Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2006 Mar;34(3):842-9.
doi: 10.1097/01.ccm.0000201876.11059.05.

Pulmonary cytomegalovirus reactivation causes pathology in immunocompetent mice

Charles H Cook  1 , Yingxue Zhang, Daniel D Sedmak, Larry C Martin, Scott Jewell, Ronald M Ferguson
Affiliations

Pulmonary cytomegalovirus reactivation causes pathology in immunocompetent mice

Charles H Cook et al. Crit Care Med. 2006 Mar.

Abstract

Objective: Cytomegalovirus (CMV) is a ubiquitous herpes virus that persists in the host in a latent state following primary infection. We have recently observed that CMV reactivates in lungs of critically ill surgical patients and that this reactivation can be triggered by bacterial sepsis. Although CMV is a known pathogen in immunosuppressed transplant patients, it is unknown whether reactivated CMV is a pathogen in immunocompetent hosts. Using an animal model of latency/reactivation, we studied the pathobiology of CMV reactivation in the immunocompetent host.

Design: Laboratory study.

Setting: University laboratory.

Subjects: Cohorts of immunocompetent BALB/c mice with or without latent murine CMV (MCMV+/MCMV-).

Interventions: Mice underwent cecal ligation and puncture. Lung tissue homogenates were evaluated after cecal ligation and puncture for tumor necrosis factor-alpha, interleukin-1beta, neutrophil chemokine KC, and macrophage inflammatory protein-2 messenger RNA by polymerase chain reaction and real-time quantitative reverse transcription-polymerase chain reaction. Because pulmonary tumor necrosis factor-alpha expression is known to cause pulmonary fibrosis, trichrome-stained sections of lung tissues were analyzed using image analysis to quantitate pulmonary fibrosis. In a second experiment, a cohort of MCMV+ mice received ganciclovir (10 mg/kg/day subcutaneously) following cecal ligation and puncture. Tumor necrosis factor-alpha messenger RNA and pulmonary fibrosis were evaluated as described previously.

Measurements and main results: All MCMV+ mice had CMV reactivation beginning 2 wks after cecal ligation and puncture. Following reactivation, these mice had abnormal tumor necrosis factor-alpha, interleukin-1beta, neutrophil chemokine KC, and macrophage inflammatory protein-2 messenger RNA expression compared with controls. Image analysis showed that MCMV+ mice had significantly increased pulmonary fibrosis compared with MCMV- mice 3 wks after cecal ligation and puncture. Ganciclovir treatment following cecal ligation and puncture prevented MCMV reactivation. Furthermore, ganciclovir-treated mice did not demonstrate abnormal pulmonary expression of tumor necrosis factor-alpha messenger RNA. Finally, ganciclovir treatment prevented pulmonary fibrosis following MCMV reactivation.

Conclusions: This study shows that CMV reactivation causes abnormal tumor necrosis factor-alpha expression, and that following CMV reactivation, immunocompetent mice have abnormal pulmonary fibrosis. Ganciclovir blocks MCMV reactivation, thus preventing abnormal tumor necrosis factor-alpha expression and pulmonary fibrosis. These data may explain a mechanism by which critically ill surgical patients develop fibroproliferative acute respiratory distress syndrome. These data suggest that human studies using antiviral agents during critical illness are warranted.

PubMed Disclaimer

Figures

Figure 1
Figure 1
a. Representative Gomori’s trichrome stained lung section from mouse following cecal ligation and puncture (40X). b. Corresponding computer segmented image of lung section utilized for estimation of fibrosis (40X). After segmentation into four colors (representing fibrosis, blank space, cytoplasm, or nuclei), image analysis software was utilized to determine % of fibrosis (blue in trichrome, green in segmented image)
Figure 2
Figure 2
Pulmonary reactivation of latent murine cytomegalovirus (MCMV) occurred between 7 and 14 days after bacterial sepsis. Mice latently infected with MCMV underwent CLP, and lung homogenates were evaluated for viral activity by RT-PCR for MCMV mRNA. Controls refer to technique controls.
Figure 3
Figure 3
Healthy mice have transcription of cytokines/chemokines after CLP. Pairs of mice underwent evaluation of pulmonary cytokine/chemokine transcription after cecal ligation and puncture (CLP). Confirming previous studies, there was detectable TNF-α, IL-1β, KC, and MIP-2 mRNA expression for 1–3 days after CLP, which became undetectable by day 7. Each lane represents 1 mouse. No RT reaction controls were performed in parallel and were all negative (data not shown).
Figure 4
Figure 4
Mice latently infected with murine cytomegalovirus (MCMV) have abnormal transcription of cytokines/chemokines after cecal ligation and puncture (CLP). Groups of mice underwent evaluation of pulmonary cytokine/chemokine transcription after CLP. Unlike uninfected hosts, there was detectable TNF-α, IL-1β, KC, and MIP-2 mRNA expression that persisted for 3 weeks after CLP, suggesting that CMV reactivation might cause prolonged inflammation and possibly pulmonary pathology following bacterial sepsis. Each lane represents 1 mouse. No RT reaction controls were performed in parallel and were all negative (data not shown).
Figure 5
Figure 5
Pulmonary murine cytomegalovirus (MCMV) reactivation following CLP is prevented by antiviral therapy. Latently infected mice underwent CLP with postoperative ganciclovir treatment (10mg/kg/day sq) and were analyzed three weeks after CLP. Nested RT-PCR shows no viral transcription. Each lane represents 1 mouse. Controls refer to technique controls.
Figure 6
Figure 6
Figure 6a Comparison of pulmonary TNF-α mRNA expression following cecal ligation and puncture (CLP) in mice latently infected with murine cytomegalovirus (CMV+) versus healthy controls (CMV−). Mice underwent CLP and lung tissue homogenates were evaluated at 0,1,2,3,7,14, and 21 days for TNF-α mRNA using real time PCR. Error bars were formed to indicate a multiple comparison adjusted p-value of .05 between groups at any time point where there is no overlap. CMV− mice showed normal TNF-α mRNA expression, which peaks at day one and returns back toward baseline levels by day 2–3 after CLP. In contrast, CMV+ mice had persistence of this day one peak in TNF-α mRNA expression for 3 days before returning toward baseline, showing a second elevation at day 21 after MCMV reactivation. Figure 6b Comparison of late pulmonary TNF-α mRNA expression following CLP in mice latently infected with MCMV treated with ganciclovir (CMV+GCV), latent MCMV (CMV+), and healthy controls (CMV−). Mice underwent CLP and lung tissue homogenates were evaluated at 7, 14, and 21 days for TNF-α mRNA using real time PCR. Error bars were formed to indicate a multiple comparison adjusted p-value of .05 between groups at any time point where there is no overlap. Treatment with GCV prevented CMV reactivation in CMV+GCV mice (see results), and CMV+GCV mice showed TNF-α mRNA expression that was not significantly different from CMV− mice.
Figure 6
Figure 6
Figure 6a Comparison of pulmonary TNF-α mRNA expression following cecal ligation and puncture (CLP) in mice latently infected with murine cytomegalovirus (CMV+) versus healthy controls (CMV−). Mice underwent CLP and lung tissue homogenates were evaluated at 0,1,2,3,7,14, and 21 days for TNF-α mRNA using real time PCR. Error bars were formed to indicate a multiple comparison adjusted p-value of .05 between groups at any time point where there is no overlap. CMV− mice showed normal TNF-α mRNA expression, which peaks at day one and returns back toward baseline levels by day 2–3 after CLP. In contrast, CMV+ mice had persistence of this day one peak in TNF-α mRNA expression for 3 days before returning toward baseline, showing a second elevation at day 21 after MCMV reactivation. Figure 6b Comparison of late pulmonary TNF-α mRNA expression following CLP in mice latently infected with MCMV treated with ganciclovir (CMV+GCV), latent MCMV (CMV+), and healthy controls (CMV−). Mice underwent CLP and lung tissue homogenates were evaluated at 7, 14, and 21 days for TNF-α mRNA using real time PCR. Error bars were formed to indicate a multiple comparison adjusted p-value of .05 between groups at any time point where there is no overlap. Treatment with GCV prevented CMV reactivation in CMV+GCV mice (see results), and CMV+GCV mice showed TNF-α mRNA expression that was not significantly different from CMV− mice.
Figure 7
Figure 7
Boxplot comparison of pulmonary fibrosis in latently infected (CMV+), non-infected (CMV−) and ganciclovir treated (CMV+GCV) mice 3 weeks after cecal ligation and puncture. White belts indicate the median value. Boxes give the range between quartiles (25th and 75th percentiles). Notched black regions are 95% confidence intervals for the medians, and the dots indicate the full range of the distributions. Because distributions of pulmonary fibrosis scores are non-normal, nonparametric tests were used to discern differences among study groups at day 21. Post hoc comparisons of pairs of groups were made using the Mann-Whitney-Wilcoxon test (nonparametric t-test). CMV reactivation was related to significant increases in pulmonary fibrosis compared to healthy controls after CLP (p<0.0007). Blocking CMV reactivation with ganciclovir after CLP appears to prevent this increased level of fibrosis, as fibrosis was significantly lower in GCV treated mice than in non treated mice (p<.0002),
See this image and copyright information in PMC

Comment in

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Simmons RL, et al. Clinical characteristics of the lethal cytomegalovirus infection following renal transplantation. Surgery. 1977;82(5):537–46. - PubMed
    1. Cook CH, et al. Occult herpes family viruses may increase mortality in critically ill surgical patients. American Journal of Surgery. 1998;176(4):357–60. - PubMed
    1. Cook CH, et al. Occult herpes family viral infections are endemic in critically ill surgical patients. Critical Care Medicine. 2003;31(7):1923–9. - PubMed
    1. Heininger A, et al. Human cytomegalovirus infections in nonimmunosuppressed critically ill patients. Critical Care Medicine. 2001;29(3):541–7. [see comments] - PubMed
    1. Curtsinger LJ, et al. Association of cytomegalovirus infection with increased morbidity is independent of transfusion. The American Journal of Surgery. 1989;158(6):606–611. - PubMed

Publication types

MeSH terms