Formation of “irreducibly complex systems” via purported scaffolding has been an ongoing debate amongst evolution and intelligent design theorists. Now a natural scaffolding has been discovered – and it may itself be part of another “irreducibly complex system”.
Sharma et al., discovered that natural fat works as a biological scaffold for “cells to grow and mature”. Then fascinatingly, “when the cells have matured into the desired tissue, they secrete another substance that breaks down and destroys the scaffold.”
Could the formation of this natural biological scaffold AND its subsequent removal form an irreducibly complex system? E.g. is such scaffolding essential or necessary to achieve a minimum growth rate? Could the secretion removing the scaffolding also be essential to trim function rather than being “bloated”? I expect this fat scaffolding/removal system will be found to be another irreducibly complex system which very efficiently reuses its materials.
. . .the sticky substance secreted by the cells. . . . derived from adipose cells—aka body fat—turned out to be a natural extracellular matrix, the very thing [Nagrath] was looking for.
Nagrath, who joined Rice in 2009, and his co-authors have since built a biological scaffold that allows cells to grow and mature. He hopes the new material, when suffused with stem cells, will someday be injected into the human body, where it can repair tissues of many types without fear of rejection. . . .
The basic idea is simple: Prompt fat cells to secrete what bioengineers call “basement membrane.” This membrane mimics the architecture tissues naturally use in cell growth, literally a framework to which cells attach while they form a network. When the cells have matured into the desired tissue, they secrete another substance that breaks down and destroys the scaffold.
Structures that support the growth of living cells into tissues are highly valuable to pharmaceutical companies for testing drugs in vitro. Companies commonly use Matrigel, a protein mixture secreted by mouse cancer cells, but for that reason it can’t be injected into patients.
“Fat is one thing that is in excess in the body. We can always lose it,” Nagrath said. The substance derived from the secretions, called Adipogel, has proven effective for growing hepatocytes, the primary liver cells often used for pharmaceutical testing. . . .
Once that goal is achieved, Adipogel may be just the ticket for transplanting cells to repair organs. “You can use this matrix as an adipogenic scaffold for stem cells and transplant it into the body where an organ is damaged. Then, we hope, these cells and the Adipogel can take over and improve their functionality.. . .”
My approach is to force the cells to secrete a natural matrix,” he said. That matrix is a honey-like gel that retains the natural growth factors, cytokines (substances that carry signals between cells) and hormones in the original tissue.
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See Article: Adipocyte-derived basement membrane extract with biological activity: applications in hepatocyte functional augmentation in vitro
Nripen S. Sharma, Deepak Nagrath, and Martin L. Yarmush
FASEB J..2010; 0: fj.09-135095v1 Published online before print March 16, 2010 as doi: 10.1096/fj.09-135095. E-mail contact: email@example.com
Natural and synthetic biomaterials utilized in tissue engineering applications require a dynamic interplay of complex macromolecular compositions of hydrated extracellular matrices (ECMs) and soluble growth factors. The challenges in utilizing synthetic ECMs is the effective control of temporal and spatial complexity of multiple signal presentation, as compared to natural ECMs that possess the inherent properties of biological recognition, including presentation of receptor-binding ligands, susceptibility to cell-triggered proteolytic degradation, and remodeling. We have developed a murine preadipocyte differentiation system for generating a natural basement membrane extract (Adipogel) comprising ECM proteins (collagen IV, laminin, hyaluronan, and fibronectin) and including relevant growth factors (hepatocyte growth factor, vascular endothelial growth factor, and leukemia inhibitory factor). We have shown the effective utilization of the growth factor-enriched extracellular matrix for enhanced albumin synthesis rate of primary hepatocyte cultures for a period of 10 d as compared to collagen sandwich cultures and comparable or higher function as compared to Matrigel cultures. We have also demonstrated comparable cytochrome P450 1A1 activity for the collagen-Adipogel condition to the collagen double-gel and Matrigel culture conditions. A metabolic analysis revealed that utilization of Adipogel in primary hepatocyte cultures increased serine, glycine, threonine, alanine, tyrosine, valine, methionine, lysine, isoleucine, leucine, phenylalanine, taurine, cysteine, and glucose uptake rates to enhance hepatocyte protein synthesis as compared to collagen double-gel cultures. The demonstrated synthesis, isolation, characterization, and application of Adipogel provide immense potential for tissue engineering and regenerative medicine applications.—Sharma, N. S., Nagrath, D., Yarmush, M. L. Adipocyte-derived basement membrane extract with biological activity: applications in hepatocyte functional augmentation in vitro.