Peter G. Alexander, PhD

Assistant Professor, Department of Orthopaedic Surgery
University of Pittsburgh School of Medicine

Research Interests

The Alexander lab has three research themes: (1) the developmental, molecular and cellular biology of skeletal tissue, (2) mesenchymal stromal cell biology in tissue repair and regeneration, and (3) modeling musculoskeletal disease and pathogenesis in vitro and in vivo.

Technique Expertise or Resources to share

Animal models: I have developed in vivo models of (1) congenital scoliosis in chick and mouse, which I used to study the process of vertebral body development, mechanisms of environmental toxicity and small gas molecular signaling (i.e nitric oxide and carbon monoxide), (2) osteomyelitis, to study cell-based and small peptide-based therapies for periprosthetic joint infection and (3) post-traumatic osteoarthritis in rabbit and goat that are used to study mechanism of cartilage degeneration and repair. These have also been used to examine signaling mechanisms and the dysregulation of cartilage and bone homeostasis. These models have also been used to test the utility of mesenchymal stromal cells (MSCs) and platelet-rich plasma in osteochondral, meniscus and peripheral nerve repair in rabbits and goats.

In vitro models: I am also involved in the development of in vitro models of adult and fetal skeletal tissues for therapeutic and toxicity testing. I am now working with a team funded by the National Center for Advancing Translational Sciences (NCATS) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) to engineer a joint organ-in-a-chip to model OA and other joint pathologies. These multi-tissue models involve the encapsulation or seeding of MSCs and other primary cells (e.g. endothelial cells) in poly-_L-lactic acid (PLLA)- and polycaprolactone (PCL)- based nanofibrous scaffolds and hydrogels, such as alginate, gelatin and polyethylene glycol (PEG) and the stimulation/maturation of the constructs in biologically-inspired bioreactors with tissue-specific biochemical and biomechanical stimulation. Mechanical stimulation is applied using a BOSE ELF-2000, Flexcell 5000, MATE mechanical loader, and other custom-built biostimulators. Analytical techniques used in the lab include: CT-imaging, X-ray, live cell imaging, bright-field, fluorescence, histology, immunohistochemistry, histomorphometry, molecular and protein analysis.

Keywords

Adult mesenchymal stromal cell, MSC, osteoarthritis, avascular necrosis, heterotopic ossification, chondrocyte, osteoblast, endothelial cells, co-culture, bone, cartilage, joint, tissue engineering, regeneration, embryo, toxicity, COL2, MMP13, 3D printing, photostereolithography, bioplotting, computer-aided tomography, meso-scale bioreactor design, meso-fluidics, microfluidics, viral transduction, mechanical testing, electrospinning