@article {1592, title = {Local release of tacrolimus from hydrogel-based drug delivery system is controlled by inflammatory enzymes in vivo and can be monitored non-invasively using in vivo imaging.}, journal = {PLoS One}, volume = {13}, year = {2018}, month = {2018}, pages = {e0203409}, abstract = {

BACKGROUND: Local drug delivery systems that adjust the release of immunosuppressive drug in response to the nature and intensity of inflammation represent a promising approach to reduce systemic immunosuppression and its side effects in allotransplantation. Here we aimed to demonstrate that release of tacrolimus from triglycerol monostearate hydrogel is inflammation-dependent in vivo. We further report that by loading the hydrogel with a near-infrared dye, it is possible to monitor drug release non-invasively in an in vivo model of vascularized composite allotransplantation.

MATERIALS AND METHODS: Inflammation was induced by local challenge with lipopolysaccharides in na{\"\i}ve rats 7 days after injection of tacrolimus-loaded hydrogel in the hind limb. Tacrolimus levels in blood and tissues were measured at selected time points. A near-infrared dye was encapsulated in the hydrogel together with tacrolimus in order to monitor hydrogel deposits and drug release in vitro and in vivo in a model of vascularized composite allotransplantation.

RESULTS: Injection of lipopolysaccharides led to increased blood and skin tacrolimus levels (p = 0.0076, day 7 vs. day 12 in blood, and p = 0.0007 in treated limbs, 48 h after injection compared to controls). Moreover, lipopolysaccharides-injected animals had higher tacrolimus levels in treated limbs compared to contralateral limbs (p = 0.0003 for skin and p = 0.0053 for muscle). Imaging of hydrogel deposits and tacrolimus release was achieved by encapsulating near-infrared dye in the hydrogel for 160 days. The correlation of tacrolimus and near-infrared dye release from hydrogel was R2 = 0.6297 and R2 = 0.5619 in blood and grafts of transplanted animals respectively and R2 = 0.6066 in vitro.

CONCLUSIONS: Here we demonstrate the inflammation-responsiveness of a tacrolimus-loaded hydrogel in vivo. Moreover, we show that encapsulating a near-infrared dye in the hydrogel provides a reliable correlation of tacrolimus and dye release from the hydrogel, and an accessible non-invasive method for monitoring drug release from hydrogel deposits.

}, keywords = {Animals, Drug Delivery Systems, Humans, Hydrogels, Immunosuppressive Agents, Inflammation, Male, Rats, Rats, Inbred BN, Rats, Inbred Lew, Tacrolimus}, issn = {1932-6203}, doi = {10.1371/journal.pone.0203409}, author = {Dzhonova, Dzhuliya and Olariu, Radu and Leckenby, Jonathan and Dhayani, Ashish and Vemula, Praveen Kumar and Prost, Jean-Christophe and Banz, Yara and Taddeo, Adriano and Rieben, Robert} } @article {1168, title = {Sterile Inflammation Enhances ECM Degradation in Integrin β1 KO Embryonic Skin.}, journal = {Cell Rep}, volume = {16}, year = {2016}, month = {2016 09 20}, pages = {3334-3347}, abstract = {

Epidermal knockout of integrin β1 results in complete disorganization of the basement membrane (BM), resulting in neonatal lethality. Here, we report that this disorganization is exacerbated by an early\ embryonic inflammatory response involving the recruitment of tissue-resident and monocyte-derived macrophages to the dermal-epidermal junction, associated with increased matrix metalloproteinase activity. Remarkably, the skin barrier in the integrin β1 knockout animals is intact, suggesting that this inflammatory response is initiated in a sterile environment. We demonstrate that the molecular mechanism involves de novo expression of integrin αvβ6 in the basal epidermal cells, which activates a TGF-β1 driven inflammatory cascade resulting in upregulation of dermal NF-κB in a Tenascin C-dependent manner. Importantly, treatment of β1 KO embryos in utero with small molecule inhibitors of TGF-βR1 and NF-κB results in marked rescue of the BM defects and amelioration of immune response, revealing an unconventional immuno-protective role for integrin β1 during BM remodeling.

}, keywords = {Animals, Extracellular Matrix, Inflammation, Integrin beta1, Macrophages, Mice, Mice, Knockout, Signal Transduction, Skin}, issn = {2211-1247}, doi = {10.1016/j.celrep.2016.08.062}, author = {Kurbet, Ambika S and Hegde, Samarth and Bhattacharjee, Oindrila and Marepally, Srujan and Vemula, Praveen K and Raghavan, Srikala} }