Osman, Mazen

Renal artery stenosis (RAS) is a common public health problem, affecting up to 7% of individuals over 65 years of age. Optimal therapy for patients with RAS is controversial, as recent studies have indicated that revascularization via stenting fails to improve renal function or patient survival. Medical therapy is associated with high morbidity and mortality, primarily due to cardiovascular disease. However, morphologic correlates for reversibility following restoration of blood flow have not been adequately defined. The purpose of this study was to standardize an experimental model for the restoration of blood flow, employing a well characterized murine RAS model. Total N=10 C57B/6J male mice were used. RAS was induced on the right renal artery by putting a polytetrafluoroethylene cuff (N=6) and sham surgery was performed without cuff placement (N=4). To determine the feasibly of restoring the blood flow to the stenotic kidney, cuff was taken off at day 7 following the RAS surgery. Blood pressure measurements were done using tail cuff method at baseline, before taking cuff off and then every week until harvest. MRI images were captured using an Avance DRX 700WB spectrometer with a vertical 16.4 T wide bore magnet connected with the imaging tools at baseline, 3 days after putting the cuff on or sham surgery, and at 3 weeks after cuff off. The animals were harvested at day 28 following surgery and kidney weights are obtained. Baseline renal perfusion (1018±41.6 ml/100g/min) was significantly reduced (634.7±141.3 ml/100g/min, p=0.01) following cuff placement. Perfusion was restored to normal (955±59.8 ml/100g/min) at 28 days following cuff removal at 7 days after RAS. Similarly, volume of the stenotic kidney was significantly reduced (at day 3 after RAS 172±8.6 mm 3 ) compared to baseline (206.3±4.4 mm 3 , p=0.0007). There was no significant difference in perfusion and volume after cuff off compared to baseline and sham groups. There was no significant difference in kidney weight between cuff‐off (167± 4.7 mg) and sham groups (163±9.95 mg). Also, there was no difference in heart weight between cuff off (150±3.7mg) and sham groups (148±6.7mg). We conclude that this model will provide the basis for determining the latest time point associated with recovery of renal structure and potential histopathologic markers that predict preservation of renal structure following cuff removal. Also, this model would provide the basis for determining efficacy of additional therapies to target inflammation, etc. to widen the “therapeutic window” during which restoration of renal blood flow is beneficial. Support or Funding Information This project is funded by National Institutes of health, NIAID R01 AI100911.

CX3CR1 is a chemokine receptor widely expressed on inflammatory cells which recognizes CX3CL1 (fractalkine) a membrane bound chemokine that can function as an adhesion receptor. Blockade of CX3CR1 has been shown to reduce inflammation and chronic renal injury in a variety of models. We sought to determine whether CX3CR1 deficient mice are protected from chronic renal injury in experimental renal artery stenosis (RAS). RAS was established in CX3CR1 knockout (KO) and wild‐type C57BLK/6 mice (WT) through placement of a cuff on the right renal artery. Sham mice underwent manipulation of the right renal artery without placement of a cuff. As assessed by MRI, mean flow reduction was 65.3% in the WT mice and 66.5% in the KO mice (p=ns) subjected to RAS. Both KO and WT mice developed hypertension, which persisted throughout the 4 week study. KO and WT mice developed a similar degree of cardiac hypertrophy (166 mg WT, 172 mg KO, p=ns; 117 mg sham). Stenotic kidney weights were reduced to a similar extent in KO and WT mice (sham 148 mg, WT 83 mg, KO 53 mg) with compensatory hypertrophy of the contralateral kidney (sham 136 mg, WT 170 mg, KO 206 mg, p=0.0016 KO vs WT). The stenotic kidney of both KO and WT mice developed severe atrophy, characterized by flattening and simplification of tubular epithelium and influx of interstitial T cells and macrophages (32.8 % cortical surface area for WT and 76.4% cortical surface area for KO, p=0.01). The contralateral kidney was without significant histopathologic abnormality. We conclude that development of severe atrophy is not prevented in CX3CR1 KO mice, indicating that alternative pathways contribute to chronic renal damage in this model. Support or Funding Information This work is supported by NIH Grant R01 AI100911.

Abstract Renal artery stenosis is common in the elderly population; biomarkers that predict response to restoration of blood flow have not been previously established. Methods We have previously shown in murine model that cuff removal 7 days (7D Cuff-off) after initial placement on the renal artery results in reversible injury whereas cuff removal 14 days (14D Cuff-off) after placement results in irreversible renal injury, when assessed at 28 days after initial surgery. Positive and negative controls consisted of cuff placement for 28 days (28D) and sham surgeries respectively. We performed RNASeq on whole renal cortex to identify innate immune pathways that correlate with reversible versus irreversible injury. Data were normalized to appropriate sham controls in all the groups. Induction of greater than log2 ratio > 2 and p < 0.00001 were considered significant (following adjustment for multiple comparisons). Results As assessed by RNASeq, progression of renal disease (14D Cuff-off & 28D mice) was associated with persistent upregulation of genes associated with T cell signaling and macrophage polarization compared to reversible injury (7D Cuff off). Upregulated genes included but not limited to: CCL5, CCR5, CCL2, CXCL1, CXCL9, CXCL10, CXCR3, TLR2, KLF6, CD74, CD4, CD14, CD44, CD83, CD84, IL1R1, IL1B, SPP1, AIF1, SLC7A2, TRAF1, S100A4, SLC9A9, CRIP1, CLEC7A, CLEC10A, EGR2, MGL2, SOCS2, CTLA2B, and FCGR1. Conclusion We have identified genes associated with T cell and macrophage activation that were down regulated in the 7D Cuff-off versus 14D Cuff-off and 28D mice; future studies in isolated T cells and macrophages will determine whether these genes represents biomarker(s) of renal disease progression in 2K-1C renovascular hypertension.

Aim Th1 cells have potent pro‐inflammatory properties and have been shown to play an important role in the development and progression of acute renal injury to chronic renal disease. The aim of this study is to test the hypothesis that chronic renal damage in mice with renal artery stenosis (RAS) would be ameliorated in mice with homozygous deletion of the Th1 transcription factor T‐bet. Methods C57BL6/J (WT) and C57BL6/J mice with homozygous deletion of T‐bet (KO) were obtained from Jackson Laboratory. Renal artery stenosis surgery (RAS) was performed by placement of a polytetrafluoroethylene cuff on the right renal artery of KO (KO RAS group, n =5) and WT mice (WT RAS group, n =6). Sham (SH) surgery was performed with manipulation of the right renal artery without cuff placement in KO (KO SH group, n =4) and WT mice (WT SH group, n =5). Renal blood perfusion and oxygenation (R2*) were measured using 16.4T MRI. Blood pressure measurements were done using tail‐cuff method. Kidneys were harvested at 28 days after RAS for assessment of histology. Results Baseline intra‐renal perfusion in both KO RAS and WT RAS mice was reduced to a similar extent following cuff placement. In KO RAS group, baseline intra‐renal perfusion (795 ± 57 ml/100g/min) was reduced to 234 ± 22 ml/100g/min ( p <0.0001 vs baseline, mean reduction 71%) and in WT RAS group, baseline intra‐renal perfusion (836 ± 87 ml/100g/min) was reduced to 220 ± 21 ml/100g/min ( p =0.002 vs baseline, mean reduction 74%). Both KO RAS and WT RAS mice developed hypertension, which persisted throughout the 4 week study. WT RAS group showed significant elevation in cortical R2*, a measure of hypoxia, following RAS compared to their baseline ( p =0.002). KO RAS mice showed slightly higher R2* value, which was not significantly different from their baseline values. The weight of the stenotic kidney of the KO RAS group (105 ± 11.6 mg) was significantly lower than the KO SH mice (178 ± 14.1 mg, p =0.0021) but significantly higher than the WT RAS group (51.7 ± 7.9 mg, p =0.0010). On histologic and immune‐histochemical analysis, we observed that the stenotic kidney of the KO RAS group had significantly lower (%) cortical tubular atrophy (15% ± 6.7, p <0.0001) compared to WT RAS mice (81.7% ± 7). KO RAS group had significantly lower macrophage (MQ) ( p =0.0016) and T cell influx ( p =0.0052) compared to the WT RAS, as assessed by the % of cortical surface areas staining positive for F4/80 (MQ) and CD3 (T cell). When compared to their respective shams, KO RAS showed no significant differences in the % cortical tubular atrophy, MQ and CD3+ T cell influx. Conclusion We conclude that deficiency of Th1 transcription factor T‐bet, protects against chronic renal injury as evidenced by the less cortical atrophy in KO RAS compared to WT RAS group, despite a similar elevation in blood pressure and reduction in perfusion. This model may provide a novel therapeutic target to prevent renal disease progression in patients with renovascular hypertension. Support or Funding Information National Institutes of Health Grant AI 100911 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Aim The aim of this study was to define the functional correlates of reversibilitiy following restoration of blood flow in the murine 2K1C model of renovascular hypertension. Method : Renal artery stenosis surgery (RAS) was performed by placement of a polytetrafluoroethylene cuff on the right renal artery (N=18). Sham surgery was performed without cuff placement (N=6). In two groups the cuff was removed at 7 days (7D cuff‐off, N=6) and 14 days (14D cuff‐off, N=6) after surgery. In the RAS group, cuff was left in place for 28 days (28D RAS, N=6). Kidneys were harvested at 28 days for assessment of histology and microvessel density (MVD). Renal blood perfusion and oxygenation were measured using 16.4T MRI. Blood pressure measurements were done using tail cuff method. Results In 7D cuff‐off group, baseline intra‐renal perfusion (891±142.8 ml/100g/min) was significantly reduced (311±73.4 ml/100g/min, p<0.0001) following cuff placement. Perfusion was restored to normal level (810±81.2 ml/100g/min) at 28 days following cuff removal at 7 days after RAS. In 14D cuff‐off group, baseline intra‐renal perfusion (846±74.5 ml/100g/min) was also significantly reduced (304±45.9 ml/100g/min, p=0.0002) following cuff placement with non‐significant improvement (579±112.9 ml/100g/min) at 28 days after cuff removal at 14 days after RAS. Baseline intra‐renal perfusion (905±54.9 ml/100g/min) in the 28D RAS group was significantly reduced (455±56.4 ml/100g/min, p<0.0034) following cuff placement and the reduction was maintained throughout the study period (478±22.2 ml/100g/min). 7D cuff‐off group (142±8.2 mg) showed no significant difference in kidney weights measured at 28 days compared to the sham group (154±4.8 mg), but was significantly higher compared to the 28D RAS group (67±10.5 mg, p=0.0010). The kidney weights of the 14D cuff‐off group (86±18.3 mg) measured at 28 days was not significantly different from the 28D RAS group. The 7D cuff‐off group had a significantly lower % atrophy (7±2.2%, p=0.0042) and higher MVD count (152±6.5, p=0.0045) compared to 28D RAS group (% atrophy 66±13%, MVD count 78±15.2). The 14D cuff‐off group had severe atrophy (56±16.6%) and reduced MVD count (94±20.1) similar to that seen in 28D RAS group. 50% of mice that developed hypoxia at day 3 had an improvement in their oxygenation after cuff removal at day 7, whereas, mice undergoing cuff removal at day 14 and 28 day ras mice remained hypoxic. Conclusion Based on these results, we conclude that the renal architecture and microvessel density are preserved when the cuff is removed no longer than 7 days post surgery. We Identified that 2 weeks after cuff placement is the “point of no return” in the renal injury in murine RAS model due to their reduction in microvessel density. Studies to identify biomarkers associated with irreversible renal injury in this model are currently being performed. Support or Funding Information NIH AI 100911 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

The accurate diagnosis of chronic myelomonocytic leukemia (CMML) and acute myeloid leukemia (AML) subtypes with monocytic differentiation relies on the proper identification and quantitation of blast cells and blast-equivalent cells, including promonocytes. This distinction can be quite challenging given the cytomorphologic and immunophenotypic similarities among the monocytic cell precursors. The aim of this study was to assess the performance of convolutional neural networks (CNN) in separating monocytes from their precursors (i.e., promonocytes and monoblasts). We collected digital images of 935 monocytic cells that were blindly reviewed by five experienced morphologists and assigned into three subtypes: monocyte, promonocyte, and blast. The consensus between reviewers was considered as a ground truth reference label for each cell. In order to assess the performance of CNN models, we divided our data into training (70%), validation (10%), and test (20%) datasets, as well as applied fivefold cross validation. The CNN models did not perform well for predicting three monocytic subtypes, but their performance was significantly improved for two subtypes (monocyte vs. promonocytes + blasts). Our findings (1) support the concept that morphologic distinction between monocytic cells of various differentiation level is difficult; (2) suggest that combining blasts and promonocytes into a single category is desirable for improved accuracy; and (3) show that CNN models can reach accuracy comparable to human reviewers (0.78 ± 0.10 vs. 0.86 ± 0.05). As far as we know, this is the first study to separate monocytes from their precursors using CNN.

Aim The aim of this is to identify the gene expression profiles indicative of reversible versus irreversible injury in experimental (murine) renal artery stenosis (RAS). Method Two‐kidney‐one‐cuff hypertension was established by placement of a polytetrafluoroethylene cuff on the right renal artery (N=18). Sham surgery was performed by manipulating the right renal artery without cuff placement (N=6). To determine potential reversibility, the cuff was removed at 7 days (7D cuff‐off, N=6) and 14 days (14D cuff‐off, N=6) after initial RAS surgery. In a control RAS group, the cuff was left in place for 28 days (28D RAS, N=6). Kidneys were harvested at 28 days for assessment of atrophy and fibrosis. Renal blood perfusion and oxygenation were measured using 16.4T MRI. RNASeq analysis was performed on all the groups at 28 days following initial surgery. Results Following cuff placement, intra‐renal perfusion was reduced by 65% (p<0.0001 vs. baseline). In the 7D cuff‐off group intra‐renal perfusion was restored to baseline values after cuff removal, whereas in the 14D cuff‐off group perfusion was not significantly improved following cuff removal. In the 28D RAS group the reduction in perfusion was maintained throughout the study period. The 7D cuff‐off group had a significantly lower % atrophy (7 ± 2.2%, p=0.0042) and % area of interstitial fibrosis (0.57 ± 0.08 %, p<0.0001) compared to 28D RAS group (atrophy 66 ± 13%, area of fibrosis 7.79 ± 0.89 %). The 14D cuff‐off group had severe atrophy (56 ± 16.6%) and interstitial fibrosis (5.05 ± 1.22%) similar to that seen in 28D RAS group. RNASeq analysis data were normalized to appropriate sham controls in all the groups and was performed at 28 days following initial surgery. Induction of greater than Log2 ratio >2 and p values < 0.00001 were considered significant (following adjustment for multiple comparisons). Fibrosis associated genes were differentially regulated in the 7D cuff‐off compared to the 14D cuff‐off and 28D RAS group (table ). Conclusion We conclude that cuff removal at 7 days is associated with relative preservation of renal structure, indicating that renal injury at this point is reversible. We have identified a number of fibrosis associated genes that are differentially regulated in the 7D cuff‐off group versus 14D cuff‐off group. Further analysis will determine the functional relevance of these differentially regulated genes. Support or Funding Information This project was funded by National Institutes of Health, NIAID R01 AI100911. Values of Log 2 Ratio Genes 7D Cuff‐off vs Sham 14D Cuff‐off vs Sham 28D RAS vs Sham COL1A1 0.96 2.62 2.23 COL1A2 0.79 2.07 1.91 COL3A1 1.26 2.60 2.35 MMP12 1.24 2.85 2.95 MMP14 1.34 2.70 2.55 MMP19 2.89 3.86 4.05 MMP2 1.55 3.49 3.22 MMP7 6.96 9.22 9.59 MTOR −0.46 −1.67 −2.06 SERPINE1 1.25 3.37 2.35 TGFB1i1 0.44 1.46 1.53 TGFB2 0.82 1.83 1.97 TGFB3 0.59 1.91 1.99 TGFBi 0.98 1.88 2.02 KLF15 −0.90 −1.76 −2.60 UBD 4.49 6.23 6.18 TIMP1 2.94 5.30 5.16 TIMP2 0.50 1.46 1.52 TIMP3 −0.35 −1.26 −1.36 HSPB1 0.16 2.00 2.13 HSPB8 1.51 2.26 2.30 CCL2 3.44 4.89 4.31 CCL12 2.88 3.71 4.12 SERPINE1 1.25 3.37 2.35 SERPINE2 1.17 2.39 2.35 SERPINF1 2.02 2.76 3.11 SERPINF2 −0.51 −2.03 −2.71 SERPING1 1.15 1.81 2.09 CLU 1.45 2.54 3.07 STC1 0.45 1.99 2.12 SPP1 1.75 3.06 3.37

Purpose. Type 2 diabetes is the leading cause of end stage renal disease in the United States. Atherosclerotic renal artery stenosis is commonly observed in diabetic patients and impacts the rate of renal and cardiovascular disease progression. We hypothesized that renal artery stenosis contributes to bilateral renal disease in diabetics. In our original study, we found that leptin-deficient diabetic (db/db) mice subjected to RAS developed severe and bilateral renal disease, with the contralateral (uncuffed) kidney showing features reminiscent of progressive diabetic nephropathy. In non-diabetic mice (WT), the cuffed kidney developed progressive atrophy, but the contralateral kidney showed minimal histopathologic alterations. In doing these studies, we observed increased sudden death in db/db mice with RAS, but not in WT mice with RAS. The objective of this study was to characterize the aortic and cardiac phenotype of db/db mice subjected to RAS. Methods . We developed a murine model of renal artery stenosis by placement of a polytetrafluoroethylene cuff on the right renal artery in db/db mice. We studied 109 WT and 95 db/db mice subjected to Renal artery stenosis (RAS) or sham surgery. Results. The mortality rate of db/db RAS mice was about 23.5%, whereas only 1.5% deaths were observed in WT RAS mice. Interestingly, 60% of mortality in the db/db mice occurred in the first two weeks following RAS surgery. Necropsy showed massive intrathoracic hemorrhage associated with aortic dissection. Aortas from db/db RAS mice showed more smooth muscle dropout, medial disruption, and hemorrhage than aortas from WT mice with RAS. Cardiac tissue from db/db RAS mice had more fibrosis than did cardiac tissue from WT RAS mice. Conclusions . Db/db mice subjected to RAS are prone to develop fatal aortic dissection, which is not observed in WT mice with RAS. The db/db RAS model provides the basis for future studies directed towards defining basic mechanisms underlying the interaction of hypertension and diabetes on the development of aortic lesions.

Purpose. Type 2 diabetes is the leading cause of end stage renal disease in the United States. Atherosclerotic renal artery stenosis is commonly observed in diabetic patients and impacts the rate of renal and cardiovascular disease progression. We sought to test the hypothesis that renovascular hypertension, induced by unilateral renal artery stenosis, exacerbates cardiac remodeling in leptin-deficient (db/db) mice, which serves as a model of human type II diabetes. Methods. We employed a murine model of renovascular hypertension through placement of a polytetrafluoroethylene cuff on the right renal artery in db/db mice. We studied 109 wild-type (non-diabetic, WT) and 95 db/db mice subjected to renal artery stenosis (RAS) or sham surgery studied at 1, 2, 4, and 6+ weeks following surgery. Cardiac remodeling was assessed by quantitative analysis of the percent of myocardial surface area occupied by interstitial fibrosis tissue, as delineated by trichrome stained slides. Aortic pathology was assessed by histologic sampling of grossly apparent structural abnormalities or by section of ascending aorta of vessels without apparent abnormalities. Results. We noted an increased mortality in db/db mice subjected to RAS. The mortality rate of db/db RAS mice was about 23.5%, whereas the mortality rate of WT RAS mice was only 1.5%. Over 60% of mortality in the db/db mice occurred in the first two weeks following RAS surgery. Necropsy showed massive intrathoracic hemorrhage associated with aortic dissection, predominantly in the ascending aorta and proximal descending aorta. Aortas from db/db RAS mice showed more smooth muscle dropout, loss of alpha smooth muscle actin expression, medial disruption, and hemorrhage than aortas from WT mice with RAS. Cardiac tissue from db/db RAS mice had more fibrosis than did cardiac tissue from WT RAS mice. Conclusions. db/db mice subjected to RAS are prone to develop fatal aortic dissection, which is not observed in WT mice with RAS. The db/db RAS model provides the basis for future studies directed towards defining basic mechanisms underlying the interaction of hypertension and diabetes on the development of aortic lesions.