Therapeutic application of intravenous human natural immunoglobulin preparation

Intravenous Immunoglobulin Attenuates Cecum Ligation and Puncture-Induced Acute Lung Injury by Inhibiting Apoptosis of Alveolar Epithelial Cells

PURPOSE

Intravenous immunoglobulin (IVIG) therapy has been used to treat sepsis, but its mechanisms of action remain unclear. Sepsis causes multiple organ failure, such as acute lung injury (ALI), which involves apoptosis of alveolar epithelial cells. In this study, we hypothesized that IVIG suppresses apoptosis in alveolar epithelial cells and evaluated mortality, cytokine levels, histological changes in the lung, and alveolar epithelial cell apoptosis after IVIG administration, in mice with experimentally induced sepsis.

METHODS

Mice received an injection of vehicle (saline) or immunoglobulin (100 mg/kg or 400 mg/kg) into the tail vein, after which they underwent cecal ligation and puncture. A sham-operated group was used as the normal control. Survival was assessed in all groups after 72 hours. Plasma levels of TNF-α and IL-6, histopathological changes and wet-to-dry ratio in lung, and alveolar epithelial cell apoptosis were evaluated in all groups at 4 hours after surgery.

RESULTS

In the vehicle group, histopathological injury of the lung was severe, and apoptosis of alveolar epithelial cells was significant. Survival and plasma cytokine levels were better in the IVIG treatment groups than in the vehicle group. IVIG 400 mg/kg suppressed apoptosis of alveolar epithelial cells and reduced ALI.

CONCLUSION

IVIG suppressed inflammatory cytokine levels and improved survival. Lung histopathology and alveolar epithelial cell apoptosis were improved by IVIG treatment, in a dose-dependent manner. Suppressing apoptosis in alveolar epithelial cells appears to be a mechanism by which IVIG improves survival.

Intravenous immunoglobulin-induced neutrophil apoptosis in the lung during murine endotoxemia

BACKGROUND

The pathophysiologic features of acute respiratory distress syndrome (ARDS) are attributed to neutrophil accumulation and over-activation. Low blood immunoglobulin G concentrations in septic shock patients are associated with higher risk of developing ARDS. This study showed the effects of intravenous immunoglobulin (IVIg) on neutrophil apoptosis and accumulation in the lung during murine endotoxemia.

METHODS

Male C57BL/6J mice were injected with saline or 7 mg/kg of lipopolysaccharide (LPS), and 3 h later also were injected with saline, IVIg 300 mg/kg, or IVIg 1000 mg/kg intraperitoneally. At 12 h after LPS injection, mice were sacrificed and peripheral blood and lungs were collected. The lung messenger ribonucleic acid expression (tumor necrosis factor-α [TNF-α], inducible nitric oxide synthase [iNOS], and intercellular adhesion molecule-1 [ICAM-1]) was determined using quantitative realtime reverse transcriptase-polymerase chain reaction. Lungs were immersed in 4% paraformaldehyde and then embedded in paraffin. Tissue slices were prepared and stained with naphthol AS-D chloroacetate esterase to detect neutrophils. The numbers of neutrophils (characterized by the segment number of their nuclei) were counted. Peripheral neutrophil apoptosis was detected by annexin V using flow cytometry and lung neutrophil apoptosis was detected by cleaved caspase-3 using immunohistochemistry.

RESULTS

The survival rates of the saline group, LPS group, and IVIg group were all 100%. Apoptosis of peripheral blood neutrophils was inhibited by LPS. Neutrophil accumulation in the lung was decreased by both IVIg 300 mg/kg and 1000 mg/kg. Segmented neutrophils were reduced by IVIg during endotoxemia. However, IVIg 300 mg/kg and 1000 mg/kg had no influence on the lung messenger ribonucleic acid expression of TNF-α, iNOS, or ICAM-1. Cleaved-caspase-3-positive neutrophils were increased in the IVIg 300 mg/kg group during endotoxemia. The 1000 mg/kg IVIG dose reduced the number of segmented neutrophils, but did not induce cleaved-caspase 3-positive neutrophils.

CONCLUSION

A therapeutic IVIg dose can attenuate neutrophil accumulation and regulate neutrophil apoptosis in the lung during endotoxemia. It is possible that the pathways by which IVIG induces neutrophil apoptosis may differ depending on the IVIg concentration.

High-dose intravenous immunoglobulin G improves systemic inflammation in a rat model of CLP-induced sepsis

OBJECTIVE

Intravenous immunoglobulin therapy has been proposed as an advanced treatment for sepsis. Yet, its benefit remains unclear and the mechanism of action is poorly understood. One key mediator in the development of sepsis is high mobility group box 1 (HMGB1). Therefore, we examined the serum and lung tissue levels of HMGB1 in a rat model of sepsis.

DESIGN AND SETTING

Prospective controlled animal study in a university laboratory.

MATERIALS

Rats received either cecal ligation and puncture-induced sepsis or had additional intravenous immunoglobulin treatment in boluses of 100, 300, or 1,000 mg/kg.

MEASUREMENTS AND RESULTS

After induction of sepsis and respective treatment conditions, histopathology, wet/dry weight ratios, and signaling molecules were examined in pulmonary tissue. Serum and pulmonary levels of cytokine and HMGB1 were measured. High dose intravenous immunoglobulin (1,000 mg/kg)-treated animals demonstrated significantly improved survival and pulmonary histopathology compared to the control rats. Serum and pulmonary HMGB1 levels were lower over time among intravenous immunoglobulin-treated animals. Furthermore, administration of intravenous immunoglobulin resulted in inhibition of NF-kappaB activity.

CONCLUSIONS

High-dose intravenous immunoglobulin decreased the mortality and pulmonary pathology in a rat model of sepsis. A significant reduction in HMGB1 levels was also observed, which may be mediated by inhibition of inflammation and NF-kappaB.

DESCRIPTOR

23. Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI): experimental models.