Hematopoietic growth factor inducible neurokinin-1 (Gpnmb/Osteoactivin) is a biomarker of progressive renal injury across species

We sought to find a urinary biomarker for chronic kidney disease and tested hematopoietic growth factor inducible neurokinin-1 (HGFIN, also known as Gpnmb/Osteoactivin) as it was found to be a kidney injury biomarker in microarray studies. Here, we studied whether HGFIN is a marker of kidney disease progression. Its increase in kidney disease was confirmed by real-time PCR after 5/6 nephrectomy, in streptozotocin-induced diabetes, and in patients with chronic kidney disease. In the remnant kidney, HGFIN mRNA increased over time reflecting lesion chronicity. HGFIN was identified in the infarct portion of the remnant kidney in infiltrating hematopoietic interstitial cells, and in distal nephron tubules of the viable remnant kidney expressed de novo with increasing time. In vitro, it localized to cytoplasmic vesicles and cell membranes. Epithelial cells lining distal tubules and sloughed luminal tubule cells of patients expressed HGFIN protein. The urine HGFIN-to-creatinine ratio increased over time after 5/6 nephrectomy; increased in patients with proteinuric and polycystic kidney disease; and remained detectable in urine after prolonged freezer storage. The urine HGFIN-to-creatinine ratio compared favorably with the urine neutrophil gelatinase-associated lipocalin (NGAL)-to-creatinine ratio (both measured by commercial enzyme-linked immunosorbent assays (ELISAs)), and correlated strongly with proteinuria, but weakly with estimated glomerular filtration rate and serum creatinine. Thus, HGFIN may be a biomarker of progressive kidney disease

Curcumin activates the p38MPAK-HSP25 pathway in vitro but fails to attenuate diabetic nephropathy in DBA2J mice despite urinary clearance documented by HPLC

<p>Abstract</p> <p>Background</p> <p>Curcumin has anti-inflammatory, anti-oxidant, and anti-proliferative properties, and depending upon the experimental circumstances, may be pro- or anti-apoptotic. Many of these biological actions could ameliorate diabetic nephropathy.</p> <p>Methods/Design</p> <p>Mouse podocytes, cultured in basal or high glucose conditions, underwent acute exposure to curcumin. Western blots for p38-MAPK, COX-2 and cleaved caspase-3; isoelectric focusing for HSP25 phosphorylation; and DNase I assays for F- to G- actin cleavage were performed for <it>in vitro </it>analyses. <it>In vivo </it>studies examined the effects of dietary curcumin on the development of diabetic nephropathy in streptozotocin (Stz)-induced diabetes in DBA2J mice. Urinary albumin to creatinine ratios were obtained, high performance liquid chromatography was performed for urinary curcuminoid measurements, and Western blots for p38-MAPK and total HSP25 were performed.</p> <p>Results</p> <p>Curcumin enhanced the phosphorylation of both p38MAPK and downstream HSP25; inhibited COX-2; induced a trend towards attenuation of F- to G-actin cleavage; and dramatically inhibited the activation of caspase-3 in <it>vitro</it>. In curcumin-treated DBA2J mice with Stz-diabetes, HPLC measurements confirmed the presence of urinary curcuminoid. Nevertheless, dietary provision of curcumin either before or after the induction of diabetes failed to attenuate albuminuria.</p> <p>Conclusions</p> <p>Apart from species, strain, early differences in glycemic control, and/or dosing effects, the failure to modulate albuminuria may have been due to a decrement in renal HSP25 or stimulation of the 12/15 lipoxygenase pathway in DBA2J mice fed curcumin. In addition, these studies suggest that timed urine collections may be useful for monitoring curcumin dosing and renal pharmacodynamic effects.</p

Glomerular type IV collagen in patients with diabetic nephropathy with and without additional glomerular disease

Glomerular type IV collagen in patients with diabetic nephropathy with and without additional glomerular disease.BackgroundType IV collagen is a constituent of mesangial matrix and is increased in amount in many forms of glomerular injury.MethodsWe performed renal biopsies in patients who (1) were donating a kidney to a relative (LRD, N = 6), (2) had diabetic glomerulopathy with or without nephrosclerosis (DM, N = 6), or (3) had diabetic glomerulopathy with a superimposed glomerular lesion (DM+, N = 5). Glomerular collagen α2(IV) and control glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNAs were measured, and the former correlated with clinical and morphological data to assess its usefulness in reflecting glomerular injury.ResultsCollagen α2(IV) mRNA levels were lowest in LRD (2.9 ± 0.6 attomol/glomerulus), higher in DM (5.9 ± 1.6, P = 0.05), and highest in DM+ (12.7 ± 2.8 attm/glomerulus, P < 0.05 vs. LRD and vs. DM). Control GAPDH mRNA levels were not significantly different (P > 0.05). Levels of proteinuria, serum creatinine, and glomerular size did not correlate with collagen α2(IV) mRNA levels. The fractional mesangial area and the fractional mesangial area occupied by type IV collagen were higher in both diabetic groups than in LRD (P < 10-6), but the intensity of type IV collagen staining in the diabetic patients was significantly less than that seen in the LRD (P < 0.01). In DM+ patients, extramesangial type IV collagen was present. Fractional mesangial area and glomerular collagen α2(IV) mRNA levels correlated (r = 0.45, P < 0.05).ConclusionThese data are consistent with a view of diabetic nephropathy as a lesion of increased α2 type IV collagen transcription, increased total amount of collagen present, but decreased mesangial density relative to other matrix molecules. These data further demonstrate that glomerular injury superimposed on diabetic nephropathy contributes to additional structural damage by inducing increased synthesis of type IV collagen at extramesangial sites

Effects of Minocycline on Urine Albumin, Interleukin-6, and Osteoprotegerin in Patients with Diabetic Nephropathy: A Randomized Controlled Pilot Trial

<div><p>Background</p><p>We tested minocycline as an anti-proteinuric adjunct to renin-angiotensin-aldosterone system inhibitors (RAASi) in diabetic nephropathy (DN) and measured urinary biomarkers to evaluate minocycline’s biological effects.</p><p>Methods</p><p><b>Design</b>: Prospective, single center, randomized, placebo-controlled, intention-to-treat pilot trial. <b>Inclusion</b>. Type 2 diabetes/DN; Baseline creatinine clearance > 30 mL/min; proteinuria ≥ 1.0 g/day; Age ≥30 years; BP <150/95 mm Hg; intolerant of/at maximum RAASi dose. <b>Protocol</b>. 3-wk screening; Baseline randomization; Urine and blood measures at months 1, 2, 4, and Month 6 study completion. Urine interleukin-6 (IL-6) and osteoprotegerin were measured in a subset. <b>Primary outcome</b>. Natural log of urine protein/creatinine (ln U P:Cr) ratio at Month 6 vs Baseline.</p><p>Results</p><p>30 patients completed the study. The 15% decline in U P: Cr in minocycline patients (6 month P:Cr ÷ Baseline P:Cr, 0.85 vs. 0.92) was not significant (p = 0.27). Creatinine clearance did not differ in the 2 groups. Urine IL-6:Cr (p = 0.03) and osteoprotegerin/Cr (p = 0.046) decrements were significant. Minocycline modified the relationship between urine IL-6 and proteinuria, suggesting a protective biological effect.</p><p>Conclusions</p><p>Although the decline in U P:Cr in minocycline patients was not statistically significant, the significant differences in urine IL-6 and osteoprotegerin suggest that minocycline may confer cytoprotection in patients with DN, providing a rationale for further study.</p><p>Trial Registration</p><p>Clinicaltrials.gov <a href="https://www.clinicaltrials.gov/ct2/show/NCT01779089" target="_blank">NCT01779089</a></p></div

Enrollment of subjects.

<p>Enrollment of subjects.</p

% change in 24-hour urine Il-6: creatinine measurements from baseline to 6 months in placebo and minocycline groups.

<p>The edges of the boxes represent the 25% and 75% percentiles, the middle lines represents the median, and the whiskers extend to the minimum and maximum values. The %change in urine IL-6: creatinine was significantly lower in the minocycline group vs. the placebo group (mean % change -0.13 vs. 0.60, P = 0.03).</p

Percent change in 24-hour urine protein/creatinine measurements from baseline to 6 months in placebo and minocycline groups.

<p>The edges of the boxes represent the 25% and 75% percentiles, the middle lines represents the median, and the whiskers extend to the minimum and maximum values. The primary outcome, ln (6Month P:Cr/baseline P:Cr), was not significantly different between the groups (p = 0.27).</p

Spaghetti plots of the urine protein: creatinine measurements of each patient in the study over the course of the trial.

<p>Spaghetti plots of the urine protein: creatinine measurements of each patient in the study over the course of the trial.</p

Spaghetti plots of the urine IL6: creatinine measurements of each patient in the study from baseline to 6 months (end of trial).

<p>Baseline urine values were not available for 3 subjects.</p