Increased Urinary Excretion of Podocyte Markers in Normoalbuminuric Patients with Diabetes.

BACKGROUND: Podocyte injury plays a crucial role in the pathogenesis and progression of diabetic nephropathy (DN). We investigated whether patients with diabetes mellitus (DM) without overt DN present podocyte markers in urine suggestive of early podocyte injury. METHODS: We studied 71 patients with DM type 2 and normal urine albumin excretion (UAE) and 39 non-diabetic controls. The mRNA abundance of 3 podocyte-specific markers in urinary sediment (nephrin, podocin and synaptopodin) was measured with real-time quantitative PCR. All the subjects were categorized according to their urinary podocyte marker profile into 2 groups, those with only synaptopodin mRNA presence (synaptopodin only group) and those with nephrin and/or podocin mRNA presence in addition to synaptopodin in their urine (nephrin and/or podocin group). RESULTS: Synaptopodin mRNA was detected in the urine of all the diabetics and controls. The presence of nephrin and/or podocin mRNA in urine was more frequent among DM patients compared to controls (53.5 vs. 30.8%, respectively; p = 0.022). Binary logistic regression analysis revealed that the only significant predictor of the presence of nephrin and/or podocin mRNA in urine was the presence of DM (OR 2.59, 95% CI 1.14-5.91, p = 0.024, adjusted for all risk factors). A strong correlation between nephrin and podocin urinary mRNA levels was noted (r = +0.796, p < 0.001). CONCLUSION: This study demonstrated that urinary podocyte markers are more prevalent in diabetic patients with normal UAE compared to controls, and this may reflect early podocyte injury. DM is the only significant determinant of the presence of nephrin and/or podocin mRNA in urine in this population. Therefore, urinary podocyte markers may emerge as a valuable tool in the early diagnosis of DN.

The PI3K/Akt/mTOR pathway is activated in murine lupus nephritis and downregulated by rapamycin.

BACKGROUND: The mammalian target of rapamycin (mTOR) inhibitor, rapamycin, has been shown to inhibit the progression of murine lupus nephritis by virtue of its potent immunosuppressive properties. The phosphoinositol-3-kinase (PI3K)/Akt pathway is a major upstream activator of mTOR and has been implicated in the propagation of cancer and autoimmunity. However, the activation status of the PI3K/Akt/mTOR pathway in lupus nephritis has not been studied so far. METHODS: In NZBW/F1 female mice, we examined the glomerular expression of Akt and mTOR by immunofluorescence and western blot. We also searched for specific phosphorylations of these kinases known to ensue during activation of the PI3K/Akt/mTOR pathway. In parallel, we examined the therapeutic role of rapamycin either before or after the development of overt lupus nephritis. RESULTS: We found that in untreated mice, as opposed to healthy controls, Akt and mTOR were over-expressed and phosphorylated at key activating residues. Rapamycin prolonged survival, maintained normal renal function, normalized proteinuria, restored nephrin and podocin levels, reduced anti-dsDNA titres, ameliorated histological lesions, and reduced Akt and mTOR glomerular expression activation. CONCLUSIONS: These results suggest that: (i) the PI3K/Akt/mTOR pathway is upregulated in murine lupus nephritis, thus justifying treatment with rapamycin; (ii) rapamycin not only blocks mTOR but also negatively regulates the PI3K/Akt/mTOR pathway; and (iii) rapamycin is an effective treatment of murine lupus nephritis. Examination of the PI3K/Akt/mTOR pathway may offer new insights into the pathogenesis of lupus nephritis in humans and may lead to more individualized and less toxic treatment.

Concurrent CMV and EBV DNAemia is significantly correlated with a delay in the response to HAART in treatment-naive HIV type 1-positive patients.

The purpose of this study was to assess the qualitative single and multiple herpes virus DNAemia in the peripheral blood leukocytes (PBLs) of HIV-1-positive patients and its impact on the response to highly active antiretroviral therapy (HAART) and immune reconstitution. All (163) HIV-1-positive patients attending "Syngros AIDS Referral Center" from November 2000 to February 2001 were recruited. CMV, HSV-1, HSV-2, EBV, and HHV-8 DNA were detected in PBLs by polymerase chain reaction (PCR). Patients' follow-up comprised regular measurements of CD4(+) T cell count and HIV-1 viral load (VL) for an average period of 21 months. Immune reconstitution was defined as an increase in the CD4 T cell count by above 200 cells/micro l, while response to HAART was defined as a decrease in HIV-1 VL to undetectable levels. Single and multiple herpetic DNAemia in PBLs was found to be significantly higher in HIV-1-positive patients compared to healthy controls (p < 0.02) for all the viruses detected apart from HSV-2, which was not detected in the PBLs of either population. Concurrent CMV and EBV DNAemia significantly correlates with a delay in the response to HAART (p = 0.033) in treatment-naive patients. Untreated patients with a CD4(+) T cell count <200 cells/micro l, and with either CMV or EBV DNAemia, presented a delayed increase in the CD4 count after initiation of HAART (p = 0.035 and p = 0.037 respectively), while multiple herpetic DNAemia in the above patients was borderline associated with immune reconstitution (p = 0.068). Conclusively, CMV and EBV DNAemia may be poor prognostic factors for the response to HAART in treatment-naive HIV-1 patients.

Systemic levels of interleukin-6 and matrix metalloproteinase-9 in patients with multiple myeloma may be useful as prognostic indexes of bone disease.

Multiple myeloma is characterized by accelerated production of the proteolytic enzyme matrix metalloproteinase (MMP)-9. We hypothesized that myeloma-produced MMP-9 may influence the rate of bone turnover in a paracrine manner. Thus, we examined the correlations of MMP-9 levels, disease severity, and bone turnover rate as evaluated by markers of bone formation and resorption. Thirty-seven newly diagnosed multiple myeloma patients (nine of Durie-Salmon stage I, 12 of stage II and 16 of stage III) and 12 age-matched controls were studied. Serum MMP-9 levels were significantly higher at stage II compared to stage I (188.78+/-91.27 vs. 59.25+/-33.09 ng/mL, p<0.004). Additionally, free urine pyridinolines (F-Pyd), free urine deoxy-pyridinolines (F-Dpd) and urine N-telopeptide fragment (NTx) were elevated, their level correlating with disease stage (p<0.001, p<0.03, p<0.001, respectively), as were bone marrow infiltration and serum interleukin-6 (IL-6) levels (p<0.0001, p<0.01, respectively). MMP-9 levels were lower in patients compared with controls (p<0.001), whereas IL-6 and bone resorption marker levels were higher in patients than in controls (p<0.001 in all cases). Significant correlation was found between infiltration, MMP-9, free urine pyd, free urine dpd and NTx for each stage of the disease (p<0.03, p<0.003, p<0.002, p<0.003 and p<0.001, respectively). Levels of MMP-9 and of IL-6 in multiple myeloma correlate well with bone turnover rate and may be useful in disease evaluation.