Selection Criteria Optimal for Recovery of Inner Ear Tissues From Deceased Organ Donors

Abstract

Objective: To identify optimal conditions for recovering viable inner ear tissues from deceased organ donors.

Setting: Tertiary recovery hospitals and Donor Network West Organ Recovery Center.

Interventions: Recovering bilateral inner ear tissues and immunohistological analysis.

Main outcome measures: Immunohistochemical analysis of utricles from human organ donors after brain death (DBD) or donors after cardiac death (DCD).

Results: Vestibular tissues from 21 organ donors (39 ears) were recovered. Of these, 18 donors (33 utricles) were examined by immunofluorescence. The sensory epithelium was present in seven utricles (two from DBD and five from DCD). Relative to DBD utricles, DCD organs more commonly displayed dense populations of hair cells and supporting cells. Relative to DBD, DCD had significantly shorter postmortem interval time to tissue recovery (<48 h). Compared to donors with no sensory epithelium, donors with intact and viable sensory epithelium (both DCD and DBD) had significantly shorter lag time to resuscitation prior to hospital admission (6.4 ± 9.2 vs 35.6 ± 23.7 min, respectively) as well as a shorter time between pronouncements of death to organ recovery (22.6 ± 30.4 vs 64.8 ± 22.8 h, respectively).

Conclusions: Organ donors are a novel resource for bilateral inner ear organs. Selecting tissue donors within defined parameters can optimize the quality of recovered inner ear tissues, thereby facilitating future research investigating sensory and nonsensory cells.

Figure 1:. Immunohistochemistry of utricles from human organ donors.

A-D) Whole mount preparation of utricles were immunolabeled for the hair cell marker Myosin7a and the supporting cell markers Sox2. In utricles from organ donors #13 and #9, many hair cells and supporting cells were observed in (A and B). A’-B’’’) Representative confocal images of the sensory epithelium at high magnification. A’’’’-B’’’’) orthogonal views of A’ and B’. (C-D) High and low magnification images showing no or few hair cells and a variable number of supporting cells in utricles from organ donors #4 and #7. E-F) In seven utricles from five organ donors, hair cell density was found to be 79.8±13.4 per 10,000 μm² and supporting cell density 165.1±51.8 per 10,000 μm². Donor #9 is a cardiac death, from whom bilateral utricles showed the highest hair cell and supporting cell density (98.6 and 215.8 per 10,000 μm² respectively). Donor #5 is a brain death donor, from whom the utricle from the right ear had the lowest hair cell and supporting cell densities (64.8 and 66.7 per 10,000 μm² respectively). Each data point represents cell density from high magnification images (1–5 per utricle). Data shown as mean±S.D., scale bars: A-D) 200 μm, A’-D’) 20 μm.

Figure 2:. Pyknotic nuclei in utricular sensory epithelia from an organ donor suffering from brain injury.

A) Low magnification image of a whole mount preparation of utricle recovered from donor #15 who sustained blunt head trauma 117 hours prior to tissue procurement, showing the presence of nuclei and some hair cells. B-D) High magnification images taken from regions in (A). Nuclei were stained with DAPI showing many cells were pyknotic (asterisks). Scale bar: A) 500 μm, B-D) 20 μm.