Chronic graft-versus-host disease (cGVHD) is a major complication of hematopoietic stem cell transplantation. Dry eye disease is the prominent ocular sequel of cGVHD and is caused by excessive inflammation and fibrosis in the lacrimal glands. Heavy chain-Hyaluronan/Pentraxin 3 (HC-HA/PTX3) is a complex purified from human amniotic membrane (AM) and known to exert anti-inflammatory and anti-scarring actions. In this study, we utilized a mouse model of cGVHD to examine whether HC-HA/PTX3 could attenuate dry eye disease elicited by cGVHD. Our results indicated that subconjunctival and subcutaneous injection of HC-HA/PTX3 preserved tear secretion and conjunctival goblet cell density and mitigated inflammation and scarring of the conjunctiva. Such therapeutic benefits were associated with suppression of scarring and infiltration of inflammatory/immune cells in the lacrimal glands. Furthermore, HC-HA/PTX3 significantly reduced the extent of infiltration of CD45+ CD4+ IL-17+ cells, CD45+CD34+ collagen I+ CXCR4+ fibrocytes, and HSP47+ activated fibroblasts that were accompanied by upregulation of collagen type Iα1, collagen type IIIα1 and NF-kB in lacrimal glands. Collectively, these pre-clinical data help prove the concept that subcutaneous and subconjunctival injection of HC-HA/PTX3 is a novel approach to prevent dry eye disease caused by cGVHD and allow us to test its safety and efficacy in future human clinical trials.
Invest Ophthalmol Vis Sci. 2016 Apr 1;57(5):ORSFh1-8. doi: 10.1167/iovs.15-17637..
HC-HA/PTX3 Purified From Amniotic Membrane as Novel Regenerative Matrix: Insight Into Relationship Between Inflammation and Regeneration.
Human limbal palisade of Vogt is an ideal model for studying and practicing regenerative medicine due to their accessibility. Nonresolving inflammation is a common manifestation of limbal stem cell deficiency, which is the major cause of corneal blindness, and presents as a threat to the success of transplanted limbal epithelial stem cells. Clinical studies have shown that the efficacy of transplantation of limbal epithelial stem cells can be augmented by transplantation of cryopreserved human amniotic membrane (AM), which exerts anti-inflammatory, antiscarring, and antiangiogenic action to promote wound healing.
Review of published data to determine the molecular action mechanism explaining how AM exerts the aforementioned therapeutic actions.
From the water-soluble extract of cryopreserved AM, we have biochemically purified one novel matrix component termed heavy chain (HC)-hyaluronan (HA)/pentraxin 3 (PTX3) as the key relevant tissue characteristic responsible for the aforementioned AM’s efficacy. Heavy chain-HA is a complex formed by a covalent linkage between HA and HC1 of inter-α-trypsin inhibitor (IαI) by tumor necrosis factor-stimulated gene-6 (TSG-6). This complex may then be tightly associated with PTX3 to form HC-HA/PTX3 complex. Besides exerting an anti-inflammatory, antiscarring, and antiangiogenic effects, HC-HA/PTX3 complex also uniquely maintains limbal niche cells to support the quiescence of limbal epithelial stem cells.
We envision that HC-HA/PTX3 purified from AM can be used as a unique substrate to refine ex vivo expansion of limbal epithelial stem cells by maintaining stem cell quiescence, self-renewal and fate decision. Furthermore, it can also be deployed as a platform to launch new therapeutics in regenerative medicine by mitigating nonresolving inflammation and reinforcing the well-being of stem cell niche.
Invest Ophthalmol Vis Sci. 2017 Mar 1;58(3):1586-1593. doi: 10.1167/iovs.16-20834.
Topical Cryopreserved Amniotic Membrane and Umbilical Cord Eye Drops Promote Re-Epithelialization in a Murine Corneal Abrasion Model.
To evaluate morselized amniotic membrane and umbilical cord (AMUC) eye drops in promoting corneal re-epithelialization.
Following a 2-mm diameter central epithelial wound in one eye of 48 normal C57BL/6 mouse corneas, 10 μL of saline with (n = 24) or without (n = 24) AMUC was applied three times a day for 6 days. The corneal epithelial defect was measured using 0.1% fluorescein, while corneal epithelial regularity was measured by assessment of a reflected light off the corneal surface. Hematoxylin and eosin and immunohistochemistry was performed for Ki-67, CD45, βIII-tubulin, and keratin12. Safety and toxicity were also assessed by monitoring physical activity and body weight.
Compared with the vehicle saline control, AMUC resulted in a significantly smaller corneal epithelial defect at 12 hours (P = 0.002), 1 day (P = 0.016), and 2 days (P = 0.04) post abrasion. Amniotic membrane and umbilical cord also achieved a more rapid complete epithelialization (3.15 ± 1.44 vs. 4.00 ± 1.63 days, P = 0.06) and induced a higher incidence of corneal regularity without affecting physical activity and body weight. Spearman correlation showed that epithelialization was significantly correlated with treatment groups (P < 0.001), time (P < 0.001), and corneal regularity (P = 0.04). Amniotic membrane and umbilical cord significantly decreased CD45+ cell infiltration in the peripheral cornea (P < 0.05) and promoted Ki-67+ cells in the central corneal epithelium (P < 0.05).
Topical AMUC significantly promotes corneal epithelialization and restores corneal regularity by reducing inflammation and promoting proliferation in a murine model of corneal abrasion without causing safety or toxicity concerns. This encouraging preclinical finding warrants a controlled human trial in the future.