Protein patch for knee cartilage repair tested in 17 patients
Protein patch for knee cartilage repair tested in 17 patients
On October 13, Advanced Science published results from the first human use of dLhCG: 17 patients were followed for 12 months after surgery, and six for at least 18 months. dLhCG is a protein patch produced by pig cartilage cells, which are then removed.
Articular cartilage covers the ends of bones and helps them glide against one another. Restoring smooth tissue in a deep defect is difficult because coarser fibrous tissue can grow at the repair site. For dLhCG, the authors chose type II collagen, the main protein in hyaline cartilage.
Before testing the patch in humans, the researchers studied it for six months in pig knee joints. To produce the clinical version, they grew pig cartilage cells in a three-dimensional gel, where the cells formed the patch’s protein framework. They then broke down the gel and removed the cells. The surgeon trimmed the remaining scaffold to fit the defect and secured it with fibrin surgical glue.
In the article, the authors described a single group of 17 patients who underwent this procedure. At 12 months, pain on a visual analogue scale had decreased by an average of 3,82 points from baseline, and the knee function score had increased by 8,68 points. The MOCART MRI score, which assesses defect filling and the condition of the repair site, was 76,27 points. Among the six patients followed for at least 18 months, it was 80,56.
In five patients, the authors compared MRI T2 measurements at the repair site with those in adjacent healthy cartilage. This measurement is related to water content and collagen fibre arrangement. The T2 signal ratio decreased from 1,62 at month three to 1,10 at month twelve; in three patients assessed after 18 months, it was 1,07. The authors interpret the increasingly similar measurements as a sign that the repair tissue has biochemical and structural properties resembling those of hyaline cartilage.
The researchers recorded no adverse events that they attributed to the patch among the 17 patients. MRI showed bone marrow oedema in some patients. In two patients, a decrease in MOCART coincided with worsening oedema, and one patient developed a subchondral cyst.
Cartilage repair options include Cartistem, a cell therapy for knee cartilage defects: donor umbilical cord blood cells are introduced into the joint, and the product is already marketed in Korea. dLhCG is placed in the defect as a cell-free scaffold. A direct comparison of the two approaches would help distinguish the patch’s effect from the effects of surgery and recovery.