Prognostic value of single-subject grey matter networks in early multiple sclerosis

The identification of prognostic markers in early multiple sclerosis (MS) is challenging and requires reliable measures that robustly predict future disease trajectories. Ideally, such measures should make inferences at the individual level to inform clinical decisions. This study investigated the prognostic value of longitudinal structural networks to predict 5-year Expanded Disability Status Scale (EDSS) progression in patients with relapsing-remitting MS (RRMS). We hypothesized that network measures, derived from MRI, outperform conventional MRI measurements at identifying patients at risk of developing disability progression. This longitudinal, multicentre study within the Magnetic Resonance Imaging in MS (MAGNIMS) network included 406 patients with RRMS (mean age = 35.7 ± 9.1 years) followed up for 5 years (mean follow-up = 5.0 ± 0.6 years). EDSS was determined to track disability accumulation. A group of 153 healthy subjects (mean age = 35.0 ± 10.1 years) with longitudinal MRI served as controls. All subjects underwent MRI at baseline and again 1 year after baseline. Grey matter atrophy over 1 year and white matter lesion load were determined. A single-subject brain network was reconstructed from T1-weighted scans based on grey matter atrophy measures derived from a statistical parameter mapping-based segmentation pipeline. Key topological measures, including network degree, global efficiency and transitivity, were calculated at single-subject level to quantify network properties related to EDSS progression. Areas under receiver operator characteristic (ROC) curves were constructed for grey matter atrophy and white matter lesion load, and the network measures and comparisons between ROC curves were conducted. The applied network analyses differentiated patients with RRMS who experience EDSS progression over 5 years through lower values for network degree [H(2) = 30.0, P < 0.001] and global efficiency [H(2) = 31.3, P < 0.001] from healthy controls but also from patients without progression. For transitivity, the comparisons showed no difference between the groups [H(2) = 1.5, P = 0.474]. Most notably, changes in network degree and global efficiency were detected independent of disease activity in the first year. The described network reorganization in patients experiencing EDSS progression was evident in the absence of grey matter atrophy. Network degree and global efficiency measurements demonstrated superiority of network measures in the ROC analyses over grey matter atrophy and white matter lesion load in predicting EDSS worsening (all P -values < 0.05). Our findings provide evidence that grey matter network reorganization over 1 year discloses relevant information about subsequent clinical worsening in RRMS. Early grey matter restructuring towards lower network efficiency predicts disability accumulation and outperforms conventional MRI predictors. Fleischer et al. examine the prognostic value of brain networks derived from MRI for predicting disability progression in patients with multiple sclerosis. They conclude that early brain network alterations identify clinical deterioration in multiple sclerosis and outperform classical MRI predictors

Prognostic value of single-subject grey matter networks in early multiple sclerosis

The identification of prognostic markers in early multiple sclerosis (MS) is challenging and requires reliable measures that robustly predict future disease trajectories. Ideally, such measures should make inferences at the individual level to inform clinical decisions. This study investigated the prognostic value of longitudinal structural networks to predict five-year EDSS progression in patients with relapsing-remitting MS (RRMS). We hypothesized that network measures, derived from magnetic resonance imaging (MRI), outperform conventional MRI measurements at identifying patients at risk of developing disability progression. This longitudinal, multicentre study within the Magnetic Resonance Imaging in MS (MAGNIMS) network included 406 patients with RRMS (mean age = 35.7 ± 9.1 years) followed up for five years (mean follow-up = 5.0 ± 0.6 years). Expanded Disability Status Scale (EDSS) was determined to track disability accumulation. A group of 153 healthy subjects (mean age = 35.0 ± 10.1 years) with longitudinal MRI served as controls. All subjects underwent MRI at baseline and again one year after baseline. Grey matter (GM) atrophy over one year and white matter (WM) lesion load were determined. A single-subject brain network was reconstructed from T1-weighted scans based on GM atrophy measures derived from a statistical parameter mapping (SPM)-based segmentation pipeline. Key topological measures, including network degree, global efficiency and transitivity, were calculated at single-subject level to quantify network properties related to EDSS progression. Areas under receiver operator characteristic (ROC) curves were constructed for GM atrophy, WM lesion load and the network measures, and comparisons between ROC curves were conducted. The applied network analyses differentiated patients with RRMS who experience EDSS progression over five years through lower values for network degree [H(2)=30.0, p<0.001] and global efficiency [H(2)=31.3, p<0.001] from healthy controls but also from patients without progression. For transitivity, the comparisons showed no difference between the groups (H(2)= 1.5, p=0.474). Most notably, changes in network degree and global efficiency were detected independent of disease activity in the first year. The described network reorganization in patients experiencing EDSS progression was evident in the absence of GM atrophy. Network degree and global efficiency measurements demonstrated superiority of network measures in the ROC analyses over GM atrophy and WM lesion load in predicting EDSS worsening (all p-values < 0.05). Our findings provide evidence that GM network reorganization over one year discloses relevant information about subsequent clinical worsening in RRMS. Early GM restructuring towards lower network efficiency predicts disability accumulation and outperforms conventional MRI predictors

Reliable and High Efficiency Extraction of Kidney Immune Cells

Immune system activation occurs in multiple kidney diseases and pathophysiological processes. The immune system consists of both adaptive and innate components and multiple cell types. Sometimes, the cell type of interest is present in very low numbers among the large numbers of total cells isolated from the kidney. Hence, reliable and efficient isolation of kidney mononuclear cell populations is important in order to study the immunological problems associated with kidney diseases. Traditionally, tissue isolation of kidney mononuclear cells have been performed via enzymatic digestions using different varieties and strengths of collagenases/DNAses yielding varying numbers of viable immune cells. Recently, with the development of the mechanical tissue disruptors for single cell isolation, the collagenase digestion step is avoided and replaced by a simple mechanical disruption of the kidneys after extraction from the mouse. Herein, we demonstrate a simple yet efficient method for the isolation of kidney mononuclear cells for every day immune cell extractions. We further demonstrate an example of subset analysis of immune cells in the kidney. Importantly, this technique can be adapted to other soft and non-fibrous tissues such as the liver and brain

Evolution of retinal degeneration and prediction of disease activity in relapsing and progressive multiple sclerosis

&lt;p&gt;&lt;span&gt;Retinal optical coherence tomography has been identified as biomarker for disease progression in relapsing-remitting multiple sclerosis (RRMS), while the dynamics of retinal atrophy in progressive MS are less clear. We investigated retinal layer thickness changes in RRMS, &lt;/span&gt;&lt;span&gt;primary and secondary progressive MS (PPMS, SPMS)&lt;/span&gt;&lt;span&gt;, and their prognostic value for disease activity. Here, we analyzed 2651 OCT measurements of 195 RRMS, 87 SPMS, 125 PPMS patients, and 98 controls from five German MS centers after quality control. Peripapillary and macular retinal nerve fiber layer (pRNFL, mRNFL) thickness &lt;/span&gt;&lt;span&gt;predicted&lt;/span&gt;&lt;span&gt; future relapses in all MS and RRMS patients while mRNFL&lt;/span&gt;&lt;span&gt; and &lt;/span&gt;&lt;span&gt;ganglion cell-inner plexiform layer (GCIPL) &lt;/span&gt;&lt;span&gt;thickness predicted &lt;/span&gt;&lt;span&gt;future &lt;/span&gt;&lt;span&gt;MRI activity &lt;/span&gt;&lt;span&gt;in RRMS (mRNFL, GCIPL) and PPMS (GCIPL). mRNFL thickness &lt;/span&gt;&lt;span&gt;predicted &lt;/span&gt;&lt;span&gt;future disability progression &lt;/span&gt;&lt;span&gt;in PPMS.&lt;/span&gt;&lt;span&gt; &lt;/span&gt;&lt;span&gt;However, thickness change rates were subject to considerable amounts of measurement variability. In conclusion, retinal degeneration, most pronounced of pRNFL and GCIPL, occurs in all subtypes. Using the current state of technology, longitudinal assessments of retinal thickness may not be suitable on a single patient level.&lt;/span&gt;&lt;/p&gt

Abstract P475: What’s in a Letter: N vs. J Determines Responses to Ang II/DOCA and DPP4 Gene Deletion

Activation of the renin-angiotensin-aldosterone system (RAAS) drives blood pressure (BP) responses and kidney injury in humans and rodent models. Previously, we reported activation of dipeptidyl peptidase 4 (DPP4) by RAAS which may play an important role in BP responses and kidney injury. Classically, either angiotensin II (Ang II) or deoxycorticosterone (DOCA)-salt administration to mice, raises their BP over a period of hours to days. Recently, the two have been combined to elicit more robust kidney injury and proteinuria. Although there are not many head to head comparison studies, it is known through historical association that different strains of mice have different baseline BPs and vary in their response to vasoconstrictor agents for BP peaks as well as associated kidney injury. In this regard, the C57Bl/6J and C57Bl/6N mice are genetically very similar although they differ with respect to their responses to circadian rhythm on salt sensitivity to BP. Therefore, we hypothesized that J versus N strain will have differential BP responses to Ang II/DOCA and kidney injury susceptibility. C57Bl/6 J and N mice ( DPP4 +/+ and DPP4 -/- ) were subjected to Ang II/DOCA salt infusion for 2 weeks (Ang II 1000ng/kg/min via miniosmotic pumps, DOCA 50mg pellet, 0.9% saline in drinking water) and compared to mice receiving saline only (osmotic pumps). BP was measured by Millar catheter. Kidney injury was quantified via albuminuria and histology. While the Ang II/DOCA treated J strain had mean BP (MBP) of 135mmHg, the Ang II/DOCA treated N strain had MBP of 125mmHg. There was no effect of DPP4 gene deletion on BP in either strain. The J strain treated with Ang II/DOCA salt had higher albuminuria when compared to the N strain (180ug/ml vs. 60ug/ml). DPP4 -/- mice on the J strain receiving Ang II/DOCA had a relative improvement in albuminuria (120ug/ml vs. 180ug/ml). Surprisingly, the DPP4 -/- mice on the N strain had higher albuminuria when compared to the DPP4 +/+ mice receiving Ang II/DOCA (143ug/ml vs. 60ug/ml). Taken together, our results suggest that mice strain plays an important role in BP and kidney injury responses to Ang II/DOCA and DPP4 gene deletion. These results highlight the importance of selecting patient populations carefully to maximize the benefit of DPP4 inhibitors. </jats:p

Angiotensin II Stimulation of DPP4 Activity Regulates Megalin in the Proximal Tubules

Proteinuria is a marker of incipient kidney injury in many disorders, including obesity. Previously, we demonstrated that megalin, a receptor endocytotic protein in the proximal tubule, is downregulated in obese mice, which was prevented by inhibition of dipeptidyl protease 4 (DPP4). Obesity is thought to be associated with upregulation of intra-renal angiotensin II (Ang II) signaling via the Ang II Type 1 receptor (AT1R) and Ang II suppresses megalin expression in proximal tubule cells in vitro. Therefore, we tested the hypothesis that Ang II will suppress megalin protein via activation of DPP4. We used Ang II (200 ng/kg/min) infusion in mice and Ang II (10−8 M) treatment of T35OK-AT1R proximal tubule cells to test our hypothesis. Ang II-infused mouse kidneys displayed increases in DPP4 activity and decreases in megalin. In proximal tubule cells, Ang II stimulated DPP4 activity concurrent with suppression of megalin. MK0626, a DPP4 inhibitor, partially restored megalin expression similar to U0126, a mitogen activated protein kinase (MAPK)/extracellular regulated kinase (ERK) kinase kinase (MEK) 1/2 inhibitor and AG1478, an epidermal growth factor receptor (EGFR) inhibitor. Similarly, Ang II-induced ERK phosphorylation was suppressed with MK0626 and Ang II-induced DPP4 activity was suppressed by U0126. Therefore, our study reveals a cross talk between AT1R signaling and DPP4 activation in the regulation of megalin and underscores the significance of targeting DPP4 in the prevention of obesity related kidney injury progression