Ultrastructural changes in tracheobronchial epithelia following experimental traumatic brain injury in rats: protective effect of erythropoietin

Study of the Safety of Extracorporeal Cardiac Shock Wave Therapy: Observation of the Ultrastructures in Myocardial Cells by Transmission Electron Microscopy

Extracorporeal cardiac shock wave therapy (CSWT) has been used to treat patients with severe coronary heart disease and cardiac failure with good results; however, the safety of this treatment is still controversial. Its safety in clinical setting and on microstructures has been confirmed, but the influence of shock wave on the ultrastructures of myocardial cells is not clear. In this study, 12 Sprague-Dawley rats were randomly divided into control (NC) and CSWT therapy (NC+SW) groups. The heart rate, blood pressure, serum troponin I (TNI), and cardiac ultrasound were evaluated, and the myocardial inflammatory responses and fibrosis changes were compared. The samples were observed by transmission electron microscopy to evaluate the changes in myocardial tissue ultrastructure. The CSWT had no significant influence on rat hemodynamics indices and serum TNI, did not affect left ventricular function, and did not cause myocardial inflammatory response and fibrosis changes. The scores of myocardial ultrastructure damage in the NC and NC+SW groups were 1.39 ± 0.982 and 2.42 ± 1.009, respectively ( P = .103). The CSWT did not cause significant additional damage to myocardial ultrastructures. The safety of CWST has been preliminarily proved at the clinical, microstructure, and ultrastructure levels, but its long-term safety needs further exploration.

Acute brain trauma, lung injury, and pneumonia: more than just altered mental status and decreased airway protection

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Even when patients survive the initial insult, there is significant morbidity and mortality secondary to subsequent pulmonary edema, acute lung injury (ALI), and nosocomial pneumonia. Whereas the relationship between TBI and secondary pulmonary complications is recognized, little is known about the mechanistic interplay of the two phenomena. Changes in mental status secondary to acute brain injury certainly impair airway- and lung-protective mechanisms. However, clinical and translational evidence suggests that more specific neuronal and cellular mechanisms contribute to impaired systemic and lung immunity that increases the risk of TBI-mediated lung injury and infection. To better understand the cellular mechanisms of that immune impairment, we review here the current clinical data that support TBI-induced impairment of systemic and lung immunity. Furthermore, we also review the animal models that attempt to reproduce human TBI. Additionally, we examine the possible role of damage-associated molecular patterns, the chlolinergic anti-inflammatory pathway, and sex dimorphism in post-TBI ALI. In the last part of the review, we discuss current treatments and future pharmacological therapies, including fever control, tracheostomy, and corticosteroids, aimed to prevent and treat pulmonary edema, ALI, and nosocomial pneumonia after TBI.

Neuropulmonology

Neuropulmonology refers to the complex interconnection between the central nervous system and the respiratory system. Neurologic injury includes traumatic brain injury, hemorrhage, stroke, and seizures, and in each there are far-reaching effects that can result in pulmonary dysfunction. Systemic changes can induce impairment of pulmonary function due to changes in the core structure and function of the lung. The conditions and disorders that often occur in these patients include aspiration pneumonia, neurogenic pulmonary edema, and acute respiratory distress syndrome, but also several abnormal respiratory patterns and sleep-disordered breathing. Lung infections, pulmonary edema - neurogenic or cardiogenic - and pulmonary embolus all are a serious barrier to recovery and can have significant effects on outcomes such as hospital course, prognosis, and mortality. This review presents the spectrum of pulmonary abnormalities seen in neurocritical care.

Brain-lung crosstalk: Implications for neurocritical care patients

Major pulmonary disorders may occur after brain injuries as ventilator-associated pneumonia, acute respiratory distress syndrome or neurogenic pulmonary edema. They are key points for the management of brain-injured patients because respiratory failure and mechanical ventilation seem to be a risk factor for increased mortality, poor neurological outcome and longer intensive care unit or hospital length of stay. Brain and lung strongly interact via complex pathways from the brain to the lung but also from the lung to the brain. Several hypotheses have been proposed with a particular interest for the recently described “double hit” model. Ventilator setting in brain-injured patients with lung injuries has been poorly studied and intensivists are often fearful to use some parts of protective ventilation in patients with brain injury. This review aims to describe the epidemiology and pathophysiology of lung injuries in brain-injured patients, but also the impact of different modalities of mechanical ventilation on the brain in the context of acute brain injury.

[Interaction brain-lungs]

The brain and the lungs interact early and rapidly when hit by a disease process. Often well tolerated by the healthy brain, an impaired respiratory function may deteriorate further a "sick" brain. Hypoxemia is a prognostic factor in the brain-injured patients. At the opposite, an acute brain damage early impacts the lung function. Local brain inflammation spreads rapidly to the lung. It initiates an immunological process weakening the lungs and increasing its susceptibility to infection and mechanical ventilation. Sometimes this process is preceded by a swelling lesion, known as neurogenic pulmonary oedema, resulting from an sympathetic overstimulation which usually follows an intense and brutal surge of intracranial pressure. The management of brain-injured patients has to be directed toward the protection of both the brain and lung. Neuronal preservation is crucial, because of the lack of regenerative potential in the brain, unlike the lung. A compromise must be obtained between the cerebral and pulmonary treatments although they may conflict in some situations.

Local administration of chitosan microspheres after traumatic brain injury in rats: a new challenge for cyclosporine--a delivery

The major aim of this study was to evaluate the efficiency of chitosan microspheres containing cyclosporine-A (Cs-A) on mitochondrial damage in traumatic brain injury (TBI) animal model. Trauma was introduced to male Sprague-Dawley (SD) rats similar to that of modified Feeney Method. Briefly, after craniectomy in the left parietal region (5 mm). Trauma was performed by dropping 24 g metal sterile rods through a teflon guide tube (9.3 cm) on a foot plate placed over the duramater. Just after the trauma, 20 mg/kg Cs-A (Sandimmune) has been administered to the traumatised SD rats intraperitoneally (i.p.). On the other hand, only chitosan microspheres containing 10 mg/kg was implanted at the craniectomy area locally after trauma in Group E. A small piece of surgicell was placed over the craniectomy hole and the scalp incision was sutured. 24 h after injury and the brain tissues were removed intact. The results were evaluated through lipid peroxidation ratio and ultrastructural grading system. The statistical comparisons were evaluated by using Mann Whitney- U test at the significance level p = 0.05. The lipid peroxidation ratios of sham (78.4  +/-  6.0 nmol/g tissue) and vehicle (80.2  +/- 10.6 nmol/g tissue) were significantly increased 24 h after TBI. However, for treatment groups (i.p. Cs-A; 20 mg/kg) and (10 mg/kg Cs-A in microspheres), statistically significant lower lipid peroxidation ratios were determined as 53.5  +/- 9.7 and 47.9  +/- 8.1 nmol/g tissue, respectively (p < 0.05). The mitochondrial damage scores of the treatment groups were recorded as 21.7  +/-2.6 and 19.4  +/- 3.9 for Group D and Group E, respectively. Both of these scores of the treatment groups were found as significantly different from the sham and vehicle groups' scores individually. The implantation of microsphere formulation has provided a better efficiency in keeping the uniformity of mitochondrial structure in this complex cascade of events after TBI.

Early physiological and biological features in three animal models of induced acute lung injury

INTRODUCTION

Critically ill patients often develop acute lung injury (ALI) in the context of different clinical conditions. We aimed to explore differences in early local and systemic features in three experimental animal models of ALI.

METHODS

Mechanically ventilated male Sprague-Dawley rats were randomized to high tidal volume (VT) ventilation (HVT) (n = 8, VT 24 ml/kg), massive brain injury (MBI) (n = 8, VT 8 ml/kg) or endotoxemia (LPS) (n = 8, VT 8 ml/kg). Each experimental group had its own control group of eight rats (VT 8 ml/kg). We measured arterial blood gases, mean arterial pressure, lung compliance, inflammatory mediators in plasma and their expression and gelatinase activity in the lungs after 3 h of injury.

RESULTS

Despite maintaining relatively normal lung function without evidence of important structural changes, we observed altered lung and systemic inflammatory responses in all three experimental models. LPS triggered the most robust inflammatory response and HVT the lowest systemic proinflammatory response. The HVT group had higher Il6, Tnf and Cxcl2 mRNA in lungs than MBI animals. Metalloproteinase activity/expression and neutrophilic recruitment in the lungs were higher in HVT than in LPS or MBI.

CONCLUSIONS

The early responses to direct or remote lung insult in our three models of ALI captured different physiological and biological features that could lead to respiratory and/or multiorgan failure.

Erythropoietin attenuates ischemia-reperfusion induced lung injury by inhibiting tumor necrosis factor-alpha and matrix metalloproteinase-9 expression

Erythropoietin (Epo) was recently defined as an endogenous agent with more than hematopoietic functions. Previously we explored the potential of this agent to ameliorate lung ischemia-reperfusion (I/R) injury. The present study aims to determine the optimal dose and timing of administration for improving lung injury, and to further investigate the mechanisms by which Epo ameliorates lung I/R injury. The left lungs of Sprague-Dawley rats underwent 90 min ischemia and 120 min reperfusion. Firstly, animals in different groups were intraperitoneally injected with various doses of recombined human erythropoietin (rhEpo) 24 h prior to operation, 2 h prior to operation, or after the onset of reperfusion. Pulmonary myeloperoxidase (MPO) activity and malondialdehyde (MDA) content were evaluated. Treatment with 3 KU/kg rhEpo 2 h prior to operation was optimal for attenuating pulmonary MPO activity and MDA content. With such treatment, ultrastructural changes of pneumocytes were observed, and the pneumocyte apoptosis index was also determined by terminal dUTP nick-end labeling method. The plasma concentrations of tumor necrosis factor (TNF)-alpha and matrix metalloproteinase (MMP)-9 were evaluated by enzyme-linked immunosorbent assay, and pulmonary expression by immunohistochemistry. When pretreated with rhEpo, the pneumocyte ultrastructure was predominantly maintained and the pulmonary apoptosis index was markedly reduced. In comparison with untreated animals, in treated animals the plasma concentrations of TNF-alpha and MMP-9 were significantly decreased, and their expression in lung tissue was markedly reduced as well. The results indicated that Epo potently protected against lung I/R injury by inhibiting systemic and local expression of TNF-alpha and MMP-9.

Erythropoietin attenuates lung injury in lipopolysaccharide treated rats

BACKGROUND

Erythropoietin (EPO) elicits protective effects in lung ischemia-reperfusion, hyperoxia, acute necrotizing pancreatitis, and some other tissues. In the present study, we investigated the possible protective roles of EPO in the lipopolysaccharide (LPS) induced lung injury.

MATERIALS AND METHODS

Male Sprague-Dawley rats were treated with EPO (3000 U/kg, i.p.) or vehicle (saline), 30 min prior to LPS administration (6 mg/kg, i.v.). Four h following LPS injection, samples of pulmonary tissue were collected. Optical microscopy was performed to examine pathological changes in lungs. Validated methods were used to measure wet/dry ratios (W/D), myeloperoxidase (MPO) activity, malondialdehyde (MDA) concentrations, and nitrite/nitrate (NO(2)(-)/NO(3)(-)) levels in lungs. Western blotting was performed to study the pulmonary expression of inducible nitric oxide synthase (iNOS) and nitrotyrosine protein.

RESULTS

Pretreatment with EPO led to (1) significant attenuation of endotoxemia induced evident lung histologic injury and edema; (2) inhibition of LPS mediated induction in MPO activity and MDA concentration; (3) inhibition of LPS mediated overproduction of pulmonary NO(2)(-)/NO(3)(-) levels; and (4) marked suppression in endotoxin induced expression of iNOS and nitrotyrosine.

CONCLUSIONS

This study provides considerable evidence that EPO has an ability to significantly attenuate endotoxin-induced acute lung injury in rats.

Protective effects of erythropoietin against acute lung injury in a rat model of acute necrotizing pancreatitis

AIM

To investigate the effect of exogenous erythro-poietin (EPO) administration on acute lung injury (ALI) in an experimental model of sodium taurodeoxycholate- induced acute necrotizing pancreatitis (ANP).

METHODS

Forty-seven male Wistar albino rats were randomly divided into 7 groups: sham group (n = 5), 3 ANP groups (n = 7 each) and 3 EPO groups (n = 7 each). ANP was induced by retrograde infusion of 5% sodium taurodeoxycholate into the common bile duct. Rats in EPO groups received 1000 U/kg intramuscular EPO immediately after induction of ANP. Rats in ANP groups were given 1 mL normal saline instead. All animals were sacrificed at postoperative 24 h, 48 h and 72 h. Serum amilase, IL-2, IL-6 and lung tissue malondialdehyde (MDA) were measured. Pleural effusion volume and lung/body weight (LW/BW) ratios were calculated. Tissue levels of TNF-alpha, IL-2 and IL-6 were screened immunohistochemically. Additionally, ox-LDL accumulation was assessed with immune-fluorescent staining. Histopathological alterations in the lungs were also scored.

RESULTS

The mean pleural effusion volume, calculated LW/BW ratio, serum IL-6 and lung tissue MDA levels were significantly lower in EPO groups than in ANP groups. No statistically significant difference was observed in either serum or tissue values of IL-2 among the groups. The level of tumor necrosis factor-alpha (TNF-alpha) and IL-6 and accumulation of ox-LDL were evident in the lung tissues of ANP groups when compared to EPO groups, particularly at 72 h. Histopathological evaluation confirmed the improvement in lung injury parameters after exogenous EPO administration, particularly at 48 h and 72 h.

CONCLUSION

EPO administration leads to a significant decrease in ALI parameters by inhibiting polymorphonuclear leukocyte (PMNL) accumulation, decreasing the levels of proinflammatory cytokines in circulation, preserving microvascular endothelial cell integrity and reducing oxidative stress-associated lipid peroxidation and therefore, can be regarded as a cytoprotective agent in ANP-induced ALI.

Bench-to-bedside review: brain-lung interaction in the critically ill--a pending issue revisited

Brain and/or lung injury is the most frequent cause of admission to critical care units and patients in this setting frequently develop multiple organ dysfunction with high rates of morbidity and mortality. Mechanical ventilation is commonly used in the management of these critically ill patients and the consequent inflammatory response, together with other physiological factors, is also thought to be involved in distal organ dysfunction. This peripheral imbalance is based on a multiple-pathway cross-talk between the lungs and other organs, including the brain. Interestingly, acute respiratory distress syndrome survivors frequently present some cognitive deterioration at discharge. Such neurological dysfunction might be a secondary marker of injury and the neuroanatomical substrate for downstream impairment of other organs. Brain-lung interactions have received little attention in the literature, but recent evidence suggests that both the lungs and brain are promoters of inflammation through common mediators. This review addresses the current status of evidence regarding brain-lung interactions, their pathways and current interventions in critically ill patients receiving mechanical ventilation.

Ultrastructural changes, nuclear factor-kappaB activation, and tumor necrosis factor-alpha expression in brain after acute normovolemic hemodilution and controlled hypotension in rats

AIM

To examine brain damage following different degrees of acute normovolemic hemodilution combined with controlled hypotension (ANH-CH) by neuronal morphological analysis and investigate the expression of nuclear factor-kappa B (NF-kappaB) activity and tumor necrosis factor-alpha (TNF-alpha) in the rat.

METHODS

Forty rats were randomly assigned to receive a sham operation or ANH-CH (with hematocrit 30%, 25%, 20%, and 15%). ANH was performed after baseline physiological parameters had been monitored for 20 minutes. CH was induced 30 minutes later using sodium nitroprusside and mean arterial pressure was maintained at 50-60 mm Hg for 1 hour. Rats were euthanatized 3 and a half hours after operation. TNF-alpha levels and NF-kappaB activities in cerebral temporal cortex were measured. Ultrastructural alterations in the CA1 region of the rat hippocampi were observed. Changes in mitochondria were evaluated semiquantitatively.

RESULTS

Marked ultrastructural alterations, such as mitochondrial denaturalization and nucleus distortion, were observed in the CA1 region of the hippocampus in the ANH-CH hematocrit 20% group and ANH-CH hematocrit 15% group. TNF-alpha expression and NF-kappaB activity in the cerebral temporal cortex significantly increased in all ANH-CH groups and peaked in the ANH-CH hematocrit 25% group.

CONCLUSION

Severe ANH-CH with hematocrit < or =20% may induce cerebral damage and should be avoided. NF-kappaB activation and TNF-alpha expression may play a functional role under the ischemic condition. A better understanding of the role of NF-kappaB and TNF-alpha in the brain may lead to a novel approach for preventing and treating various neurological disorders.

Protective effects of erythropoietin against acute lung injury in a rat model of acute necrotizing pancreatitis

AIM: To investigate the effect of exogenous erythro-poietin (EPO) administration on acute lung injury (ALI) in an experimental model of sodium taurodeoxycholate-induced acute necrotizing pancreatitis (ANP).

METHODS: Forty-seven male Wistar albino rats were randomly divided into 7 groups: sham group (n = 5), 3 ANP groups (n = 7 each) and 3 EPO groups (n = 7 each). ANP was induced by retrograde infusion of 5% sodium taurodeoxycholate into the common bile duct. Rats in EPO groups received 1000 U/kg intramuscular EPO immediately after induction of ANP. Rats in ANP groups were given 1 mL normal saline instead. All animals were sacrificed at postoperative 24 h, 48 h and 72 h. Serum amilase, IL-2, IL-6 and lung tissue malondialdehyde (MDA) were measured. Pleural effusion volume and lung/body weight (LW/BW) ratios were calculated. Tissue levels of TNF-α, IL-2 and IL-6 were screened immunohistochemically. Additionally, ox-LDL accumulation was assessed with immune-fluorescent staining. Histopathological alterations in the lungs were also scored.

RESULTS: The mean pleural effusion volume, calculated LW/BW ratio, serum IL-6 and lung tissue MDA levels were significantly lower in EPO groups than in ANP groups. No statistically significant difference was observed in either serum or tissue values of IL-2 among the groups. The level of tumor necrosis factor-α (TNF-α) and IL-6 and accumulation of ox-LDL were evident in the lung tissues of ANP groups when compared to EPO groups, particularly at 72 h. Histopathological evaluation confirmed the improvement in lung injury parameters after exogenous EPO administration, particularly at 48 h and 72 h.

CONCLUSION: EPO administration leads to a significant decrease in ALI parameters by inhibiting polymorphonuclear leukocyte (PMNL) accumulation, decreasing the levels of proinflammatory cytokines in circulation, preserving microvascular endothelial cell integrity and reducing oxidative stress-associated lipid peroxidation and therefore, can be regarded as a cytoprotective agent in ANP-induced ALI.

Brain damage following severe acute normovolemic hemodilution in combination with controlled hypotension in rats

BACKGROUND AND AIM

The reduced oxygen content and perfusion pressure during acute normovolemic hemodilution (ANH) and controlled hypotension (CH) raise concerns about hypoperfusion and ischemic injury to the brain. In this study on rats, we examined the brain damage following four different degrees of ANH combined with CH.

METHODS

Forty rats were randomly assigned to receive a sham operation or CH and ANH [with a hematocrit (Hct) of 30, 25, 20 or 15%]. ANH was performed after baseline physiological parameters had been monitored for 20 min; 30 min later, CH was induced using sodium nitroprusside, and the mean arterial blood pressure was maintained at 50-60 mmHg for 1 h. Rats were killed 3.5 h after hemodilution. Ultrastructural alterations in the CA1 region of the rat hippocampus were observed, and serum concentrations of S100B and neuron-specific enolase (NSE) were measured before and after ANH.

RESULTS

The serum S100B concentration increased significantly in the Hct 20% + CH and Hct 15% + CH groups. However, there were no significant differences in the serum levels of NSE between the groups. In the CA1 region of the rat hippocampus, marked ultrastructural alterations, such as mitochondrial denaturalization and nucleus distortion, were observed in the Hct 20% + CH and Hct 15% + CH groups.

CONCLUSION

Severe ANH (Hct < or = 20%) combined with CH may induce cerebral damage, as confirmed by marked ultrastructural alterations in the CA1 region of the rat hippocampus and significantly increased serum levels of S100B, and should be avoided.

Intranasal recombinant human erythropoietin protects rats against focal cerebral ischemia

Erythropoietin (EPO) is a hematopoietic growth factor with tissue-protective properties, and can protect animals from cerebral ischemic injury. However, the central nervous effects of EPO as a glycoprotein is limited by the potential complication resulted from its erythropoietic activity and the problem of the penetration through blood-brain barrier (BBB). To avoid these limitations, in this study we administered recombinant human EPO (rhEPO) intranasally (i.n.) to evaluate its neuroprotective effect in the rats with focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). We found that rhEPO i.n. at doses of 4.8, 12 and 24 U (administered 10 min after MCAO and 1h after reperfusion) reduced infarct volume, brain swelling and cell damage in the ischemic hemispheres, and improved behavioral dysfunction 24 h after cerebral ischemia. Intraperitoneal rhEPO (5000 U/kg) also showed the protective effect, but the heat-inactivated rhEPO did not show any effect. Thus, intranasal administration of relatively small doses of rhEPO protects rats from acute injury after focal cerebral ischemia, suggesting that intranasal rhEPO may be a more effective and safer administration route for treatments of ischemic or other brain diseases.