New Frontiers and Future Technologies: Biomaterials, Stem Cells and Tissue Engineering

Transcription

1 New Frontiers and Future Technologies: Biomaterials, Stem Cells and Tissue Engineering W. John Kao PhD Professor of Biomedical Engineering, Pharmacy, and Surgery University of Wisconsin Madison John.Kao.Lab New Frontiers (challenges) and Future Technologies: Biomaterials, Stem Cells and Tissue Engineering Acknowledgments: those who kept us going! My Students: K Kleinbeck, H Waldeck, Y Fu, C Drifka, K Xu, D Cantu, J Li, A Chung, D Schmidt, S Zuckerman, H Yang, Y Gao, J Phillips, J Meyers, E Joyce, W Johnson, H Cohen Physician Collaborators: J Niezgoda, L Faucher, M Schurr, P Hematti, H Summer, J Farinas Basic Science Collaborators: L Allen-Hoffman, G Kwon Wisconsin Alumni Research Association (WARF): L Cagan, J Burmania, C Gunbrandson Funding Agencies NIH, NSF, UWF, UW BME, UW Surgery, UW Pharmacy, WARF, MatriLab 1

2 Outline for this talk Introduction to clinical challenges Advanced wound healing therapy: basic research > Biomaterial-enabled tissue engineering strategies > Cell-based therapy + HBO 2 T strategies What s next? Going beyond basic research in academia Introduction to Clinical Challenges Clinical needs: acute and chronic cutaneous wound healing Cost of trauma-related deaths in US is 2.4X higher than cancer and cardiovascular diseases combined. * By 2020, trauma will equal or surpass communicable diseases as the number one cause of disability-adjusted life years worldwide. * Greater than 50% of wounds remain refractory to current conventional treatment. * Outcome of acute and chronic cutaneous wound healing can t be reliably predicted. * 2

3 Challenges The choice of treatment and the development of novel therapeutics depend on the underlying biology and comorbidity. Current understanding of many cellular and molecular processes has advanced substantially. However, efficacy of biomolecules as single agent therapeutics is disappointing. Complex biochemical pathway Dynamic wound healing cascade Underlying pathology Challenges: complex biochemical pathways Altered genes (+ 5000) in a neutrophil when exposed to LPS from Calvano SE et al. A netowrk based analysis of systemic inflammation in human, Nature. 2005; 437, 13, Challenges: dynamic wound healing cascade Hemostasis: fibrin clot, platelet aggregation Inflammation: exudation, phagocytosis, cytokine/growth factor release Granulation/proliferation: fibroblast/endothelial cells, angiogenesis, provisional matrix formation, wound contracture Remodeling / Reepithelialization: Resorption of type III collagen, Type I collagen formation and fiber orientation, keratinocyte Time proliferation and epithelialization Chronic or impaired wounds result when tissues fail to progress through these stages of healing!! 3

4 Advanced Wound Healing Therapy Biomaterial-enabled tissue engineering strategies: biomimetic biomaterials New therapeutic paradigm: using biomaterials and therapeutic cells to recapitulate the lost tissue structure and to address underlying disease to improve healing. Adapted from Clark et al.j Invest Derm 2007 Ideal biomaterial properties Well-characterized Biocompatible, safe and effective: Adheres to tissue and conforms to complex contour Maintains moist healing environment Functionalizable to promote healing and patient care IP protected Cost effective to synthesize and manufacture Easily adaptable to current clinical practice Easy patient compliance 4

5 Examples of clinical biomaterial-based treatment (for granulation wounds) foams, hydrogels, transparent films, hydrocolloids provide a moist environment, some insulation Allevyn, Curafoam, Curasol Gel, Biolex Wound Gel, Bioclusive, Tegaderm, DuoDerm, Replicare Adjunctive Therapies: NPT, acellularized tissue grafts VAC,Oasis Although all meets some aspects of ideal biomaterials, there remains room for improvement product differentiation labor-intensive patient care needs to address co-morbidity and underlying pathology unclear mechanism theory: why and how it works Extracellular matrix (ECM) mimics semi-interpenetrating networks (sipn) Scaffolds PEGdA-PEGSH : chemically modified gelatin To study cell-material interaction To promote cell integration and tissue regeneration To study material structure-function. Present actives: Therapeutic cells, peptides, proteins, analgesics, antimicrobials, immunocytokines as soluble or immobilized PEGylated molecules To influence cell-material interaction, To enhance clinical utility. sipn-mediated wound healing in full thickness defects Day 0 FO Day 21 sipn with soluble KGF and grafted RGD (day 21) sipn w/o loaded biomolecules (day 21) Conventional cotton dressing with Ag (day 21) Waldeck H, Kao WJ. J Biomaed Mat Res (2007), 82A,

6 This image cannot currently be displayed sipn-mediated wound healing in partial defects Acticoat graft Tisseel/Telfa graft IPN graft Xeroform 3 weeks later: sipn promotes healing by modulating monocyte, fibroblast, keratinocyte paracrine regulation Expanding sipn clinical utility as a drug delivery matrix pharmaceuticals: AgSD, Bupivacaine to manage co-morbidity S. Aureus freshly plated confluent methicillin resistant S. aureus freshly plated confluent P. aeruginosa freshly plated confluent Drug loaded sipn Area of bacterial kill released silver sulfadiazine maintained bioactivity in bacteria kill efficiency 6

7 Expanding sipn clinical utility as a drug delivery matrix pharmaceuticals: WBG reactive oxygen species scavenger OxyBurst H 2HFF-BSA + PMA L-WBG Chamber A PMNs Chamber B M-WBG Extracellular ROS probe Stimulates ROS production by PMNs Equivalent fluorescein MFI (nm) Chamber A Chamber B 0 L-WBG M-WBG S-WBG No WBG S-WBG No WBG a decrease in detected ROS with the addition of L-WBG Advanced Wound Healing Therapy Cell-based therapy strategies New therapeutic paradigm: using biomaterials and therapeutic cells to recapitulate the lost tissue structure and to address underlying disease to improve healing. Adapted from Clark et al.j Invest Derm

8 Epidermal, dermal, epidermal/dermal equivalents Epidermal constructs (permanent transplant): Autologous keratinocytes on various substrates CellSpray, Epicel, Epidex, EPIBASE, MySkin Dermal constructs (permanent to temporary usages): Decellularized ECM, neonatal allogeneic fibroblasts on collagen Alloderm, SureDerm, Matriderm, OASIS,EZDerm Transcyte, Dermagraft, Hyalograft Epidermal/dermal equivalents (temporary applications): Allogeneic keratinocytes/fibroblasts on collagen Apligraft,Orcel, PolyActive Primary mode of action is to deliver cell-derived factors Room for improvement Epidermal constructs (permanent transplant): +3 weeks waiting period for autologous cells to expand Not effective in full thickness wounds or acute care Cost Dermal constructs (permanent to temporary usages): Compositionally complex ECM Although immune tolerant, allogeneic fibroblasts undergo functional changes during established entrapment methods and storage Requires second procedure for removal Epidermal/dermal equivalents (temporary applications): +4 weeks of complex, labor-intensive manufacturing process Cost Requires second procedure for removal Entrap therapeutic cells within sipn facile, in situ forming, organogenetic epidermal/dermal equivalent to deliver cell-derived healing promoting factors to the wound bed Gelatin modified with biofunctional peptides Mix Therapeutic cells in suspension + + PEGdA PEG-dithiol Gelatin Cell encapsulated sipn matrix 8

9 Feasibility in-gel cells maintained viability +14 days in vitro in vivo in situ gel formation post subcutaneous injection material-modulated keratinocyte-fibroblast interaction viability In vivo tissue-sipn interface post sub-q injection active cellmaterial interaction active cytoskeletal formation modulation of protein release Promising therapeutic cells to be delivered via sipn Allogeneic human dermal fibroblasts/keratinocytes clinical experience Mesenchymal stem(stromal) cells (MSC) easily accessible, multiple tissue sources positive for mesodermal lineage markers CD29, CD44, CD90 negative for hematopoietic marker CD14 upon proper stimuli, differentiable to various lineages immune tolerant and inflammatory modulatory Human epithelial progenitor cells (NIKS ) genetically identical, proliferative undergo normal epidermal differentiation long-lived phenotype enables stable transfection Allogeneic BM-MSC injected into partial thickness wounds dressed with: Acticoat, Tisseel, Autograft, sipn in pigs sipn with MSC MSC Tissue MSC MSC + sipn in in 7d 7 d MSC improved macroscopic wound healing (VSS: vascualrity, pigmentation, pliability and height), However, delivered MSC only lasted up to 7 days in vivo. 9

10 The role of hyperbaric oxygen therapies (HBO 2 T): Increased native circulating MSC mobilization and wound recruitment in diabetic patients * Circ endothelial Progen cells HBO 2T increased: circulating endothelial progenetor cells (L) and platelet NOS activity (R) in diabetic patients undergoing treatments vs. healthy patients Lower extremity wound margin with HIS for HIF-1, endothelial progenetor cell markers CD34, CD133 after 3wkofHBO 2T * Thom SR et al. Wound Rep Regen. 2011, 19, NIKS genetically modified to overexpress VEGF promote HuMVEC proliferation in vitro seeded onto gelatin, cultured, transplanted into full-thickness wounds in db/db diabetic mice resulted in improved healing Future challenges for biomaterial-enabled cell-based advanced wound therapies Difficult to harmonize various pre-clinical & clinical results Multiple delivery matrices (hyalluronic acid, alginate, chitosan, fibrin, synthetic hydrogels) Multiple cell sources and manipulation methods (autografts vs allografts vs xenografts) Multiple methods of cell introduction (timing as a function of wound progression, injection vs implant) Incomplete understanding of the mode of action (engraftment vs paracrine regulation) Commercialization scale-up, manufacturing, batch consistency, regulatory pathway, cost, competitiveness over other methods of care 10

11 What s Next? Going beyond basic science research in academia Traditional role of university in translational research: idea generation, patent prosecution, licensing Idea or invention Manufacturing Initial clinical safety testing Regulatory (FDA) review Research Prototyping Clinical trials Commercialization US Patent Office review Patent Patent application issued Traditional licensing window traditional role of university Highest commercial risk Lowest commercial risk Problems with the old model: Investors and industry increased cost sensitivity and risk aversion. Lack of commercial pathways for numerous issued patents held by universities. Too few promising drugs and devices in development pipeline to tackle current clinical needs. Formation of National Center for Advancing Translational Sciences at the National Institutes of Health (US). Mission: to de-risk promising technologies so they are attractive to potential licensers for product development commercialization. 11

12 Paradigm Shift: the role of university in de-risking a technology de-risking = value-added Idea or invention Manufacturing Initial clinical safety testing Regulatory (FDA) review Research Prototyping Clinical trials Commercialization US Patent Office review Patent Patent application issued traditional role of university Traditional licensing window Current licensing window PARADIGM SHIFT: redefined role of university? Highest commercial risk Lowest commercial risk Roadmap for FIM study: a collaborative effort 1. Establish manufacturing process for sipn base formulation 2. product validation and verification 3. Complete a first-in-human safety trial in a controlled and clinically relevant model: skin donor graft site wounds in traumatic acute wound patients 4. Later project may address sipn in other types of wound and/or to present actives. Key Benchmarks: unfamiliar territory for academia Develop packaging system and methods Determine sterilization methods Develop manufacturing processes Design Verification and Validation testing Complete additional animal studies (if needed) Complete Biocompatibility tests Develop first-in-man (FIM) Protocol Approval from governing body for clinical human use 12

13 Challenges for technology translation in academia Alignment with institutional missions and priorities. Ability to predict market needs Ability to select and to develop commercialization pathways for numerous issued and filed patents in the portfolio. Lack of quality systems and know-how s in product development to de-risk promising technologies in medical devices, drugs or combination products. Lack of human resources and capitals to pursuit business ventures. General Conclusions: Wound healing remains a pressing clinical challenge. Innovation and interdisciplinary approaches are absolutely essential to develop advanced wound therapies. Biomaterial-enabled, cell-based approaches coupled with existing practices such as HBO 2 T are promising in improving current therapies, patient management, and healing outcome. Technology translation pathways and know-how s from academia to industry remain a challenge to fully realize the clinical impact of promising technologies. Thank You! W. John Kao wjkao@wisc.edu 13