Functionalized Nanogels with Endothelin-1 and Bradykinin Receptor Antagonist Peptides Decrease Inflammatory and Cartilage Degradation Markers of Osteoarthritis in a Horse Organoid Model of Cartilage.

Osteoarthritis (OA) is a degenerative and heterogeneous disease that affects all types of joint structures. Current clinical treatments are only symptomatic and do not manage the degenerative process in animals or humans. One of the new orthobiological treatment strategies being developed to treat OA is the use of drug delivery systems (DDS) to release bioactive molecules over a long period of time directly into the joint to limit inflammation, control pain, and reduce cartilage degradation. Two vasoactive peptides, endothelin-1 and bradykinin, play important roles in OA pathogenesis. In this study, we investigated the effects of two functionalized nanogels as DDS. We assessed the effect of chitosan functionalized with a type A endothelin receptor antagonist (BQ-123-CHI) and/or hyaluronic acid functionalized with a type B1 bradykinin receptor antagonist (R-954-HA). The biocompatibility of these nanogels, alone or in combination, was first validated on equine articular chondrocytes cultured under different oxic conditions. Further, in an OA equine organoid model via induction with interleukin-1 beta (IL-1ß), a combination of BQ-123-CHI and R-954-HA (BR5) triggered the greatest decrease in inflammatory and catabolic markers. In basal and OA conditions, BQ-123-CHI alone or in equimolar combinations with R-954-HA had weak pro-anabolic effects on collagens synthesis. These new nanogels, as part of a composite DDS, show promising attributes for treating OA.

In vitro pharmacological profile of PHA-022121, a small molecule bradykinin B2 receptor antagonist in clinical development.

PHA-022121 is a novel small molecule bradykinin B2 receptor antagonist, in clinical development for the treatment and prevention of hereditary angioedema attacks. The present study describes the in vitro pharmacological characteristics of PHA-022121 and its active metabolite, PHA-022484 (M2-D). In mammalian cell lines, PHA-022121 and PHA-022484 show high affinity for the recombinant human bradykinin B2 receptor with Ki values of 0.47 and 0.70 nM, respectively, and potent antagonism of the human bradykinin B2 receptor with Kb values of 0.15 and 0.26 nM, respectively (calcium mobilization assay). Antagonist potency at the recombinant cynomolgus monkey bradykinin B2 receptor is similarly high (Kb values of 1.42 and 1.12 nM for PHA-022121 and PHA-022484, respectively), however, potency at rat, mouse, rabbit and dog bradykinin B2 receptors is at least 100-fold lower than the potency at the human receptor for both compounds. In the human umbilical vein contractility assay, both PHA-022121 and PHA-022484 show a potent, surmountable and reversible B2 antagonist activity with pA2 values of 0.35 and 0.47 nM, respectively. The in vitro off-target profile of PHA-022121 and PHA-022484 demonstrates a high degree of selectivity over a wide range of molecular targets, including the bradykinin B1 receptor. It is concluded that PHA-022121 is a novel, low-molecular weight, competitive antagonist of the human bradykinin B2 receptor with high affinity, high antagonist potency, and high selectivity. It is about 20-fold more potent than icatibant at the human bradykinin B2 receptor as assessed using recombinant or endogenously expressed receptors.

Multiple Inhibitory Mechanisms of Lidocaine on Bradykinin Receptor Activity in Model Sensory Neurons.

BACKGROUND AND OBJECTIVES: Local anesthetics (LAs) are often infiltrated subcutaneously for localized perioperative numbing. In addition to blocking nerve conduction, LAs act on pathways used by a variety of pain-inducing and inflammatory mediators. We describe the effects in isolated model sensory neurons of LAs on responses to the algogenic and sensitizing peptide, bradykinin (BK). METHODS: ND/7 sensory neurons were stimulated by different concentrations of BK in the presence or absence of LAs, with transient increases in intracellular calcium (Δ[Ca]in) detected fluorometrically in fields of cells. Equilibrium saturable binding of radiolabeled BK also was conducted on the same type of cells, with and without LA. RESULTS: Responses to low BK (5 nM) were inhibited by lidocaine at 1 mM (approximately 35% inhibition) and 10 mM (approximately 70% inhibition), whereas responses to high BK (100 nM) were unaffected by 1 mM yet inhibited (approximately 75%) by 10 mM lidocaine. Bupivacaine (1 and 2 mM) did not reduce peak Δ[Ca]in (using 5 nM BK). Lidocaine's quaternary derivative, QX-314 (10 mM), also was ineffective on peak Ca (5 nM BK). Saturation binding of BK showed that lidocaine lowered the binding capacity (Bmax) without changing the KD, consistent with noncompetitive inhibition. CONCLUSIONS: At subclinical concentrations, lidocaine suppresses BK's activation of model sensory neurons. This effect adds to the known analgesic mechanisms of LAs and likely contributes to the reduction of postincisional pain.

Angiotensin-converting enzyme inhibitors reduce oxidative stress intensity in hyperglicemic conditions in rats independently from bradykinin receptor inhibitors.

AIM: To investigate whether endogenous bradykinin is involved in the antioxidant action of angiotensin-converting enzyme inhibitors (ACEIs) in acute hyperglycemia. METHODS: Male Wistar rats were divided into the normoglycemic group (n=40) and the hyperglycemic group (n=40). Hyperglycemia was induced by a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg body weight) dissolved in 0.1 mol/L citrate buffer (pH 4.5) 72 hours before sacrifice. The normoglycemic group received the same volume of citrate buffer. Each group was divided into five subgroups (n=8): control group, captopril group, captopril + bradykinin B1 and B2 receptor antagonists group, enalapril group, and enalapril + bradykinin B1 and B2 receptor antagonists group. Captopril, enalapril, B1 and B2 receptor antagonists, or 0.15 mol/L NaCl were given at 2 and 1 hour before sacrifice. Oxidative status was determined by measuring the concentration of malondialdehyde and H2O2, and the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). RESULTS: In STZ-induced hyperglycemic rats ACEIs significantly reduced H2O2 concentration, while they significantly enhanced SOD and GPx activity. The hyperglycemic group treated simultaneously with ACEIs and bradykinin B1 and B2 receptor antagonists showed a significant decrease in H2O2 concentration compared to the control hyperglycemic group. CONCLUSION: These results suggest the existence of the bradykinin -independent antioxidative effect of ACEIs in hyperglycemic conditions, which is not related to the bradykinin mediation and the structure of the drug molecule.