Anti-inflammatory effects induced by ultralow concentrations of bupivacaine in combination with ultralow concentrations of sildenafil (Viagra) and vitamin D3 on inflammatory reactive brain astrocytes

A randomized, triple-blinded controlled clinical study with a novel disease-modifying drug combination in equine lameness-associated osteoarthritis

Objective

This study aimed to test a novel treatment combination (TC) (equivalent to sildenafil, mepivacaine, and glucose) with disease-modifying properties compared to Celestone® bifas® (CB) in a randomized triple-blinded phase III clinical study in horses with mild osteoarthritis (OA). Joint biomarkers (reflecting the articular cartilage and subchondral bone remodelling) and clinical lameness were used as readouts to evaluate the treatment efficacy.

Methods

Twenty horses with OA-associated lameness in the carpal joint were included in the study and received either TC (n = 10) or CB (n = 10) drug intra-articularly-twice in the middle carpal joint with an interval of 2 weeks (visit 1 & 2). Clinical lameness was assessed both objectively (Lameness locator) and subjectively (visually). Synovial fluid and serum were sampled for quantification of the extracellular matrix (ECM) neo-epitope joint biomarkers represented by biglycan (BGN²⁶²) and cartilage oligomeric matrix protein (COMP¹⁵⁶). Another two weeks later clinical lameness was recorded, and serum was collected for biomarkers analysis. The overall health status was compared pre and post-intervention by interviewing the trainer.

Results

Post-intervention, SF BGN²⁶² levels significantly declined in TC (P = 0.002) and COMP¹⁵⁶ levels significantly increased in CB (P = 0.002). The flexion test scores improved in the TC compared to CB (P =0.033) and also had an improved trotting gait quality (P =0.044). No adverse events were reported.

Conclusion

This is the first clinical study presenting companion diagnostics assisting in identifying OA phenotype and evaluating the efficacy and safety of a novel disease-modifying osteoarthritic drug.

Bupivacaine in combination with sildenafil (Viagra) and vitamin D3 have anti-inflammatory effects in osteoarthritic chondrocytes

Aims

To treat osteoarthritic chondrocytes and thereby reduce the inflammation with a drug combination that primarily affects 5-HT- and ATP-evoked Ca²⁺ signaling. In osteoarthritic chondrocytes, Ca²⁺ signaling is elevated, resulting in increased production of ATP and inflammatory mediators. The expression of TLR4 and Na⁺/K⁺-ATPase was used to evaluate the inflammatory status of the cells.

Main methods

Equine chondrocytes were collected from joints with mild structural osteoarthritic changes and cultured in monolayers. The cells were treated with a combination of bupivacaine (1 pM) and sildenafil (1 ​μM) in combination with vitamin D3 (100 ​nM). A high-throughput screening system, the Flexstation 3 microplate reader, was used to measure intra- and extracellular Ca²⁺ signaling after exposure to 5-HT, glutamate, or ATP. Expression of inflammatory receptors was assessed by Western blotting.

Key findings

Drug treatment substantially reduced 5-HT- and ATP-evoked intracellular Ca²⁺ release and TLR4 expression compared to those in untreated chondrocytes. The combination of sildenafil, vitamin D3 together with metformin, as the ability to take up glucose is limited, increased Na⁺/K⁺-ATPase expression.

Significance

The combination of these three therapeutic substances at concentrations much lower than usually used, reduced expression of the inflammatory receptor TLR4 and increased the cell membrane enzyme Na⁺/K⁺-ATPase, which regulates cell volume and reduces increased intracellular Ca²⁺ concentrations. These remarkable results indicate that this drug combination has disease-modifying osteoarthritis drug (DMOAD) properties and may be a new clinical therapy for osteoarthritis (OA).