Publications

Candida albicans is the most common cause of serious fungal disease in humans. Creation of isogenic null mutants of this diploid organism, which requires sequential gene targeting, allows dissection of virulence mechanisms. Published analyses of such mutants show a near-perfect correlation between C. albicans pathogenicity and the ability to undergo a yeast-to-hypha morphological switch in vitro. However, most studies have used mutants constructed with a marker that is itself a virulence determinant and therefore complicates their interpretation. Using alternative markers, we created approximately 3,000 homozygous deletion strains affecting 674 genes, or roughly 11% of the C. albicans genome. Screening for infectivity in a mouse model and for morphological switching and cell proliferation in vitro, we identified 115 infectivity-attenuated mutants, of which nearly half demonstrated normal morphological switching and proliferation. Analysis of such mutants revealed that virulence requires the glycolipid glucosylceramide. To our knowledge, this is the first C. albicans small molecule that has been found to be required specifically for virulence.

BACKGROUND

Chronic kidney disease (CKD) screening beyond patients with diabetes mellitus or hypertension increasingly is discussed. Some guidelines recommend kidney function testing of patients with benign prostatic hyperplasia; however, the significance of extending this to general population screening is unclear.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

30,466 men from the HUNT II (Second Health Study in Nord-Trøndelag; 1995-1997) representing 66.8% of the entire adult male population in Nord-Trøndelag County, Norway.

PREDICTOR

The International Prostate Symptom Score was used to detect the presence and severity of lower urinary tract symptoms (LUTS), a surrogate measure of benign prostate hyperplasia suitable for use in general practice.

OUTCOMES

Kidney failure was defined as starting renal replacement therapy or CKD death with a documented stable estimated glomerular filtration rate<15 mL/min/1.73 m2.

RESULTS

During 10.5 years of follow-up, 78 men developed kidney failure. Kidney failure risks were 2.60 (95% CI, 1.47-4.58) and 4.08 (95% CI, 1.74-9.53) times higher for men with moderate and severe LUTS compared with men with no/mild LUTS, respectively. However, age-stratified analysis showed that the incidence rate ratio for moderate/severe LUTS versus no/mild LUTS was 1.27 (95% CI, 0.76-2.13), and multivariable Cox analysis showed no significant association between LUTS and risk of kidney failure. Screening effectiveness was improved only slightly by including men with moderate/severe LUTS in addition to patients with diabetes, hypertension, or cardiovascular disease. Better effectiveness was achieved by simply including all men older than 60 years.

LIMITATIONS

The ability of the International Prostate Symptom Score to predict the presence and severity of obstruction is only moderate. Ascertainment of severe CKD (estimated glomerular filtration rate, 30-15 mL/min/1.73 m2) was not possible.

CONCLUSION

LUTS were not significantly associated with future kidney failure after adjusting for age and therefore in isolation are not a basis for kidney failure screening.

In these studies, we find that the vascular endothelial growth factor (VEGF) receptor KDR is expressed on subsets of mitogen-activated CD4(+) and CD8(+) T cells in vitro. We also found that KDR colocalizes with CD3 on mitogen-activated T cells in vitro and on infiltrates within rejecting human allografts in vivo. To evaluate whether VEGF and KDR mediate lymphocyte migration across endothelial cells (ECs), we used an in vitro live-time transmigration model and observed that both anti-VEGF and anti-KDR antibodies inhibit the transmigration of both CD4(+) and CD8(+) T cells across tumor necrosis factor α (TNFα)-activated, but not unactivated ECs. In addition, we found that interactions among CD4(+) or CD8(+) T cells and TNFα-activated ECs result in the induction of KDR on each T cell subset, and that KDR-expressing lymphocytes preferentially transmigrate across TNFα-activated ECs. Finally, using a humanized severe combined immunodeficient mouse model of lymphocyte trafficking, we found that KDR-expressing lymphocytes migrate into human skin in vivo, and that migration is reduced in mice treated with a blocking anti-VEGF antibody. These observations demonstrate that induced expression of KDR on subsets of T cells, and locally expressed VEGF, facilitate EC-dependent lymphocyte chemotaxis, and thus, the localization of T cells at sites of inflammation.