Synovial fluid lubricin increases in spontaneous canine cruciate ligament rupture

Abstract

Lubricin is an important boundary lubricant and chondroprotective glycoprotein in synovial fluid. Both increased and decreased synovial fluid lubricin concentrations have been reported in experimental post-traumatic osteoarthritis (PTOA) animal models and in naturally occurring joint injuries in humans and animals, with no consensus about how lubricin is altered in different species or injury types. Increased synovial fluid lubricin has been observed following intra-articular fracture in humans and horses and in human late-stage osteoarthritis; however, it is unknown how synovial lubricin is affected by knee-destabilizing injuries in large animals. Spontaneous rupture of cranial cruciate ligament (RCCL), the anterior cruciate ligament equivalent in quadrupeds, is a common injury in dogs often accompanied by OA. Here, clinical records, radiographs, and synovial fluid samples from 30 dogs that sustained RCCL and 9 clinically healthy dogs were analyzed. Synovial fluid lubricin concentrations were nearly 16-fold greater in RCCL joints as compared to control joints, while IL-2, IL-6, IL-8, and TNF-α concentrations did not differ between groups. Synovial fluid lubricin concentrations were correlated with the presence of radiographic OA and were elevated in three animals sustaining RCCL injury prior to the radiographic manifestation of OA, indicating that lubricin may be a potential biomarker for early joint injury.

Recombinant manufacturing of multispecies biolubricants

“…The apparent molecular weights of >400 KDa on SDS-PAGE for the multispecies lubricins were comparable to the expected molecular weights of native human, equine, and canine lubricins . 51,52 The O-glycans of the engineered recombinant human lubricin, which we heretofore refer to as rHnLub, were profiled using liquid chromatography tandem mass spectrometry following release from the polypeptide backbone through β-elimination. We detected a mix of sialylated and non-sialylated core-1 and core-2 O-glycans, similar to the glycan profile that has been reported previously for native human lubricin isolated from synovial fluid (Fig.…”

“…The apparent molecular weights of >400 KDa on SDS-PAGE for the multispecies lubricins were comparable to the expected molecular weights of native human, equine, and canine lubricins . 51,52…”

Determining predictive metabolomic biomarkers of meniscal injury in dogs with cranial cruciate ligament disease

“…SF has been found to contain a unique source of biomarkers of joint disease, due to its close proximity to structures within joints, (de Bakker et al, 2017, Anderson et al, 2018b). Previous studies have investigated potential cytokine and protein biomarkers of CCLR within canine stifle joint SF, including interleukin-8 (IL-8) (de Bruin et al ., 2007b), anti-collagen type 1 antibodies (de Bruin et al ., 2007a), matrix metalloproteinases (MMP) 2 and MMP9 (Boland et al ., 2014, Murakami et al ., 2016) and lubricin (Wang et al ., 2020). There are relatively few studies examining biomarkers specific to meniscal injury within SF in any species.…”