Cyclophilin D promotes tubular cell damage and the development of interstitial fibrosis in the obstructed kidney

Cyclophilin D (CypD) is an important component in mitochondrial‐dependent tubular cell death in acute kidney injury. However, it is not known whether CypD contributes to tubular cell damage in chronic interstitial fibrosis. We investigated this question in the unilateral ureter obstruction (UUO) model of renal interstitial fibrosis. Groups of CypD^?/? and wild type (WT) mice were killed 7 or 12 days after UUO surgery. The significant tubular cell apoptosis seen in WT UUO was significantly reduced in CypD^?/? UUO based on TUNEL and cleaved caspase 3 staining. Other markers of tubular cell damage; loss of E‐cadherin and AQP1 expression, were also reduced in the CypD^?/? UUO kidney. This reduced tubular damage was associated with less inflammation and a partial protection against loss of peritubular capillaries. The prominent accumulation of α‐SMA+ myofibroblasts and interstitial collagen deposition seen in WT UUO was significantly reduced in CypD^?/? UUO on day 12, but not day 7. Activation of several pro‐fibrotic signalling pathways (p38 MAPK, JNK and Smad3) was unaltered in CypD^?/? UUO, arguing that CypD acts independently to promote renal fibrosis. CypD deletion in cultured tubular cells attenuated oxidative stress‐induced pro‐inflammatory, pro‐fibrotic and apoptotic responses; however, responses to angiotensin II and LPS were unaffected. In contrast, CypD deletion in cultured renal fibroblasts did not affect PDGF‐induced proliferation or TGF‐β1‐induced collagen I expression, suggesting no direct role of CypD in the fibroblast response. In conclusion, we have identified a role for CypD in chronic tubular cell damage and in the development of renal interstitial fibrosis.     

Psychometric properties of the Brazilian version of the Early Childhood Oral Health Impact Scale (B-ECOHIS)

Background

Oral disorders can have a negative impact on the functional, social and psychological wellbeing of young children and their families and cause pain/discomfort for the child. Oral health-related quality of life (OHRQoL) has emerged as an important health outcome in clinical trials and healthcare research. The Early Childhood Oral Health Impact Scale (ECOHIS) is a proxy measure of children's OHRQoL designed to assess the negative impact of oral disorders on the quality of life of preschool children. The objective of this study was to evaluate the psychometric properties of the Brazilian version of the ECOHIS (B-ECOHIS).

Methods

This investigation was carried out in preliminary and field studies. The preliminary study comprised a cross-sectional study carried out in the city of Petropolis, Brazil. A sample of 150 children from two to five years of age was recruited at a public hospital. In the field study, an epidemiological survey was carried out in public and private preschools of Belo Horizonte, Brazil. The B-ECOHIS was answered by 1643 parents/caregivers of five-year-old male and female preschool children. In both phases, oral examinations were performed by a single previously calibrated dentist. Reliability was determined through test-retest reliability and internal consistency. Validity was determined through convergent and discriminant validities. The correlation between the scores obtained on the child and family impact sections was assessed.

Results

In the preliminary (P) and field (F) study, test-retest reliability correlation values were 0.98 and 0.99 for the child impact section and 0.97 and 0.99 for the family impact section, respectively. The B-ECOHIS demonstrated internal consistency: child impact section (P: α = 0.74; F: α = 0.80) and family impact section (P: α = 0.59; F: α = 0.76). The correlation between the scores obtained on the child and family impact sections was statistically significant (P: r_s = 0.54; F: r_s = 0.62; p ≤ 0.001). In both phases of the study, B-ECOHIS scores were significantly associated with the decayed, missing and filled teeth index, decayed teeth and discolored upper anterior teeth (p < 0.05).

Conclusion

The B-ECOHIS proved reliable and valid for assessing the negative impact of oral disorders on the quality of life of preschool children.     

Myeloid Mineralocorticoid Receptor Activation Contributes to Progressive Kidney Disease

Clinical and experimental studies have shown that mineralocorticoid receptor (MR) antagonists substantially reduce kidney injury. However, the specific cellular targets and mechanisms by which MR antagonists protect against kidney injury must be identified. We used conditional gene deletion of MR signaling in myeloid cells (MR^flox/flox LysM^Cre mice; MyMRKO) or podocytes (MR^flox/flox Pod^Cre mice; PodMRKO) to establish the role of MR in these cell types in the development of mouse GN. Accelerated anti–glomerular basement membrane GN was examined in groups of mice: MyMRKO, PodMRKO, wild-type (WT) littermates, and WT mice receiving eplerenone (100 mg/kg twice a day; EPL-treated). At day 15 of disease, WT mice had glomerular crescents (37%±5%), severe proteinuria, and a 6-fold increase in serum cystatin-C. MyMRKO, PodMRKO, and EPL-treated mice with GN displayed proteinuria similar to that in these disease controls. However, MyMRKO and EPL-treated groups had a 35% reduction in serum cystatin-C levels and reduced crescent numbers compared with WT mice, whereas PodMRKO mice were not protected. The protection observed in MyMRKO mice appeared to result predominantly from reduced recruitment of macrophages and neutrophils into the inflamed kidney. Suppression of kidney leukocyte accumulation in MyMRKO mice correlated with reductions in gene expression of proinflammatory molecules (TNF-α, inducible nitric oxide synthase, chemokine (C-C motif) ligand 2, matrix metalloproteinase-12), tubular damage, and renal fibrosis and was similar in EPL-treated mice. In conclusion, MR signaling in myeloid cells, but not podocytes, contributes to the progression of renal injury in mouse GN, and myeloid deficiency of MR provides protection similar to eplerenone in this disease.Mineralocorticoid receptor (MR) antagonists are known to inhibit renal and cardiovascular disease (CVD) by direct blockade of MR in tissues and by reducing hypertension.¹ They can also suppress kidney damage in animal models of GN and diabetic nephropathy without affecting BP.^2–6 In addition, MR antagonists provide added protection against proteinuria and loss of renal function when used with standard antihypertensive therapies in patients with diabetic and nondiabetic CKD.^7–9The clinical use of MR antagonists is limited by the development of hyperkalemia due to the importance of the MR in tubular regulation of salt balance.¹⁰ This consequence of MR blockade in the distal tubule is most evident during renal impairment and can require a reduction in the dosage of MR antagonist or withdrawal of the agent as a therapy.^7,8 The specific renal cell types that are targeted by MR antagonists to reduce injury during kidney disease have not been clearly identified. Establishing the identity of these cells is an important step toward developing more selective inhibitors of MR signaling that do not interfere with tubular cell function.Animal studies demonstrate that the protection afforded by MR antagonists in GN and diabetic nephropathy is associated with reductions in renal inflammation, proteinuria, and glomerular injury.^2,3,5,11 These studies also link MR blockade to suppression of leukocyte recruitment and podocyte injury. This suggests that the major pathologic effects of MR signaling may occur in podocytes and inflammatory cells.Recent in vitro studies have suggested that MR signaling can induce apoptosis in podocytes and oxidative stress in macrophages,^12,13 which supports a role for MR signaling in these cell types in kidney disease. In addition, an MR deficiency in myeloid cells protects against cardiovascular injury and ischemic cerebral infarcts by reducing inflammation and fibrosis.^14–16 However, no in vivo studies have identified whether MR signaling in podocytes or macrophages is specifically important to the development of kidney disease.In this study, we created mice with a selective genetic deficiency of MR in myeloid cells or podocytes and used these strains to evaluate the hypothesis that MR signaling in macrophages or podocytes is required for the development of renal injury in a normotensive model of progressive GN.     

Evidence of a novel staphylococcal mec-encoded element (mecR) controlling expression of penicillin-binding protein 2''.

A region was identified on the methicillin resistance determinant (mec) isolated from Staphylococcus epidermidis and cloned into Staphylococcus carnosus which was responsible for a novel downregulation of the expression of methicillin resistance. The presence of this region reduced the overall expression of methicillin resistance and the synthesis of the mec-encoded penicillin-binding protein 2' (PBP 2') in S. carnosus. This region was located by Bal31 deletion mutagenesis upstream of the structural gene for PBP 2'. Deletions within this region resulted in higher levels of expression of methicillin resistance and increased levels of PBP 2' synthesis. We tentatively called this region mecR. Analysis of selected Mcr strains of Staphylococcus aureus and S. epidermidis by Southern hybridization suggested that the natural occurrence of two types of mec resistance determinants differ by the presence or absence of mecR-specific sequences.     

Correlation between the levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry in patients with temporomandibular disorders

Recent studies showed that patients with chronic TMD pain also feature increased sensitivity in other craniofacial regions, and even in remote peripheral areas, suggesting that nociceptive processing is centrally facilitated in this patient population. The aim of this study was to investigate the existence of a negative correlation between the levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry at sites distant from the chief complaint of oro‐facial pain in patients with TMD. A total of 20 female patients were evaluated comprising 11 patients diagnosed with myofascial pain (Group I of RDC/TMD) and 9 patients with arthralgia (Group III of RDC/TMD), with both reporting chronic TMD pain for at least 3 months. Patients were tested by the pressure algometry technique, and, in the same visit, clinical diagnosis and levels of non‐specific physical symptoms, including pain‐related issues or not, were obtained. The raw scores were then standardised into a T‐score. The possible correlation between the dependent variable levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry at sites distant from the chief complaint of oro‐facial pain was assessed with Spearman's correlation coefficient. Results were considered statistically significant, which stood a lower than 5% probability of occurring by chance (P < 0·05). A statistically significant (P = 0·02) negative correlation (?0·51) was found to exist between the levels of non‐specific physical symptoms, only if including issues involving pain‐related symptoms, and experimental pressure pain thresholds in patients with painful TMD.     

Monocyte chemoattractant protein 1-dependent leukocytic infiltrates are responsible for autoimmune disease in MRL-Fas(lpr) mice

Infiltrating leukocytes may be responsible for autoimmune disease. We hypothesized that the chemokine monocyte chemoattractant protein (MCP)-1 recruits macrophages and T cells into tissues that, in turn, are required for autoimmune disease. Using the MRL-Fas(lpr) strain with spontaneous, fatal autoimmune disease, we constructed MCP-1-deficient MRL-Fas(lpr) mice. In MCP-1-intact MRL-Fas(lpr) mice, macrophages and T cells accumulate at sites (kidney tubules, glomeruli, pulmonary bronchioli, lymph nodes) in proportion to MCP-1 expression. Deleting MCP-1 dramatically reduces macrophage and T cell recruitment but not proliferation, protects from kidney, lung, skin, and lymph node pathology, reduces proteinuria, and prolongs survival. Notably, serum immunoglobulin (Ig) isotypes and kidney Ig/C3 deposits are not diminished in MCP-1-deficient MRL-Fas(lpr) mice, highlighting the requirement for MCP-1-dependent leukocyte recruitment to initiate autoimmune disease. However, MCP-1-deficient mice are not completely protected from leukocytic invasion. T cells surrounding vessels with meager MCP-1 expression remain. In addition, downstream effector cytokines/chemokines are decreased in MCP-1-deficient mice, perhaps reflecting a reduction of cytokine-expressing leukocytes. Thus, MCP-1 promotes MRL-Fas(lpr) autoimmune disease through macrophage and T cell recruitment, amplified by increasing local cytokines/chemokines. We suggest that MCP-1 is a principal therapeutic target with which to combat autoimmune diseases.