Multinukleære

Multinukleäre, or multinucleated, describes cells that contain more than one nucleus within a single cytoplasm. This condition can arise as a normal part of development, as a functional adaptation, or as a response to disease. Multinucleation occurs mainly through two mechanisms: cell fusion, where two or more cells fuse their plasma membranes and cytoplasm to form a common cell with multiple nuclei; and division of the nucleus without completing cytokinesis, leading to a cytoplasm that houses several nuclei (a process sometimes described as syncytialization or endomitosis in specific contexts).

Examples of multinucleated cells are found across diverse organisms and tissues. Skeletal muscle fibers are a well-known example: they originate from the fusion of many precursor myoblasts, producing long, multinucleated fibers whose nuclei are typically located near the periphery just under the cell membrane. Osteoclasts, the bone-resorbing cells, are another key example, formed by fusion of monocyte/macrophage precursors and containing multiple nuclei. In the placenta, the multinucleated syncytiotrophoblast layer arises from fusion of cytotrophoblasts and plays a critical role in nutrient exchange between mother and fetus. In certain fungi and in plasmodial slime molds, the cytoplasm can be coenocytic, containing many nuclei within a shared cytoplasmic mass due to lack of cross-walled septa.

Function and significance vary by tissue. Multinucleation often supports large cell size and high rates of protein synthesis, enabling rapid metabolic activity across extensive cytoplasm. In some pathological contexts, multinucleated giant cells form by macrophage fusion during granulomatous inflammation or foreign body responses.