This study was supported by the Swedish Research Council, Strategic Research Area Exodiab, Dnr 2009-1039, the Swedish Foundation for Strategic Research Dnr IRC15-0067 to LUDC-IRC, the Royal Physiographic Society in Lund, Diabetesf&#246;rbundet and Barndiabetesf&#246;rbundet.

The Regional Ethics Committee in Lund, Sweden, approved the study according to the Act Concerning the Ethical Review of Research Involving Humans. Animal experiments were performed in strict accordance with the Swedish ethics of animal experiments and approved by the ethics committees of Malm&#246; and Lund. 6 to 8-week-old immunodeficient NOD.(Cg)-Gt(ROSA)26Sortm4-Rag2-/- (NOD.ROSA-tomato.Rag2-/-) recipient mice were used as recipients for tra...

<ol>
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The authors have nothing to disclose.

A method is presented to study the human pancreatic islet cell grafting process by observing the involvement of recipient and donor tissue. After a minimal invasive surgery implanting human islets into the anterior chamber of an immunodeficient mouse eye, the mouse recovers quickly within minutes after surgery. The procedure is performed on one eye. Generally, from 5&#8211;7 days postimplantation onwards the cornea is sufficiently healed to perform intravital imaging.
In this protocol, the qua...

Diabetes mellitus describes a group of metabolic diseases characterized by elevated levels of blood glucose as results of insufficient insulin production from loss or dysfunction of pancreatic islet beta cells, often accompanied by insulin resistance. Type 1 (T1D) and type 2 diabetes (T2D) are complex diseases in which the progressive dysfunction of the beta cells causes disease development. T1D is precipitated by an autoimmune attack on the beta cells, while T2D is considered to be driven by metabolic factors, albeit with increasing evidence of low-grade systemic inflammation1. Transplantation of donor human islets, particularly to T1D patients, offers the potential for providing physiological glycemic control. However, a shortage of tissue donors and poor islet engraftment has prevented islet transplantation to become a mainstream therapeutic option. A substantial proportion of the functional islet graft is lost in the immediate posttransplantation period (24&#8211;48 h) due to the hypoxic, in&#64258;ammatory, immunogenic host environment2,3. To evaluate the efficiency of intervention methods for the improvement of islet survival, continuous monitoring of such transplantations is necessary.
In vivo techniques to image and track the fate of transplanted human pancreatic islets after transplantation still remains a challenge for diabetes research4,5. To date, noninvasive imaging techniques, including positron emission tomography (PET), magnetic resonance imaging (MRI), or ultrasound (US) show potential for the quantification and functional evaluation of transplanted islets in experimental conditions5. However, given the small islet sizes, quantitative measurements by those modalities suffer from insufficient resolution. The anterior chamber of the eye (ACE) as a transplantation site for observation is a promising noninvasive imaging solution offering effectively higher spatial resolution and frequent monitoring over long time periods6. This method has been successfully exploited to study mouse islet biology (reviewed in Yang et al.7), autoimmune immune responses8, as well as human islet grafting9,10.
Here the ACE transplantation method is combined with a 2-photon imaging approach to investigate the dynamics of the human pancreatic islet engraftment process by continuous and repeated recordings on individual islet grafts for up to 10 months after transplantation. The multiphoton imaging properties of greater imaging depths and reduced overall photobleaching and photo damage overcome the imaging limitations of confocal microscopy11. Quantification of fluorescent imaging involves several stages, including islet sample preparation, islet transplantation, image acquisition, image filtering to remove islet noise or background, segmentation, quantification, and data analysis. The most challenging step is usually partitioning or segmenting an image into multiple parts or regions. This could involve separating signal from background noise, or clustering regions of voxels based on similarities in color or shape to detect and label voxels of a 3D volume that represents islet vasculature, for example. Once segmented, statistics such as object volume sizes are typically straightforward to extract. Provided is a method for the quantification and extraction of the imaging data, such as segmentation and data visualization. Particular attention is paid to the removal of autofluorescence in human islets and distinction between islet vasculature and islet capsule forming recipient cells.

<table>
	<tbody>
		<tr>
			<td>Anasthesia machine, e.g. Anaesthesia Unit U-400</td>
			<td>Agnthos</td>
			<td>8323001</td>
			<td>used for isofluran anasthesia during surgery and imaging</td>
		</tr>
		<tr>
			<td>-induction chamber 1.4 L</td>
			<td>Agnthos</td>
			<td>8329002</td>
			<td>connect via tubing to U-400</td>
		</tr>
		<tr>
			<td>-gas routing switch</td>
			<td>Agnthos</td>
			<td>8433005</td>
			<td>connect via tubing to U-400</td>
		</tr>
		<tr>
			<td>AngioSense 680 EX</td>
			<td>Percin Elmer</td>
			<td>NEV10054EX</td>
			<td>imaging agent for injection, used to image blood vessels in human islet grafts</td>
		</tr>
		<tr>
			<td>Aspirator tubes assemblies</td>
			<td>Sigma</td>
			<td>A5177-5EA</td>
			<td>connect with pulled capillary pipettes for manual islet picking</td>
		</tr>
		<tr>
			<td>Buprenorphine (Temgesic) 0.3mg/ml</td>
			<td>Schering-Plough Europ&#233;</td>
			<td>64022</td>
			<td>fluid, for pain relief</td>
		</tr>
		<tr>
			<td>Capillary pipettes</td>
			<td>VWR</td>
			<td>321242C</td>
			<td>used together with Aspirator tubes assemblies</td>
		</tr>
		<tr>
			<td>Dextran-Texas Red (TR), 70kDa</td>
			<td>Invitrogen</td>
			<td>D1830</td>
			<td>imaging agent for injection</td>
		</tr>
		<tr>
			<td>Eye cannula, blunt end , 25 G</td>
			<td>BVI Visitec/BD</td>
			<td>BD585107</td>
			<td>custom made from Tapered Hydrode lineator [Blumenthal], dimensions: 0.5 x 22mm (25G x 7/8in) (45&#8304;), tip tapered to 30 G (0.3mm)</td>
		</tr>
		<tr>
			<td>Eye gel</td>
			<td>Novartis</td>
			<td></td>
			<td>Viscotears, contains Carbomer 2 mg/g</td>
		</tr>
		<tr>
			<td>Hamilton syringe 0.5 ml, Model 1750 TPLT</td>
			<td>Hamilton</td>
			<td>81242</td>
			<td>Plunger type gas-tight syringe for islet injection</td>
		</tr>
		<tr>
			<td>Head holder</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Head holding adapter</td>
			<td>Narishige</td>
			<td>SG-4N-S</td>
			<td>assemled onto metal plate</td>
		</tr>
		<tr>
			<td>-gas mask</td>
			<td>Narishige</td>
			<td>GM-4-S</td>
			<td></td>
		</tr>
		<tr>
			<td>-UST-2 Solid Universal Joint</td>
			<td>Narishige</td>
			<td>UST-2</td>
			<td>assemled onto metal plate</td>
		</tr>
		<tr>
			<td>-custom made metal plate for head-holder assembly</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Dumont #5, straight</td>
			<td>Agnthos</td>
			<td>0207-5TI-PS or 0208-5-PS</td>
			<td>attached to UST-2 (custom made)</td>
		</tr>
		<tr>
			<td>Heating pad, custom made</td>
			<td></td>
			<td></td>
			<td>taped to the stereotaxic platform</td>
		</tr>
		<tr>
			<td>Human islet culture media</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-CMRL 1066</td>
			<td>ICN Biomedicals</td>
			<td></td>
			<td>cell culture media for human islets</td>
		</tr>
		<tr>
			<td>-HEPES</td>
			<td>GIBCO BRL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-L-glutamin</td>
			<td>GIBCO BRL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Gentamycin</td>
			<td>GIBCO BRL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Fungizone</td>
			<td>GIBCO BRL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Ciproxfloxacin</td>
			<td>Bayer healthcare AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Nicotinamide</td>
			<td>Sigma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Image analysis software</td>
			<td>Bitplane</td>
			<td></td>
			<td>Imaris 9</td>
		</tr>
		<tr>
			<td>Image Aquisition software</td>
			<td>Zeiss</td>
			<td></td>
			<td>ZEN 2010</td>
		</tr>
		<tr>
			<td>Infrared lamp</td>
			<td>VWR</td>
			<td>1010364937</td>
			<td>used to keep animals warm in the wake-up cage</td>
		</tr>
		<tr>
			<td>Isoflurane Isoflo</td>
			<td>Abott Scandinavia/Apotek</td>
			<td></td>
			<td>fluid, for anesthesia</td>
		</tr>
		<tr>
			<td>Needle 25 G (0.5 x 16mm), orange</td>
			<td>BD</td>
			<td>10442204</td>
			<td>used as scalpel</td>
		</tr>
		<tr>
			<td>Petri dishes, 90mm</td>
			<td>VWR</td>
			<td>391-0440</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Photon/confocal microscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-LSM7 MP upright microscope</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Ti:Sapphire laser Tsunami</td>
			<td>Spectra-Physics, Mai Tai</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-long distance water-dipping lens 20x/NA1.0</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-ET710/40m (Angiosense 680)</td>
			<td>Chroma</td>
			<td>288003</td>
			<td></td>
		</tr>
		<tr>
			<td>-ET645/65m-2p (TR)</td>
			<td>Chroma</td>
			<td>NC528423</td>
			<td></td>
		</tr>
		<tr>
			<td>-ET525/50 (GFP)</td>
			<td>Chroma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-ET610/75 (tomato)</td>
			<td>Chroma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-main beam splitter T680lpxxr</td>
			<td>Chroma</td>
			<td>T680lpxxr</td>
			<td>Dichroic mirror to transmit 690 nm and above and reflect 440 to 650 nm size 25.5 x 36 x 1 mm</td>
		</tr>
		<tr>
			<td>Polythene tubing (0.38mm ID, 1.09 mm OD)</td>
			<td>Smiths Medical Danmark</td>
			<td>800/100/120</td>
			<td>to connect with Hamilton syringe and eye canula</td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Nikon</td>
			<td></td>
			<td>Model SMZ645, for islet picking</td>
		</tr>
		<tr>
			<td>Stereomicroscope (Flourescence)</td>
			<td></td>
			<td></td>
			<td>for islet graft imaging</td>
		</tr>
		<tr>
			<td>-AZ100 Multizoom</td>
			<td>Nikon</td>
			<td></td>
			<td>wide field and long distance</td>
		</tr>
		<tr>
			<td>-AZ Plan Apo 1x</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-AZ Plan Apo 4x</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-AZ-FL Epiflourescence with C-LHGFI HG lamp</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-HG Manual New Intensilight</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>-Epi-FL Filter Block TEXAS RED</td>
			<td>Nikon</td>
			<td></td>
			<td>contains EX540-580, DM595 and BA600-660</td>
		</tr>
		<tr>
			<td>-Epi-FL Filter Block G-2A</td>
			<td>Nikon</td>
			<td></td>
			<td>(EX510-560, DM575 and BA590)</td>
		</tr>
		<tr>
			<td>-Epi-FL Filter Block B-2A</td>
			<td>Nikon</td>
			<td></td>
			<td>(EX450-490, DM505 and BA520)</td>
		</tr>
		<tr>
			<td>-DS-Fi1 Colour Digital Camera (5MP)</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe 1-ml, Omnitix</td>
			<td>Braun</td>
			<td>9161406V</td>
			<td>for Buprenorphine injection, used with 27 G needle</td>
		</tr>
		<tr>
			<td>Surgical tape</td>
			<td>3M</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

longitudinal in vivo imaging and quantification of human pancreatic islet grafting and contributing host cells in the anterior eye chamber

Imaging beta cells is a key step towards understanding islet transplantation. Although different imaging platforms for the recording of beta cell biology have been developed and utilized in vivo, they are limited in terms of allowing single cell resolution and continuous longitudinal recordings. Because of the transparency of the cornea, the anterior chamber of the eye (ACE) in mice is well suited to study human and mouse pancreatic islet cell biology. Here is a description of how this approach can be used to perform continuous longitudinal recordings of grafting and revascularization of individual human islet grafts. Human islet grafts are inserted into the ACE, using NOD.(Cg)-Gt(ROSA)26Sortm4-Rag2-/-mice as recipients. This allows for the investigation of the expansion of recipient versus donor cells and the contribution of recipient cells in promoting the encapsulation and vascularization of the graft. Further, a step-by-step approach for image analysis and quantification of the islet volume or segmented vasculature and islet capsule forming recipient cells is outlined.

Non-labeled human islets were transplanted into the ACE of 8-week-old female NOD.(Cg)-Gt(ROSA)26Sortm4-Rag2-/-(NOD.ROSA-tomato.Rag2&#8722;/&#8722;) recipient mice. To prevent human tissue rejection, immunodeficient Rag2 knockout mice were chosen as recipients. In these transgenic mice, all cells and tissues expressed a membrane-targeted tomato fluorescence protein (mT) that allows clear identification of the recipient and the donor tissue. Repe...

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Longitudinal In Vivo Imaging and Quantification of Human Pancreatic Islet Grafting and Contributing Host Cells in the Anterior Eye Chamber

The goal of this protocol is to continuously monitor the dynamics of the human pancreatic islet engraftment process and the contributing host versus donor cells. This is accomplished by transplanting human islets into the anterior chamber of the eye (ACE) of an NOD.(Cg)-Gt(ROSA)26Sortm4-Rag2-/-mouse recipient followed by repeated 2-photon imaging.

Imaging beta cells is a key step towards understanding islet transplantation. Although different imaging platforms for the recording of beta cell biology ...

The ACE is an optimal imaging sights. It supports to repeat it in long-term in vivo imaging of islet cells in order to study their function and viability in a grafting situation. It can also be extended to study other aspects under physiological and pathological conditions in real time.The advantage of the ACE technique lies in the fact that the same individual human pancreatic islets can be followed noninvasively with sub-cellular resolution for an extended period of time. Success rates of beta cell replacement therapy continue to improve. However, evaluating the efficiency of islet grafting and survival in vivo, remains still challenging.This method could help assess and optimize the outcomes of islet transplantations. This approach is not restricted to pancreatic islets only. It is also well-suited to study tissues affected.For example, in diabetic complications, like kidney glomeruli or liver pieces, just to name a few. To begin place the mouse on a warm heating pad position it in the head holder and put on the nose mask. Use the thumb and index finger to lift the head slightly.Fasten it with the metallic pieces on the sides. Making sure that the ear pieces fix the head directly below the ears. Subcutaneously inject buprenorphine solution into the back of the mouse.Gently retract the eyelids of the eye to be transplanted using blunt forceps. Pop the eye out and loosely fix it with a pair of tweezers covered with a polythene tube. After transferring the eyelids to a Petri dish with PBS, pick up approximately 20 to 30 islets in the eye cannular.Using a 25 gauge needle level upwards, carefully insert the tip into the cornea and make a single lateral incision. Carefully lift the cornea with the cannula preloaded with islets, and slowly release the islets into the eye. Slowly retract the cannula and apply eye gel to the eye.After 10 minutes, remove the forceps, holding the eyelid and put the eye back to its normal position. For imaging of implanted human islets with two photon microscopy, place the head holder platform under the microscope and administer eye gel onto the eye as an immersion liquid between the cornea and the lens. Position the eye under the objective and image the implanted human islets as described in the text manuscript.To remove the autofluorescence, go to the image processing tab, choose channel arithmetics and type channel one minus channel two. This creates a new channel four. Rename it vasculature.Repeat this process and type channel three minus channel two to create a new channel five and rename it tomato all. To define the islet manually create a new surface and choose edit manually in the wizard. Keep the pointer in select mode and in 3D view.And click volume to visualize sections. In the drawing tab choose contour and click draw to start drawing contours around the islet border, starting in slice position one. Then move to a new slice position and repeat drawing contours.Finish with the last slice on the top of the islet and end by clicking the create surface tab. Next segment, islet vasculature and islet tomato fluorescence using islet mask. Choose the previously defined islet mask object, go to the editing tab and click the mask all tab, which opens a new window.Choose the vasculature channel in the channel selection dropdown menu and activate options duplicate channel before applying mask. Constant inside, outside and set voxels outside surface to 0.000 which creates a new channel six. Rename this channel islet vasculature.Repeat the previous steps and choose the tomato all in the channel selection dropdown menu, to create the new channel, rename it, islet tomato. Then create a new surface in the scene menu and choose automatic creation in the wizard. Set the source channel to the previously created islet vasculature and choose background subtraction.Optionally use filters. For example choose volume and adjust the filter in the window, which can remove selected service objects. Finish the wizard and name the new surface object, islet vasculature.In the islet vasculature service object go to the editing tab and click the mask all tab, which opens a new window. Choose the islet tomato channel in the channel selection dropdown menu and set voxels outside surface to 10.000 which creates a new channel. Rename this channel islet tomato vasculature.To segment tomato capsule fluorescent signal choose channel arithmetics in the image processing tab and type channel seven minus channel eight creating the new channel. Rename it tomato capsule. Create a new surface as previously described and choose source channels, islet tomato vasculature or tomato capsule in the wizard.Then perform background subtraction. Open the islet backscatter file and create a new surface. In the wizard, choose automatic creation and define region of interest.If needed, adjust the threshold in absolute intensity. The surface object can be clicked on or off, to crosscheck with corresponding channel intensity. When finished close the wizard.Finally, perform quantification, select a created surface object in the scene menu, and go to the statistics tab. To retrieve detailed volume data, choose the detailed tab and select specific values and volume from the dropdown menu. To retrieve total volume value go to the detailed tab and choose average values.This protocol was used to transplant non labeled human islets into the interior chamber of the eye of eight-week old female red fluorescent recipient mice. Interactive imaging software was then used to extract quantitative data from the images. In vivo fluorescens imaging, the human islet grafts was compromised by significant interference from tissue autofluorescence which was not observed in mice islet grafts.To improve the signal to noise ratio, the autofluorescence channel was subtracted. Then the islet boundary called islet mask and the corresponding channels were defined manually. Finally, the segmentation of the tomato signal into the eyelid vasculature and eyelid capsule and final surface rendering was used to extract quantitative data.Here as a representative longitudinal imaging session of the same human islet graft at two weeks, two months, five months and eight months post transplantation. MIP images of originally recorded raw data, processed images after islet autofluorescence removal and a segmented islet objects are shown. When performing the eyelid injection, make sure to preload the islets in a small volume and use flexible twin light arms on your stereo microscope, to highlight the eye chamber space in order to successfully inject the islets into the ACE.Following the in vivo imaging the eyes can be fixed and further investigated for antibody staining and conventional histology. This technique is very useful for functional studies of individual human islets in real time and under physiological conditions, especially in the context of vascularization, viability and metabolic studies.

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JoVE Journal

Medicine

5.0K vistas.  Lund University. El ACE es una mira de imagen óptima. Es compatible con repetirlo en imágenes in vivo a largo plazo de células de islotes con el fin de estudiar su función y viabilidad en una situación de injerto. También se puede extender para estudiar otros aspectos bajo condiciones fisiológicas y patológicas en tiempo real.La ventaja de la técnica ACE radica en el hecho de que los mismos islotes pancreáticos humanos individuales pueden seguirse de forma no invasiva con resolución subcelul...