Name: multimodal quantitative phase imaging with digital holographic microscopy accurately assesses intestinal inflammation and epithelial wound healing
Uploaded: 2016-09-13T14:00:00
Description: Watch this Scientific Journal Video about Multimodal Quantitative Phase Imaging with Digital Holographic Microscopy Accurately Assesses Intestinal Inflammation and Epithelial Wound Healing at JoVE.com

We thank Faekah Gohar for proofreading the manuscript. We thank Sonja Dufentester and Elke Weber for expert technical assistance.

All animal experiments were approved by the regional ethics committee (the Landesamt fu&#776;r Natur, Umwelt und Verbraucherschutz, LANUV, Germany) according to German Animal Protection Law. The local ethics committee of the University of M&#252;nster approved the use of human tissues for histological and microscope analysis.
1. Animals and Materials
<ol>
	<li>Use female or male mice of the required DSS-susceptible strain that weigh 20 to 25 g, and house according to local animal care legisl...

We demonstrate that DHM provides accurate assessment of histological damage in murine colitis models and human colonic tissue samples ex vivo. Furthermore, we shown DHM can continuously monitor epithelial wound healing whilst simultaneously providing multimodal information about cellular alterations. In DHM, the reconstruction of digitally captured holograms is performed numerically32. Therefore, in comparison to bright field microscopy, Zernike phase contrast and differential interference contrast mi...

Inflammatory bowel disease (IBD), i.e., Ulcerative Colitis (UC) and Crohn&#39;s disease (CD) are idiopathic inflammatory disorders of the gastrointestinal tract1. Research into the underlying pathophysiology of IBD and the evaluation of potential new drugs or novel diagnostic approaches is particularly of importance. In both basic research and the clinical management of IBD patients, the intestinal mucosa has become a focus of attention2,3. The mucosa represents an anatomical boundary, at which the interaction between commensal bacteria, epithelial cells and various cellular components of the intestinal immune system orchestrate gut homeostasis4,5. However, in IBD patients, uncontrolled and persistent intestinal inflammation leads to mucosal damage, detectable as ulcerations or stenosis, which can finally culminate in breakdown of epithelial barrier function, which itself aggravates local inflammation6.
Epithelial wound healing is therefore crucial for epithelial regeneration following inflammation but is also a core requirement for the healing of gastrointestinal ulcers or anastomotic leakage after gastrointestinal surgery7. Epithelial wound healing can be simulated in in vitro wound healing assays and in murine models of intestinal inflammation8,9. Both in vitro and in vivo approaches have drawbacks, which limit the accuracy of experimental assessment. In vitro assays, like classical scratch assays, require protracted staining procedures or transfection with fluorescent chromophores. They are often limited by their discontinuous monitoring of cell proliferation and migration that cannot be automated10. In vivo models, such as dextran sodium sulphate (DSS)-induced colitis, frequently lack robust read-outs, in part due to the significant variation seen in laboratory markers, making such markers inappropriate to evaluate colitis severity11,12. Histological analysis of the inflamed mucosa is currently still the most valid approach to determine colitis severity but this, like in vitro epithelial wound healing assays, requires staining and is dependent on investigator&#39;s expertise13.
Recently digital holographic microscopy (DHM), a variant of quantitative phase microscopy14, was identified as useful tool for the evaluation of epithelial wound healing in vitro and in vivo15. DHM allows assessment of tissue density by measuring optical path length delay (OPD), which prospects novel cancer diagnosis16-18 and quantification of inflammation related tissue alterations19. Additionally, DHM allows monitoring of cell morphology dynamics by determining cell thickness, cell covered surface area and intracellular (protein) content quantity15,20. In in vitro assays, DHM also enables the analysis of physiological processes, e.g., cellular water permeability by evaluating changes in cell volume and thickness21,22. Moreover, DHM measurements can be automated which prevents investigator-associated sample bias.
Here, we demonstrate the use of DHM in a murine model of intestinal inflammation, and also apply DHM to analysis of human tissues samples for quantitative monitoring of wound healing as a label-free in vitro assay. First, we evaluate inflammatory alterations of different colonic wall-layers in colitic mice and tissue sections from humans with IBD. After describing the DHM quantitative phase imaging procedure, we provide detailed instructions for using the microscope components, the preparation of tissue sections and also describe the evaluation of the acquired quantitative phase images.
Next, we show that DHM can be utilized for continuous multimodal monitoring of epithelial wound healing in vitro, and describe the analysis of cellular characteristics like cell layer thickness, dry mass and cellular volume give insight into drug induced and physiologic cell alterations.

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			<td>Reagents</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Azoxymethane (AOM)</td>
			<td>Sigma - Aldrich, Deisenhofen, Germany</td>
			<td>A5486</td>
		</tr>
		<tr>
			<td>Cell Culture Flask</td>
			<td>Greiner Bio-One, Frickenhausen, Germany</td>
			<td>658170</td>
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		<tr>
			<td>Costar Stripette</td>
			<td>Corning Inc., New York, USA</td>
			<td>4488</td>
		</tr>
		<tr>
			<td>Dextran sulphate sodium (DSS)</td>
			<td>TdB Consulatancy, Uppsala, Sweden</td>
			<td>DB001</td>
		</tr>
		<tr>
			<td>DMEM/Ham&#180;s F12</td>
			<td>PAA Laboratories - Pasching - Austria</td>
			<td>E15-813</td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>Sigma - Aldrich, Deisenhofen, Germany</td>
			<td>SPR3196</td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid (EDTA)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td>Sigma - Aldrich, Deisenhofen, Germany</td>
			<td>E 9884</td>
		</tr>
		<tr>
			<td>Falcon Tube 50ml</td>
			<td>BD Biosciences, Erembodegem, Belgium</td>
			<td>352070</td>
		</tr>
		<tr>
			<td>Isopentane (2- Methylbutane)</td>
			<td>Sigma - Aldrich, Deisenhofen, Germany</td>
			<td>M32631-1L</td>
		</tr>
		<tr>
			<td>Methylene blue</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1159430025</td>
		</tr>
		<tr>
			<td>Mitomycin C</td>
			<td>Sigma - Aldrich, Deisenhofen, Germany</td>
			<td>M4287</td>
		</tr>
		<tr>
			<td>Microscope Slides</td>
			<td>G. Menzel, Braunschweig, Germany</td>
			<td>J1800AMNZ</td>
		</tr>
		<tr>
			<td>O.C.T. Tissue Tek compound&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td>Sakura, Zoeterwonde, Netherlands</td>
			<td>4583</td>
		</tr>
		<tr>
			<td>Pen/Strep/Amphotericin B</td>
			<td>Lonza, Verviers, Belgium</td>
			<td>1558</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline, PBS</td>
			<td>Lonza, Verviers, Belgium</td>
			<td>4629</td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Lonza, Verviers, Belgium</td>
			<td>3626</td>
		</tr>
		<tr>
			<td>Sodium Chloride 0,9%</td>
			<td>Braun, Melsungen, Germany</td>
			<td>5/12211095/0411</td>
		</tr>
		<tr>
			<td>Standard diet</td>
			<td>Altromin, Lage, Germany</td>
			<td>1320</td>
		</tr>
		<tr>
			<td>Tissue-Tek Cryomold</td>
			<td>Sakura, Leiden, Netherlands</td>
			<td>4566</td>
		</tr>
		<tr>
			<td>Trypsin EDTA</td>
			<td>Lonza, Verviers, Belgium</td>
			<td>7815</td>
		</tr>
		<tr>
			<td>Vitro &#8211; Clud&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td>R. Langenbrinck, Teningen, Germany</td>
			<td>04-0002&#160;</td>
		</tr>
		<tr>
			<td>&#160;&#181;-Dish 35 mm with Culture-Insert, high</td>
			<td>ibidi GmbH, Munich, Germany</td>
			<td>81176</td>
		</tr>
		<tr>
			<td>DIC Lid for &#181;-Dishes, with a glass insert</td>
			<td>ibidi GmbH, Munich, Germany</td>
			<td>80050</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MICROM HM550</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, USA</td>
			<td>46320</td>
		</tr>
		<tr>
			<td>Digital holographic microscope</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Component</td>
			<td>Model</td>
			<td>Company</td>
		</tr>
		<tr>
			<td>Inverted Microscope</td>
			<td>iMIC</td>
			<td>Till Photonics, Graefelfing, Germany</td>
		</tr>
		<tr>
			<td>Laser</td>
			<td>Compass 315M</td>
			<td>Coherent GmbH, Luebeck, Germany</td>
		</tr>
		<tr>
			<td>Microscope lens</td>
			<td>Zeiss EC Plan Neofluar 10x/0.3</td>
			<td>Zeiss, Goettingen, Germany</td>
		</tr>
		<tr>
			<td>CCD camera</td>
			<td>DMK 41BF02</td>
			<td>The Imaging Source, Bremen, Germany</td>
		</tr>
	</tbody>
</table>

multimodal quantitative phase imaging with digital holographic microscopy accurately assesses intestinal inflammation and epithelial wound healing

The incidence of inflammatory bowel disease, i.e., Crohn&#39;s disease and Ulcerative colitis, has significantly increased over the last decade. The etiology of IBD remains unknown and current therapeutic strategies are based on the unspecific suppression of the immune system. The development of treatments that specifically target intestinal inflammation and epithelial wound healing could significantly improve management of IBD, however this requires accurate detection of inflammatory changes. Currently, potential drug candidates are usually evaluated using animal models in vivo or with cell culture based techniques in vitro. Histological examination usually requires the cells or tissues of interest to be stained, which may alter the sample characteristics and furthermore, the interpretation of findings can vary by investigator expertise. Digital holographic microscopy (DHM), based on the detection of optical path length delay, allows stain-free quantitative phase contrast imaging. This allows the results to be directly correlated with absolute biophysical parameters. We demonstrate how measurement of changes in tissue density with DHM, based on refractive index measurement, can quantify inflammatory alterations, without staining, in different layers of colonic tissue specimens from mice and humans with colitis. Additionally, we demonstrate continuous multimodal label-free monitoring of epithelial wound healing in vitro, possible using DHM through the simple automated determination of the wounded area and simultaneous determination of morphological parameters such as dry mass and layer thickness of migrating cells. In conclusion, DHM represents a valuable, novel and quantitative tool for the assessment of intestinal inflammation with absolute values for parameters possible, simplified quantification of epithelial wound healing in vitro and therefore has high potential for translational diagnostic use.

Typical Setup for DHM Imaging for Digital Holographic Microscopy (DHM)
To perform bright field imaging and quantitative DHM phase contrast imaging, we applied an inverted microscope as depicted in Figure 1B. The system was modified by attaching a DHM module, as described earlier25. Digital holograms were generated by illumination the sample with the l...

Watch this Scientific Journal Video about Multimodal Quantitative Phase Imaging with Digital Holographic Microscopy Accurately Assesses Intestinal Inflammation and Epithelial Wound Healing at JoVE.com

Multimodal Quantitative Phase Imaging with Digital Holographic Microscopy Accurately Assesses Intestinal Inflammation and Epithelial Wound Healing

Accurate assessment of anti-inflammatory effects is of utmost importance for the evaluation of potential new drugs for the treatment of inflammatory bowel disease. Digital holographic microscopy provides assessment of inflammation in murine and human colonic tissue samples as well as automated multimodal evaluation of epithelial wound healing in vitro.

The incidence of inflammatory bowel disease, i.e., Crohn&#39;s disease and Ulcerative colitis, has significantly increased over the last decade. The ...

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