Significance of the hepatic mitochondrial redox state in the development of posttraumatic jaundice

Diagnostic Approach to the Patient with Jaundice following Trauma

Background and Aims:

Jaundice in trauma patients may reflect serious underlying pathology. The aim of this review was to determine the appropriate diagnostic approach to the patient with jaundice following trauma.

Methods:

A MEDLINE search was performed to retrieve publications which outlined the causes of jaundice in trauma patients.

Results:

The main causes of jaundice in trauma patients were found to be bilirubin overload caused by breakdown of transfused- and extravasated blood and hepatic dysfunction caused by sepsis, infections, initial shock and systemic hypotension. Bile duct injury or drug induced liver injury are rare. Liver function tests are often uninformative but commonly show a cholestatic pattern. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used. Abdominal ultrasound and CT may reveal specific organ injuries, bile duct dilatation, intraabdominal fluid collections, hematomas or acalculus cholecystitis. ERCP is often diagnostic and permits a therapeutic intervention when a bile duct injury is present.

Conclusions:

The primary aim of the diagnostic approach should be to identify all cases of bile duct injury or obstruction. Sepsis and infections should be actively looked for. The number of blood transfusions must be calculated. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used.

Can peripheral blood mononuclear cells be used as a proxy for mitochondrial dysfunction in vital organs during hemorrhagic shock and resuscitation?

INTRODUCTION

Although mitochondrial dysfunction is thought to contribute to the development of posttraumatic organ failure, current techniques to assess mitochondrial function in tissues are invasive and clinically impractical. We hypothesized that mitochondrial function in peripheral blood mononuclear cells (PBMCs) would reflect cellular respiration in other organs during hemorrhagic shock and resuscitation.

METHODS

Using a fixed-pressure HS model, Long-Evans rats were bled to a mean arterial pressure of 40 mmHg. When blood pressure could no longer be sustained without intermittent fluid infusion (decompensated HS), lactated Ringer's solution was incrementally infused to maintain the mean arterial pressure at 40 mmHg until 40% of the shed blood volume was returned (severe HS). Animals were then resuscitated with 4× total shed volume in lactated Ringer's solution over 60 min (resuscitation). Control animals underwent the same surgical procedures, but were not hemorrhaged. Animals were randomized to control (n = 6), decompensated HS (n = 6), severe HS (n = 6), or resuscitation (n = 6) groups. Kidney, liver, and heart tissues as well as PBMCs were harvested from animals in each group to measure mitochondrial oxygen consumption using high-resolution respirometry. Flow cytometry was used to assess mitochondrial membrane potential (Ψm) in PBMCs. One-way analysis of variance and Pearson correlations were performed.

RESULTS

Mitochondrial oxygen consumption decreased in all tissues, including PBMCs, following decompensated HS, severe HS, and resuscitation. However, the degree of impairment varied significantly across tissues during hemorrhagic shock and resuscitation. Of the tissues investigated, PBMC mitochondrial oxygen consumption and Ψm provided the closest correlation to kidney mitochondrial function during HS (complex I: r = 0.65; complex II: r = 0.65; complex IV: r = 0.52; P < 0.05). This association, however, disappeared with resuscitation. A weaker association between PBMC and heart mitochondrial function was observed, but no association was noted between PBMC and liver mitochondrial function.

CONCLUSIONS

All tissues including PBMCs demonstrated significant mitochondrial dysfunction following hemorrhagic shock and resuscitation. Although PBMC and kidney mitochondrial function correlated well during hemorrhagic shock, the variability in mitochondrial response across tissues over the spectrum of hemorrhagic shock and resuscitation limits the usefulness of using PBMCs as a proxy for tissue-specific cellular respiration.

Plasma bilirubin correlations in non-obstructive cholestasis after partial hepatectomy

BACKGROUND

The aim of this study was to provide an improved outline of the patterns and correlates of changes in plasma bilirubin after partial hepatectomy.

METHODS

A large series of blood measurements and complementary variables were prospectively collected from 85 patients undergoing liver resection, and bilirubin correlations were assessed by regression analysis.

RESULTS

Early postoperatively, the best simultaneous correlates of increasing bilirubin were the preoperative value, the duration of surgery, and the number of blood transfusions (r2 = 0.74, p < 0.001). Subsequently, increasing bilirubin became related to the number of resected liver segments, the duration of intraoperative liver ischemia, the use of continuous vs. intermittent ischemia, and the presence of sepsis (r2 = 0.82, p < 0.001); these were also the best simultaneous correlates of peak bilirubin. This pattern was characterized by prominently conjugated hyperbilirubinemia, hypocholesterolemia, and moderately increased alkaline phosphatase, and occurred in the absence of obstructive cholestasis.

CONCLUSIONS

Major hepatectomy, parenchymal ischemia, and sepsis have similar and synergistic impacts as determinants of prominently conjugated hyperbilirubinemia after liver resection. This is likely related to impaired hepatocellular bilirubin transport and occurs in the absence of obstructive components.

Effects of intra-abdominal hypertension on hepatic energy metabolism in a rabbit model

BACKGROUND

Intra-abdominal hypertension is known to decrease hepatic blood flow, but its effect on hepatic energy level has not described.

METHODS

Fifty-three rabbits were mechanically ventilated and divided into five groups. Intra-abdominal hypertension was induced by saline infusion and maintained for 30 minutes. Hepatic sinusoidal functional blood flow was evaluated by means of indocyanine green disappearance rate (ICG-K), hepatic mitochondrial redox status was evaluated by arterial ketone body ratio, and tissue energy level was evaluated by energy charge (EC).

RESULTS

At an intra-abdominal pressure of 20 mm Hg, ICG-K was significantly decreased, with no decrease in EC. At 30 mm Hg, hypoxemia developed and the ICG-K decreased further, with significant decreases observed in arterial ketone body ratio and EC. The latter were not increased by administration of oxygen.

CONCLUSION

At an intra-abdominal pressure of 20 mm Hg, a slight decrease in sinusoidal flow did not affect hepatic energy level. At 30 mm Hg, a reduced hepatic mitochondrial redox status and a decreased energy level were attributed to a decrease in sinusoidal flow in this animal model.