Publications

Angiotensin-converting enzyme (ACE) inhibitors ameliorate the progression of renal disease. In combination with vitamin D receptor activators, they provide additional benefits. In the present study, uremic (U) rats were treated as follows: U+vehicle (UC), U+enalapril (UE; 25 mg/l in drinking water), U+paricalcitol (UP; 0.8 μg/kg ip, 3 × wk), or U+enalapril+paricalcitol (UEP). Despite hypertension in UP rats, proteinuria decreased by 32% vs. UC rats. Enalapril alone, or in combination with paricalcitol, further decreased proteinuria (≈70%). Glomerulosclerosis and interstitial infiltration increased in UC rats. Paricalcitol and enalapril inhibited this. The increase in cardiac atrial natriuretic peptide (ANP) seen in UC rats was significantly decreased by paricalcitol. Enalapril produced a more dramatic reduction in ANP. Renal oxidative stress plays a critical role in inflammation and progression of sclerosis. The marked increase in p22(phox), a subunit of NADPH oxidase, and decrease in endothelial nitric oxide synthase were inhibited in all treated groups. Cotreatment with both compounds inhibited the uremia-induced increase in proinflammatory inducible nitric oxide synthase (iNOS) and glutathione peroxidase activity better than either compound alone. Glutathione reductase was also increased in UE and UP rats vs. UC. Kidney 4-hydroxynonenal was significantly increased in the UC group compared with the normal group. Combined treatment with both compounds significantly blunted this increase, P < 0.05, while either compound alone had no effect. Additionally, the expression of Mn-SOD was increased and CuZn-SOD decreased by uremia. This was ameliorated in all treatment groups. Cotreatment with enalapril and paricalcitol had an additive effect in increasing CuZn-SOD expression. In conclusion, like enalapril, paricalcitol alone can improve proteinuria, glomerulosclerosis, and interstitial infiltration and reduce renal oxidative stress. The effects of paricalcitol may be amplified when an ACE inhibitor is added since cotreatment with both compounds seems to have an additive effect on ameliorating uremia-induced changes in iNOS and CuZn-SOD expression, peroxidase activity, and renal histomorphometry.

Activation of Raf/Ras/mitogen-activated protein kinase (MEK)/mitogen-activated protein kinase signaling and elevated expression of membrane type-1 matrix metalloproteinase (MT1-MMP) are associated with von Hippel-Lindau gene alterations in renal cell carcinoma. We postulated that the degree of MEK activation was related to graded expression of MT1-MMP and the resultant phenotype of renal epithelial tumors. Madin Darby canine kidney epithelial cells transfected with a MEK1 expression plasmid yielded populations with morphologic phenotypes ranging from epithelial, mixed epithelial/mesenchymal to mesenchymal. Clones were analyzed for MEK1 activity, MT1-MMP expression and extent of epithelial-mesenchymal transition. Phenotypes of the MDCK-MEK1 clones were evaluated in vivo with nu/nu mice. Tissue microarray of renal cell cancers was quantitatively assessed for expression of phosphorylated MEK1 and MT1-MMP proteins and correlations drawn to Fuhrman nuclear grade. Graded increases in the MEK signaling module were associated with graded induction of epithelial-mesenchymal transition of the MDCK cells and induction of MT1-MMP transcription and synthesis. Inhibition of MEK1 and MT1-MMP activity reversed the epithelial-mesenchymal transition. Tumors generated by epithelial, mixed epithelial/mesenchymal and mesenchymal MDCK clones demonstrated a gradient of phenotypes extending from well-differentiated, fully encapsulated non-invasive tumors to tumors with an anaplastic morphology, high Fuhrman nuclear score, neoangiogenesis and invasion. Tumor microarray demonstrated a statistically significant association between the extent of phosphorylated MEK1, MT1-MMP expression and nuclear grade. We conclude that graded increases in the MEK1 signaling module are correlated with M1-MMP expression, renal epithelial cell tumor phenotype, invasive activity and nuclear grade. Phosphorylated MEK1 and MT1-MMP may represent novel, and mechanistic, biomarkers for the assessment of renal cell carcinoma.

Disrupted lung alveolar myofibroblast and bronchial smooth muscle (BSM) cell development may lead to pulmonary disorders such as bronchopulmonary dysplasia. The molecular mechanisms that regulate BSM and alveolar myofibroblast development are not fully understood. Here we show that mSmile (murine Smile), a novel transmembrane protein with tetratricopeptide repeats, functions in lung alveolar myofibroblast and BSM cell development. mSmile mutant mice exhibit early neonatal lethality with few mice surviving up to 3 weeks. Mutant lungs display both airway branching morphogenesis defect during fetal lung development and alveolarization defect after birth. These defects are associated with reduced numbers of BSM cells in the peribronchial subepithelial region and clefts and myofibroblasts in alveolar septae. Expression of fibroblast growth factor-10 and its down stream target Bmp-4, which are important for BSM formation, is decreased. In vitro, mSmile mutant embryonic fibroblasts show reduced receptor activation and induction of myofibroblast formation in response to Transforming growth factor-β (Tgf-β), indicating that mSmile may mediate myofibroblast development through modulation of Tgf-β signaling. These studies identify mSmile as a novel gene specifying both the BSM and lung alveolar myofibroblast lineages, contributing to our understanding of the biological control of the development of these cells, and may provide insights into the aberrant smooth muscle and alveolar myofibroblast development that occur in pathological conditions.

BACKGROUND

East Africa has experienced a rapid expansion in access to antiretroviral therapy (ART) for HIV-infected patients. Regionally representative socio-demographic, laboratory and clinical characteristics of patients accessing ART over time and across sites have not been well described.

METHODS

We conducted a cross-sectional analysis of characteristics of HIV-infected adults initiating ART between 2002 and 2009 in Kenya, Uganda and Tanzania and in the International Epidemiologic Databases to Evaluate AIDS Consortium. Characteristics associated with advanced disease (defined as either a CD4 cell count level of less than 50 cells/mm3 or a WHO Stage 4 condition) at the time of ART initiation and use of stavudine (D4T) or nevirapine (NVP) were identified using a log-link Poisson model with robust standard errors.

RESULTS

Among 48,658 patients (69% from Kenya, 22% from Uganda and 9% from Tanzania) accessing ART at 30 clinic sites, the median age at the time of ART initiation was 37 years (IQR: 31-43) and 65% were women. Pre-therapy CD4 counts rose from 87 cells/mm3 (IQR: 26-161) in 2002-03 to 154 cells/mm3 (IQR: 71-233) in 2008-09 (p<0.001). Accessing ART at advanced disease peaked at 35% in 2005-06 and fell to 27% in 2008-09. D4T use in the initial regimen fell from a peak of 88% in 2004-05 to 59% in 2008-09, and a greater extent of decline was observed in Uganda than in Kenya and Tanzania. Self-pay for ART peaked at 18% in 2003, but fell to less than 1% by 2005. In multivariable analyses, accessing ART at advanced immunosuppression was associated with male sex, women without a history of treatment for prevention of mother to child transmission (both as compared with women with such a history) and younger age after adjusting for year of ART initiation and country of residence. Receipt of D4T in the initial regimen was associated with female sex, earlier year of ART initiation, higher WHO stage, and lower CD4 levels at ART initiation and the absence of co-prevalent tuberculosis.

CONCLUSIONS

Public health ART services in east Africa have improved over time, but the fraction of patients accessing ART with advanced immunosuppression is still high, men consistently access ART with more advanced disease, and D4T continues to be common in most settings. Strategies to facilitate access to ART, overcome barriers among men and reduce D4T use are needed.