Paradoxical effects of brain death and associated trauma on rat mesenteric microcirculation: an intravital microscopic study

Angiotensin-converting enzyme 2 activation attenuates inflammation and oxidative stress in brain death donor followed by rat lung transplantation

Brain death (BD) provides most of the donor organs destined for lung transplantation (LTx). However, the organs may be affected by inflammatory and oxidative processes. Based on this, we hypothesize that the angiotensin-converting enzyme 2 (ACE2) activation can reduce the lung injury associated with LTx. 3 h after BD induction, rats were injected with saline (BD group) or an ACE2 activator (ACE2a group; 15 mg/kg-1) and kept on mechanical ventilation for additional 3 h. A third group included a control ventilation (Control group) prior to transplant. After BD protocol, left LTx were performed, followed by 2 h-reperfusion. ACE2 activation was associated with better oxygenation after BD management (p = 0.01), attenuating edema (p = 0.05) followed by the reduction in tissue resistance (p = 0.01) and increase of respiratory compliance (p = 0.02). Nrf2 expression was also upregulated in the ACE2a group (p = 0.03). After transplantation, ACE2a group showed lower levels of TNF-α (p = 0.02), IL-6 (p = 0.001), IL-1β (p = 0.01), ROS (p = 0.004) and MDA (p = 0.002), in addition to higher CAT activity (p = 0.04). In conclusion, our study suggests that ACE2 activation improves anti-inflammatory and antioxidant activity in a model of LTx.

Anti-inflammatory effect of thalidomide in an experimental lung donor model of brain death

Lung transplantation stands as a vital treatment for severe lung diseases, primarily sourcing organs from donors with brain death (BD). This research delved into the potential anti-inflammatory effects of thalidomide in rats with BD-induced lung complications. In this study twenty-four Wistar rats were divided into three groups: the control (CTR), brain death (BD) and brain death + thalidomide (TLD) groups. Post specific procedures, a 360 min monitoring period ensued. Comprehensive analyses of blood and heart-lung samples were conducted. Elevated IL-6 levels characterized both BD and TLD groups relative to the CTR (p = 0.0067 and p = 0.0137). Furthermore, TNF-α levels were notably higher in the BD group than both CTR and TLD (p = 0.0152 and p = 0.0495). Additionally, IL-1β concentrations were significantly pronounced in both BD and TLD compared to CTR, with the BD group surpassing TLD (p = 0.0256). Immunohistochemical assessments revealed augmented NF-ĸB expression in the BD group in comparison to both CTR and TLD (p = 0.0006 and p = 0.0005). With this study we can conclude that BD induced acute pulmonary inflammation, whereas thalidomide manifested a notable capability in diminishing key inflammatory markers, indicating its prospective therapeutic significance in lung transplantation scenarios.

Comparison of acute kidney injury following brain death between male and female rats

BACKGROUND

Clinical reports associate kidneys from female donors with worse prognostic in male recipients. Brain Death (BD) produces immunological and hemodynamic disorders that affect organ viability. Following BD, female rats are associated with increased renal inflammation interrelated with female sex hormone reduction. Here, the aim was to investigate the effects of sex on BD-induced Acute Kidney Injury (AKI) using an Isolated Perfused rat Kidney (IPK) model.

METHODS

Wistar rats, females, and males (8 weeks old), were maintained for 4h after BD. A left nephrectomy was performed and the kidney was preserved in a cold saline solution (30 min). IPK was performed under normothermic temperature (37°C) for 90 min using WME as perfusion solution. AKI was assessed by morphological analyses, staining of complement system components and inflammatory cell markers, perfusion flow, and creatinine clearance.

RESULTS

BD-male kidneys had decreased perfusion flow on IPK, a phenomenon that was not observed in the kidneys of BD-females (p < 0.0001). BD-male kidneys presented greater proximal (p = 0.0311) and distal tubule (p = 0.0029) necrosis. However, BD-female kidneys presented higher expression of eNOS (p = 0.0060) and greater upregulation of inflammatory mediators, iNOS (p = 0.0051), and Caspase-3 (p = 0.0099). In addition, both sexes had increased complement system formation (C5b-9) (p=0.0005), glomerular edema (p = 0.0003), and nNOS (p = 0.0051).

CONCLUSION

The present data revealed an important sex difference in renal perfusion in the IPK model, evidenced by a pronounced reduction in perfusate flow and low eNOS expression in the BD-male group. Nonetheless, the upregulation of genes related to the proinflammatory cascade suggests a progressive inflammatory process in BD-female kidneys.

17β-Estradiol as a New Therapy to Preserve Microcirculatory Perfusion in Small Bowel Donors

BACKGROUND

Intestine graft viability compromises retrieval in most brain-dead donors. Small bowel transplantation is a complex procedure with worse outcomes than transplantation of other abdominal organs. The hormone 17β-estradiol (E2) has shown vascular protective effects in lung tissue of brain death (BD) male rats. Thus, estradiol might be a treatment option to improve the quality of intestinal grafts.

METHODS

Male Wistar rats were divided into 3 groups (n = 10/group): rats that were trepanned only (sham-operated), rats subjected to rapid-onset BD, and brain-dead rats treated with E2 (280 µg/kg, intravenous) (BD-E2). Experiments performed for 180 minutes thereafter are included: (a) laser-Doppler flowmetry and intravital microscopy to evaluate mesenteric perfusion; (b) histopathological analysis; (c) real-time polymerase chain reaction of endothelial nitric oxide synthase (eNOS) and endothelin-1; (d) immunohistochemistry of eNOS, endothelin-1, P-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 expression; and (e) ELISA for cytokines and chemokines measurement.

RESULTS

17β-Estradiol improved microcirculatory perfusion and reduced intestinal edema and hemorrhage after BD. The proportions of perfused small vessels were (mean ± scanning electron microscope) BD rats (40% ± 6%), sham-operated rats (75% ± 8%), and BD-E2 rats (67% ± 5%) (P = 0.011). 17β-Estradiol treatment was associated with 2-fold increase in eNOS protein (P < 0.0001) and gene (P = 0.0009) expression, with no differences in endothelin-1 expression. BD-E2 rats exhibited a reduction in vascular cell adhesion molecule 1 expression and reduced cytokine-induced neutrophil chemoattractant 1 and interleukina-10 serum levels.

CONCLUSIONS

17β-Estradiol was effective in improving mesenteric perfusion and reducing intestinal edema and hemorrhage associated with BD. The suggestion is that E2 might be considered a therapy to mitigate, at least in part, the deleterious effects of BD in small bowel donors.

Sex differences in the coagulation process and microvascular perfusion induced by brain death in rats

Brain death (BD) leads to a systemic inflammation associated with the activation of coagulation, which could be related to decreased microcirculatory perfusion. Evidence shows that females exhibit higher platelet aggregability than males. Thus, we investigated sex differences in platelets, coagulation and microcirculatory compromise after BD. BD was induced in male and female (proestrus) Wistar rats. After 3 h, we evaluated: (i) intravital microscopy to evaluate mesenteric perfusion and leucocyte infiltration; (ii) platelet aggregation assay; (iii) rotational thromboelastometry; and (iv) Serum NO x - . Female rats maintained the mesenteric perfusion, whereas male reduced percentage of perfused vessels. Male BD presented higher platelet aggregation than the controls. In contrast, female BD had lower platelet aggregation than the control. Thromboelastometry indicated a reduction in clot firmness with increased clotting time in the female group compared with the male group. Serum NO x - level in female BD was higher than that in the male BD and female control. There is sex dimorphism in platelet function and clotting process, which are altered in different ways by BD. Thus, it is possible to connect the reduction in microcirculatory perfusion in males to intravascular microthrombi formation and the maintenance of perfusion in females to a higher inflammatory response and NO synthesis.

Hypertonic Saline Solution Reduces Microcirculatory Dysfunction and Inflammation in a Rat Model of Brain Death

BACKGROUND

Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion, leading to increased organ inflammation and dysfunction. This study investigated the effects of 7.5% hypertonic saline solution (HSS) on mesenteric microcirculatory dysfunction and inflammation in a rat model of BD.

METHODS

Male Wistar rats were anesthetized and mechanically ventilated. BD was induced by rapidly inflating an intracranial balloon catheter. The rats were randomly divided into: SH, sham-operated rats subjected to trepanation; NS, rats treated with NaCl 0.9%, 4 mL/kg immediately after BD; T1, rats treated with HSS (NaCl 7.5%, 4 mL/kg) immediately or 60 min after BD, T60. All groups were analyzed 180 min after the start of the experiment.

RESULTS

Rats in BD groups presented with a similar hypertensive peak, followed by hypotension. Proportion of perfused small vessels was decreased in the NS group (46%) compared with the SH group (74%, P = 0.0039). HSS restored the proportion of perfused vessels (T1 = 71%, P = 0.0018). The anti-endothelial nitric oxide synthase (eNOS) protein expression significantly increased in rats given HSS (T1, and T60, P = 0.0002). Similar results were observed regarding endothelin-1 (P < 0.0001). Increased numbers of rolling (P = 0.0015) and migrated (P = 0.0063) leukocytes were observed in the NS group compared with the SH group. Rats given HSS demonstrated an overall reduction in leukocyte-endothelial interactions. The ICAM-1 levels increased in the NS group compared with the SH group, and decreased in the HSS-treated groups (P = 0.0002).

CONCLUSIONS

HSS may improve the density of mesenteric perfused small vessels due to its effects on eNOS and endothelin-1 protein expression, and reduces inflammation by decreasing leukocyte adhesion and migration in a rat model of BD.

Hypertonic saline reduces cell infiltration into the lungs after brain death in rats

BACKGROUND

Lung transplantation is a treatment method for end stage lung disease, but the availability of donor lungs remains a major constraint. Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion and increased inflammation, leading to pulmonary dysfunction. Hypertonic saline solution (HSS) is a volume expander possessing immunomodulatory effects. This study evaluated the influence of HSS on pulmonary dysfunction and inflammation in a rat model of BD.

METHODS

BD was induced by inflation of an intracranial balloon catheter. Rats were divided into [1]: Sham, without BD [2]; NS, NaCl treatment (0.9%, 4 mL/kg, i.v.) immediately after BD [3]; HSS₁, HSS treatment (NaCl 7.5%, 4 mL/kg, i.v.) immediately after BD; and [4] HSS₆₀, HSS treatment 60 min post BD. All groups were analyzed after 360 min.

RESULTS

Animals subjected to BD exhibited increased exhaled O₂ and decreased CO₂.The number of leukocytes in the lungs was significantly increased in the NS group (p = 0.002) and the HSS treatment was able to reduce it (HSS₁, p = 0.018 and HSS₆₀ = 0.030). In parallel, HSS-treated rats showed reduced levels of ICAM-1 expression, which was increased in the NS compared to Sham group. Lung edema was found increased in the NS group animals compared to Sham and no effect of the HSS treatment was observed. There were no differences among the groups in terms of TNF-α, VEGF, and CINC-1 lung concentrations.

CONCLUSIONS

HSS is capable of reducing inflammatory cell infiltration into the lung after BD induction, which is associated with the reduction of ICAM-1 expression in organ vessels.

The Cholinergic Anti-Inflammatory Pathway as a Conceptual Framework to Treat Inflammation-Mediated Renal Injury

BACKGROUND

The cholinergic anti-inflammatory pathway, positioned at the interface of the nervous and immune systems, is the efferent limb of the "inflammatory reflex" which mainly signals through the vagus nerve. As such, the brain can modulate peripheral inflammatory responses by the activation of vagal efferent fibers. Importantly, immune cells in the spleen express most cholinergic system components such as acetylcholine (ACh), choline acetyltransferase, acetylcholinesterase, and both muscarinic and nicotinic ACh receptors, making communication between both systems possible. In general, this communication down-regulates the inflammation, achieved through different mechanisms and depending on the cells involved.

SUMMARY

With the awareness that the cholinergic anti-inflammatory pathway serves to prevent or limit inflammation in peripheral organs, vagus nerve stimulation has become a promising strategy in the treatment of several inflammatory conditions. Both pharmacological and non-pharmacological methods have been used in many studies to limit organ injury as a consequence of inflammation. Key Messages: In this review, we will highlight our current knowledge of the cholinergic anti-inflammatory pathway, with emphasis on its potential clinical use in the treatment of inflammation-triggered kidney injury.

Direct peritoneal resuscitation reduces intestinal permeability after brain death

BACKGROUND

The profound inflammatory response associated with brain death is frequently cited as the reason organs procured from brain dead donors are associated with worse graft function. The intestine releases inflammatory mediators in other types of shock, but its role is brain death has not been well-studied. Direct peritoneal resuscitation (DPR) improves visceral organ blood flow and reduces inflammation after hemorrhagic shock. We hypothesized that use of DPR would maintain intestinal integrity and reduce circulating inflammatory mediators after brain death.

METHODS

Brain death was induced in male Sprague-Dawley rats by inserting a 4F Fogarty catheter into the epidural space and slowly inflating it. After herniation, rats were resuscitated with normal saline to maintain a mean arterial pressure of 80 mm Hg and killed with tissue collected immediately (time 0), or 2 hours, 4 hours, or 6 hours after brain death. Randomly selected animals received DPR via an intraperitoneal injection of 30-mL commercial peritoneal dialysis solution.

RESULTS

Levels of proinflammatory cytokines, including IL-1β and IL-6, as well as high-mobility group box 1 protein and heat shock protein 70, were all increased after brain death and decreased with DPR. Fatty acid binding protein and lipopolysaccharide, both markers of intestinal injury, were increased in the serum after brain death and decreased with DPR. Immunohistochemistry staining for zona occludin-1 showed decreased intestinal tight junction integrity after brain death, which improved with DPR.

CONCLUSIONS

Intestinal permeability increases after brain death, and this contributes to the increased inflammation seen throughout the body. Using DPR prevents intestinal ischemia and helps preserve intestinal integrity. This suggests that using this novel therapy as an adjunct to the resuscitation of brain dead donors has the potential to reduce inflammation and potentially improve the quality of transplanted organs.

Differential Effects of Brain Death on Rat Microcirculation and Intestinal Inflammation: Female Versus Male

Brain death (BD) affects organs by multiple mechanisms related to hemodynamic effects, hormonal changes, and the systemic inflammatory response, which reduce organ function and viability. BD reduces microcirculatory perfusion in rat mesentery; this disturbance is also observed in the pancreas and lungs. Sex hormones can affect microcirculatory function, altering tissue perfusion and influencing the inflammatory process. Here, we present differences between sexes in the microcirculatory alterations generated by BD and in inflammatory infiltrate. Male, female, and ovariectomized-female Wistar rats were submitted to BD by intracranial balloon catheter sudden inflation. BD was confirmed by maximally dilated and fixed pupils, apnea, absence of reflexes, and a drop in mean arterial pressure. Perfusion and flow of the mesenteric microcirculation were analyzed. Intestinal myeloperoxidase activity and leukocyte infiltration were quantified. ELISA quantified serum estradiol, corticosterone, and inflammatory mediators, whereas expression of eNOS, endothelin, and endothelial adhesion molecule was measured by immunohistochemistry. Male rats presented lower percentages of mesenteric perfused microvessels and reduced blood flow compared to females. The female group presented higher eNOS and endothelin expression. Leukocyte infiltration into intestinal walls was higher in females in comparison to that in males. Moreover, the female group showed higher mesenteric vessel ICAM-1 expression than males, whereas serum TNF-α, IL-1β, and IL-10 levels did not differ between sexes. The high estradiol concentration before BD and high eNOS expression apparently favored the maintenance of microvascular perfusion/flow; however, BD caused an acute reduction of female sex hormone concentration and higher ICAM-1 level; thus, the proinflammatory organ status after BD is favored.

17β-Estradiol protects against lung injuries after brain death in male rats

BACKGROUND

Brain death elicits microvascular dysfunction and inflammation, and thereby compromises lung viability for transplantation. As 17β-estradiol was shown to be anti-inflammatory and vascular protective, we investigated its effects on lung injury after brain death in male rats.

METHODS

Wistar rats were assigned to: sham-operation by trepanation only (SH, n = 7); brain death (BD, n = 7); administration of 17β-estradiol (280 μg/kg, iv) at 60 minutes after brain death (BD-E2, n = 7). Experiments were performed 180 minutes thereafter. Histopathological changes in the lung were evaluated by histomorphometry. Gene expression of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and endothelin-1 was measured by real-time polymerase chain reaction. Protein expression of NO synthases, endothelin-1, platelet endothelial cell adhesion molecule-1 (PECAM-1), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), BCL-2, and caspase 3 was assessed by immunohistochemistry. Cytokines were quantified by enzyme-linked immunosorbent assay.

RESULTS

Treatment with 17β-estradiol after brain death decreased lung edema and hemorrhage (p < 0.0001), and serum levels of cytokine-induced neutrophil chemoattractant-1 (CINC-1; p = 0.0020). iNOS (p < 0.0001) and VCAM-1 (p < 0.0001) also diminished at protein levels, while eNOS accumulated (p = 0.0002). However, gene expression of iNOS, eNOS, and endothelin-1 was comparable among groups, as was protein expression of endothelin-1, ICAM-1, BCL-2, and caspase 3.

CONCLUSIONS

17β-Estradiol effectively reduces lung injury in brain-dead rats mainly due to its ability to regulate NO synthases. Thus, the drug may improve lung viability for transplantation.

Evidence of bone marrow downregulation in brain-dead rats

Experimental findings support the evidence of a persistent leucopenia triggered by brain death (BD). This study aimed to investigate leucocyte behaviour in bone marrow and blood after BD in rats. BD was induced using intracranial balloon catheter inflation. Sham-operated (SH) rats were trepanned only. Thereafter bone marrow cells were harvested every six hours from the femoral cavity and used for total and differential counts. They were analysed further by flow cytometry to characterize lymphocyte subsets, granulocyte adhesion molecules expression and apoptosis/necrosis [annexin V/propidium iodide (PI) protocol]. BD rats exhibited a reduction in bone marrow cells due to a reduction in lymphocytes (40%) and segmented cells (45%). Bone marrow lymphocyte subsets were similar in BD and SH rats (CD3, P = 0.1; CD4, P = 0.4; CD3/CD4, P = 0.4; CD5, P = 0.4, CD3/CD5, P = 0.2; CD8, P = 0.8). Expression of L-selectin and beta₂ -integrins on granulocytes did not differ (CD11a, P = 0.9; CD11b/c, P = 0.7; CD62L, P = 0.1). There were no differences in the percentage of apoptosis and necrosis (Annexin V, P = 0.73; PI, P = 0.21; Annexin V/PI, P = 0.29). In conclusion, data presented suggest that the downregulation of the bone marrow is triggered by brain death itself, and it is not related to changes in lymphocyte subsets, granulocyte adhesion molecules expression or apoptosis and necrosis.

Sex differences on solid organ histological characteristics after brain death1

PURPOSE

To investigate gender differences in the evolution of the inflammatory process in rats subjected to brain death (BD).

METHODS

Adult Wistar rats were divided into three groups: female; ovariectomized female; and male rats. BD was induced using intracranial balloon inflation and confirmed by maximal pupil dilatation, apnea, absence of reflex, and drop of mean arterial pressure. Six hours after BD, histological evaluation was performed in lungs, heart, liver and kidneys, and levels of inflammatory proteins, estrogen, progesterone, and corticosterone were determined in plasma.

RESULTS

In the lungs, females presented more leukocyte infiltration compared to males (p<0.01). Ovariectomized female rat lungs were more hemorrhagic compared to other groups (p<0.001). In the heart, females had higher leukocyte infiltration and tissue edema compared to males (p<0.05). In the liver and kidneys, there were no differences among groups. In female group estradiol and progesterone were sharply reduced 6 hours after BD (p<0.001) to values observed in ovariectomized females and males. Corticosterone levels were similar.

CONCLUSIONS

Sex hormones influence the development of inflammation and the status of organs. The increased inflammation in lungs and heart of female rats might be associated with the acute reduction in female hormones triggered by BD.

Mesenteric hypoperfusion and inflammation induced by brain death are not affected by inhibition of the autonomic storm in rats

OBJECTIVES

Brain death is typically followed by autonomic changes that lead to hemodynamic instability, which is likely associated with microcirculatory dysfunction and inflammation. We evaluated the role of the microcirculation in the hemodynamic and inflammatory events that occur after brain death and the effects of autonomic storm inhibition via thoracic epidural blockade on mesenteric microcirculatory changes and inflammatory responses.

METHODS

Male Wistar rats were anesthetized and mechanically ventilated. Brain death was induced via intracranial balloon inflation. Bupivacaine (brain death-thoracic epidural blockade group) or saline (brain death group) infusion via an epidural catheter was initiated immediately before brain death induction. Sham-operated animals were used as controls (SH group). The mesenteric microcirculation was analyzed via intravital microscopy, and the expression of adhesion molecules was evaluated via immunohistochemistry 180 min after brain death induction.

RESULTS

A significant difference in mean arterial pressure behavior was observed between the brain death-thoracic epidural blockade group and the other groups, indicating that the former group experienced autonomic storm inhibition. However, the proportion of perfused small vessels in the brain death-thoracic epidural blockade group was similar to or lower than that in the brain death and SH groups, respectively. The expression of intercellular adhesion molecule 1 was similar between the brain death-thoracic epidural blockade and brain death groups but was significantly lower in the SH group than in the other two groups. The number of migrating leukocytes in the perivascular tissue followed the same trend for all groups.

CONCLUSIONS

Although thoracic epidural blockade effectively inhibited the autonomic storm, it did not affect mesenteric hypoperfusion or inflammation induced by brain death.

Steroid Anti-Inflammatory Effects Did Not Improve Organ Quality in Brain-Dead Rats

Effect of glucocorticoid administration on improving the outcomes of kidney and liver allografts has not been clearly elucidated. This study investigated the effect of prednisolone administration after onset of brain death (BD) on kidney and liver in a controlled rat model of BD. BD was induced in rats by inflating an epidurally placed balloon catheter. Animals were treated with saline or prednisolone (5, 12.5, or 22.5 mg/kg) one hour after the onset of BD. After 4 hours of BD, experiments were terminated and serum and tissues were collected. Tissue gene and protein expression were measured for markers of inflammation, apoptosis, and cellular stress response markers. Prednisolone caused a reduction of plasma levels of IL-6, while the tissue expression of IL-6, IL-1β, and MCP-1 in both kidney and liver were also reduced. Creatinine plasma levels, complement (C3) expression, HSP-70, HO-1, Bcl2/BAX ratio, and PMN influx did not significantly change in kidney nor liver. Plasma AST and LDH levels were increased in the prednisolone treated group. Our results demonstrate prednisolone can has an anti-inflammatory effect mediated through reducing serum circulating cytokines. However, this anti-inflammatory effect does not translate into improved kidney function and indeed was associated with increased liver injury markers.

Brain death scintigraphy and pathology results in a rat model

OBJECTIVES

Brain scintigraphy with Tc-99m-labeled diethylenetriaminopenta-acetic acid is a sensitive diagnostic method showing loss of cerebral blood flow that occurs after brain death. Cerebral blood flow can be quantitatively estimated by this method. The aim of this study was to compare histopathologic changes occurring with the decrease of cerebral blood flow (as shown by Tc-99m-labeled diethylenetriaminopenta-acetic acid brain death scintigraphy) after brain death in an experimental model.

MATERIALS AND METHODS

The study included examination of cerebral blood flow by Tc-99m-labeled diethylenetriaminopenta-acetic acid brain scintigraphy in the 20 rats, 1 day before brain death, after producing brain death in 11 surviving rats. Tc-99m-labeled diethylenetriaminopenta-acetic acid brain scintigraphy was performed under intubation and monitored. The Mann-Whitney U test was performed to compare groups (scintigraphic quantification results before and after brain death).

RESULTS

In the time activity curves generated from the analysis of the scintigraphies, decreases in counts in the brain death group were obtained in the arterial phase (P < .01). Decreases of the cerebral blood flow between the first and the sixth minutes were statistically significant (P < .05). Common principal histopathologic changes of the brain death (ie, autolysis and color loss in the nerve cells, diffuse edema, petechial hemorrhage in the brain tissues) were observed in all subjects.

CONCLUSIONS

Quantitative findings of the brain scintigraphy by Tc-99m-labeled diethylenetriaminopenta-acetic acid was related with the histopathologic findings seen during the early brain death, with significant decreases of the cerebral blood flow. Quantification of Tc-99m-labeled diethylenetriaminopenta-acetic acid brain death scintigraphy as an easier and less-expensive scintigraphic method of cerebral blood flow might indicate a definite diagnosis of brain death and thus, potential donors can be determined earlier, leaving to increased transplant rates.

Heart transplantation outcomes from cardiac arrest-resuscitated donors

BACKGROUND

The aim of this study was to compare the outcomes of heart transplantation from cardiopulmonary-resuscitated donors (CPR(+)) to those who received hearts from donors who did not require cardiopulmonary resuscitation (CPR(-)).

METHODS

This investigation was a retrospective analysis of UNOS adult heart transplantation donor and recipient data from May 1994 through July 2012. Discrete variables were compared using the chi-square test. Continuous variables were compared using the t-test. Patient and graft survival rates were calculated using the actuarial method and compared using Wilcoxon's test.

RESULTS

Of the 29,242 adult heart transplantations performed in USA during the study period, 1,396 patients (4.7%) received hearts from CPR(+) donors. The patients in the CPR(+) group were younger (25.5 ± 15 years vs 28.5 ± 14 years; p < 0.0001) and more likely to be female (31% vs 27%; p = 0.001). Mean duration of CPR in these donors was 20 minutes. UNOS listing status at the time of transplantation was Status 1A for 54.3% of those in the CPR(+) group and 46.9% in the CPR(-) group (p < 0.0001). More recipients were hospitalized and were in the intensive care unit at transplantation in the CPR(+) group (56% vs 51%; p = 0.0008). Recipient survival at 30 days, 1 year and 5 years was 95.2%, 88.2% and 72.9% in CPR(+) group, and 94.7%, 87.7% and 74.4% in the CPR(-) group, respectively. Similarly, graft survival at 30 days, 1 year and 5 years was 94.7%, 87.6% and 71.9% in the CPR(+) donor hearts, and 94.4%, 87.3% and 73.2% in the CPR(-) donor hearts, respectively.

CONCLUSIONS

This large, multicenter adult heart transplant database from across the USA did not show inferior outcomes in recipients of heart transplantation from selected CPR(+) donors. Recipient and graft survival were similar over 5 years of follow-up.

Influence of brain death and associated trauma on solid organ histological characteristics

PURPOSE

To evaluate histopathological alterations triggered by brain death and associated trauma on different solid organs in rats.

METHODS

Male Wistar rats (n=37) were anesthetized with isoflurane, intubated and mechanically ventilated. A trepanation was performed and a balloon catheter inserted into intracraninal cavity and rapidly inflated with saline to induce brain death. After induction, rats were monitored for 30, 180, and 360 min for hemodynamic parameters and exsanguinated from abdominal aorta. Heart, lung, liver, and kidney were removed and fixed in paraffin to evaluation of histological alterations (H&E). Sham-operated rats were trepanned only and used as control group.

RESULTS

Brain dead rats showed a hemodynamic instability with hypertensive episode in the first minute after the induction followed by hypotension for approximately 1 h. Histological analyses showed that brain death induces vascular congestion in heart (p<0.05), and lung (p<0.05); lung alveolar edema (p=0.001), kidney tubular edema (p<0.05); and leukocyte infiltration in liver (p<0.05).

CONCLUSIONS

Brain death induces hemodynamic instability associated with vascular changes in solid organs and compromises most severely the lungs. However, brain death associated trauma triggers important pathophysiological alterations in these organs.