Correlation of tubular atrophy/interstitial fibrosis (TA/IF) score and albumin excretion in urine, r = 0.51, p<0.05 (A), progress, non-significant (B) and glomerular filtration rate, r = −0.68, p<0.01 (C).

<p>Correlation of tubular atrophy/interstitial fibrosis (TA/IF) score and albumin excretion in urine, r = 0.51, p<0.05 (A), progress, non-significant (B) and glomerular filtration rate, r = −0.68, p<0.01 (C).</p

Summary of key pathological features according to the Oxford classification system.

<p>Mesangial score ≤0.5 (M0) or >0.5 (M1).</p><p>Segmental glomerulosclerosis, absent (S0) or present (S1).</p><p>Endocapillary hypercellularity, absent (E0) or present (E1).</p><p>TA/IF ≤25% (T0), 26–50% (T1), or >50% (T2).</p

PAS staining of sclerotic glomeruli from a representative IgAN patient (A), and the consecutive section stained for decorin (B) shows overlap of the sclerotic area and decorin staining.

<p>PAS staining of glomeruli without sclerosis (C) and consecutive section showing no staining for decorin (D) in the same patient. Decorin is abundantly expressed in sclerotic glomeruli both in controls and patients with IgAN, but not in non-sclerotic glomeruli. Magnification ×63.</p

Relative gene expression of proteoglycan core proteins and enzymes in glomeruli (A) and tubulo-interstitial compartment (B) of biopsies from IgAN patients compared to controls.

<p>Controls values are defined as 1, and higher values indicate up-regulation while lower values indicate down-regulation. Error bars represent SEM. *p<0.05, **p<0.01, ***p<0.001.</p

Protein expression of perlecan in sections from control (A), a patient with IgAN (B), and a negative control (C).

<p>Protein expression of Perlecan in frozen biopsy sections from another set of patients with IgAN stained significantly stronger for perlecan (n = 45, 6.3±0.7%) than controls (n = 30, 9.4±0.7%) P<0.01. Magnification ×63.</p

Clinical characteristics of patients with IgAN at time of biopsy.

<p>Abbreviations; GFR, glomerular filtration rate; MAP, mean arterial pressure; BP, blood pressure; RAAS, Renin-angiotensin-aldosterone system.</p><p>*estimated GFR calculated using MDRD formula (ml/min/1.73 m²), the other GFRs presented in the table are determined using ⁵¹Cr-EDTA clearance.</p>†<p>calculated from tU-protein.</p

Protein expression of TGF-β in sections from control (A), patient with IgAN (B) and negative control (C).

<p>IgAN sections stained significantly stronger for TGF-β, and the average arbitrary unit score for IgAN (n = 83 glomeruli, 4.51±0.25) was higher than control (n = 19 glomeruli, 2.89±0.28) P<0.05 (D). In (B) there is some auto-fluorescence of red blood cells, this phenomenon can also be seen in the negative control, and were not included in the analysis of staining intensity of TGF-β. Magnification ×63.</p

The relative gene expression of perlecan in the glomeruli from patients with IgAN at time of the biopsy correlates inversely to the patient's albumin excretion in urine, n = 17, r = −0.58, p<0.05 (A) and disease progression, n = 18, r = −0.52, p<0.05 (C).

<p>A high expression of perlecan at the time of the biopsy correlates to a lower albumin excretion and slower progression of the disease, implicating that the relative gene expression of perlecan can be used as a prognostic molecular marker in IgAN. The relative gene expression of nephrin did not correlate to urinary albumin excretion, n = 17 (B), but correlated inversely to disease progression, n = 18, r = −0.47, P<0.05 (D). This suggests that even the smallest changes in gene expression of nephrin may be important for disease progression in IgAN.</p