[Detection of infectious agents in heart valves during endocarditis using PCR technique]

Infectious endocarditis can be caused by various microorganisms. Diagnostics of local infection by microbiological methods is not always effective. For that reason we performed a study aimed for direct detection of potential infectious agents by polymerase chain reaction in patients' heart valve tissue. DNA of infectious agents was revealed in 72% of heart valve tissue samples from patients with septic endocarditis; in studied samples, along with bacterial DNA, herpesviruses' DNA was detected. Obtained results confirm the presence of infection, which allows to perform specific diagnostics of infectious complications after implantation of prosthetic cardiac valves.

[Mesenchymal dysplasia of heart valves, cystic medianecrosis of the aorta and herpetic infection]

Histologic and immunohistochemical studies (use of antibodies for viruses of herpes simplex type 1 and 2, desmin, vimentin, SMA as well as polymerase chain reaction to DNA of viruses of herpes simplex) were made on the material of the valves taken from 1326 patients with valvular heart disease, the ascending aorta of 30 patients with aneurysm, valves of 35 deceased patients without cardiovascular pathology. As a result, expression of viruses of herpes simplex type 1 and/or 2 was found in all cases with mesenchymal dysplasia and cystic medianecrosis in endotheliocytes, fibroblasts, smooth muscle cells of valves and aorta. This indicates the role of these viruses in the pathogenesis of these diseases and their common etiology.

Detection of herpes simplex virus type 1 in rheumatic valvular tissue

BACKGROUND

Rheumatic heart disease (RHD) is the most important sequela of rheumatic fever (RF): evidence that streptococcal infection is aetiological is prominent, but sometimes contradictory. Acute HSV-1 infection in mouse leads to carditis and valvulitis whereas recurrent infection results in inflammatory granulomatous lesions that resemble Aschoff bodies. Cells containing HSV-1 inclusions or virus infected giant cells appear similar to Anitschkow cells or Aschoff cells respectively. We hypothesized that HSV-1 infection also may be involved in RHD.

METHODS

Formalin-fixed, paraffin-embedded valvular tissue samples from 32 patients with RHD were investigated for evidence of HSV-1 infection. HSV-1 antigen was detected by immunohistochemistry, using HSV-1-specific monoclonal and polyclonal antibodies. HSV-1 glycoprotein D gene sequences were amplified by nPCR, using beta-globin gene amplification in the same samples as internal control. Valvular tissue from 5 cases of sudden death and 3 cases died of neisseria meningitis without a history of valvular disease was used for comparison. HSV-1-infected lung tissue was used as positive control.

RESULTS

HSV-1 antigens were detected in valvular tissues from 21 of 32 (65.6%) patients. Fifteen of these 21 (46.9% of cases), but no antigen-negative sample, were positive also for HSV DNA. Nucleotide sequence of PCR products was homologous to the targeted region of the HSV-1 glycoprotein D gene. HSV-1 antigen was present also in one case of sudden death but viral DNA was not found in any tissue sample from the comparison group. Results from reagent and positive controls were as anticipated.

CONCLUSIONS

This is the first study to show the presence of HSV-1 antigen and genomic DNA in valvular tissues from patients with RHD and provides evidence for an association of HSV-1 infection with some cases of rheumatic valvular disease.

Enterovirus replication in valvular tissue from patients with chronic rheumatic heart disease

AIMS

To investigate the involvement of enterovirus infection in chronic, rheumatic heart disease.

METHODS AND RESULTS

Formalin-fixed, paraffin-embedded, surgical samples of valve tissue were examined for the presence of enteroviral RNA and virus capsid protein VP1 by in situ hybridization and immunostaining. Of 53 cases, 33 were patients with chronic rheumatic heart disease and 20 had Marfan's syndrome or degenerative valve disease. Enterovirus RNA was detected in 8 (24.2%) of 33 patients with chronic rheumatic heart disease by in situ hybridization using strand-specific oligonucleotide probes, complementary to conserved sequences in enterovirus genomic (positive strand) RNA. The replication template (negative strand) RNA also was found in seven of these eight cases. The viral capsid protein VP1 was detected in 16 (48.5%) of 33 patients with chronic rheumatic heart disease by immunohistochemistry and correlated with viral RNA detection. Virus was localized generally to valvular tissue. Neither viral RNA nor capsid protein VP1 were found in valvular tissue from any of the 20 comparison cases.

CONCLUSIONS

This is the first demonstration of detection and localization of both enterovirus RNA and capsid protein in chronic rheumatic heart disease. The presence of negative strand RNA and VP1 indicates enteroviral RNA replication and protein synthesis and suggests an aetiological role of enterovirus in the pathogenesis of chronic rheumatic heart disease.