The histologic findings of a subretinal band and epiretinal membrane (ERM) excised from two patients who developed retinal detachments (RDs) after non-U.S. Food and Drug Administration-regulated intravitreal “stem cell” injections are reported. Both membranes were composed of fibrocellular tissue that stained positively with Smooth Muscle Actin and Masson's trichrome, consistent with collagenous and smooth muscle composition. CD34 immunostain (for hematopoietic cells) was negative for the subretinal band and minimally positive for the ERM. The authors speculate that the “stem cells” may cause RDs by differentiation into myofibroblasts that cause tractional membranes, though further studies are warranted.
[Ophthalmic Surg Lasers Imaging Retina. 2019;50:125–131.]
Enthusiasm for stem cell treatment has given rise to numerous for-profit clinics offering unproven autologous “stem cell” injections (ASCIs) without the oversight of the U.S. Food and Drug Administration (FDA).1 The “stem cells” are derived most commonly from autologous adipose tissue or bone marrow. Since the exact composition of the cellular injection cannot be confirmed, the injected cells are referred to as “stem cells” throughout this paper. Several reports have documented profound vision loss following ASCIs.2–5 The causes of vision loss described have included tractional and rhegmatogenous retinal detachment (TRD and RRD) with proliferative vitreoretinopathy (PVR), epiretinal membrane (ERM) formation, vitreous hemorrhage, hemorrhagic retinopathy, lens dislocation, and ocular hypertension.2–5 The histologic findings of two cases are presented, in which a subretinal band (Case 1) and an ERM (Case 2) were excised during surgery to repair retinal detachment following ASCI.
A 77-year-old woman with advanced exudative AMD in both eyes underwent periumbilical liposuction and received intravenous and bilateral ASCI derived from the adipose tissue at an outside institution.
Prior to treatment, her best-corrected visual acuity (BCVA) was 20/400 in the right eye. Her clinical course has been reported.4 She developed a combined TRD/RRD in the right eye 3 months after ASCI, for which she underwent pars plana vitrectomy (PPV) and lensectomy. Seven months after ASCI, she presented to our institution. BCVA was hand motions (HM) in the right eye. The right eye was aphakic with a TRD/RRD with prominent subretinal fibrotic bands under the macula under silicone oil (SO) (Figures 1G and IH). Optical coherence tomography (OCT) confirmed macular detachment in the right eye (Figure 1I).
Baseline optical coherence tomography (OCT) images are shown 4 months prior to autologous “stem cell” injections (ASCIs) in the right (A) and left (B) eyes. Three weeks after ASCI, the normal retinal contour was blunted by epiretinal membrane (ERM) formation in the right (C) and left (D) eyes. Vitreous hemorrhage and debris were noted bilaterally. Five weeks after ASCI, the ERM in the right eye progressed, resulting in progressive irregularities in the retinal contour (E). The left eye developed a tractional retinal detachment (RD) (F). By 7 months after ASCI, the patient had undergone a retinal detachment repair in the right eye at an outside institution. Fundus photographs show recurrent rhegmatogenous /tractional RDs with proliferative vitreoretinopathy in the right (G) and left (H) eyes. The view in the left eye is limited by a brunescent cataract. OCT imaging showed detachment of the right macula with a thin, hyperreflective overlying membrane (I). OCT imaging of the left eye showed thinned and atrophic retina with a thin, hyperreflective overlying membrane (J).
The right eye underwent scleral buckle, 25-gauge PPV, subretinal membrane peel, retinectomy, endolaser, and SO tamponade. A subretinal band was sent for histologic examination. One month after the surgery, BCVA was HM in the right eye, and the retina remained flat under SO, though there was extensive PVR with some traction on the scleral buckle. Ultimately the retina re-detached and the patient opted not to attempt further surgery.
Pathology Results of Case 1 (Figure 2)
Histologic examination disclosed fibrovascular tissue that contained pigment-containing cells and spindle-shaped cells with fragments of glial tissue (Figure 2). Foci of dropout spaces were present (silicone oil). The membrane stained strongly positive with Smooth Muscle Actin (SMA) immunostain (Leica Biosystems, Wetzlar, Germany) and positively for collagen deposition with Masson's trichrome stain. CD34 immunostain (Leica Biosystems, Wetzlar, Germany) (for hematopoietic cells) was negative. CD45 stain (common leukocyte antigen) was moderately positive for inflammatory cells.
(A) Histology of subretinal band from Case 1 demonstrates a fibrovascular tissue that contained an admixture of pigment-containing cells (asterisk) and spindle-shaped cells with fragments of glial tissue (presumed neural retina). Foci of dropout spaces were present, consistent with silicone oil (hematoxylin-eosin, original magnification ×200). (B) The membrane stained strongly positive with Smooth Muscle Actin immunostain (Leica Biosystems, Wetzlar, Germany), colored red and marked with an asterisk (original magnification ×200). (C) The specimen was positive for collagen deposition with Masson's trichrome, colored green and marked with an asterisk (original magnification ×200). (D) CD34 immunostain (Leica Biosystems, Wetzlar, Germany) was negative (original magnification ×200).
A 70-year-old woman with bilateral autoimmune optic neuropathy received bilateral bone-marrow derived “stem cell” injections at an outside center. Pre-procedure BCVA was 3/200 and 20/800 in the right and left eyes, respectively. The “stem cell” treatments were given as part of a patient-funded clinical trial (NCT01920867). Her right eye underwent PPV with “stem cell” injection into the optic nerve head, vitreous, and retrobulbar space. The left eye received intravitreal and retrobulbar injection of “stem cells” without injection to the optic nerve head. She also received intravenous “stem cell” injection.
Within a week of the procedure, she presented to our institution with no light perception (NLP) vision in the right eye. View of the fundus was hazy bilaterally due to vitreous cells. Both eyes had optic nerve pallor at baseline (Figures 3A and 3B). There was new hemorrhage around the right optic nerve head but no RD at that time.
(A) Fundus photo of the right eye taken 1 week after autologous “stem cell” injections (ASCIs) shows a peripapillary hemorrhage, which is most likely secondary to the injection into the optic nerve. The media is mildly hazy due to presence of vitreous cells. (B) Fundus photo of the left eye shows hazy media due to vitreous cells. Both eyes had optic nerve pallor prior to ASCI.
Three months later, she was noted to have new extensive ERMs with cystoid macular edema in the left eye greater than right eye, which worsened further 6 months post-procedure (Figures 4A and 4B). OCT showed disruption of outer retinal ellipsoid zones and RPE irregularities in both eyes (Figures 4C and 4D).
Six months after autologous “stem cell” injections (ASCIs), the red-free photo (A) and optical coherence tomography (OCT) (B) of the right eye show a dense epiretinal membrane (ERM) with loss of the foveal contour. The OCT shows cystoid macular edema (CME) with appearance of outer retinal schisis. Red-free photo of the left eye (C) shows a denser ERM that is causing tenting of the retina. The OCT of the left eye (D) shows that the ERM is accompanied by severe CME that has resulted in a large schisis cavity that disrupts the photoreceptor segments.
In May 2017 (almost 3 years after ASCI), BCVA deteriorated to HM bilaterally. She had dense nuclear sclerotic and posterior subcapsular cataracts in both eyes. The right eye had ERM but no RD (Figures 5A and 5C). The left eye had a macula-involving RD with significant PVR and ERM (Figure 5B). She underwent PPV, lensectomy, membrane peel, surgical iridectomy, and SO injection in the left eye. An ERM was sent for histologic examination. At postoperative month 6, the macula in the left eye was detached and BCVA was limited to LP bilaterally (Figure 6B). The right eye continued to have ERM without RD (Figure 6A).
Eleven months after autologous “stem cell” injections (ASCIs), the widefield fundus photo of the right eye (A) shows persistence of the epiretinal membrane (ERM), but no retinal detachment (RD). Widefield fundus photo of the left eye (B) shows an inferior macula-involving RD with proliferative vitreoretinopathy. Optical coherence tomography (OCT) of the right eye (C) shows worsening of the ERM. An OCT of the left eye was attempted but a satisfactory image could not be captured due to the bullous nature of the RD.
At last follow-up (17 months after autologous “stem cell” injections [ASCIs] and 6 months after retinal detachment repair in the left eye), the optical coherence tomography (OCT) of the right eye (A) shows stable appearance of the epiretinal membrane. OCT of the left eye (B) shows that the macula has re-detached.
Pathology Results of Case 2 (Figure 7)
Histologic examination disclosed periodic acid Schiff-positive internal limiting membrane and a thick fibrocellular tissue present along one margin. The specimen stained positively for collagen deposition with Masson's trichrome. SMA stained moderately positive, whereas CD34 (for hematopoietic cells) stained minimally positive.
One clinicopathologic case report of ERM formation following intravitreal injection of bone marrow “stem cells” exists. This occurred in a 71-year-old Korean woman with retinitis pigmentosa who received bilateral bone marrow derived ASCI within the context of a patient-funded clinical trial (email communication with Oh Woong Kwon, May 2018), and then developed a dense ERM in the left eye 4 months later. Many CD34-positive cells and NeuN-positive neuronal cells were noted in the biopsy specimen, causing the authors to speculate that CD34-positive hematopoietic “stem cells” differentiated into neuronal cells.6 The CD34 protein is a transmembrane sialomucin protein that is classically expressed on early hematopoietic and vascular-associated tissue and is a well-established marker for bone marrow derived stem cells.7
In contrast, neither of the membrane specimens we present stained strongly with CD34 immunostain. The ERM (Case 2) had only minimal CD34 staining, even though the injected “stem cells” were derived from bone marrow, the site of hematopoiesis. Both specimens stained positively with Masson's trichrome and SMA, suggesting that collagen and smooth muscle were prominent components of the membranes.
It has been theorized that stem cells may settle on the retinal surface, differentiate into myofibroblast-like cells, and produce contractile membranes similar to PVR.2 If this is true, they may cause RD similar to RPE cells that migrate to the surface of the retina after RRD.8 The possibility that the membranes in the current study were typical PVR following retinal breaks cannot be excluded. However, the repeated association of ERM formation and delayed combined TRD/RRD with early PVR has now been documented in multiple eyes following ASCI. The specimens detailed in this report suggest that “stem cells,” though present, make up a minor component of these membranes, with the majority of the membranes composed of differentiated cells seen in typical PVR (which may include glial and neuroendocrine cells, RPE, collagen, and smooth muscle).9
There are several ongoing FDA-regulated clinical trials that explore the safety and efficacy of intravitreal bone marrow stem cell injection for degenerative retinal conditions. Although sample sizes are small, these studies showed a favorable safety profile without evidence of toxicity.10,11 Subretinal transplantation of human embryonic stem cell-derived RPE has also been tolerated without evidence of post-surgical ERM or RD according to a phase 1/2 trial for AMD and SMD.12 Many of the reported cases of ERM or RD following ASCI occurred at unregulated stem cell clinics, limiting our knowledge of the exact methods and compositions used to prepare these injections. The lack of these details prevents us from drawing meaningful conclusions about the difference between the membranes found after intravitreal injection of adipose-derived “stem cells” or bone marrow-derived “stem cells.” The stromal vascular fraction used to isolate adipose-derived “stem cells” is known to include fibroblast or fibroblast-like cells.13 Intravitreal injection of fibroblasts has been used to create a rabbit PVR model.14 Adipose- and bone marrow-derived mesenchymal stem cells have a fibroblast-like appearance and are found to have upregulation of gene expression for fibronectin, which is thought to play a role in PVR pathogenesis.15,16 Larger prospective studies are warranted to further characterize the safety profile of intravitreal and subretinal stem cell transplantation.
- Turner LG. US clinics marketing unproven and unlicensed adipose-derived autologous stem cell interventions. Regen Med. 2015;10(4):397–402. doi:10.2217/rme.15.10 [CrossRef]
- Kuriyan AE, Albini TA, Townsend JH, et al. Vision loss after intravitreal injection of autologous “stem cells” for AMD. N Engl J Med. 2017;376(11):1047–1053. doi:10.1056/NEJMoa1609583 [CrossRef]
- Leung EH, Flynn HW Jr, Albini TA, Medina CA. Retinal detachment after subretinal stem cell transplantation. Ophthalmic Surg Lasers Imaging Retina. 2016;47(6):600–601. doi:10.3928/23258160-20160601-16 [CrossRef]
- Saraf SS, Cunningham MA, Kuriyan AE, et al. Bilateral retinal detachments after intravitreal injection of adipose-derived ‘stem cells’ in a patient with exudative macular degeneration. Ophthalmic Surg Lasers Imaging Retina. 2017;48(9):772–775. doi:10.3928/23258160-20170829-16 [CrossRef]
- Rong AJ, Lam BL, Ansari ZA, Albini TA. Vision loss secondary to autologous adipose stem cell injections: A rising problem. JAMA Ophthalmol. 2018;136(1):97–99. doi:10.1001/jamaophthalmol.2017.5453 [CrossRef]
- Kim JY, You YS, Kim SH, Kwon OW. Epiretinal membrane formation after intravitreal autologous stem cell implantation in a retinitis pigmentosa patient. Retin Cases Brief Rep. 2017;11(3):227–231. doi:10.1097/ICB.0000000000000327 [CrossRef]
- Calloni R, Cordero EA, Henriques JA, Bonatto D. Reviewing and updating the major molecular markers for stem cells. Stem Cells Dev. 2013;22(9):1455–1476. doi:10.1089/scd.2012.0637 [CrossRef]
- Pennock S, Haddock LJ, Eliott D, Mukai A, Kazlauskas A. Is neutralizing vitreal growth factors a viable strategy to prevent proliferative vitreoretinopathy?Prog Retin Eye Res. 2014;40:16–34. doi:10.1016/j.preteyeres.2013.12.006 [CrossRef]
- Brown KR, Dubovy SR, Relhan N, Flynn HW Jr., Clinicopathologic correlation of a subretinal proliferative vitreoretinopathy band in a patient with chronic recurrent retinal detachment. Case Reports in Ophthalmology. 2018;9(2):279–282. doi:10.1159/000488931 [CrossRef]
- Park SS, Bauer G, Abedi M, et al. Intravitreal autologous bone marrow CD34+ cell therapy for ischemic and degenerative retinal disorders: preliminary phase 1 clinical trial findings. Invest Ophthalmol Vis Sci. 2014;56(1):81–89. doi:10.1167/iovs.14-15415 [CrossRef]
- Siqueira RC, Messias A, Voltarelli JC, Scott IU, Jorge R. Intravitreal injection of autologous bone marrow-derived mononuclear cells for hereditary retinal dystrophy: A phase I trial. Retina. 2011;31(6):1207–1214. doi:10.1097/IAE.0b013e3181f9c242 [CrossRef]
- Schwartz SD, Regillo CD, Lam BL, et al. Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt's macular dystrophy: Follow-up of two open-label phase 1/2 studies. Lancet. 2015;385(9967):509–516. doi:10.1016/S0140-6736(14)61376-3 [CrossRef]
- Yoshimura K, Shigeura T, Matsumoto D, et al. Characterization of freshly isolated and cultured cells derived from the fatty and fluid portions of liposuction aspirates. J Cell Physiol. 2006;208(1):64–76. doi:10.1002/jcp.20636 [CrossRef]
- Ophir A, Blumenkranz MS, Claflin AJ. Experimental intraocular proliferation and neovascularization. Am J Ophthalmol. 1982;94(4):450–457. doi:10.1016/0002-9394(82)90238-0 [CrossRef]
- Kern S, Eichler H, Stoeve J, Külter H, Bieback K. Comparative analysis of mesenchymal stem cells from bone marrow, umbilical cord blood, or adipose tissue. Stem Cells. 2006;24(5):1294–1301. doi:10.1634/stemcells.2005-0342 [CrossRef]
- Robbins SG, Brem RB, Wilson DJ, et al. Immunolocalization of integrins in proliferative retinal membranes. Invest Ophthalmol Vis Sci. 1994;35(9):3475–3485.