Combination of Pre-Operative Radiotherapy and Surgery Suppresses Local Accumulation of Collagen and TGF-β1 in Rats

The effect of gender on early colonic anastomotic wound healing

PURPOSE

Clinically, male patients subjected to colorectal surgery are more prone to develop anastomotic leakage than female patients by unknown mechanisms. Our aim was to investigate the impact of gender on anastomotic wound healing using an experimental model.

METHODS

One-layer colonic anastomosis was constructed in 8-week-old 28 male and 32 female Sprague-Dawley rats. Animals of one group (n = 30) were sacrificed immediately after surgery day 0 and the other group (n = 30) on postoperative day 3. Anastomotic breaking strength, total collagen (hydroxyproline), soluble collagen (Sircol), matrix metalloproteinase (MMP)-9, and transforming growth factor (TGF)-β1 were measured.

RESULTS

The anastomotic breaking strength decreased from day 0 to day 3 with no significant gender differences either in the extent of decline (P = 0.122) or absolute day 3 strengths (P = 0.425). Analogously, total collagen concentration in the anastomotic wounds decreased postoperatively and were lower (P = 0.043) in the male compared with the female rats on day 3. MMP-9 levels increased in the anastomoses postoperatively, but they did not differ (P = 0.391) between male and female animals. Soluble collagen levels were lower in the day-3 anastomoses of male versus female rats (P = 0.015) and correlated positively with total TGF-β1 levels (r_S = 0.540, P = 0.006). Although TGF-β1 tended to be lower in male compared with the female rats, the differences did not reach statistical significance.

CONCLUSION

Our findings point towards a less favorable collagen metabolism in colonic anastomoses of male compared with female rats during early wound healing.

MMP7 Modulation by Short- and Long-term Radiotherapy in Patients with Rectal Cancer

BACKGROUND/AIM

Matrix metalloproteinase 7 (MMP7) expression is highly associated with colorectal cancer and modulates tumour growth and invasion. Radiation injury induces inflammation with increases in MMP7 and in transforming growth factor beta (TGFβ). The aim of this study was to investigate the effect on MMP7 and TGFβ. expression in patients with rectal cancer undergoing different regimens of neoadjuvant radiotherapy (RT).

PATIENTS AND METHODS

We studied 53 patients in three RT treatment groups receiving RT of 25 Gy, long-term RT 50 Gy and controls receiving no RT. Three biopsies were obtained from each patient during the treatments: before RT, after RT and after surgery. Tissue samples were formalin fixed, paraffin embedded and tissue microarrays were constructed and stained for MMP7 and TGFβ. Mann-Whitney U-tests and Wilcoxon Z-tests were used to determine differences between patients before and after RT, and after surgery, as well as between the RT groups.

RESULTS

In all three patient groups, increases of MMP7 and TGFβ expression were observed after surgery. MMP7 expression was significantly increased in patients receiving short-term RT but TGFβ expression was not affected by RT.

CONCLUSION

50 Gy Irradiation of rectal cancer gives less tumour activation of MMP7, whilst it is up-regulated by 25 Gy and surgery regardless of RT.

Mitigating effects of hUCB-MSCs on the hematopoietic syndrome resulting from total body irradiation

This study evaluated the clinical and pathologic effects of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in the recovery from total body irradiation by comparing it with the effects of granulocyte-colony stimulating factor (G-CSF), an efficacious drug in the treatment of acute bone marrow radiation syndrome. BALB/c mice were treated with G-CSF or hUCB-MSCs after they were irradiated with 7 Gy cobalt-60 γ-rays. Circulating blood counts, histopathologic changes in the bone marrow, and plasma level of Flt-3L and transforming growth factor (TGF-β1) were monitored in the postirradiation period. Hematologic analysis revealed that the peripheral leukocyte counts were markedly increased in the hUCB-MSCs-treated group, whereas G-CSF-treated mice did not recover significantly. Moreover, differential counts showed that hUCB-MSC treatment has regenerative effects on white blood cells, lymphocytes, and monocytes compared with the irradiated group. Treatment with hUCB-MSCs or G-CSF significantly increased immunoreactivity of Ki-67 until 3 weeks after total body irradiation. However, at 3 weeks, the number of Ki-67 immunoreactive cells significantly increased in the hUCB-MSCs-treated group compared with the G-CSF-treated group. Furthermore, hUCB-MSC treatment significantly modulated plasma levels of the hematopoietic cytokines Flt-3L and TGF-β1, whereas G-CSF treatment failed to decrease the plasma Flt-3L levels at 2 weeks after irradiation. Based on the differences in circulating blood cell reconstitution and cell density of bone marrow, the authors suggest that MSC treatment is superior to G-CSF treatment for hematopoietic reconstitution following sublethal dose radiation exposure.

Aloe vera oral administration accelerates acute radiation-delayed wound healing by stimulating transforming growth factor-β and fibroblast growth factor production

BACKGROUND

Delayed wound healing is a significant clinical problem in patients who have had previous irradiation. This study investigated the effectiveness of Aloe vera (Av) on acute radiation-delayed wound healing.

METHODS

The effect of Av was studied in radiation-exposed rats compared with radiation-only and control rats. Skin wounds were excised on the back of rats after 3 days of local radiation. Wound size was measured on days 0, 3, 6, 9, and 12 after wounding. Wound tissues were examined histologically and the expressions of transforming growth factor β-1 (TGF-β-1) and basic fibroblast growth factor (bFGF) were examined by immunohistochemistry and reverse-transcription polymerase chain reaction.

RESULTS

Wound contraction was accelerated significantly by Av on days 6 and 12 after wounding. Furthermore, the inflammatory cell infiltration, fibroblast proliferation, collagen deposition, angiogenesis, and the expression levels of TGF-β-1 and bFGF were significantly higher in the radiation plus Av group compared with the radiation-only group.

CONCLUSIONS

These data showed the potential application of Av to improve the acute radiation-delayed wound healing by increasing TGF-β-1 and bFGF production.

Matrilysin expression related to radiation and microflora changes in murine bowel

BACKGROUND

Matrilysin (MMP-7) elevation after radiotherapy is shown in humans. Matrilysin regulates certain cytokines and the production of bactericidal proteins when the mucosa is exposed to bacterial antigens. We investigate the effect of irradiation on matrilysin and microflora in murine bowel, after modulation with antibiotics.

METHODS

Animals were divided into two different groups a radiation group (72 animals) and sham radiation group (36 animals). Animals were divided into smaller groups of six according to radiation dose (19 or 38 Gy or sham). Seven days before radiotherapy ampicillin 500 mg/kg/d was administered intramuscularly, in the antibiotic groups. An exteriorized segment of ileum was subjected to single high dose radiation (19 or 38 Gy). Samples were collected 2, 24, and 48 h and analyzed for microflora, MIP-2, TGF-β, and MMP-7.

RESULTS

The combination of antibiotics and irradiation leads to an early significant reduction of bacteria, down-regulates MIP-2, up-regulates TGF-β and elevation of MMP-7 to levels achieved by antibiotics or irradiation alone. Lactobacilli were reduced to non-existent levels after antibiotics.

CONCLUSIONS

Pretreatment with Ampicillin before irradiation and laparotomy in a murine model leads to Matrilysin over-expression as achieved by radiotherapy alone. Microfloral regulation does not affect MMP-7 stimulation after surgical or radiological trauma. Radiotherapy overrides the effect of antibiotics leading to an up-regulation of MMP-7, TGF-β and MIP-2 expression between 24 h and 48 h.

Platelet-rich fibrin versus albumin in surgical wound repair: a randomized trial with paired design

OBJECTIVE

To study the effects of autologous platelet-rich fibrin (PRF) versus human albumin on incisional wound breaking strength and subcutaneous collagen deposition in patients undergoing laparoscopic cholecystectomy in a randomized trial.

SUMMARY BACKGROUND DATA

Platelet peptidic growth factors may stimulate collagen synthesis and tissue repair.

METHODS

One expanded polytetrafluoroethylene (ePTFE) tube was inserted subcutaneously from the edge of each of the two 10-mm trocar incisions in 51 patients. Treatment with PRF prepared from the patient's own blood or human albumin was randomized to respective wound site by concealed allocation. On postoperative day 10, breaking strength of the incisional wounds as well as the collagen concentration, type I procollagen mRNA, type III procollagen mRNA, matrix metalloproteinase-1 mRNA, and fibroblast density in the ePTFE tubes were determined. All analyses were assessor-blinded. The trial was registered in the Current Controlled Trials Registry (ISRCTN34481461).

RESULTS

Local PRF had no significant effect on incisional wound-breaking strength. In the ePTFE tubes, PRF treatment decreased collagen concentration by 24% (P=0.046) and type I procollagen mRNA level by 29% (P=0.003), but had no significant impact on type III procollagen mRNA, matrix metalloproteinase-1 mRNA or fibroblast infiltration. The profibrotic transforming growth factor-beta1 level increased (P<0.0001) 2-fold with PRF. Collagen concentration in albumin-treated ePTFE tubes correlated with breaking strength of the skin incisions (rs=0.48, P=0.03).

CONCLUSIONS

PRF did not improve wound strength significantly compared with albumin but suppressed subcutaneous collagen synthesis and deposition during early repair of surgical wounds in humans. Furthermore, deposition of reparative collagen in the subcutaneous ePTFE tube model partly predicted the breaking strength of an incisional skin wound.

Evaluation of cellular wound healing using flow cytometry and expanded polytetrafluroethylene implants

In wound healing studies that investigate therapeutic interventions, it is important to characterize cellular responses. In a randomized trial enrolling patients at risk for surgical infection, one goal is to phenotype cells within a polytetrafluoroethylene implant using flow cytometry and immunohistochemistry, together with standard hematoxylin- and eosin-based histology. Subcutaneous implants are removed 8-9 days postoperatively. To obtain single cells associated with the mechanism of wound healing, we initially used a mouse skin digestion protocol. We optimized this to increase the cell yield and isolate sufficient cells for flow cytometry. The modifications increased the total cells recovered per subject from an average of 5.3 x 10(4)-41 x 10(4) with an average viability of 80%. The immunoflourescent staining assay was verified for our samples, which have smaller cell sample numbers than tissue biopsies. Thirty-two samples were stained. Cells from the polytetrafluoroethylene tubes were isolated and stained positively with fluorescent-labeled antibodies to CD3, CD20, CD31, CD34, CD68, CD133, and VEGF receptor type 2. Flow cytometry data correlated with immunohistochemistry data especially with respect to CD68. This antigen was the most prevalent in both the cell analysis methods. Our findings demonstrate that flow cytometry can be used with polytetrafluoroethylene samples as an additional evaluation method to document and describe cellular wound healing responses.

Preoperative radiotherapy and extracellular matrix remodeling in rectal mucosa and tumour matrix metalloproteinases and plasminogen components

BACKGROUND. Preoperative radiotherapy reduces recurrence but increases postoperative morbidity. The aim of this study was to explore the effect of radiotherapy in rectal mucosa and rectal tumour extracellular matrix (ECM) by studying enzymes and growth factors involved in ECM remodeling. MATERIALS AND METHODS. Twenty patients with short-term preoperative radiotherapy and 12 control patients without radiotherapy were studied. Biopsies from rectal mucosa and tumour were collected prior to radiotherapy and at surgery. Tissue MMP-1, -2, -9, TIMP-1, uPA, PAI-1, TGF-beta1 and calprotectin were determined by ELISA. Biopsies from irradiated and non-irradiated peritoneal areas were also analysed. RESULTS. Radiotherapy increased the tissue levels of MMP-2 and PAI-1 in both the rectal mucosa and tumours while calprotectin and uPA showed an increase only in the mucosa after irradiation. The increase of calprotectin was due to an influx of inflammatory cells as revealed by immunohistochemistry. Prior to irradiation, the tumour tissues had increased levels of MMP-1, -2, -9, total TGF-beta1, uPA, PAI-1 and calprotectin compared to mucosa, while TIMP-1 and the active TGF-beta1 fraction showed no statistical difference. CONCLUSIONS. This study indicates a radiation-induced effect on selected ECM remodeling proteases. This reaction may be responsible for early and late morbidity. Interference of this response might reduce these consequences.

Transforming growth factor beta-1 in rectal tumour, mucosa and plasma in relation to radiotherapy and clinical outcome in rectal cancer patients

BACKGROUND

Rectal cancer patients are treated with surgery and sometimes radiotherapy. Transforming growth factor-beta1 (TGF-beta1) acts both as an inhibitor of tumour growth and as a promoter of tumour progression. The aim of this study was to determine the levels of TGF-beta1 in tumour tissue, adjacent mucosa and plasma in rectal cancer patients and relate these to the effect of radiotherapy and clinical outcome.

MATERIALS AND METHODS

One hundred and ten patients scheduled for rectal cancer surgery were included, 49% received pre-operative radiotherapy three-field treatment 5 x 5 Gy. Blood samples and biopsies were taken during surgery and later assayed with enzyme-linked immunosorbent assay for total TGF-beta1 and active TGF-beta1. Patients were then followed for 3 years.

RESULTS

Total and active TGF-beta1 was higher in tumour tissue compared with rectal mucosa (p < 0.0001). Active TGF-beta1 in tumour tissue and rectal mucosa was lower in the irradiated group (p = 0.007; p < 0.0001). Total TGF-beta1 was higher in patients with metastases at primary diagnosis (p = 0.005) compared to patients without. In patients who later developed metastases, the levels of active TGF-beta1 in plasma were lower (p = 0.004). Local recurrence was associated with lower levels of total TGF-beta1 in the rectal mucosa (p = 0.038).

CONCLUSIONS

Higher levels of total TGF-beta1 in tumour tissue at surgery may be indicative of distant metastases, and low levels of active TGF-beta1 in plasma may indicate a risk of developing secondary metastases. Lower levels of total TGF-beta1 in rectal mucosa may influence risk of local recurrence. Measurement of TGF-beta1 in rectal cancer patients may be of clinical use in the future.