Rons formation under restrictive reperfusion does not affect organ dysfunction early after hemorrhage and trauma

Secretome Conveys the Protective Effects of ASCs: Therapeutic Potential Following Hemorrhagic Shock?

OBJECTIVES

We tested whether resuscitation supplemented with rat adipose-derived stem cells (ASCs) or secretome (conditioned media) of ASCs can ameliorate inflammation, cell/organ injury, and/or improve outcome after hemorrhagic traumatic shock (HTS).

INTERVENTIONS

Rats were subjected to HTS and a resuscitation protocol that mimics prehospital restrictive reperfusion followed by an adequate reperfusion phase. Twenty minutes into the restrictive reperfusion, animals received an intravenous bolus of 2 × 10 cells (ASC group) or the secretome produced by 2 × 10 ASCs/24 h (ASC-Secretome group). Controls received the vehicle (Vehicle group). All rats were observed for 28-day survival.

MEASUREMENTS AND MAIN RESULTS

HTS-induced inflammation represented by IL-6 was inhibited in the ASC (80%, P < 0.001) and in ASC-Secretome (59%, P < 0.01) group at 48 h compared with Vehicle group. At 24 h, HTS-induced liver injury reflected in plasma alanine aminotransferase was ameliorated by 36% (P < 0.001) in both the ASC and ASC-Secretome groups when compared with the Vehicle. There was no effect on kidney function and/or general cell injury markers. HTS induced a moderate 28-day mortality (18%) that was prevented (P = 0.08) in the ASC but not in the ASC-Secretome group (12%).

CONCLUSIONS

Our data suggest that the ASC-secretome supplemented resuscitation following HTS, in the absence of the stem cells, exerts anti-inflammatory and liver protective effects. Given its ease of preparation, storage, availability, and application (in contrast to the stem cells) we believe that the cell-free secretome has a better therapeutic potential in the early phase of an acute hemorrhagic shock scenario.

Experimental Models of Endotheliopathy: Impact of Shock Severity

BACKGROUND

Hemorrhagic shock (HS) followed by resuscitation is often associated with sympathoadrenal activation (SAA) and endothelial damage (ED).

OBJECTIVE

We aimed to evaluate the impact of HS alone on the magnitude of SAA and consecutive ED, and to characterize potential targets for a standardized and reproducible model of HS-induced endotheliopathy in rats.

METHODS

Rats were subjected either to a volume-controlled HS (40% of total blood volume: v-HS group) or to a laboratory-guided HS (l-HS) targeting base deficit (BD) more than 5.5 mmol/L and/or lactate more than 2.2 mmol/L using a pressure-controlled volume loss.

RESULTS

At the end of shock, mean arterial pressure was significantly higher in the v-HS than the l-HS group (36 ± 5.6 vs. 30 ± 3.0 mmHg; P < 0.01). Base deficit and lactate were higher in l-HS than the v-HS group (BD: 9.5 ± 2.5 vs. 3.0 ± 1.0 mmol/L; P < 0.001; lactate: 4.1 ± 1.3 vs. 1.6 ± 0.6 mmol/L; P < 0.001). sVEGFR-1 and syndecan-1 were approximately 50% higher in the l-HS than the v-HS group (% changes vs. baseline: 160 ± 10 vs. 116 ± 36; P < 0.01; 170 ± 37 vs. 113 ± 27; P < 0.001). Adrenaline was 2-fold higher in l-HS than the v-HS group (1964 ± 961% vs. 855 ± 451%; P < 0.02, respectively). Moreover, linear regression analysis revealed an independent association of shock severity BD with syndecan-1 (rho = 0.55, P = 0.0005), sVEGFR1 (rho = 0.25, P < 0.05), and adrenaline (rho = 0.31, P = 0.021).

CONCLUSIONS

Our findings indicate that ED has already occurred during HS without reperfusion; intensity is strongly related to the severity of HS and consecutive SAA; and severity may appropriately be targeted and standardized in a HS model controlled by biological endpoints such as BD and/or lactate.

Organ-Specific Oxidative Events under Restrictive Versus Full Reperfusion Following Hemorrhagic Traumatic Shock in Rats

Background aim: Reperfusion after hemorrhagic traumatic shock (HTS) is often associated with complications that are partly ascribed to the formation of reactive oxygen species (ROS). The aim of our study was to compare the effects of restrictive reperfusion (RR) to rapid full reperfusion (FR) on ROS formation and/or oxidative events.

MATERIALS AND METHODS

Anesthetized male rats were randomly subjected to HTS followed by FR (75 mL/kg/h) or RR (30 mL/kg/h for 40 min, followed by 75 mL/kg/h) with Ringer's solution (n = 8/group). Compartment-specific ROS formation was determined by infusion of ROS scavenger 1-hydroxy-3-carboxy-2,2,5,5-tetramethyl-pyrrolidine hydrochloride (CP-H) during resuscitation, followed by electron paramagnetic resonance spectroscopy. Sham-operated animals (n = 8) served as controls. The experiment was terminated 100 min post-shock.

RESULTS

Mean arterial pressure was significantly higher in the FR compared to the RR group during early reperfusion. Only RR animals, not FR animals, showed significantly higher ROS concentrations in erythrocytes (1951 ± 420 vs. 724 ± 75 AU) and in liver (474 ± 57 vs. 261 ± 21 AU) compared to sham controls. This was accompanied by elevated alanine aminotransferase and creatinine levels in RR animals compared to both shams and FR animals, while lipid peroxidation products (thiobarbituric acid reactive substances) were significantly increased only in the kidney in the FR group (p < 0.05). RR animals showed significantly higher plasma peroxiredoxin-4 values when compared to the FR group (20 ± 2 vs. 14 ± 0.5 RLU).

CONCLUSION

Restrictive reperfusion after HTS is associated with increased ROS formation in erythrocytes and liver compared to sham controls. Moreover, the restrictive reperfusion is associated with a more pronounced injury to the liver and kidney, which is likely mediated by other than lipid peroxidation process and/or oxidative stress reactions.

Pathological Impact of the Interaction of NO and CO with Mitochondria in Critical Care Diseases

The outcome of patients with critical care diseases (CCD) such as sepsis, hemorrhagic shock, or trauma is often associated with mitochondrial dysfunction. In turn, mitochondrial dysfunction is frequently induced upon interaction with nitric oxide (NO) and carbon monoxide (CO), two gaseous messengers formed in the body by NO synthase (NOS) and heme oxygenase (HO), respectively. Both, NOS and HO are upregulated in the majority of CCD. A multitude of factors that are associated with the pathology of CCD exert a potential to interfere with mitochondrial function or the effects of the gaseous messengers. From these, four major factors can be identified that directly influence the effects of NO and CO on mitochondria and which are defined by (i) local concentration of NO and/or CO, (ii) tissue oxygenation, (iii) redox status of cells in terms of facilitating or inhibiting reactive oxygen species formation, and (iv) the degree of tissue acidosis. The combination of these four factors in specific pathological situations defines whether effects of NO and CO are beneficial or deleterious.

Transient increase of free iron in rat livers following hemorrhagic-traumatic shock and reperfusion is independent of heme oxygenase 1 upregulation

Hemorrhagic-traumatic shock (HTS) followed by reperfusion induces heme oxygenase (HO) 1. Free iron (Fe2+) may cause oxidative stress, if not adequately sequestered. We aimed to characterize HO-1-mediated effects on Fe2+ levels in liver and transferrin-bound iron (TFBI) in plasma following HTS, including laparotomy, bleeding, and inadequate and adequate reperfusion. Anesthetized rats showed upregulated HO-1 mRNA at 40 min after HTS, which was followed by increased HO activity at 3 h after shock. Fe2+ levels were transiently increased at 40 min after shock, a time point when HO activity was not affected yet. Levels of plasma TFBI were higher in HTS animals, showing the highest levels at 40 min after shock, and decreased thereafter. In addition, we modulated HO activity 6 h before HTS by administering an inhibitor (zinc-protoporphyrin IX) or an activator (hemin) of HO. At 18 h after HTS in all shock groups, HO activity was increased, the highest being in the hemin-pretreated group. The zinc-protoporphyrin IX-treated HTS animals showed increased HO-1 mRNA and Fe2+ levels in the liver compared with the untreated HTS animals. Transferrin-bound iron levels were affected by pharmacological modulation before shock. All animals undergoing HTS displayed increased TFBI levels after reperfusion; however, in animals pretreated with hemin, TFBI levels increased less. Our data indicate that increase in Fe2+ levels in liver and plasma early after HTS is not mediated by HO-1 upregulation, but possibly reflects an increased mobilization from internal iron stores or increased cell damage. Thus, upregulation of HO activity by hemin does not increase Fe2+ levels following HTS and reperfusion.