Tissue Proteolysis in Appendicitis with Perforation

Diagnostic Value of Serum Urokinase-Type Plasminogen Activator Receptor in Children With Acute Appendicitis

OBJECTIVES

Acute appendicitis (AA) is the most common surgical emergency in children. The accurate and timely diagnosis of AA in children can be challenging, and delayed diagnosis rates have been reported to range from 5.9% to 27.6%. Although combining clinical history and repeated physical examination with laboratory tests and radiographic imaging modalities help reach the diagnosis, novel biomarkers can support the surgeons' decision as well. The aims of this study were to evaluate a new plasma marker, urokinase-type plasminogen activator receptor (uPAR), to improve diagnostic accuracy in AA patients, and to determine a cutoff value of uPAR, which can safely include/exclude the diagnosis of AA.

METHODS

We conducted a prospective study of children who underwent surgery for AA. Patients were categorized into the following 3 groups: group 1, controls consisted of 32 healthy volunteers; group 2, patients underwent surgery for nonperforated AA (n = 35); and group 3, patients underwent surgery for perforated AA (n = 21). Blood was sampled from group 1 at the admission and from group 2 and 3 before appendectomy. Serum uPAR, white blood cell count, absolute neutrophil count (ANC), and C-reactive protein concentrations were measured.

RESULTS

Urokinase-type plasminogen activator receptor, ANC, and white blood cell count values were significantly higher in group 2 and 3 than group 1, but there was no significant difference between group 2 and 3. C-reactive protein values were significantly higher only in group 3 than other groups. The cutoff value for uPAR is 2.2 ng/mL with sensitivity of 85.7% and specificity of 84.3% and ANC is 5900 cells/mm with sensitivity of 91.1% and specificity of 96.9% to diagnose appendicitis. The specificity was 81.3% and sensitivity was raised to 98.2% when evaluated together.

CONCLUSIONS

The incorporation of uPAR count and ANC could be a strong predictor of AA in children.

Infections Associated With Streptococcus Constellatus in Children

Streptococcus constellatus is a viridans Streptococcus belonging to the Anginosus group. It was associated with abscesses in 37 children, 80% of whom had acute appendicitis with perforation and abscess formation in 50%. None of the children was <3 years of age.

Evaluation of effects on the peritoneum after intraperitoneal α-radioimmunotherapy with (211)At

The introduction of the short-lived α-emitter (211)At to intraperitoneal radioimmunotherapy has raised the issue of the tolerance dose of the peritoneum. The short range of the α-particles (70 μm) and the short half-life (7.21 h) of the nuclide yield a dose distribution in which the peritoneum is highly irradiated compared with other normal tissues. To address this issue, mice were injected with (211)At-trastuzumab to irradiate the peritoneum to absorbed doses ranging between 0 and 50 Gy and followed for up to 34 weeks. The peritoneum-to-plasma clearance of a small tracer, (51)Cr-ethylenediamine tetraacetic acid, was measured for evaluation of the small solute transport capacity of the peritoneal membrane. The macroscopic status of the peritoneum and the mesenteric windows was documented when the mice were sacrificed. Biopsies of the peritoneum were taken for morphology and immunohistochemical staining against plasminogen activator inhibitor-1 and calprotectin. Peritoneum-to-plasma clearance measurements indicated a dose-dependent decrease in peritoneal transport capacity in irradiated mice. However, macroscopic and microscopic evaluations of the peritoneal membrane showed no difference between irradiated mice versus controls. The results imply that the peritoneal membrane tolerates absorbed doses as high as 30-50 Gy from α-particle irradiation with limited response.

Local and systemic expressions of MMP-9, TIMP-1 and PAI-1 in patients undergoing surgery for clinically suspected appendicitis

BACKGROUND/AIMS

To examine, compare and correlate the expressions of matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1) and plasminogen activator inhibitor type 1 (PAI-1) in appendiceal tissue and pre- and postoperative blood samples in patients undergoing surgery for clinically suspected appendicitis.

METHODS

Fifty-seven patients with complete tissue and blood samples were included and divided into groups of noninflamed appendix/lymphadenitis (n = 7), phlegmonous appendicitis (n = 30), gangrenous appendicitis (n = 11) and perforated appendicitis (n = 9). The protein expressions were assessed with ELISAs. The local expressions of MMP-9, TIMP-1 and PAI-1 were correlated with the systemic expressions at the time of surgery while the systemic individual differences between surgery and recovery were compared.

RESULTS

There was a positive correlation between tissue and plasma PAI-1 (p < 0.05). The individual differences for plasma MMP-9 and PAI-1 were statistically nonsignificant, while they were higher for TIMP-1 in patients with perforated appendicitis compared with phlegmonous (p < 0.0001) and gangrenous appendicitis (p < 0.01).

CONCLUSIONS

Plasma PAI-1 reflected the levels in appendiceal tissue at the time of surgery. Systemic TIMP-1 could have the potential of distinguishing perforated from nonperforated appendicitis.