It is inefficient for the body to replace tissue that is repeatedly injured with the same tissue. Yet, that is what is happening in acute inflammation.  During chronic inflammation, the body begins to replace the damaged tissue with tissue that can handle the repeated injury better.  In essence, the tissue remodels – i.e. changes from one tissue type to another.  This is possible as cells that can still mitose can undergo differentiation – i.e. change from one mature cell type to another.

In most parts of the body, tissue remodeling often involves connective tissue replacing original tissue. As a result, the connective tissue does not have the same properties:  often, the remodeled tissue is stiffer and more durable. This causes noticeable changes as there is a shrinkage and tightening of once-elastic tissues (contracture), a narrowing of a luminal space (stricture), or attachment of structures which normally don’t attach (adhesions).  The exception to this rule is the lung:  lung tissue remodeling causes an expansion of the lung, as opposed to shrinkage.  This will become evident as we discuss the pathophysiology of emphysema.

Section Review

• To adapt to repeated injury and subsequent inflammation, tissue will remodel and change its make-up in order to tolerate the repeated injury better.
• Remodelled tissue no longer has the properties of the original tissue.  Often, remodelled tissue is more stiff and durable (i.e. addition of tough connective tissue during remodeling) thus affecting an organs original elasticity, compliance, and lumen size.

Review Questions