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Inflammation is a major determinant for the progression of chronic kidney disease (CKD). NF-κB is a master transcription factor upregulated in CKD that promotes inflammation and regulates apoptosis and vascular remodeling. We aimed to modulate this pathway for CKD therapy in a swine model of CKD using a peptide inhibitor of the NF-κB p50 subunit (p50i) fused to a protein carrier [elastin-like polypeptide (ELP)] and equipped with a cell-penetrating peptide (SynB1). We hypothesized that intrarenal SynB1-ELP-p50i therapy would inhibit NF-κB-driven inflammation and induce renal recovery. CKD was induced in 14 pigs. After 6 wk, pigs received single intrarenal SynB1-ELP-p50i therapy (10 mg/kg) or placebo ( n = 7 each). Renal hemodynamics were quantified in vivo using multidetector computed tomography before and 8 wk after treatment. Pigs were then euthanized. Ex vivo experiments were performed to quantify renal activation of NF-κB, expression of downstream mediators of NF-κB signaling, renal microvascular density, inflammation, and fibrosis. Fourteen weeks of CKD stimulated NF-κB signaling and downstream mediators (e.g., TNF-α, monocyte chemoattractant protein-1, and IL-6) accompanying loss of renal function, inflammation, fibrosis, and microvascular rarefaction versus controls. All of these were improved after SynB1-ELP-p50i therapy, accompanied by reduced circulating inflammatory cytokines as well, which were evident up to 8 wk after treatment. Current treatments for CKD are largely ineffective. Our study shows the feasibility of a new treatment to induce renal recovery by offsetting inflammation at a molecular level. It also supports the therapeutic potential of targeted inhibition of the NF-κB pathway using novel drug delivery technology in a translational model of CKD.

Chronic kidney disease (CKD) universally associates with renal microvascular rarefaction and inflammation, but whether a link exists between these 2 processes is unclear. We designed a therapeutic construct of VEGF (vascular endothelial growth factor) fused to an ELP (elastin-like polypeptide) carrier and show that it improves renal function in experimental renovascular disease. We test the hypothesis that ELP-VEGF therapy will improve CKD, and that recovery will be driven by decreasing microvascular rarefaction partly via modulation of macrophage phenotype and inflammation. CKD was induced in 14 pigs, which were observed for 14 weeks. At 6 weeks, renal blood flow and filtration were quantified using multidetector computed tomography, and then pigs received single intrarenal ELP-VEGF or placebo (n=7 each). Renal function was quantified again 4 and 8 weeks later. Pigs were euthanized and renal microvascular density, angiogenic and inflammatory markers, fibrosis, macrophage infiltration, and phenotype were quantified. Loss of renal hemodynamics in CKD was progressively recovered by ELP-VEGF therapy, accompanied by improved renal microvascular density, fibrosis, and expression of inflammatory mediators. Although renal macrophage infiltration was similar in both CKD groups, ELP-VEGF therapy distinctly shifted their phenotype from proinflammatory M1 to VEGF-expressing M2. Our study unravels potential mechanisms and feasibility of a new strategy to offset progression of CKD using drug-delivery technologies. The results indicate that renal recovery after ELP-VEGF therapy was largely driven by modulation of renal macrophages toward VEGF-expressing M2 phenotype, restoring VEGF signaling and sustaining improvement of renal function and microvascular integrity in CKD.

A 71-year-old woman presented with several months of progressive lower extremity weakness, followed by bulbar weakness. On examination, she had diffuse muscle atrophy, fasciculations, weakness, and hyperreflexia. A diagnosis of clinically definite ALS was made using the El Escorial criteria. At the time of presentation and imaging, she had both severe upper and lower motor neuron involvement. Her ALSFRS-R score was 15, indicating advanced disease. Her brain MRI showed increased signal on susceptibility-weighted imaging, consistent with superficial siderosis along the central sulcus (figure). This finding has been named the “motor band sign”.1 The intracellular iron may be from microglial phagocytosis of degenerated neurons in the motor strip.2 Careful scrutiny of susceptibility-weighted imaging should be performed when considering motor neuron disease, as this can be helpful in making the diagnosis.

Background: Chronic renovascular disease (RVD) can lead to a progressive loss of renal function, and current treatments are inefficient. We designed a fusion of vascular endothelial growth factor (VEGF) conjugated to an elastin-like polypeptide (ELP) carrier protein with an N-terminal kidney-targeting peptide (KTP). We tested the hypothesis that KTP-ELP-VEGF therapy will effectively recover renal function with an improved targeting profile. Further, we aimed to elucidate potential mechanisms driving renal recovery. Methods: Unilateral RVD was induced in 14 pigs. Six weeks later, renal blood flow (RBF) and glomerular filtration rate (GFR) were quantified by multidetector CT imaging. Pigs then received a single intrarenal injection of KTP-ELP-VEGF or vehicle. CT quantification of renal hemodynamics was repeated 4 weeks later, and then pigs were euthanized. Ex vivo renal microvascular (MV) density and media-to-lumen ratio, macrophage infiltration, and fibrosis were quantified. In parallel, THP-1 human monocytes were differentiated into naïve macrophages (M0) or inflammatory macrophages (M1) and incubated with VEGF, KTP-ELP, KTP-ELP-VEGF, or control media. The mRNA expression of macrophage polarization and angiogenic markers was quantified (qPCR). Results: Intrarenal KTP-ELP-VEGF improved RBF, GFR, and MV density and attenuated MV media-to-lumen ratio and renal fibrosis compared to placebo, accompanied by augmented renal M2 macrophages. In vitro, exposure to VEGF/KTP-ELP-VEGF shifted M0 macrophages to a proangiogenic M2 phenotype while M1s were nonresponsive to VEGF treatment. Conclusions: Our results support the efficacy of a new renal-specific biologic construct in recovering renal function and suggest that VEGF may directly influence macrophage phenotype as a possible mechanism to improve MV integrity and function in the stenotic kidney.

Despite advances in renovascular disease (RVD) research, gaps remain between experimental and clinical outcomes, translation of results, and the understanding of pathophysiological mechanisms. A predictive tool to indicate support (or lack of) for biological findings may aid clinical translation of therapies. We created a Boolean model of RVD and hypothesized that it would predict outcomes observed in our previous studies using a translational swine model of RVD. Our studies have focused on developing treatments to halt renal microvascular (MV) rarefaction in RVD, a major feature of renal injury. A network topology of 20 factors involved in renal MV rarefaction that allowed simulation of 5 previously tested treatments was created. Each factor was assigned a function based upon its interactions with other variables and assumed to be “on” or “off”. Simulations of interventions were performed until outcomes reached a steady state and analyzed to determine pathological processes that were activated, inactivated, or unchanged vs. RVD with no intervention. Boolean simulations mimicked the results of our previous studies, confirming the importance of MV integrity on treatment outcomes in RVD. Furthermore, our study supports the potential application of a mathematical tool to predict therapeutic feasibility, which may guide the design of future studies for RVD.

Deep brain stimulation (DBS) is a widely used neurosurgical approach to treating tremor and other movement disorders1,2,3. In addition, the use of DBS in a number of psychiatric diseases, including obsessive-compulsive disorders and depression, is currently being tested4,5,6. Despite the rapid increase in the number of individuals with surgically implanted stimulation electrodes, the cellular pathways involved in mediating the effects of DBS remain unknown1. Here we show that DBS is associated with a marked increase in the release of ATP, resulting in accumulation of its catabolic product, adenosine. Adenosine A1 receptor activation depresses excitatory transmission in the thalamus and reduces both tremor- and DBS-induced side effects. Intrathalamic infusion of A1 receptor agonists directly reduces tremor, whereas adenosine A1 receptor–null mice show involuntary movements and seizure at stimulation intensities below the therapeutic level. Furthermore, our data indicate that endogenous adenosine mechanisms are active in tremor, thus supporting the clinical notion that caffeine, a nonselective adenosine receptor antagonist, can trigger or exacerbate essential tremor7. Our findings suggest that nonsynaptic mechanisms involving the activation of A1 receptors suppress tremor activity and limit stimulation-induced side effects, thereby providing a new pharmacological target to replace or improve the efficacy of DBS.