Introduction
Rolfing is often said to work on the fascia. But what, exactly, is this fascia? This tissue tends to be reduced to a single term — connective tissue — yet there was a time, during my years as a postdoc in a laboratory, when I looked at it from the level of the cell.
Today I want to write about those research days: how I see this tissue now, after ten years of working as a bodyworker, and where that perspective came from.
Cells and Adhering Cells
When I was in the lab, what I studied was a cytokine called IL-2 (interleukin-2). What I worked with was mainly suspension cells — the lymphocyte-derived cells that IL-2 acts upon. Those cells, drifting in the culture medium and dividing without ever touching one another, were my main focus. Immunity is a world of freely flowing cells in the bloodstream — that had become ingrained in my body.
The fibroblasts I occasionally handled, on the other hand, had an altogether different feel. Primary mouse embryonic fibroblasts (MEF: Mouse Embryonic Fibroblast) and the immortalized NIH/3T3 line. These cannot live unless they anchor down onto a surface — in my case, a collagen-coated dish.
Unlike suspension cells, they need something to hold on to before they can live at all. They stretch across the bottom of the dish and spread out, dividing until they cover the whole surface; once they reach confluence and crowd against one another, they stop proliferating. The primary MEF, in particular, eventually enter senescence as the passages accumulate — the cell’s own form of aging. Living in the same culture, they nonetheless lived in an altogether different way from the suspension cells.
As an aside: the “-blast” at the end of the name fibroblast denotes a cell that produces and shapes something. The osteoblast, which builds bone, belongs to the same “-blast” family. Both are, in a sense, makers of form, building the tissues that support the body — connective tissue in the one case, bone in the other. By its very name, the fibroblast was a “cell that builds structure.”
Within me at the time, these two — the immune cells that float free and the fibroblasts that live by attaching — clearly belonged to separate worlds. Immunity over here, structure over there.
Fibroblasts are easy to obtain and easy to culture. They grow well, are hardy, and take little effort to handle. For that very reason they were prized as experimental material. When one wanted to express a certain protein inside a cell and examine its behavior, the fibroblast was the first thing one reached for.
A stage, as it were, on which to set the real subject of the research. Something of a background player, quietly producing collagen and matrix. That was what the fibroblast was to me back then.
The Wall Was Made by the Culture Dish
And yet that division was not as certain as I had thought.
Immune cells — white blood cells — are, as the name says, white. Having no color, they can’t be told apart by sight; there is no way to see which cell does what. So immunology learned to distinguish their types and roles by the proteins (antigens) on the cell-membrane surface — their markers.
Once a cell is identified this way, it is activated, or shifts how it works, through cytokines: the molecules that carry information between cells. Cytokines are the “words” that immunity exchanges, and the IL-2 I was chasing was one of them.
By its surface antigens, the fibroblast does not count as an “immune cell”; it sits outside the classification altogether. And yet it spoke the same language.
I did not learn this at my own bench, but at the one next to it. The lab where I chased IL-2 also worked on interferon (IFN), and I often watched the others there — graduate students, postdocs, an associate professor — work with it. That was where I learned that IFN-β had long been known as “fibroblast interferon.”
The name comes from the fact that fibroblasts are what release IFN-β when they sense a virus. A cell that its surface markers had placed “outside immunity” turned out to take part, as a matter of course, in the conversation cytokines carry. The same cell I had watched as a background worker on the dish was, one bench over, treated as one that speaks the language of immunity.
Suspension cells and adherent cells did not have separate languages; they were calling to each other in the same words.
Recent research has brought this blurred boundary into plain view.
Fibroblasts are no longer seen as passive matrix factories; they have even been called “confederates of the immune system.” The extracellular matrix they weave — hyaluronan, fibronectin — shapes how immune cells move. In injury and repair, it draws immune cells in and guides what they do.
And fascia itself has immune cells — macrophages, mast cells — living in it from the start.
In a sense, research eventually gave shape to the blurred boundary I had only vaguely felt back in that lab. The wall between immunity and structure was never in the living body. It was in the culture dish — in the method itself.
The Web Those Cells Weave Flows Through the Whole Body
What is connective tissue for, in the first place? Put simply, it lets scattered cells work together as one body. Filling the space between cell and cell, linking them, supporting them, holding them into a whole — that is its work.
Consider a grapefruit. Almost all of it is juice, and yet what wraps it, divides it into segments, and holds its round shape is a thin membrane. Strip only the connective tissue from a body and it would lose its shape, collapsing into a mere lump of flesh. The body holds together as one, instead of falling apart, only because this tissue weaves and supports the whole.
And the substances that make this possible are exactly the ones fibroblasts produced day after day — collagen, fibronectin, hyaluronan. Fibers that bear tension, adhesive molecules that hold cells in place, polysaccharides that hold water and let it flow. Woven together, they make a place where cells can live in common. Fascia — connective tissue — is another name for that place.
Earlier I placed the fibroblast and the osteoblast side by side as “makers of form.” They build from different materials, but the two are kin, branched from the same mesenchymal cells. Where the fibroblast weaves collagen and hyaluronan, the result is soft connective tissue — fascia. Where the osteoblast lays calcium onto that same collagen scaffold, the result is hard connective tissue — bone.
Bone is essentially calcified connective tissue, and in the body the two are not sharply divided. Bundled more densely, fascia becomes tendon and ligament, then the membrane that wraps bone (the periosteum), and finally bone itself. From soft fascia to hard bone, the supporting tissues form one continuous web. What looks like a boundary is only a difference in how hard the material is. The weavers on either side belong to the same lineage.
And the space this weave creates has lately been brought back into the light.
Anyone familiar with Rolfing may already have seen the footage. Since the 2000s, the French hand surgeon Jean-Claude Guimberteau has threaded a video endoscope into the living body and filmed fascia as it actually is. Beneath the skin appears tissue that glistens as if wet and half-transparent, a chaos of fibers shifting without pattern, and water — carrying hyaluronan — in motion. There are no clear boundaries anywhere in it.
Skin, fat, fascia — all of it runs together without break. From what he saw, Guimberteau built his own account: a multifibrillar structure of the body, with the “microvacuole” as its basic unit. His footage was screened in 2007 at the first Fascia Research Congress in Boston, and his work spread among bodyworkers. It was, in effect, the first window onto living, moving tissue rather than a fixed specimen.
A little over a decade later, a report pointing the same way came from an entirely different direction — the clinical world of gastrointestinal imaging. In 2018, Benias and colleagues, using a new technique that observes living tissue in place (probe-based confocal laser endomicroscopy), reported a striking finding.
A layer long taken to be dense connective tissue turned out to be a network of fluid-filled, interconnected compartments. It runs continuously through the body — under the skin, in the walls of the gut and lungs, around blood vessels, and in the fascia between muscles. This space, the interstitium, is thought to be a major source of lymph; as a kind of highway for bodily fluid, it may play a part in how cells communicate and in inflammation.
Two researchers, starting from different places and using different methods, arrived at the same picture once they looked into living tissue. Why had it stayed hidden so long? Fix a specimen onto a slide and the fluid-filled space collapses, so the tissue looks densely packed. Fixing tissue, slicing it thin, staining it, viewing it under a microscope — that way of seeing had been standard for well over a century.
For all that time, the living, flowing space sat collapsed on dead specimens, seen by no one. The irony is that fascia resisted observation precisely because it was alive. Only once there was a way to observe it while still living did its true form come into view.
Something similar runs through cell culture. To cut cells from the living body and set them on a dish was itself a kind of fixation, an abstraction. MEFs come from mice; NIH/3T3 is an immortalized line — neither is living human fascia. What I had been watching on the dish were fragments cut out of a continuum. Just as fixed specimens erased the interstitium, culture too must have quietly dropped part of what it was trying to see.
Not as Parts, but as a Continuum
The blurred line between suspension cells and adherent ones. An immunologically active fascia. An interstitium that gives rise to lymph and runs through the whole body. All of it converges on a single way of seeing: the body is not an assembly of separate parts, but one order in continuous communication with itself.
Body as an Operating System — a way of seeing the body not as a collection of parts but as one system that moves as a whole. What Rolfing works on is not the chasing of individual complaints, but this continuous layer of tissue itself: not the surface symptom, but the foundation beneath it that supports the body, connects it, and keeps it flowing.
What had looked like two worlds breathes as one in the living body. Once I saw that, connective tissue stopped being mere “white packing.”
Being Honest About What Cannot Be Asserted
Having come this far, I want to be clear about one thing.
The interstitium research, and the immunological side of the fibroblast, are real. But none of it shows that “Rolfing boosts immunity” or “calms inflammation.” Researchers have not even settled whether the interstitium should be called a “new organ.” What these findings change is how we understand the tissue that hands-on work touches — not any claim about what it does.
I want to keep the same stance as the large study of Rolfing case records I mentioned recently, which chose the careful word “Influence” over “Effect” in its title. Let me draw an honest line between what is known and what is not. All I can really say is this: the way we see how this tissue is put together has been changing.
👉 Related article: “Twenty-Three Years of Records, Brought to Light by a Leading Fascia Researcher — From a New Study of the Rolfing Ten-Series“
Conclusion
There is a tissue that medicine long treated as a “white thing to be cut away.” I once looked at it that way too, on the dish — sorting it into suspension cells and adherent cells, convinced that immunity and structure were separate worlds.
But the living body does not hold to that division. The fibroblast speaks the language of immunity; connective tissue is a site of immune activity; and the web woven from it joins the whole body into one flow. The categories that had looked so clean in the dish were only lines the method had drawn.
Seen this way, even the tissue under my palms feels a little different. What is there is not scattered parts, but a single living order that keeps answering to itself.
I would be glad if this piece offered even a small occasion to feel the body, once again, as a continuum.