Treatment with a cyclin-dependent kinase inhibitor, seliciclib, is effective in reducing glomerular macrophage numbers and the severity of established experimental glomerulonephritis

AIM

The cyclin-dependent kinase inhibitor, seliciclib (R-roscovitine, CYC202), has anti-proliferative activity through its inhibition of cyclin-dependent kinase 2. We hypothesized that treatment with seliciclib would reduce glomerular macrophage numbers and glomerular crescent formation in experimental crescentic glomerulonephritis even when treatment is started after onset of disease.

METHOD

Nephrotoxic nephritis (NTN) was induced in Wistar Kyoto rats. In experiment 1, seliciclib (150 mg/kg per day) was given by oral gavage from 1 h before induction of NTN and continued to day 14. In experiment 2, treatment was started on day 4 of NTN and continued to day 14 in order to examine the effect of seliciclib in established glomerulonephritis.

RESULTS

In experiment 1, seliciclib reduced proteinuria (119.5 ± 13.9 vs 191.4 ± 18.8 mg/day, P < 0.01), serum creatinine (54.0 ± 3.0 vs 81.0 ± 2.5 µmol/L, P < 0.005) and glomerular crescent score (23.9 ± 2.1 vs 44.6 ± 2.2, P < 0.005) in comparison with controls. In experiment 2, seliciclib ameliorated established glomerulonephritis, with reduction in proteinuria (58 ± 16 vs 165 ± 13 mg/day, P < 0.005), serum creatinine (39 ± 3 vs 62 ± 5 µmol/L, P < 0.05), glomerular macrophage numbers (6.8 ± 2.5 vs 18.5 ± 1.2 ED1+ cells per glomerular cross section, P < 0.05), glomerular cell proliferation (1.2 ± 0.37 vs 4.2 ± 0.80 bromodeoxyuridine (BrdU)+ cells per glomerular section, P < 0.05) and crescent score (10.8 ± 1.6 vs 43.9 ± 1.4, P < 0.05), in comparison with the controls.

CONCLUSION

Seliciclib is effective in both prevention and treatment of established crescentic glomerulonephritis in Wistar Kyoto rats, in association with a reduction in the number of glomerular macrophages. We suggest that seliciclib, or other cyclin-dependent kinase inhibitors, may represent a novel therapeutic approach for patients with proliferative glomerulonephritis.

800 facets of retinal degeneration

In today's world of genomics and large computational analyses, rapid progress has been made in identifying genes associated with human retinal diseases. Nevertheless, before significant advances toward effective therapeutic intervention is made, a clearer understanding of the molecular and cellular role of these gene products in normal and diseased photoreceptor cell biology is required. Given the complexity of the vertebrate retina, these advancements are unlikely to be revealed in isolated human cell lines, but instead, will require the use of numerous model systems. Here, we describe several parallels between vertebrate and invertebrate photoreceptor cell biology that are beginning to emerge and advocate the use of Drosophila melanogaster as a powerful genetic model system for uncovering molecular mechanisms of human retinal pathologies, in particular photoreceptor neurodegeneration.

Low vitamin D levels in Northern American adults with the metabolic syndrome

Metabolic syndrome (MetS), is a constellation of cardiometabolic disease risk factors, that affects 1 in 3 US adults and predisposes to increased risks for both diabetes and cardiovascular disease. While epidemiological studies show low vitamin D [(25(OH)D] levels in MetS, there is sparse data on vitamin D status in MetS patients in North America. Thus, the aim of our study was to examine plasma vitamin D concentration among adults with MetS in Northern California (sunny climate), but without diabetes or cardiovascular disease. 25(OH)D levels were significantly decreased in MetS compared to controls. 8 % of controls and 30% of MetS North American adult subjects were deficient in 25(OH)D (<20 ng/ml; p=0.0236, Controls vs. MetS). There were no significant differences between the groups with respect to blood sampling in winter and summer months, total calcium and phosphate, and creatinine levels. Vitamin D levels were significantly inversely correlated with fasting glucose (r=-0.29, p=0.04) and HOMA (r=-0.34, p=0.04). Future studies of vitamin D supplementation in these subjects on subsequent risk of diabetes will prove instructive with respect to potential health claims in these high risk patients with MetS.

Mice lacking C1q or C3 show accelerated rejection of minor H disparate skin grafts and resistance to induction of tolerance

Complement activation is known to have deleterious effects on organ transplantation. On the other hand, the complement system is also known to have an important role in regulating immune responses. The balance between these two opposing effects is critical in the context of transplantation. Here, we report that female mice deficient in C1q (C1qa(-/-)) or C3 (C3(-/-)) reject male syngeneic grafts (HY incompatible) at an accelerated rate compared with WT mice. Intranasal HY peptide administration, which induces tolerance to syngeneic male grafts in WT mice, fails to induce tolerance in C1qa(-/-) or C3(-/-) mice. The rejection of the male grafts correlated with the presence of HY D(b)Uty-specific CD8(+) T cells. Consistent with this, peptide-treated C1qa(-/-) and C3(-/-) female mice rejecting male grafts exhibited more antigen-specific CD8(+)IFN-gamma(+) and CD8(+)IL-10(+) cells compared with WT females. This suggests that accumulation of IFN-gamma- and IL-10-producing T cells may play a key role in mediating the ongoing inflammatory process and graft rejection. Interestingly, within the tolerized male skin grafts of peptide-treated WT mice, IFN-gamma, C1q and C3 mRNA levels were higher compared to control female grafts. These results suggest that C1q and C3 facilitate the induction of intranasal tolerance.

The new Oxford Clinico-Pathological Classification of IgA nephropathy

The new Oxford Classification of the Pathology of IgA nephropathy originated from an international collaborative effort of the Working Group of the International IgA Nephropathy Network and Renal Pathology Society. It provides a new common language to categorizing glomerular and tubulo-interstitial lesions in IgA nephropathy having a proved effect on progression. Although retrospective in design and requiring future prospective validation, the Oxford collaboration defined and scored four pathologic parameters having an influence on outcome (independently of clinical information at renal biopsy or during follow-up); including mesangial (M) and endocapillary (E) proliferation (hypercellularity), glomerulosclerosis (S) and tubular atrophy and interstitial fibrosis (T). The scheme will likely become known as the OXFORD-MEST scoring system.

Audit of performance of size 1.5 ProSeal laryngeal mask airways in infants less than six months undergoing inguinal herniotomy

Many anaesthetists have found the size 1.5 classic Laryngeal Mask Airway unsuitable for use in children under 10 kg, whereas recent studies evaluating the ProSeal Laryngeal Mask Airway (PLMA) show high success rates, even during laparoscopic surgery. Our routine practice has been to use tracheal intubation for inguinal herniotomy in children weighing less than 10 kg. Following the introduction of the PLMA to our hospital, we decided to audit our use of the PLMA 1.5 in this group of patients. We included 20 consecutive infants, aged less than six months and weighing 5 to 10 kg. We recorded patient, anaesthetic and insertion details, device performance data and complications. No aspect of anaesthetic practice was changed by involvement in this audit. The PLMA was inserted successfully at the first attempt in 85% (17/20) of infants. Overall successful insertion occurred in 90% (18/20) and satisfactory airway maintenance was provided for the duration of anaesthesia in 90% (18/20). The mean leak pressure was 24 cmH2O (range 15 to 30 cmH2O). We found the 1.5 PLMA provided a satisfactory airway in 90% of infants. This report adds to the evidence that the PLMA 1.5 can provide a satisfactory alternative to intubation in selected infants.