Swine Midkine (MK) is a heparin-binding growth factor and cytokine that plays important roles in cell growth, development, and tissue repair in pigs (Sus scrofa). Midkine is highly expressed during embryonic development and can also be induced in adult tissues in response to injury, inflammation, or physiological stress. Swine midkine interacts with several cell surface receptors, including receptor-type protein tyrosine phosphatase ζ (PTPRZ1), low-density lipoprotein receptor–related proteins (LRPs), and integrins, activating intracellular signaling pathways such as MAPK, PI3K–AKT, and NF-κB that regulate cell proliferation, migration, survival, and inflammatory responses. Through these mechanisms, midkine contributes to processes including tissue regeneration, angiogenesis, neural development, and immune cell recruitment. In pigs, midkine is also associated with developmental processes and responses to tissue injury or infection. In cell culture, recombinant swine midkine is commonly used to stimulate cell proliferation and migration and to study growth factor–mediated signaling pathways involved in development, inflammation, and tissue repair. Swine midkine is also studied in veterinary and translational research, as pigs serve as valuable models for human cardiovascular, metabolic, and regenerative biology studies.