Anaphylaxis Imaging: Non-Invasive Measurement of Surface Body Temperature and Physical Activity in Small Animals

<div><p>In highly sensitized patients, the encounter with a specific allergen from food, insect stings or medications may rapidly induce systemic anaphylaxis with potentially lethal symptoms. Countless animal models of anaphylaxis, most often in BALB/c mice, were established to understand the pathophysiology and to prove the safety of different treatments. The most common symptoms during anaphylactic shock are drop of body temperature and reduced physical activity. To refine, improve and objectify the currently applied manual monitoring methods, we developed an imaging method for the automated, non-invasive measurement of the whole-body surface temperature and, at the same time, of the horizontal and vertical movement activity of small animals. We tested the anaphylaxis imaging in three <i>in vivo</i> allergy mouse models for i) milk allergy, ii) peanut allergy and iii) egg allergy. These proof-of-principle experiments suggest that the imaging technology represents a reliable non-invasive method for the objective monitoring of small animals during anaphylaxis over time. We propose that the method will be useful for monitoring diseases associated with both, changes in body temperature and in physical behaviour.</p></div

Additional file 1: Figure S1. of Prime and boost aerosol exposure via fog machine or shisha smoke followed by cinnamon hypersensitivity and anaphylaxis to spiced food

A) Chemical formulas of substances related to cinnamaldehyde which were related to adverse reactions in the patient; B) Chemical formulas of substances contained in smoke fluids; C) Glycerol can be transformed to acrolein under subtraction of water, and vice versa. (TIF 158 kb

Surface body temperature imaging in the milk allergy model.

<p>Mice M1-M3 were sham-treated (PBS), M4-M6 were specifically sensitized with aluminium-absorbed milk allergen casein (alum-casein), all mice were i.v. challenged with casein and monitored in the imaging cage over 20 minutes, with an image frequency of 4 frames/sec. (A) Temperature curves of individual mice; y-axis represents temperature in °C, x-axis: number of frames during 20 min. (B) The mean results of drop of the body surface temperatures over time of each mouse group were compared and differed significantly (** p<0.01).</p

The schematic (left panels) and real set up (right panels) of the imaging cage.

<p>(A) The complete device is composed of a type II animal cage, a photo- and a thermo-camera, which are connected to a computer and software. (1) Outer box. (2) Outer sidewall. (3) Above the cage and height-adjustable, a heat camera or heat image camera (false colour infrared camera or infrared camera) is fixed with a reference heat electrode placed in the field of view for precise calibration against a reference temperature module. (4) Mounted true colour camera, which records live real image pictures during the experiment. (5) Data are recorded and processed, and translated by software to a personal computer for processing, identifying grey scales in video input from connected infrared camera 3. The software comprises a data processing part and (7) a graphical user interface, which is commonly displayed on (6) a screen. (B) Four small animals, in this case mice, can be placed and monitored at the same time in the cage. (8) Transparent enclosure adapted to house four mice. (9) The cage comprises four outer sidewalls and (10) two inner walls, as well as a bottom portion. (11) Vertical movements can be additionally recorded to the imaging data by photo sensors comprising transmitters and receivers. (C) The mice are individually monitored, where the thermo measurements and the live video from the cage appear at the same time on the monitor. (12) False colour screen output. Two pictures are recorded and may be visualized on screens. The software translates the grey image recordings from the infrared camera (Fig 1A-3) in real-time into a false colour screen output. (13) True colour image of the true colour camera is displayed in parallel. (D) Rectal temperature (RT) was measured manually before and 20 minutes after i.v. allergen challenge of hypersensitive or negative control mice. Immediately after the challenge, the same mice were placed into the imaging cage (0 min), and the cameras monitored surface body temperature and movement activity continuously for 20 minutes (20 min).</p

Monitoring of surface body temperature in the peanut allergy model.

<p>Mice M1-M3 were sham-treated (PBS), M4-M6 were specifically sensitized with peanut allergen Ara h 2 (Ara h 2), all mice were i.v. challenged with Ara h 2 and monitored in the imaging cage over 20 minutes, with an image frequency of 4 frames/sec. (A) Temperature curves of individual mice; y-axis represents temperature in °C, x-axis: number of frames during 20 min. (B) The mean drops of the body surface temperatures over time of each mouse group were compared and differed significantly (*** p<0.001).</p

Comparison of body temperature measurements: rectally by hand-held thermometer (core body temperature) versus imaging cage (surface body temperature) before and after allergen challenge in 2 different allergy mouse models.

<p>Comparison of body temperature measurements: rectally by hand-held thermometer (core body temperature) versus imaging cage (surface body temperature) before and after allergen challenge in 2 different allergy mouse models.</p

Monitoring of mouse rearing activity in the peanut allergy model.

<p>(A) Readout of vertical physical activity of individual mice. Mice M1-M3 were sham-treated (PBS), M4-M6 were specifically sensitized against peanut allergen Ara h 2 (Ara h 2), and all mice were i.v. challenged with Ara h 2. The mouse cross sectional image area in pixels was recorded (y-axis). The number of signals over 20 min is given in the x-axis (4 frames/second). The frequency of the cross sectional area changes and the area variations drastically decreased in the anaphylactic Ara h 2-sensitized group, while the PBS-group with high frequency and big variations of area changes remained stable during 20 minutes. (B) Statistical analysis of the difference of mean values of changes in the cross sectional area (delta) of the PBS and alum-casein groups (**** p<0.0001).</p

Monitoring of mouse vertical physical activity in the milk allergy model.

<p>(A) Readout of vertical physical activity of individual mice. Mice M1-M3 were sham-treated (PBS), M4-M6 were specifically sensitized with aluminium-absorbed milk allergen casein (alum-casein), and all mice were i.v. challenged with casein. The mouse cross sectional image area in pixels was recorded (y-axis). The number of signals over 16 min is given in the x-axis (4 frames/second). (B) Statistical analysis of the differences (delta) of mean values of cross sectional area changes in the PBS and alum-casein groups (** p = 0.0019).</p

Horizontal physical activity of mice in the milk allergy model.

<p>Heat image frames of animals were captured (4 frames/second), and centre-of-heat-points and the distance among them calculated over a pre-set period of time. Y-axis: moved distance (pixel); x-axis: number of frames (images) captured during 20 min. Mice M1-M3 were sham-treated (PBS), M4-M6 were specifically sensitized against aluminium-absorbed milk allergen casein (alum-casein), all mice were i.v. challenged with casein. (A) Distance records of individual mice during 20 min; boxes: corresponding tracking curves of horizontal moves of each mouse. (B) Statistical comparison of the sum of moved distances between the PBS and alum-casein groups (mean+SD) showed a significant difference (****p<0.0001).</p

Expression of FcεRI α- and γ-chain but not β-chain mRNA in human intestinal epithelial cells.

<p>The expression pattern of the FcεRI complex was analyzed by real-time PCR analysis using specific primers for detection of (A) FcεRI α-, β- (not shown), and (B) γ-chain. Target gene expression levels were normalized to the average of housekeeping genes and are depicted relative to the value of subconfluent Caco-2/TC7 cells. The values are presented as means +/− SD (n = 3) from one experiment. The results are representative of two independent experiments.</p