Reduced Tissue Hypoxia Research Articles

Why is therapeutic exercise the best treatment for knee osteoarthritis?

Osteoarthritis (OA) of the knee joints (KJ) has a high social significance and is therefore a relevant pathology for scientific research. The authors have proposed an original hydraulic theory for the pathogenesis of OA in KJ. This approach is based on the notion of primary mechanical damage to the internal ligamentous structures and synovial membrane accompanied by posttraumatic edema, synovial hypervolemia, and hypertension. The authors demonstrated that regular physical activity at all stages of the disease is pathogenetically justified and allows the patient to improve lymphatic and venous outflow and thus resist increasing fibrosis. Improved arterial blood flow will reduce tissue hypoxia. Any type of symptom-modifying therapy can be harmful because it reduces the protective role of pain reflexes in protecting the KJ from excessive loads, leading to injury. The necessity of maintaining a walking speed of more than 4.3 km/h with an increase in cadence is emphasized from the perspective of reducing static stress during walking and extending life expectancy.

Mildronate Ameliorates Kidney Function and Reduces Inflammation in SCD Mice

INTRODUCTION:Sickle cell disease (SCD) is a genetic hemoglobin disorder characterized by hemolytic anemia, vaso-occlusive crisis and inflammation that affects organs such as the kidney, liver, brain, spleen, and heart. SCD is driven by a mutation in the β-globin gene that causes sickling of red blood cells (RBCs). More than 50% of SCD patients are affected by chronic kidney diseases (CKD) and other comorbidities. Vasculopathy is caused by hemolysis-related endothelial dysfunction and inflammation, which collectively contribute to the development of renal disease. Mildronate (also known as Meldonium) is an anti-ischemic and cardio protecting medication approved in Eastern Europe. Mildronate facilitates a switch from fatty acid oxidation to less oxygen-intensive glycolysis that allows less oxygen consumption by peripheral tissues and higher oxygenation of heart. We hypothesized that mildronate administration would reduce tissue hypoxia and decrease inflammation in SCD mice. METHODS: The study was approved by the Institutional Animal Care and Use Committee at Howard University (IACUC). We employed the Townes SCD mouse model, which mimics SCD complications. SCD and control mice were injected with mildronate (400 mg/kg in saline) intraperitoneally or saline as vehicle control over the course of ten days. Blood and plasma were collected and used for hematological parameters analysis. Cytokines were measured by Bio-plex suspension array in plasma and real-time RT-PCR or ELISA in organs. Protein expression of HO-1, HIF-1α, NFκB and NRF2 was measured by Western blot. The effect of Mildronateon systemic and renal oxidative stress was measured by malondialdehyde (MDA) using ELISA (Abcam). RESULTS: We observed significant reduction in the cytokine's levels of IFN-γ, IL-1, and TNF-α in plasma of SCD mice after mildronate injection. We also observed reduction in IL-6, IL-10 and IL-17 levels but differences were not statistically significant. There were no significant changes in hematological parameters (Hematocrit, MCV, MCH, CMCH, Erythrocytes, Hemoglobin) after mildronate injection. Also, we did not observe changes in MDA levels in plasma or kidney in SCD mice compared to control mice, both non-injected and mildronate injected. We further evaluated HO-1 and NRF2 protein expression by western blot and observed no significant differences between SCD mice with or without mildronate injection. In H&E staining, cortex glomerular area and medullar congestion area were significantly reduced after mildronate injection. We also observed reduction of proteinuria in SCD mice injected with mildronate. DISCUSSION: Our examination of the effect of mildronate showed decreases inflammation in the mildronate injected SCD mice evidenced by reduced levels of IFN-γ, IL-1, IL-17, IL-6, IL-10, and TNF-α in circulation. There was a slight decrease in the expression levels of Nrf2 and HO-1 after mildronate injection. HO-1 is crucial for the catabolism of hemoglobin and protects against tissue damage in hemolysis. The HO-1 promoter has binding sites for several transcription factors, including phosphorylated Nrf2. Previous studies from our lab showed increased HIF-1α expression in PBMCs obtained from SCD patients. Here we did not detect significant changes in NFκB-p65 or HIF-1α expression levels. While we expected mildronate to decrease the oxidative stress, we did not observe significant reduction in MDA levels in treated mice compared to control mice. CONCLUSION: Mildronate improved kidney function in SCD mice by reducing circulatory and renal inflammation. In future, we plan to assess in more details the mildronate's impact on kidney function and inflammation. ACKNOWLEDGMENTS: This work was supported by NIH grants 1R01HL125005, 5U54MD007597, and 1SC1HL150685.

Attenuated reactive hyperemia after prolonged sitting is associated with reduced local skeletal muscle metabolism: insight from artificial intelligence.

Blunted post-occlusive reactive hyperemia (PORH) after prolonged sitting (PS) has been used as evidence of microvascular dysfunction. However, it has not been determined if confounding variables are responsible for the reduction in PORH after PS. Therefore, the purpose of this study was to examine the PS-mediated changes in cardiovascular and metabolic factors that affect PORH using artificial intelligence (AI). We hypothesized that calf muscle metabolic rate (MMR) is attenuated after PS, which may reduce tissue hypoxia during an arterial occlusion (i.e., oxygen deficit) and PORH. Thirty-one subjects (male = 13, female = 18) sat for 2.5 h. A rapid-inflation cuff was placed around the thigh above the knee to generate an arterial occlusion. PORH was represented by the reoxygenation rate (RR) of the near-infrared spectroscopy (NIRS) tissue oxygenation index (TOI) after 5-min of arterial occlusion. An artificial intelligence model (AI) defined the stimulus-response relationship between the oxygen deficit (i.e., ΔTOI and TOI deficit), and RR with 65 previous PORH recordings. If the AI predicts the experimental RRs, then the change in RR is related to the change in the oxygen deficit. RR (Δ -0.27 ± 0.55 lnTOI%·s-1, P = 0.001), MMR (Δ -0.46 ± 0.61 lnTOI%·s-1, P < 0.001), ΔTOI (Δ -0.34 ± 0.62 lnTOI%, P < 0.001), and the TOI deficit (Δ -0.42 ± 0.68 lnTOI%·s, P < 0.001) were reduced after PS. In addition, strong linear associations were found between MMR and the TOI deficit (r2 = 0.900, P < 0.001) and ΔTOI (r2 = 0.871, P < 0.001). Furthermore, the AI accurately predicted the RRs pre- and post-PS (P = 0.471, P = 0.328, respectively). Therefore, blunted PORH after PS may be caused by attenuated MMR and not microvascular dysfunction.NEW & NOTEWORTHY Prolonged sitting reduces lower leg skeletal muscle metabolic rate in healthy individuals. Artificial intelligence revealed that impaired post-occlusive reactive hyperemia after prolonged sitting is related to a reduced stimulus for vasodilation and may not be evidence of microvascular dysfunction. Current post-occlusive reactive hyperemia protocols may be insufficient to assess micro- and macrovascular function after prolonged sitting.

Evaluating the Effectiveness of Intravenous Ozonated Normal Saline in the Treatment of Severe COVID-19 Disease: A randomized control trial

Background: There is still no specific treatment strategy for COVID-19 other than supportive management. The potential biological benefits of ozone therapy include reduced tissue hypoxia, decreased hypercoagulability, modulated immune function by inhibiting inflammatory mediators, improved phagocytic function, and impaired viral replication. This study aimed to evaluate the effect of intravenous ozonated normal saline on patients with severe COVID-19 disease. Methods: In this study, a single centralized randomized clinical trial was conducted on 80 hospitalized patients with severe COVID-19. The patients were selected by random allocation method and divided into two groups A and B. In group A (control group), patients were given standard drug treatment, and in group B (intervention group), patients received ozonated normal saline in addition to the standard drug treatment. In the intervention group, 400 mL of normal saline was weighed by 40 μg/ kg of body weight and was injected into patients within 15 to 30 minutes (80 to 120 drops per minute). This process was done daily every morning for a week. Primary and secondary outcomes of the disease included changes in the following items: length of hospital stay, inflammatory markers including C-reactive protein (CRP), clinical recovery, arterial blood oxygen status, improvement of blood disorders such as leukopenia and leukocytosis, duration of ventilator attachment, and rapid clearance of lung lesions on CT scans. The need for intensive care unit (ICU) hospitalization, the length of ICU stay, and the mortality rate in patients of the two groups was compared. Results: According to the results of the initial outcome variable analysis, the probability of discharge of patients who received the normal ozonated saline intervention was 33% higher than patients who did not receive this intervention; however, this relationship was not statistically significant (HR=0.67, 95%, CI=0.42-1.06, P value=0.089). The chance of ICU hospitalization in patients of the intervention group was three times more than that of the comparison group, but this relationship was not significant (odds ratio=4.4 95% CI=1.32-14.50, P value=0.016). The use of ozonated normal saline was found to increase the risk of death by 1.5 times but this relationship was not statistically significant (odds ratio=1.5, 95% CI=.24-9.75, P value=0.646). Ozonated normal saline had a significant effect on changes in respiration rate (in the intervention group the number of breaths was decreased) and the erythrocyte sedimentation rate (in the intervention group the erythrocyte sedimentation rate was increased); however, it had no significant effect on other indicators. Conclusion: The present study showed that ozone therapy in hospitalized patients with severe COVID-19 could help improve some primary and secondary outcomes of the disease. Governments and health policymakers should make ozone therapy an available care service so that the need for advanced treatment facilities decreases; consequently, this measure may improve patient safety, prevent lung tissue destruction, and control cytokine storms in patients. Additionally, health decision-makers need to aim for the effective clinical improvement of patients, especially severe ones, and the reduction of their mortality. However, further large-scale multicenter studies with larger sample sizes considering drug side effects and other variables influencing the clinical course of COVID-19 can provide more information on the effectiveness and importance of ozone therapy.

Inhibition of CXCR4 Enhances the Efficacy of Radiotherapy in Metastatic Prostate Cancer Models.

Radiotherapy (RT) is a standard treatment for patients with advanced prostate cancer (PCa). Previous preclinical studies showed that SDF1α/CXCR4 axis could mediate PCa metastasis (most often to the bones) and cancer resistance to RT. We found high levels of expression for both SDF1α and its receptor CXCR4 in primary and metastatic PCa tissue samples. In vitro analyses using PCa cells revealed an important role of CXCR4 in cell invasion but not radiotolerance. Pharmacologic inhibition of CXCR4 using AMD3100 showed no efficacy in orthotopic primary and bone metastatic PCa models. However, when combined with RT, AMD3100 potentiated the effect of local single-dose RT (12 Gy) in both models. Moreover, CXCR4 inhibition also reduced lymph node metastasis from primary PCa. Notably, CXCR4 inhibition promoted the normalization of bone metastatic PCa vasculature and reduced tissue hypoxia. In conclusion, the SDF1α/CXCR4 axis is a potential therapeutic target in metastatic PCa patients treated with RT.

MORPHOLOGICAL EVALUATION OF EFFECTIVENESS OF NECROFASCIOTOMY AND INFILTRATION WITH OZONATED SALINE AREA OF DEEP CIRCULAR BURN OF SKIN WITH UNDERLYING TISSUES COMPLICATED BY COMPARTMENT SYNDROME

Compartment syndrome is one of the complications of tissue damage of various origins, the basis of which is the compression of blood vessels and disruption of blood supply to tissues due to an increased local pressure in the closed space of the fascial sheath. The consequences of compartment syndrome can be local and general. An effective treatment of compartment syndrome in burns is to perform a necrotomy, which due to decompression helps to reduce intra−tissue pressure and diminish the scale of necrotic changes in tissues. In order to morphologically evaluate the effectiveness of necrofasciotomy, as well as the one in combination with infiltration of ozonated saline area of deep circular skin burns with underlying tissues, complicated by compartment syndrome, an experimental study was conducted. Circular deep burns, complicated by the formation of compartment syndrome, were simulated in 18 WAG rats. To reduce the pressure in the burned and surrounding tissues, surgical interventions such as necrofasciotomy were performed, which provided a notable reduction in pressure. In parallel, infiltration of damaged tissues with ozonated saline was performed, which was bubbled for 15 minutes at a dissolved ozone concentration of 4.0±0.2 mg / l, which improved microcirculation and reduced tissue hypoxia. The findings indicate that the compartment syndrome is characterized by a significant severity of general pathology. Performance of necrofasciotomy of a burn wound with its infiltration by ozonated physiological solution in comparison with just necrofasciotomy has more positive medical effect, and efficiency of these medical measures increases when they are performed at early terms (day 1) of formation of a burn wound in comparison with late terms (day 3). Key words: burns, surgical treatment, compartment syndrome, histological examinations.

Evaluation of the effectiveness of surgical elimination of gum recession using non-invasive methods of vascular wall endothelial dysfunction correction in the area of surgery

Relevance. The problem of treating gum recession has become particularly urgent due to the high incidence of the disease, as well as the increased aesthetic requirements of patients. Purpose. To increase the efficiency of surgical treatment of gum recession by using non-invasive methods of correction of vascular wall endothelial dysfunction in the area of surgery. Materials and methods . Sixty patients with gingival recession were included. They were randomly allocated in three groups based on the material used and applied methods of treatment: I group – «Mucograft», II group – «Bio-Ost MUCO Plast», III group – «Bio-Ost MUCO Plast» with THF-therapy. Sixty patients with gingival recession were included. They were randomly allocated in three groups based on the material used and applied methods of treatment: I group – «Mucograft», II group – «Bio-Ost MUCO Plast», III group – «Bio-Ost MUCO Plast» with THF-therapy. Results . The use of THF-therapy at the atmospheric oxygen frequency of 129.0 GHz allows to activate endogenous mechanisms of blood flow normalization in the area of recession, to reduce tissue hypoxia in the preoperative period, to reduce the signs of tissue inflammatory response to traumatic surgery in eliminating recession, to correct the indices of endothelial dysfunction in the preand postoperative period, to improve blood supply to the new tissue, to reduce the wound healing time. Conclusion. The spongy structure of the collagen matrix «Bio-Ost MUCO Plast» and the effect of THF-therapy at the atmospheric oxygen frequency of 129.0 GHz in the process of the treatment and rehabilitation of patients with gum recession provide improved microcirculation of the emerging tissue due to faster penetration of new vessels into the spongy framework.

Pharmacological Increase of Hb-O2 Affinity with a Voxelotor Analog Does Not Decrease Brain Tissue pO2 or Limit O2 Extraction in Brain Tissues of Sickle Cell Mice

Sickle Cell Disease (SCD) is characterized by hemolytic anemia, vaso-occlusion, and progressive end-organ damage. The underlying mechanism of SCD is the polymerization of sickle hemoglobin (HbS) that occurs when sickle erythrocytes (SS RBCs) are partially deoxygenated in microcirculation, leading to SCD pathophysiologic features. One of the most devastating complications of SCD occurs in the central nervous system (CNS), where overt stroke or repeated silent cerebral infarcts lead to significant physical and neurocognitive consequences. In SCD, the brain's response to insufficient oxygen (O2) delivery is balanced by increased blood flow to preserve O2 supply. However, the systemic endothelial dysfunction in SCD limits the capacity for vascular regulatory and compensatory changes to preserve appropriate tissue oxygenation, especially in tissues with high O2 demand like the brain. Low hemoglobin (Hb) levels and increased cerebral blood flow (CBF) are associated with increased stroke risk, suggesting that anemia-induced tissue hypoxia is an important factor contributing to subsequent morbidity in SCD patients. Voxelotor (GBT440) is a small molecule, HbS polymerization inhibitor being developed by Global Blood Therapeutics (GBT) for the treatment of SCD. By addressing the underlying mechanism of SCD, voxelotor has the potential to be disease-modifying and alleviate the clinical manifestations of SCD. Mechanistically, voxelotor increases Hb-O2 affinity and delays the transition from oxyHb to deoxyHb under hypoxic conditions. This study assessed the impact of a pharmacologically mediated increase in Hb-O2 affinity on brain tissue oxygenation under both normoxic and hypoxic conditions in Townes transgenic sickle mice (SCD mice). Two compounds that increase the Hb-O2 affinity with similar potency, voxelotor and an analog to voxelotor, GBT1118, were considered for the study. The target for Hb occupancy with test compounds was ≥30% based on the therapeutic target occupancies observed with voxelotor in clinical studies. The effects of increased Hb-O2 affinity on brain tissue oxygenation were assessed directly with O2-specific microelectrodes in a cranial window and indirectly with hypoxyprobe staining (pimonidazole) of brain tissue. Unique to this SCD model, the targeted Hb occupancy (≥30%) could not be consistently achieved by voxelotor. In contrast, repeat oral dosing of GBT1118 at 200 mg/kg/day for 2 weeks in SCD mice achieved steady state concentrations of 802 ± 81 µM (mean ± SD; n=5), corresponding to a Hb occupancy of 44 ± 5%. Consequently, GBT1118 decreased the p50 (partial pressure of O2 at which Hb is 50% saturated) values of SCD mouse blood from 39 ± 0.8 mmHg (Vehicle-dosed) to 21 ± 1.6 mmHg (GBT1118-dosed). While we could not achieve the desired Hb occupancy (≥30%) with voxelotor in this model, the Hb occupancy and change in p50 achieved with GBT1118 afforded us the opportunity to ask whether significantly increasing Hb-O2 affinity affects brain O2 tension. Measurements of cortical O2 tension (pO2) showed no difference in pO2 values under normoxia (21% O2) (Figure A), and slightly higher pO2 values under hypoxia (10% O2) (Figure B) for GBT1118-dosed SCD mice compared with vehicle-dosed SCD mice. Collectively across all brain tissues, the GBT1118-induced increase in Hb-O2 affinity reduced tissue hypoxia in SCD mice under hypoxia as measured by pimonidazole staining (Figure C). Together, these results indicate that a pharmacological increase of Hb-O2 affinity does not decrease cortical tissue pO2 in SCD mice and may reduce brain hypoxia under hypoxic conditions. Figure Disclosures Dufu: Global Blood Therapeutics: Employment, Equity Ownership. Lucas:Global Blood Therapeutics: Research Funding. Muller:Global Blood Therapeutics: Research Funding. Williams:Global Blood Therapeutics: Research Funding. Zhang:Global Blood Therapeutics: Employment, Equity Ownership. Rademacher:Global Blood Therapeutics: Employment, Equity Ownership. Alt:Global Blood Therapeutics: Employment, Equity Ownership. Oksenberg:Global Blood Therapeutics: Employment, Equity Ownership. Cabrales:Global Blood Therapeutics: Research Funding.

Endothelin receptor B affects the perfusion of newborn intestine: possible mechanism of necrotizing enterocolitis development.

Necrotizing enterocolitis (NEC) is one of the most severe gastrointestinal diseases in infancy. Hypoxia is known as one of the major risk factors for the development of NEC. Endothelin, known to regulate vasoconstriction, has two receptors (A and B). However, the role of endothelin receptor B (EDNRB) in neonatal intestinal injury remains unclear. We aimed to investigate whether EDNRB is involved in NEC pathophysiology. Following ethical approval (#44032), EDNRB hetero knockout mice pups (EDNRB±) and their wild-type (WT) littermates were studied. NEC was induced from postnatal day 5-9 (P5-P9) by hypoxia, gavage feeding of formula and administration of lipopolysaccharide. On P9, the ileum was harvested. NEC induction in WT mice was associated with mucosal injury. However, EDNRB± NEC mice had reduced mucosal injury. Similarly, EDNRB± mice had significantly lower expression of IL-6 mRNA compared to WT NEC mice. Pimonidazole immunostaining was also significantly lower in EDNRB± compared to WT NEC, suggesting reduced tissue hypoxia. Partial knockout of EDNRB results in reduced NEC severity and reduced tissue hypoxia. Intestinal perfusion and hypoxia are important elements of NEC pathogenesis. These findings are relevant to the understanding of NEC pathophysiology and to the development of novel preventive strategies for NEC.

Effects of physical exercises on inflammatory biomarkers and cardiopulmonary function in patients living with HIV: a systematic review with meta-analysis

BackgroundPro-inflammatory cytokines expressed in human immune deficiency virus (HIV) infection, may induce oxidative stress likely to compromise the patency of the airways or damage the lung tissues/cardiac function. However, physical (aerobic and/or resistance) exercise-induced release of heat shock protein, immune function alteration or reduced tissue hypoxia, have been highlighted as possible mechanisms by which increasing physical activity may reduce plasma pro-inflammatory cytokines in uninfected individuals and should be appraised in the literature for evidence of similar benefits in people living with HIV (PLWH). Therefore, we evaluated the effects of physical exercises on 1) inflammatory biomarkers and 2) cardiopulmonary function (VO2 Max) in PLWH.MethodA systematic review was conducted using the Cochrane Collaboration protocol. Searching databases, up to January 2018. Only randomized control trials investigating the effects of either aerobic or resistance or a combination of both exercise types with a control/other intervention(s) for a period of at least 4 weeks among adults living with HIV, were included. Two independent reviewers determined the eligibility of the studies. Data were extracted and risk of bias (ROB) was assessed with the Cochrane Collaboration ROB tool. Meta-analyses were conducted with random effect models using the Review Manager (RevMan) computer software.ResultTwenty-three studies met inclusion criteria (n = 1073 participants at study completion) comprising male and female with age range 18–65 years. Three meta-analyses across three sub-groups comparisons were performed. The result showed no significant change in biomarkers of inflammation (IL-6 and IL-1β) unlike a significant (Z = 3.80, p < 0.0001) improvement in VO2 Max. Overall, the GRADE evidence for this review was of moderate quality.ConclusionThere was evidence that engaging in either aerobic or resistance exercise, or a combination of both exercises, two to five times per week can lead to a significant improvement in cardiopulmonary function but not biomarkers of inflammation (IL-6 and IL-1β). However, this should not be interpreted as “No evidence of effect” because the individual trial studies did not attain sufficient power to detect treatment effects. The moderate grade evidence for this review suggests that further research may likely have an important impact on our confidence in the estimate of effects and may change the estimate.

Renal hypoxia in kidney disease: Cause or consequence?

Tissue hypoxia has been proposed as an important factor in the pathophysiology of both chronic kidney disease (CKD) and acute kidney injury (AKI), initiating and propagating a vicious cycle of tubular injury, vascular rarefaction, and fibrosis and thus exacerbation of hypoxia. Here, we critically evaluate this proposition by systematically reviewing the literature relevant to the following six questions: (i) Is kidney disease always associated with tissue hypoxia? (ii) Does tissue hypoxia drive signalling cascades that lead to tissue damage and dysfunction? (iii) Does tissue hypoxia per se lead to kidney disease? (iv) Does tissue hypoxia precede pathology? (v) Does tissue hypoxia colocalize with pathology? (vi) Does prevention of tissue hypoxia prevent kidney disease? We conclude that tissue hypoxia is a common feature of both AKI and CKD. Furthermore, at least under in vitro conditions, renal tissue hypoxia drives signalling cascades that lead to tissue damage and dysfunction. Tissue hypoxia itself can lead to renal pathology, independent of other known risk factors for kidney disease. There is also some evidence that tissue hypoxia precedes renal pathology, at least in some forms of kidney disease. However, we have made relatively little progress in determining the spatial relationships between tissue hypoxia and pathological processes (i.e. colocalization) or whether therapies targeted to reduce tissue hypoxia can prevent or delay the progression of renal disease. Thus, the hypothesis that tissue hypoxia is a "common pathway" to both AKI and CKD still remains to be adequately tested.

P309 Pulsed electromagnetic field (PEMF) improves microcirculation and reduces hypoxia and neuronal death in a hypertensive rat brain

Introduction We previously showed that pulsed electromagnetic field (PEMF) increased microvascular blood flow and tissue oxygenation by nitric oxide-induced vasodilation in a healthy rat brain ( Bragin et al., 2015 ). We also showed that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow, tissue hypoxia and blood brain barrier (BBB) degradation ( Bragin et al., 2011 ). Objectives To evaluate whether PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP. Materials and methods By in vivo 2-photon laser scanning microscopy over the rat parietal cortex, we evaluated the effects of PEMF on microvascular blood flow, tissue oxygenation (NADH), BBB permeability (dye extravasation) and neuronal necrosis (i.v. propidium Iodide) during 4 h of high ICP. Doppler cortical flux, rectal and cranial temperatures, ICP and arterial pressure, blood gases and electrolytes were monitored. After baseline imaging at normal ICP (10 mmHg), rats were subjected to high ICP (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to the cisterna magna. At ICP of 30 mmHg, PEMF was applied for 30 min and imaging continuously performed after the treatment. Controls were untreated with PEMF. Results PEMF decreased tissue hypoxia (NADH reduced by 14.6 ± 3.7% compared to control, n = 10 rats per group, mean ± SEM, p Conclusions PEMF reduced tissue hypoxia, BBB degradation and neuronal necrosis by modulating cerebral blood flow at high ICP. PEMF could be an effective treatment for high ICP after severe cerebral insults. Support Rio Grande Neurosciences.

Beneficial Role of Erythrocyte Adenosine A2B Receptor-Mediated AMP-Activated Protein Kinase Activation in High-Altitude Hypoxia.

High altitude is a challenging condition caused by insufficient oxygen supply. Inability to adjust to hypoxia may lead to pulmonary edema, stroke, cardiovascular dysfunction, and even death. Thus, understanding the molecular basis of adaptation to high altitude may reveal novel therapeutics to counteract the detrimental consequences of hypoxia. Using high-throughput, unbiased metabolomic profiling, we report that the metabolic pathway responsible for production of erythrocyte 2,3-bisphosphoglycerate (2,3-BPG), a negative allosteric regulator of hemoglobin-O2 binding affinity, was significantly induced in 21 healthy humans within 2 hours of arrival at 5260 m and further increased after 16 days at 5260 m. This finding led us to discover that plasma adenosine concentrations and soluble CD73 activity rapidly increased at high altitude and were associated with elevated erythrocyte 2,3-BPG levels and O2 releasing capacity. Mouse genetic studies demonstrated that elevated CD73 contributed to hypoxia-induced adenosine accumulation and that elevated adenosine-mediated erythrocyte A2B adenosine receptor activation was beneficial by inducing 2,3-BPG production and triggering O2 release to prevent multiple tissue hypoxia, inflammation, and pulmonary vascular leakage. Mechanistically, we demonstrated that erythrocyte AMP-activated protein kinase was activated in humans at high altitude and that AMP-activated protein kinase is a key protein functioning downstream of the A2B adenosine receptor, phosphorylating and activating BPG mutase and thus inducing 2,3-BPG production and O2 release from erythrocytes. Significantly, preclinical studies demonstrated that activation of AMP-activated protein kinase enhanced BPG mutase activation, 2,3-BPG production, and O2 release capacity in CD73-deficient mice, in erythrocyte-specific A2B adenosine receptor knockouts, and in wild-type mice and in turn reduced tissue hypoxia and inflammation. Together, human and mouse studies reveal novel mechanisms of hypoxia adaptation and potential therapeutic approaches for counteracting hypoxia-induced tissue damage.

Drag-Reducing Polymer Enhances Microvascular Perfusion in the Traumatized Brain with Intracranial Hypertension.

Current treatments for traumatic brain injury (TBI) have not focused on improving microvascular perfusion. Drag-reducing polymers (DRP), linear, long-chain, blood-soluble, nontoxic macromolecules, may offer a new approach to improving cerebral perfusion by primary alteration of the fluid dynamic properties of blood. Nanomolar concentrations of DRP have been shown to improve hemodynamics in animal models of ischemic myocardium and ischemic limb, but have not yet been studied in the brain. We recently demonstrated that DRP improved microvascular perfusion and tissue oxygenation in a normal rat brain. We hypothesized that DRP could restore microvascular perfusion in hypertensive brain after TBI. Using in vivo two-photon laser scanning microscopy we examined the effect of DRP on microvascular blood flow and tissue oxygenation in hypertensive rat brains with and without TBI. DRP enhanced and restored capillary flow, decreased microvascular shunt flow, and, as a result, reduced tissue hypoxia in both nontraumatized and traumatized rat brains at high intracranial pressure. Our study suggests that DRP could constitute an effective treatment for improving microvascular flow in brain ischemia caused by high intracranial pressure after TBI.

Hyperbaric Oxygen Therapy for Chronic Antibiotic-Refractory Ischemic Pouchitis

Hyperbaric oxygen therapy (HBOT) has been shown to be efficacious in treating various conditions including perianal Crohn's disease. Here, we present a case of a 59-year-old male with a history of UC status post proctocolectomy and 2-stage J-pouch construction. He later developed chronic antibiotic-refractory pouchitis (CARP) with endoscopic signs of ischemia, believed to be secondary to vascular compromise (Figure 1). He underwent HBOT with a total 20 sessions, at 2.5-3.0 ATA, for 60-90 minutes per session. At the completion of therapy, repeat pouchoscopy showed marked improvement of the mucosal disease (Figure 2). HBOT is known to increase tissue oxygenation, reduce tissue hypoxia, alter inflammatory pathways and promote tissue healing. This case demonstrates the therapeutic role of HBOT as well as possible disease mechanism in chronic antibioticrefractory pouchitis.Figure 1Figure 2

Blockade of MMP14 activity in murine breast carcinomas: implications for macrophages, vessels, and radiotherapy.

Matrix metalloproteinase (MMP) 14 may mediate tumor progression through vascular and immune-modulatory effects. Orthotopic murine breast tumors (4T1 and E0771 with high and low MMP14 expression, respectively; n = 5-10 per group) were treated with an anti-MMP14 inhibitory antibody (DX-2400), IgG control, fractionated radiation therapy, or their combination. We assessed primary tumor growth, transforming growth factor β (TGFβ) and inducible nitric oxide synthase (iNOS) expression, macrophage phenotype, and vascular parameters. A linear mixed model with repeated observations, with Mann-Whitney or analysis of variance with Bonferroni post hoc adjustment, was used to determine statistical significance. All statistical tests were two-sided. DX-2400 inhibited tumor growth compared with IgG control treatment, increased macrophage numbers, and shifted the macrophage phenotype towards antitumor M1-like. These effects were associated with a reduction in active TGFβ and SMAD2/3 signaling. DX-2400 also transiently increased iNOS expression and tumor perfusion, reduced tissue hypoxia (median % area: control, 20.2%, interquartile range (IQR) = 6.4%-38.9%; DX-2400: 1.2%, IQR = 0.2%-3.2%, P = .044), and synergistically enhanced radiation therapy (days to grow to 800mm(3): control, 12 days, IQR = 9-13 days; DX-2400 plus radiation, 29 days, IQR = 26-30 days, P < .001) in the 4T1 model. The selective iNOS inhibitor, 1400W, abolished the effects of DX-2400 on vessel perfusion and radiotherapy. On the other hand, DX-2400 was not capable of inducing iNOS expression or synergizing with radiation in E0771 tumors. MMP14 blockade decreased immunosuppressive TGFβ, polarized macrophages to an antitumor phenotype, increased iNOS, and improved tumor perfusion, resulting in reduced primary tumor growth and enhanced response to radiation therapy, especially in high MMP14-expressing tumors.

Characterization of a Novel Necrotic Granuloma Model of Latent Tuberculosis Infection and Reactivation in Mice

We sought to develop and characterize a novel paucibacillary model in mice, which develops necrotic lung granulomas after infection with Mycobacterium tuberculosis. Six weeks after aerosol immunization with recombinant Mycobacterium bovis bacillus Calmette-Guerin overexpressing the 30-kDa antigen, C3HeB/FeJ mice were aerosol infected with M. tuberculosis H37Rv. Six weeks later, mice were treated with one of three standard regimens for latent tuberculosis infection or tumor necrosis factor (TNF)-neutralizing antibody. Mouse lungs were analyzed by histological features, positron emission tomography/computed tomography, whole-genome microarrays, and RT-PCR. Lungs and sera were studied by multiplex enzyme-linked immunosorbent assays. Paucibacillary infection was established, recapitulating the sterilizing activities of human latent tuberculosis infection regimens. TNF neutralization led to increased lung bacillary load, disrupted granuloma architecture with expanded necrotic foci and reduced tissue hypoxia, and accelerated animal mortality. TNF-neutralized mouse lungs and sera showed significant up-regulation of interferon γ, IL-1β, IL-6, IL-10, chemokine ligands 2 and 3, and matrix metalloproteinase genes. Clinical and microbiological reactivation of paucibacillary infection by TNF neutralization was associated with reduced hypoxia in lung granulomas and induction of matrix metalloproteinases and proinflammatory cytokines. This model may be useful for screening the sterilizing activity of novel anti-tuberculosis drugs, and identifying mycobacterial regulatory and metabolic pathways required for bacillary growth restriction and reactivation.

Abstract W P197: Pulsed Electromagnetic Field Attenuates High Intracranial Pressure Induced Microvascular Shunting in Rats

Introduction: We previously reported that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow associated with tissue hypoxia and increased blood brain barrier (BBB) permeability. We also showed that pulsed electromagnetic field (PEMF) increases blood flow velocity and tissue oxygenation in the normal rat brain. We hypothesized that PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP. Methods: Using in vivo 2-photon laser scanning microscopy (2PLSM) over the rat parietal cortex, we studied the effects of PEMF on microvascular blood flow velocity, tissue oxygenation (NADH) and BBB permeability (dye extravasation) before and during 4 hours of elevated ICP. Doppler cortical flow, rectal and cranial temperatures, intracranial and arterial pressures, blood gases and electrolytes were monitored. After baseline imaging at normal ICP (10 mmHg), rats were subjected to intracranial hypertension (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to a catheter in the cisterna magna. After control recording at high ICP of 30 mmHg, PEMF was applied for 30 min and imaging was continuously performed for up to 4 hours after the treatment. In control animals PEMF was not applied. Results: PEMF treatment reduced tissue hypoxia as reflected by a decrease in NADH by 14.6±3.7% (n=7 rats per group, mean ± SEM, p&lt;0.05). BBB permeability was also reduced as reflected by reduction of dye extravasation by 17.2±5.4% (p&lt;0.05). This effect was consistent with dilation of arterioles (+4.5±3.2%) and an increase in capillary blood flow velocity (+4.7±3.2%). PEMF did not completely mitigated the gradual increase in MVS flow at high ICP but, as reflected by MVS/capillary ratio, the transition to non-nutritive flow over 4 hours was less steep in the PEMF treated rats compared to the untreated (2.3±1.1 and 3.8±2.1% change per hour, respectively, p&lt;0.05). Conclusions: PEMF reduces tissue hypoxia and BBB degradation by modulating cerebral blood flow topography at intracranial hypertension in a rat brain. PEMF could be an effective treatment for intracranial hypertension after severe cerebral insults.

Lactate and Venoarterial Carbon Dioxide Difference/Arterial-Venous Oxygen Difference Ratio, but Not Central Venous Oxygen Saturation, Predict Increase in Oxygen Consumption in Fluid Responders*

During circulatory failure, the ultimate goal of treatments that increase cardiac output is to reduce tissue hypoxia. This can only occur if oxygen consumption depends on oxygen delivery. We compared the ability of central venous oxygen saturation and markers of anaerobic metabolism to predict whether a fluid-induced increase in oxygen delivery results in an increase in oxygen consumption. Prospective study. ICU. Fifty-one patients with an acute circulatory failure (78% of septic origin). Before and after a volume expansion (500 mL of saline), we measured cardiac index, o2- and Co2-derived variables and lactate. Volume expansion increased cardiac index ≥ 15% in 49% of patients ("volume-responders"). Oxygen delivery significantly increased in these 25 patients (+32% ± 16%, p < 0.0001). An increase in oxygen consumption ≥ 15% concomitantly occurred in 56% of these 25 volume-responders (+38% ± 28%). Compared with the volume-responders in whom oxygen consumption did not increase, the volume-responders in whom oxygen consumption increased ≥ 15% were characterized by a higher lactate (2.3 ± 1.1 mmol/L vs. 5.5 ± 4.0 mmol/L, respectively) and a higher ratio of the veno-arterial carbon dioxide tension difference (P(v - a)Co2) over the arteriovenous oxygen content difference (C(a - v)o2). A fluid-induced increase in oxygen consumption greater than or equal to 15% was not predicted by baseline central venous oxygen saturation but by high baseline lactate and (P(v - a)Co2/C(a - v)o2 ratio (areas under the receiving operating characteristics curves: 0.68 ± 0.11, 0.94 ± 0.05, and 0.91 ± 0.06). In volume-nonresponders, volume expansion did not significantly change cardiac index, but the oxygen delivery decreased due to a hemodilution-induced decrease in hematocrit. In volume-responders, unlike markers of anaerobic metabolism, central venous oxygen saturation did not allow the prediction of whether a fluid-induced increase in oxygen delivery would result in an increase in oxygen consumption. This suggests that along with indicators of volume-responsiveness, the indicators of anaerobic metabolism should be considered instead of central venous oxygen saturation for starting hemodynamic resuscitation.

Design, Manufacture, Mechanical Testing and Clinical/Mri Assessment of the Medical Elastic Compression Stockings, Base on Taiwanese’s Leg Size

Chronic Venous Insufficiency (CVI) in the lower limb is commonly associated with varicose veins. In Asian countries, demand has increased for Medical Elastic Compression Stockings (MECS) as conservative treatment for varicose veins and CVI; however, their efficacy requires further investigation. The legs of 726 Taiwanese participants were measured, and MECS were designed and manufactured accordingly. Manufacturing processes included “fixation of the elastic fiber,” “design of the fabric,” “application of techniques for high-pressure stockings,” and “application of techniques for configuration.” Further techniques used for the production of functional MECS included “elastic yarn composite techniques,” “incremental pressure fabric weaving,” and “pressure shaping of fabrics.” Parameters for the mechanical testing of MECS included size measurement, extensibility, practical elongation, compression, and residual pressure on corresponding points of the leg. Clinical assessments and Magnetic Resonance Imaging (MRI) analyses using noncontract-enhanced Magnetic Resonance Venous (MRV) techniques were also performed on 100 participants with varicose veins pre-and post-MECS use. The average circumferences and lengths of specific points of the lower legs of the 726 participants were smaller than U.S. measurements by approximately 12% to 19%. This suggested that Taiwanese - and possibly Asian - MECS should not be manufactured according to Western sizes. Subjective clinical questionnaire results included relief of symptoms of heaviness of the legs, spasticity in the evenings, and convulsion during sleep. According to MRV analyses, deep venous blood flow increased significantly (relief of high pressure), and available hemoglobin in the deep vein increased (reduced tissue hypoxia) post-MECS use. Our findings provide important reference material for the establishment of Taiwanese and Asian standards for MECS. Results from clinical and MRV analyses confirmed the efficacy of prolonged use of MECS, with results indicating that 4 h/d and 112 h of use is sufficient to improve deep venous insufficiency.