Pulmonary Blood Flow Increases in Damaged Regions Directly after Acid Aspiration in Rats

Richter, Torsten; Bergmann, Ralf; Knels, Lilla; Hofheinz, Frank; Kasper, Michael; Deile, Martin; Pietzsch, Jens; Ragaller, M.; Koch, Thea

doi:10.1097/aln.0b013e3182a17e5b

Cited by 13 publications

(23 citation statements)

References 37 publications

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“…The latter observation is likely caused by greatly increased pyruvate levels in the hyperperfused lungs as shown in Figures and . This supposition is supported by earlier findings that showed an increased lung permeability index and an increased pulmonary blood flow using PET . Despite significant variability among the cohorts' lactate‐to‐pyruvate ratio trends during injury progression, a combination of the lactate‐to‐pyruvate ratio with lung compliance provides a reliable means to separate the cohorts at the third injection time point.…”

Section: Discussionsupporting

confidence: 66%

“…To explain this discrepancy, we postulate that locally increased pyruvate concentration, rather than decreased lactate production, was responsible for the low lactate‐to‐pyruvate in severely injured rats. The increased pyruvate concentration is caused by the retention of hyperpolarized pyruvate in the extracellular space of edematous lungs .…”

Section: Discussionmentioning

confidence: 99%

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In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

Pourfathi

Xin

Kadlecek

et al. 2017

Magnetic Resonance in Med

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Purpose To investigate pulmonary metabolic alterations during progression of acute lung injury. Methods Using hyperpolarized [1-13C] pyruvate imaging, we measured pulmonary lactate and pyruvate in fifteen ventilated rats one, two and four hours after initiation of mechanical ventilation. Lung compliance was used as a marker for injury progression. Five untreated rats were used as controls; five rats (injured-1) received 1 ml/kg and another five rats (injured-2) received 2 ml/kg hydrochloric acid (pH 1.25) in the trachea at 70 minutes. Results The mean lactate-to-pyruvate ratio of the injured-1 cohort was 0.15±0.02 and 0.15±0.03 at baseline and one hour after the injury, and significantly increased from the baseline value three hours after the injury to 0.23±0.02 (p=0.002). The mean lactate-to-pyruvate ratio of the injured-2 cohort decreased from 0.14±0.03 at baseline to 0.08±0.02 one hour after the injury and further decreased to 0.07±0.02 (p=0.08) three hours after injury. No significant change was observed in the control group. Compliance in both injured groups decreased significantly after the injury (p<0.01). Conclusion Our findings suggest that in severe cases of lung injury, edema and hyperperfusion in the injured lung tissue may complicate interpretation of the pulmonary lactate-to-pyruvate ratio as a marker of inflammation. However, combining the lactate-to-pyruvate ratio with pulmonary compliance provides more insight into the progression of the injury and its severity.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

Pourfathi

Xin

Kadlecek

et al. 2017

Magnetic Resonance in Med

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“…These results indicate that the hemodynamic changes observed in the regional pulmonary artery during lung consolidation are complex. However, this phenomenon was consistent with the increased pulmonary blood flow observed in the damaged regions of an ARDS rat model induced directly by acid aspiration because the relaxing factors released from the damaged alveoli limit hypoxic pulmonary vasoconstriction [57–59]. …”

Section: Introductionsupporting

confidence: 70%

Lung ultrasound: a promising tool to monitor ventilator-associated pneumonia in critically ill patients

Wang

et al. 2016

Crit Care

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Ventilator-associated pneumonia (VAP) is the most frequent intensive care unit (ICU)-acquired infection that is independently associated with mortality. Accurate diagnosis and timely treatment have been shown to improve the prognosis of VAP. Chest X-ray or computed tomography imaging are used for conventional assessment of VAP, but these methods are impractical for real-time measurement in critical patients. Therefore, lung ultrasound (LUS) has been increasingly used for the assessment of VAP in the ICU. Traditionally, LUS has seemed unsuitable for the detection of lung parenchyma owing to the high acoustic impedance of air; however, the fact that the reflection and reverberation in the detection region of the ultrasound reflect the underlying pathology of lung diseases has led to the increased use of ultrasound imaging as a standard of care supported by evidence-based and expert consensus in the ICU. Considering that any type of pneumonia causes air volume changes in the lungs, accumulating evidence has shown that LUS effectively measures the presence of VAP as well as dynamic changes in VAP. This review offers evidence for ultrasound as a noninvasive, easily repeatable, and bedside means to assess VAP; in addition, it establishes a protocol for qualitative and quantitative monitoring of VAP.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1487-y) contains supplementary material, which is available to authorized users.

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“…However, it has been shown that pulmonary blood flow increases significantly following acute lung injury [32], and in hyperpolarized pyruvate experiments performed by our group (data not shown) significantly increased pyruvate signal in uninjured regions of the lung was observed following acute injury to other parts of the lung. Given these observations, we believe that significantly higher hyperpolarized signal should be present in all regions of the lungs despite the injury being heterogeneously distributed.…”

Section: Discussionmentioning

confidence: 56%

In vivo pH mapping of injured lungs using hyperpolarized [1‐¹³C]pyruvate

Drachman

Kadlecek

Pourfathi

et al. 2016

Magnetic Resonance in Med

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Purpose To optimize the production of hyperpolarized 13C-bicarbonate from the decarboxylation of hyperpolarized [1-13C]pyruvate and use it to image pH in the lungs and heart of rats with acute lung injury. Methods Two forms of catalysis are compared calorimetrically to maximize the reaction rate of decarboxylation and rapidly produce hyperpolarized bicarbonate from pyruvate while minimizing signal loss. Rats are injured using an acute lung injury model combining VILI and acid aspiration. Carbon images are obtained from both healthy (n=4) and injured (n=4) rats using a slice-selective CSI sequence with low flip angle. pH is calculated from the relative HCO3− and CO2 signals using the Henderson-Hasselbalch equation. Results It is demonstrated that base-catalysis is more effective than metal-ion catalysis for this decarboxylation reaction. Bicarbonate polarizations up to 17.2% are achieved using the base-catalyzed reaction. A mean pH difference between lung and heart of 0.14 pH units is measured in the acute lung injury model. A significant pH difference between injured and uninjured lungs is also observed. Conclusions It is demonstrated that hyperpolarized 13C-bicarbonate can be efficiently produced from the base-catalyzed decarboxylation of pyruvate. This method is used to obtain the first regional pH image of the lungs and heart of an animal.

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Pulmonary Blood Flow Increases in Damaged Regions Directly after Acid Aspiration in Rats

Abstract: The data suggest that 10 min after acid aspiration, damaged areas are characterized by increased pulmonary blood flow. The results may impact further treatment strategies, such as drug targeting.

Cited by 13 publications

References 37 publications

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

Lung ultrasound: a promising tool to monitor ventilator-associated pneumonia in critically ill patients

In vivo pH mapping of injured lungs using hyperpolarized [1‐¹³C]pyruvate

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Pulmonary Blood Flow Increases in Damaged Regions Directly after Acid Aspiration in Rats

Abstract: The data suggest that 10 min after acid aspiration, damaged areas are characterized by increased pulmonary blood flow. The results may impact further treatment strategies, such as drug targeting.

Cited by 13 publications

References 37 publications

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐13C] pyruvate

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐13C] pyruvate

Lung ultrasound: a promising tool to monitor ventilator-associated pneumonia in critically ill patients

In vivo pH mapping of injured lungs using hyperpolarized [1‐13C]pyruvate

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Product

Resources

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In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

In vivo imaging of the progression of acute lung injury using hyperpolarized [1‐¹³C] pyruvate

In vivo pH mapping of injured lungs using hyperpolarized [1‐¹³C]pyruvate