Pharmacological enhancement of the kallikrein-kinin system promotes anti-fibrotic responses in human mesangial cells

The aim of the present study was to investigate whether pharmacological enhancement of the renal kallikrein-kinin system using the vasopeptidase inhibitor omapatrilat plays a direct role in modulating the fibrotic responses of human mesangial cells to injury. Treatment with 40µmol/L omapatrilat was able to reduce macrophage-conditioned medium (MPCM)-induced fibronectin levels without affecting mRNA expression. MPCM injury also suppressed kallikrein and low molecular weight kininogen mRNA. Omapatrilat was able to attenuate this suppression. Bradykinin levels in contrast were increased by MPCM and treatment with omapatrilat further augmented levels. Co-incubation with the bradykinin B2 receptor antagonist HOE 140 attenuated the omapatrilat-induced lowering of fibronectin. Moreover, inhibition of cGMP release had a similar effect. Paradoxically, RT-PCR and Southern blotting demonstrated that bradykinin B2 receptor mRNA levels were down regulated in response to omapatrilat. Western blotting supported this data. Supernatant levels of tissue plasminogen activator (tPA), a product of bradykinin stimulation, were decreased by omapatrilat while cell associated tPA levels were increased. Matrix metalloproteinase-9 (MMP-9) mRNA expression was up regulated by omapatrilat treament, although no difference in active zymogen levels was observed. In conclusion enhancement of kallikrein-kinin system appears to play a direct role in promoting anti-fibrotic responses in MPCM-injured human mesangial cells

Kallikrein gene 'knock-down' by small interfering RNA transfection induces a profibriotic phenotype in rat mesangial cells.

Background: Emerging evidence suggests that kallikrein exerts renoprotective effects independent of its haemodynamic actions. The aim of the current investigation was to delineate the role of kallikrein in the regulation of fibrosis, by 'knocking down' its expression using specific small interfering RNAs (siRNA). Methods: Rat mesangial cells were treated with 12, 60, 120 nmol/l kallikrein-specific siRNAs. The consequent cellular genotypes and phenotypes were analysed. Results: Western blotting demonstrated that mesangial cells produced a kallikrein protein, which was of a different molecular weight to urinary kallikrein from rats of the same species. Treatment of cells with siRNA resulted in a dose-dependent decrease in kallikrein mRNA levels, which impacted on other components of the kallikrein-kinin system, dose-dependently reducing bradykinin B2 receptor mRNA expression. Kallikrein suppression resulted in significant increases in fibronectin and transforming growth factor-[beta] protein levels in culture supernatants over control levels. Gelatin zymography demonstrated a siRNA dose-dependent decrease in active MMP-2 enzyme levels. Bradykinin, an effector molecule of the kallikrein system, is known to stimulate tissue plasminogen activator production. Paradoxically, however, tissue plasminogen activator protein levels were augmented with increasing kallikrein mRNA silencing. This was accompanied by a dose-dependent decrease in low-density lipoprotein receptor-related protein mRNA levels, indicating that increased tissue plasminogen activator levels were due to an attenuation of receptor-mediated protease clearance. Conclusion: These data lend strong support to the hypothesis that kallikrein exerts antifibrotic, renoprotective effects that are independent of its classical haemodynamic actions

Primary care-based disease management of chronic kidney disease (CKD), based on estimated glomerular filtration rate (eGFR) reporting, improves patient outcomes.

Background. The majority of patients with chronic kidney disease (CKD) stages 3–5 are managed within primary care. We describe the effects, on patient outcomes, of the introduction of an algorithm-based, primary care disease management programme (DMP) for patients with CKD based on automated diagnosis using estimated glomerular filtration rate (eGFR) reporting. Methods. Patients within West Lincolnshire Primary Care Trust, UK, population 223, 287 with CKD stage 4 or 5 were enrolled within the DMP between March 2005 and October 2006. We have analysed the performance against clinical targets looking at a change in renal function prior to and following joining the DMP and the proportion of patients achieving clinical targets for blood pressure control and lipid abnormalities. Results. Four hundred and eighty-three patients with CKD stage 4 or 5 were enrolled in the programme. There were significant improvements in the following parameters, expressed as median values (interquartile range) after 9 months in the programme, compared to baseline and percentage values patients achieving target at 9 months: total cholesterol 4.2 (3.45–5.0) mmol/l versus 4.6 (3.9–5.4) mmol/l (P < 0.01), 75.0% versus 64.5% (P < 0.001); LDL 2.2 (1.6–2.8) mmol/l versus 2.5 (1.9–3.2) mmol/l (P < 0.01), 81.9% versus 69.2% (P < 0.05); systolic blood pressure 130 (125–145) mmHg versus 139 (124–154) mmHg (P < 0.05), 56.2% versus 37.1% (P < 0.05) and diastolic blood pressure 71 (65–79) mmHg versus 76 (69–84) mmHg (P < 0.01), 68.4% versus 90.3% (P < 0.01). The median fall (interquartile range) in eGFR in the 9 months prior to joining the programme was 3.69 (1.49–7.46) ml/min/1.73 m2 compared to 0.32 (−2.61–3.12) ml/min/1.73 m2 in the 12 months after enrolment (P < 0.001). One hundred and twenty-two patients experienced a fall in eGFR of ≥5 ml/min/1.73 m2, median 9.90 (6.55–12.36) ml/min/1.73 m2 in the 9 months prior to joining the programme, whilst in the 12 months after enrolment, their median fall in eGFR was −1.70 (−6.41–1.64) ml/min/1.73 m2 (P < 0.001). In the remaining patients, the median fall in eGFR was 1.92 (0.41–3.23) ml/min/1.73 m2 prior to joining the programme and 0.86 (−1.03– 3.53) ml/min/1.73 m2 in the 12 months after enrolment (P = 0.082). Conclusions. These data suggest that chronic disease management in this form is an effective method of identifying and managing patients with CKD within the UK. The improvement in cardiovascular risk factors and reduction in the rate of decline of renal function potentially have significant health benefits for the patients and should result in cost savings for the health economy