Which is a better source of stem cells: bone marrow or fat (ie., adipose)? Controversy still exists but most papers now acknowledge that fat has a richer source of stem cells. 

Stem cells are cells that are able to differentiate (ie, turn into) any tissue depending on its surrounding environment. If one inserts a stem cell into a muscle tissue, that stem cell can can become a muscle cell is its surrounding environment helps it thrive. This hold incredible potential. Their ability to differentiate into many different cells gives us a potential source of renewable body cells after our birth. For this reason, stem cells are being used to treat various traumatic and degenerative disorders. 

Below are more references provided by my research fellow.

The key points are: (Number References refer to Reference 1 below)

• Fat has stem cells that can become other types of cells such as nerve cells [8], [9], [10]., bone cells, endothelial cells (the key cells for blood vessels), muscle cells [6], [7], other fat cells, fibroblasts [2], [3], [4], [5]. It is possible that stem cells from fat would easily become meibum or meibomian gland oil if inserted into the meibomian gland. 
• Stem cells from fat is similar to other mesenchymal stem cells
• Stem cells from fat are present in higher concentration than those obtained from bone marrow[13], [14], [15]. 
• Treatment with ASCs is considered essential for tissue regeneration owing to their chemotactic, paracrine, and immunomodulatory activities and in situ differentiation [16], [17], [18], [19]. 
• Adipose-derived stem cells secrete a cytokine profile that is angiogenic, immunosuppressive, and antioxidative [20]. 
• The cytokine profile of adipose-derived stem cells contains large amounts of vascular endothelial growth factor, transforming growth factor-β, hepatocyte growth factor, platelet-derived growth factor, placental growth factor, and basic fibroblast growth factor, which explains their impressive angiogenic capacity and ability to induce tissue neovascularization [21]. 
• Further, adipose-derived stem cells are immune-privileged because of a lack of human leukocyte antigen–DR expression and suppression of proliferation of activated allogenic lymphocytes [22], [23]. 
• Adipose-derived stem cells also inhibit the production of inflammatory cytokines and stimulate the production of anti-inflammatory cytokines [20], [24], [25], [26].
• ASCs are part of the stromal vascular fraction (SVF) of adipose tissue, along with a heterogeneous population of many other cell types including preadipocytes, endothelial cells, pericytes, haematopoietic-lineage cells, and fibroblasts [27]. 
• The regenerative features of the SVF are attributed to its paracrine effects. 
• SVF cells secrete vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor-β in the presence of stimuli such as hypoxia and other growth factors [28] and strongly influence the differentiation of stem cells, promoting angiogenesis and wound healing and potentially aiding new tissue growth and development [29], [30].

Human mesenchymal stem cells from adipose tissue: Differentiation into hepatic lineage