Substance P and neprilysin in chronic pancreatitis

BACKGROUND/AIMS

We aimed to analyze substance P (SP) and neprilysin (NEP), the membrane metallopeptidase that degrades SP, in chronic pancreatitis (CP).

METHODS

SP and NEP mRNA levels were analyzed by qRT-PCR in tissue samples from 30 patients with CP and 8 organ donors. In addition, SP serum levels were determined before and after surgery in the same patients, by means of a competitive ELISA assay. Genetic and epigenetic analyses of the NEP gene were also performed.

RESULTS

SP mRNA expression levels were higher in CP tissues compared to controls (p = 0.0152), while NEP mRNA showed no significant differences between CP and healthy subjects (p = 0.2102). In CP patients, SP serum levels correlated with those in tissue, and after surgical resection SP serum levels were reduced compared to the preoperative values. Failure of NEP to overexpress in CP tissues was associated with significant miR-128a overexpression (p = 0.02), rather than with mutations in the NEP coding region or the presence of hypermethylation sites in the NEP promoter region.

CONCLUSION

Tissue and serum levels of SP were increased in CP, while NEP levels remained unaltered. In an SP/NEP-mediated pathway, it would appear that NEP fails to provide adequate surveillance of SP levels. Failure of NEP to overexpress could be associated with miRNA regulation.

Effectiveness of neoadjuvant radiotherapy in the treatment of locally advanced rectal cancer: a single-center experience in 263 patients

AIM

To determine the frequency of local recurrence (LR) and distant recurrence (DR) with 5-year survival analysis.

METHODS

Patients with T3-T4 rectal cancer located within 10 cm from the anal verge. Radiotherapy protocol: 36 Gy, delivered in 12 daily doses of 3 Gy each for 5 days/week, followed by surgery after a 2-week break.

RESULTS

263 patients were recruited. Radiotherapy was well tolerated. None of the patients broke off treatment. Complete histological response was 3% and maximum radio-induced downstaging 31.4%. Overall complication rate was 25.8% and direct radio-induced complications 0.4%. Mean duration of treatment was 35.7 days. In 172 patients with a minimum follow-up of 5 years, the rate of LR was 6.0% and DR 24.4%. Five-year overall survival was 70.2%, overall specific survival 78.0%, disease-free survival 70.7%, LR-free specific survival 92.9%, and DR-free specific survival 73.5%.

CONCLUSIONS

In our experience, local disease control was achieved in 94% of patients. Any changes in our treatment protocols will aim at improving results in terms of LR and DR. In view of the four-fold higher rate of DR as compared to LR, improvement of DR can be defined as the challenge for the future.

The ECM proteoglycan decorin links desmoplasia and inflammation in chronic pancreatitis

BACKGROUND

Recurrent inflammation in chronic pancreatitis (CP) is not well understood.

AIMS

To investigate whether decorin, an extracellular matrix (ECM) proteoglycan with macrophage modulating activity, is a pathogenic factor allowing diseased pancreatic stroma to sustain inflammation by affecting the cytokine profile of accumulating inflammatory cells.

METHODS

Decorin was examined in 18 donors and 32 patients with CP by quantitative reverse transcription polymerase chain reaction (QRT-PCR), western blotting, and immunohistochemistry of pancreatic specimens. QRT-PCR was used to assess cytokine expression in donor peripheral blood mononuclear cells (PBMC), exposed or not to decorin in vitro, and to compare it with the cytokine profile of circulating and resident mononuclear cells (MNC) of patients with CP.

RESULTS

In CP, desmoplasia is associated with overexpression of decorin in the growing ECM and enlarged pancreatic nerves. In culture, exposure of MNC to decorin stimulated expression of the MNC recruiting chemokine MCP-1. In biopsies, MNC infiltrates in decorin rich CP tissue showed a 300-fold upregulation of MCP-1 compared with decorin free peripheral blood, whereas no difference was found in basal MCP-1 expression in PBMC of patients versus donors. This effect was specific for MCP1-other inflammatory cytokines, such as interleukin 1beta and tumour necrosis factor alpha, were not affected.

CONCLUSION

Decorin is a molecular marker of desmoplasia in CP, and excessive decorin may allow fibrotic masses to nourish and protract inflammation by deregulating the process of MNC accumulation and activation. These data provide a molecular basis for surgical resection of diseased tissue as a treatment option in CP.