How does damage to basement membrane affect epithelial tissue repair and what diseases involve basement membrane defects?

• A. Impairs regeneration and structural integrity; diseases include epidermolysis bullosa and certain nephropathies involving GBM defects.
• B. Accelerates wound healing and increases barrier function; common allergies.
• C. Has no effect on repair; basement membrane is not essential.
• D. Causes excessive keratin production; thickening of the epidermis.

Answer: (A)

Basement membrane provides a scaffold and signaling platform that epithelial cells rely on to migrate, attach, and re-establish layers during repair. When this membrane is damaged, the cells have a harder time re-epithelializing the wound, and the tissue loses some of its cohesion and mechanical stability as the anchoring cues and barrier function are compromised. This disruption can slow or misdirect healing and weaken the repaired tissue.

In disease, defects in basement membrane components lead to fragile epithelium and organ dysfunction. For the skin, epidermolysis bullosa involves problems at the dermal–epidermal junction that cause blistering with minor trauma due to faulty adhesion. In the kidney and other organs, defects in the glomerular basement membrane (GBM) disrupt filtration and structure; conditions like Alport syndrome arise from mutations in collagen IV chains of the GBM, and autoimmune targeting of GBM (as seen in Goodpasture syndrome) damages this barrier as well.