1) Acute respiratory infection caused by influenza virus led to excessive plaque inflammation in the aortas of ApoE knockout mice, implicating acute infection in triggering acute coronary events. 2) Influenza infection increased plaque inflammation and macrophage infiltration in the mice with or without plaque rupture/erosion. 3) Further examination of infected mice tissue found polymorphic inflammatory cell infiltrates associated with platelets and fibrin near the plaques, indicating proinflammatory and procoagulant effects of acute influenza infection.

1. Respiratory Infection of Apo E
KO Mice Causes Excessive
Plaque Inflammation
Implication for triggering effect of flu in human
heart attack
Adeeba Akhtar MD, Silvio Litovsky, MD, Philip Wyde PhD,
Mohammad Madjid MD, Ward Casscells MD, James
Willerson MD, Morteza Naghavi MD.

2. Background
• The role of infection in atherosclerosis has been
known for years.
• A number of pathogens such as C. pneumonia,
HSV, CMV have been reported to be present in
the plaque and moreover related to CHD
• Other chronic infections such as H. pylori, and
dental infection were also found to increase
likelihood of chronic coronary heart disease.

3. Background
• However, acute effect of infection in
triggering coronary events has not received
as much attention.
• A number of retrospective epidemiological
studies have shown the relationship
between acute upper respiratory infection
and myocardial infarction.

4. Background
• The role of inflammation and inflammatory
cytokines in the development of vulnerable
plaque and plaque rupture is now well established.
• Increased circulating cytokines was shown to
accelerate plaque formation in Apo E mice.
• Influenza infection can increase thrombogenecity
of blood by increasing platelet aggregation.
• We have previously shown in a case-control study
that flu vaccination is associated with reduced
recurrence of MI.

5. Background
Therefore we have hypothesized :
• 1) Acute influenza infection of old Apo E
deficient mice may cause acute coronary
event and heart attack.
• 2) Acute influenza infection can increase
plaque inflammation and macrophage
infiltration, with or without rupture/erosion.

6. Study Design
42 ApoE Mice
Controls infected with Influenza virus
Hong Kong P9 LD50
9 Direct infection
24 Intranasal inoculation
9
33
6 sacrificed 3died
11sacrificed 13died

7. Procedure:
• We measured the baseline weight , heart rate,
pulse oximetry of all the infected mice and
measured these parameters again before
sacrificing.
• This was a short term (15 days) study and the mice
were sacrificed at 3, 5, 10, 15 days.
• After sacrifice we took the heart and aorta in
formalin and cut 5 sections for each aorta and one
mid-transverse ventricular section of the heart.

8. Examinations
• Weight (substitute for Temp)
• Oxygen sat.
• Pulse
• Lung virus titration.
• rtPCR for influenza virus.
• CBC and Hb.
• Blood smear.
• Multiple aorta and heart specimens for pathology
examinations, H&E, Movat, CD68, TUNEL, actin,
CD3 staining.

9. General Findings
• - As expected based on LD 50%, old mice
were prompted to die mainly due to
overwhelming lung infection . But we
sacrificed most of them at their maximum
load of infection.
• Significant weight loss occurred in all
infected mice but not in control mice.

10. Specific Findings
• Hot and ground-breaking !!!
…

11. Control mice 1(power10)

12. Control mice 1(Power40)

13. Control mice 2(power 40)

14. Control mice 3(power 10)

15. Control mice 3(power40)

16. Infected Mice 1(Intra nasal
group)Power 10

17. Power 40

18. Power100

19. Infected mice2( Intranasal
group) power10

20. Power 40

21. Power100

22. Infected mice3(Intranasal group)
power4

23. power10

24. Power40

25. power100

26. Infected mice4(Intranasal Group)
Power 10

27. Power 40

28. Power100

29. Infected Mice5 (Intranasal
group) power 4

30. Power10

31. Power40

32. Infected Mice6 (Intranasal
group)power4

33. Power10

34. Power40a

35. Power40b

36. Power100

37. Infected Mice 7( Direct group)
Power10

38. Power40

39. Infected Mice8 (Intranasal
Group) Power 10

40. power40

41. Power100

42. Infected Mice 1(Intranasal
Group) Power10

43. Power40

44. InfectedMice2(Intranasal Group
Power4)

45. Power10

46. Power40

47. Infected mice 6(Intransal
Group)Power4

48. Power 10

49. Power 40

50. Actin staining 1power40

51. Actin staining2 power100

52. CD3staining Power 40

53. CD3staining power 100

54. KP-1 staining (Power 40)

55. Conclusion:
• One third of the infected mice developed this
inflammatory infiltrate associated with clusters of
platelets and occasionally fibrin overlying the
infiltrate.
• The infiltrate is polymorphic (macrophages,
smooth muscle cells, T-lymphocytes). Next set of
stainings will be done on frozen tissue to improve
antigenicity.
• Upregulation of inflammatory and procoagulant
cytokines and receptors will be investigated.
• Longer-term studies will investigate the possible

58. Adeeba
!
Mitra !
Mort !
Khawar !
Tania !
Birendra !Mohammad !
Silvio
!
Moein !
Sadaf !
Reza !