Optimising the management of dysplastic lesions in the oesophagus with photodynamic therapy

The outcome of patients suffering from adeno and squamous carcinoma of the oesophagus remains poor. In the west, the incidence of adenocarcinoma has increased dramatically, with most cases occurring in association with Barrett's oesophagus (BE). Both adeno and squamous carcinoma are believed to progress through worsening degrees of dysplasia. This thesis assesses the role of Elastic Scattering Spectroscopy (ESS) as an objective diagnostic test for dysplasia and Photodynamic Therapy (PDT) with 5-aminolevulinic acid (ALA) as a less invasive treatment option. It also looks for a better understanding of the factors influencing mucosal healing after PDT. Using ESS, the sensitivity and specificity was 83% for distinguishing HGD/cancer from LGD/non dysplastic BE. Low dose ALA (30mg/kg) PDT eradicated 38% of HGD in BE compared with 67% eradication with a higher dose (60mg/kg). The higher dose also decreased the length of BE. In a study comparing red with green light (fixed light doses) for treating HGD, at 30 mg/kg ALA, 63% and 13 % of patients were clear of HGD with red and green laser respectively. At 60 mg/kg, the corresponding figures were 78% and 33% for the same light dose. 5 of 5 patients with LGD in BE and 4 of 5 patients with HGD in squamous mucosa had their dysplasia eradicated with ALA PDT. Successful PDT involves healing by regeneration of normal squamous mucosa. My in vitro studies created a PDT wound model using malignant oesophageal cell lines to assess the role of different cytokines in healing. Keratinocyte Growth Factor (KGF) was found to promote wound healing after PDT and significantly encouraged (p 0.001) the development of squamous cell lines. In conclusion: 1. ESS can differentiate dysplasia and early cancer from non-dysplastic and normal mucosa (sensitivity and specificity 83%). 2. PDT using high dose (60mg/kg) ALA (but not low dose) is effective in eradicating HGD in BE using red light. 3. The cytokine, KGF may promote healing with squamous mucosa after PDT. 4. Larger scale clinical trials are now required to confirm these results

Turbinate size-related changes in immunophenotypic characteristics.

<p>hTMSCs in the hypertrophic turbinate (A) and the contralateral turbinate (B) were negative for CD14, CD19, CD34, and HLA-DR, and positive for CD29, CD73, CD90, a phenotype characteristic of mesenchymal stem cells. The hTMSCs in the two groups expressed a comparable proportion of specific surface markers.</p

Effect of turbinate size on the osteogenic differentiation potential of hTMSCs.

<p>Cells were cultured in osteogenic induction medium. RT-PCR analysis of bone sialoprotein (BSP), runt-related transcription factor 2 (Runx2), bone morphogenetic protein-2 (BMP-2), osterix (Osx), osteocalcin (OC), and type I collagen (Col1) mRNA in osteogenically differentiated hTMSCs during 2 weeks of culture. The experiment was repeated in triplicate for each sample. No significant difference between the groups was identified by unpaired t-test (<i>p</i><0.05).</p

Data of patients with nasal septal deviation showing their cellular count and viabilty of hTMSCs.

<p>Data of patients with nasal septal deviation showing their cellular count and viabilty of hTMSCs.</p

Turbinate size-related changes in the number and viability of hTMSCs.

<p>After isolation from the inferior turbinate, hTMSCs were enumerated using an automated cell counter. There was no significant difference in the number of cells between the hypertrophic and contralateral turbinates.</p

Oligonucleotide primer sequences used for reverse transcriptase polymerase chain reaction (RT-PCR).

<p>Oligonucleotide primer sequences used for reverse transcriptase polymerase chain reaction (RT-PCR).</p

Oligonucleotide primer sequences used for reverse transcriptase polymerase chain reaction (RT-PCR).

<p>Oligonucleotide primer sequences used for reverse transcriptase polymerase chain reaction (RT-PCR).</p

RT-PCR analysis of osteoblast-specific genes expression during 2 weeks of culture in osteogenically differentiated hTMSCs.

<p>Bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), bone sialoprotein (BSP), type I collagen (Col1), osteocalcin (OC), osterix (Osx), and osteopontin (OP) mRNA expression were analyzed. The experiment was performed in triplicate for each sample. Differences among the groups were evaluated by one-way analysis of variance (ANOVA; <i>p</i><0.05). Except for OP, there were no significant differences in expression levels among the groups.</p

Effect of donor age on the osteogenic differentiation potential of hTMSCs.

<p>Cells were cultured in osteogenic induction medium. Cells aggregated, formed nodules, and accumulated calcium deposits over a 2-week period. A–D: Alkaline phosphatase staining of hTMSCs cultured from each age group before osteogenic induction. E–H: Alkaline phosphatase staining of hTMSCs cultured from each age group after osteogenic induction. Alkaline phosphatase activity, which is indicative of osteoblastic differentiation, is shown as red staining. I–L: Alizarin red staining of hTMSCs cultured from each age group after osteogenic induction. (A, E, and I: group I; B, F, and J: group II; C, G, and K: group III; D, H, and L: group IV). Alizarin Red staining was used to detect precipitated calcium salt, which is a marker of differentiation. Scale bars: 100 µm. Visual assessment data demonstrated that hTMSCs cultured from donors of all age groups showed the alkaline phosphatase activity increase after osteogenic induction and similar levels of alkaline phosphatase and Alizarin Red staining.</p

Proliferation of hTMSCs according to age group.

<p>Cellular proliferation was monitored over a period of 14 days. hTMSCs from all groups exhibited rapid proliferation from day 2 to 4; hTMSCs from group (II) expanded more rapidly than those from the other groups. However, there were no statistically significant differences in proliferation rate among the groups.</p