble IL-33 receptor ST2 (IL-1R1) in serum, and enhanced local innate lymphoid cells type 2 cell numbers. Together, these results demonstrate that DON facilitates allergic sensitization to food proteins and that development of sensitization can be induced by different molecular mechanisms and local immune responses. Our data illustrate the possible contribution of food contaminants in allergic sensitization in humans.

iNOS-dependent sweating and eNOS-dependent cutaneous vasodilation are evident in younger adults, but are diminished in older adults exercising in the heat

Nitric oxide synthase (NOS) contributes to sweating and cutaneous vasodilation during exercise in younger adults. We hypothesized that endothelial NOS (eNOS) and neuronal NOS (nNOS) mediate NOS-dependent sweating, whereas eNOS induces NOS-dependent cutaneous vasodilation in younger adults exercising in the heat. Further, aging may upregulate inducible NOS (iNOS), which may attenuate sweating and cutaneous vasodilator responses. We hypothesized that iNOS inhibition would augment sweating and cutaneous vasodilation in exercising older adults. Physically active younger (n = 12, 23 ± 4 yr) and older (n = 12, 60 ± 6 yr) adults performed two 30-min bouts of cycling at a fixed rate of metabolic heat production (400 W) in the heat (35°C). Sweat rate and cutaneous vascular conductance (CVC) were evaluated at four intradermal microdialysis sites with: 1) lactated Ringer (control), 2) nNOS inhibitor (nNOS-I, NPLA), 3) iNOS inhibitor (iNOS-I, 1400W), or 4) eNOS inhibitor (eNOS-I, LNAA). In younger adults during both exercise bouts, all inhibitors decreased sweating relative to control, albeit a lower sweat rate was observed at iNOS-I compared with eNOS-I and nNOS-I sites (all P < 0.05). CVC at the eNOS-I site was lower than control in younger adults throughout the intermittent exercise protocol (all P < 0.05). In older adults, there were no differences between control and iNOS-I sites for sweating and CVC during both exercise bouts (all P > 0.05). We show that iNOS and eNOS are the main contributors to NOS-dependent sweating and cutaneous vasodilation, respectively, in physically active younger adults exercising in the heat, and that iNOS inhibition does not alter sweating or cutaneous vasodilation in exercising physically active older adults.

Do nitric oxide synthase and cyclooxygenase contribute to the heat loss responses in older males exercising in the heat?

This study evaluated the separate and combined roles of nitric oxide synthase (NOS) and cyclooxygenase (COX) in forearm sweating and cutaneous vasodilatation in older adults during intermittent exercise in the heat. Twelve healthy older (62 ± 7 years) males performed two 30 min cycling bouts at a fixed rate of metabolic heat production (400 W) in the heat (35°C, 20% relative humidity). The exercise bouts were followed by 20 and 40 min of recovery, respectively. Forearm sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC, laser Doppler perfusion units/mean arterial pressure) were evaluated at four skin sites that were continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control), (2) 10 mm ketorolac (non-selective COX inhibitor), (3) 10 mm N(G) -nitro-l-arginine methyl ester (l-NAME; non-selective NOS inhibitor) or (4) a combination of 10 mm ketorolac + 10 mm l-NAME. Sweating was not different between the four sites during either exercise bout (main effect P = 0.92) (average of last 5 min of second exercise, Control, 0.80 ± 0.06; ketorolac, 0.77 ± 0.09; l-NAME, 0.74 ± 0.07; ketorolac + l-NAME, 0.77 ± 0.09 mg min(-1) cm(-2) ). During both exercise bouts, relative to CVC evaluated at the Control site (average of last 5 min of second exercise, 69 ± 6%max), CVC was similar at the ketorolac site (P = 0.62; 66 ± 4%max) whereas it was attenuated to a similar extent at both the l-NAME (49 ± 8%max) and ketorolac + l-NAME (54 ± 8%max) sites (both P < 0.05). Thus, we demonstrate that NOS and COX are not functionally involved in forearm sweating whereas only NOS contributes to forearm cutaneous vasodilatation in older adults during intermittent exercise in the heat.

Can intradermal administration of angiotensin II influence human heat loss responses during whole body heat stress?

It is unclear if angiotensin II, which can increase the production of reactive oxygen species (oxidative stress), modulates heat loss responses of cutaneous blood flow and sweating. We tested the hypothesis that angiotensin II-induced increases in oxidative stress impair cutaneous perfusion and sweating during rest and exercise in the heat. Eleven young (24 ± 4 yr) healthy adults performed two 30-min cycling bouts at a fixed rate of metabolic heat production (400 W) in the heat (35°C). The first and second exercises were followed by a 20- and 40-min recovery. Four microdialysis fibers were placed in the forearm skin for continuous administration of either: 1) lactated Ringer (control), 2) 10 μM angiotensin II, 3) 10 mM ascorbate (an antioxidant), or 4) a combination of 10 μM angiotensin II + 10 mM ascorbate. Cutaneous vascular conductance (CVC; laser-Doppler perfusion units/mean arterial pressure) and sweating (ventilated capsule) were evaluated at each skin site. Compared with control, angiotensin II reduced both CVC and sweating at baseline resting and during each recovery in the heat (all P < 0.05). However, during both exercise bouts, there were no differences in CVC or sweating between the treatment sites (all P > 0.05). When ascorbate was coinfused with angiotensin II, the effect of angiotensin II on sweating was abolished (all P > 0.05); however, its effect on CVC at baseline resting and during each recovery remained intact (all P < 0.05). We show angiotensin II impairs cutaneous perfusion independent of oxidative stress, while it impairs sweating through increasing oxidative stress during exposure to an ambient heat stress before and following exercise.

Cyclopiazonic acid attenuates the divalent cations and augments the mRNA level of iNOS in the liver and kidneys of chickens

An investigation was carried out into the occurrence of cyclopiazonic acid (CPA) producing fungi, the level of CPA contamination in chickens' diet, CPA effects on serum levels of divalent cations, on nitric oxide (NO) content and mRNA level of inducible nitric oxide synthase (iNOS) in the liver and kidney of chickens, as well as the cellular and molecular pathways of CPA toxicity. Mycological and HPLC analyses were used to determine the mycobiota and CPA level, respectively. The mycological studies revealed that 34.46 and 23.07% of the isolated fungi were Aspergillus flavus and Penicillium cyclopium, respectively. HPLC analyses showed the highest (0.95±0.35 μg/g) and lowest (0.08±0.03 μg/g) levels of CPA in maize and mix diet, respectively. For toxicological studies, male chickens (Ross 308) were assigned to the control and test groups (n=8), which received normal saline and 10, 25 and/or 50 μg/kg CPA for 28 days. The effects of CPA on NO content of the liver and kidneys were determined using the Griess reaction, and the effects on the serum level of divalent cations were established using commercially available kits. The effects of CPA on the mRNA level of iNOS were investigated using RT-PCR. CPA lowered the serum level of divalent cations, while NO contents were enhanced significantly (P<0.05). The mRNA level of iNOS in birds of the CPA test groups showed a reverse relationship with NO increase. These data suggest that CPA producing fungi along with CPA contamination in chickens' diet result in hepatic and renal disorders. Moreover, CPA induced disorders might contribute to the biochemical alterations such as NO increase that is reversely associated with mRNA level of iNOS.

Biochemical characterization of a novel high-affinity and specific plasma kallikrein inhibitor

BACKGROUND AND PURPOSE

Kallikrein acts on high molecular weight kininogen (HK) to generate HKa (cleaved HK) and bradykinin (BK). BK exerts its effects by binding to B(2) receptors. The activation of B(2) receptors leads to the formation of tissue plasminogen activator, nitric oxide (NO) and prostacyclin (PGI(2) ). An elevated kallikrein-dependent pathway has been linked to cardiovascular disease risk. The aim of this study was to investigate whether our novel plasma kallikrein inhibitor abolishes kallikrein-mediated generation of BK from HK and subsequent BK-induced NO and PGI(2) formation, thereby influencing endothelial pathophysiology during chronic inflammatory diseases.

EXPERIMENTAL APPROACH

Kinetic analysis was initially used to determine the potency of PF-04886847. Biochemical ligand binding assays, immunological methods and calcium flux studies were used to determine the selectivity of the kallikrein inhibitor. In addition, the effect of PF-04886847 on BK-induced relaxation of the rat aortic ring was determined in a model of lipopolysaccharide-induced tissue inflammation.

KEY RESULTS

Evidence was obtained in vitro and in situ, indicating that PF-04886847 is a potent and specific inhibitor of plasma kallikrein. PF-04886847 efficiently blocked calcium influx as well as NO and PGI(2) formation mediated through the BK-stimulated B(2) receptor signalling pathway. PF-04886847 blocked kallikrein-induced endothelial-dependent relaxation of isolated rat aortic rings pre-contracted with phenylephrine.

CONCLUSIONS AND IMPLICATIONS

PF-04886847 was shown to be the most potent small molecule inhibitor of plasma kallikrein yet described; it inhibited kallikrein in isolated aortic rings and cultured endothelial cells. Overall, our results indicate that PF-04886847 would be useful for the treatment of kallikrein-mediated inflammatory disorders.

Cyclopiazonic acid augments the hepatic and renal oxidative stress in broiler chicks

Generation of reactive oxygen species (ROS) leads to serious tissue injuries. The effect of cyclopiazonic acid (CPA) on oxidative stress markers in the liver and kidneys of broiler chicks was studied. Ten-day-old male broiler chicks (Ross 308) were assigned into the control and test groups, which received normal saline and 10, 25, and 50 μg/kg CPA, respectively, for 28 days. Body weight gain, serum level of alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), uric acid, creatinine, and blood urea nitrogen (BUN) were measured after 2 and 4 weeks exposure. Moreover, the total thiol molecules (TTM) and malondialdehyde (MDA) content of the liver and kidneys were assessed. No significant differences (p > 0.05) were found in body weight gain between the control and test groups. Whereas, the hepatic weight increased significantly (p < 0.05) in animals that received 25 and 50 μg/kg CPA. Both ALP and GGT level in serum were elevated in comparison to the control group. CPA also resulted in uric acid, creatinine, and BUN enhancement in broilers. The MDA content of the liver and kidneys showed remarkable increase. By contrast, the TTM levels in the liver and kidneys were significantly (p < 0.05) attenuated. Histopathological findings confirmed the biochemical changes in either organ characterized by inflammatory cells infiltration along with severe congestion and cell swelling, suggesting an inflammatory response. These data suggest that exposure to CPA resulted in hepatic and renal disorders, which were reflected as biochemical markers alteration and pathological injuries in either organ. The biochemical alteration and pathological abnormalities may be attributed to CPA-induced oxidative stress.