Hypoxia-induced hypotension elicits adenosine-dependent phrenic long-term facilitation after carotid denervation.

Moderate acute intermittent hypoxia (AIH) elicits a persistent, serotonin-dependent increase in phrenic amplitude, known as phrenic long-term facilitation (pLTF). Although pLTF was originally demonstrated by carotid sinus nerve stimulation, AIH still elicits residual pLTF in carotid denervated (CBX) rats via a distinct, but unknown mechanism. We hypothesized that exaggerated hypoxia-induced hypotension after carotid denervation leads to greater spinal tissue hypoxia and extracellular adenosine accumulation, thereby triggering adenosine 2A receptor (A2A)-dependent pLTF. Phrenic activity, arterial pressure and spinal tissue oxygen pressure were measured in anesthetized CBX rats. Exaggerated hypoxia-induced hypotension after CBX was prevented via intravenous phenylephrine; without the hypotension, spinal tissue hypoxia during AIH was normalized, and residual pLTF was no longer observed. Spinal A2A (MSX-3), but not serotonin 2 receptor (5-HT2) inhibition (ketanserin), abolished residual pLTF in CBX rats. Thus, pLTF regulation may be altered in conditions impairing sympathetic activity and arterial pressure regulation, such as spinal cord injury.

Comparing Standard Performance and Outcome Measures in Hospitalized Pituitary Tumor Patients with Secretory versus Nonsecretory Tumors.

BACKGROUND: Patient safety indicators (PSIs) and hospital-acquired conditions (HACs) are reported quality measures. We compared their prevalence in patients with secretory and nonsecretory pituitary adenoma using the National (Nationwide) Inpatient Sample (NIS), Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. METHODS: The NIS was queried for hospitalizations 2002-2014 involving pituitary adenomas. Prevalence of PSI, HAC, and 9 pituitary-related complications was determined using International Classification of Diseases, Ninth Revision codes. Patient risk factors were evaluated through multivariate analysis. RESULTS: A total of 20,743 patients with nonsecretory tumor and 3385 patients with secretory tumor were identified. Among patients with nonsecretory tumor, 3.79% experienced any PSI or HAC. Of patients with secretory tumor, 2.54% had any PSI or HAC. Before adjusting for covariation, secretory patients were less likely to have any PSI or HAC (odds ratio [OR], 0.652; P = 0.0002), experience any pituitary-related complication (OR, 0.804; P < 0.0001), have a poor outcome (hazard ratio [HR], 0.435; P < 0.0001), and die during hospitalization (HR, 0.293; P = 0.0015). Secretory patients had significantly shorter mean hospital length of stay (secretory/nonsecretory percent difference, -11.95%; P < 0.0001). However, inverse propensity score-weighted ORs comparing the groups' outcomes showed that there was no significant difference in the prevalence of any PSIs and HACs (OR, 0.963; P = 0.8570), pituitary-related complications (OR, 0.894; P = 0.1321), poor outcomes (HR, 0.990; P = 0.9287), in-hospital death (HR, 0.663; P = 0.2967), and length of stay (percent difference, -2.31%; P = 0.2967) between groups. CONCLUSIONS: Lack of significant difference in outcome measures after controlling for covariation is consistent with our finding that patients with nonsecretory tumor have more comorbidities on presentation for treatment. PSIs and HACs have limited ability to measure complications specific to pituitary tumors.

Heterogeneous and dynamic lumen remodeling of the entire infrainguinal vein bypass grafts in patients.

OBJECTIVE: To examine the regional variation and temporal change in lumen size along the entire autogenous vein bypass graft used for treating arterial occlusive disease in lower extremity and to explore the factors associated with graft expansive or constrictive remodeling. METHODS: Patients were prospectively scanned using contrast-enhanced computed tomography at 1 week and 1, 6, and 12 months postoperatively to obtain lumen cross-sectional areas at 1-mm intervals along the entire grafts. Graft lumen remodeling characteristics and the associated demographic and clinical factors were examined. RESULTS: Fifty-six patients with at least two consecutive computed tomography scans were analyzed. Patients with a composite or longer graft, or with diabetes, had a larger lumen cross-sectional area variation along the graft. The mean lumen cross-sectional areas of all the grafts demonstrated no significant changes through 12 months. However, individually, graft remodeling was time dependent and there was a more dramatic change in lumen cross-sectional area within the first postoperative month. At 12 months, a near equal distribution between expansive and constrictive grafts existed. A negative relation between the initial lumen diameters and the subsequent lumen diameter changes was observed. Eleven grafts failed within 12 months; failed and patent grafts had similar mean lumen cross-sectional areas at all four time points, but failed grafts had a larger maximal local cross-sectional area reduction from 1 week to 1 month (58.0 ± 6.7% vs 38.1 ± 3.1%, mean ± standard error of the mean, failed vs patent, P = .004). Black patients had a smaller mean lumen cross-sectional area than white patients at all four time points and also had a higher early percent mean area reduction (-20.5 ± 6.3% vs -1.0 ± 3.7%, black vs white, P = .018). Cilostazol use was associated with early expansive graft remodeling. CONCLUSIONS: Vein grafts remodel heterogeneously and dynamically. Remodeling is associated with initial graft lumen size, race, and cilostazol use. It is found that remodeling that produces some critical minimum area or maximal percent reduction during the first postoperative month may predispose to vein graft failure. These findings offer insight into further investigation to examine the underlying mechanisms and opportunities to improve graft remodeling and durability.

The IDH1 Mutation-Induced Oncometabolite, 2-Hydroxyglutarate, May Affect DNA Methylation and Expression of PD-L1 in Gliomas.

Background: Malignant gliomas are heterogeneous brain tumors with the potential for aggressive disease progression, as influenced by suppressive immunoediting. Given the success and enhanced potential of immune-checkpoint inhibitors in immunotherapy, we focused on the connections between genetic alterations affected by IDH1 mutations and immunological landscape changes and PDL-1 expression in gliomas. Methods: Paired surgically resected tumors from lower-grade gliomas (LGGs) and glioblastomas (GBM) were investigated, and a genetic analysis of patients' primary tumor samples culled from TCGA datasets was performed. Results: The results demonstrate that when compared with IDH1-mutant tumors, IDH1 wildtype tumors represent an immunosuppression landscape and elevated levels of PD-L1 expression. DNA hypo-methylation of the PD-L1 gene, as well as high gene and protein expressions, were observed in the wildtype tumors. We also found that quantitative levels of IDH1 mutant proteins were positively associated with recurrence-free survival (RFS). A key product of the IDH1 mutation (2-hydroxyglutarate) was found to transiently increase DNA methylation and suppress PD-L1 expression. Conclusions: IDH1 mutations impact the immune landscape of gliomas by affecting immune infiltrations and manipulating checkpoint ligand PD-L1 expression. Applications of immune checkpoint inhibitors may be beneficial for chemoradiation-insensitive IDH1-wildtype gliomas.

Validation of a neurovascular comorbidities index for retrospective database analysis.

OBJECTIVE: Comorbidities have a significant effect on patient outcomes. Accounting for this effect is especially important in retrospective reviews of large databases; overpowered studies are at risk for finding significant results because of inaccurate patient risk stratification. The authors previously created a neurovascular comorbidities index (NCI) for patients with an unruptured intracranial aneurysm and found that the model's ability to predict patient outcomes was statistically significantly improved over that of the routinely used Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Index (ECI). In this study, the authors aimed to validate use of the NCI over that of the CCI and ECI for risk stratification of patients with other neurovascular diseases. METHODS: The authors queried the National (Nationwide) Inpatient Sample database for the years 2002-2012 to compare the accuracy of the previously validated NCI with that of the CCI and ECI with respect to predicting outcomes for patients who had an arteriovenous malformation, a ruptured intracranial aneurysm, carotid artery stenosis, or dural arteriovenous fistula and who underwent surgical intervention. RESULTS: For patients with an arteriovenous malformation, the NCI outperformed the CCI and ECI in predicting poor outcome, hospital length of stay (LOS), and total cost but was equivalent to the CCI in predicting death. For patients with a ruptured intracranial aneurysm, the NCI outperformed the ECI and CCI in predicting death, poor outcome, LOS, and total cost. For patients with carotid artery stenosis, the NCI outperformed the ECI and CCI in predicting LOS, but it was equivalent to the ECI in predicting death and total cost and inferior to the CCI in predicting poor outcome (p < 0.002 for all). An insufficient number of patients with dural arteriovenous fistula who underwent surgical intervention were available for analysis (n < 10), and they therefore were excluded from study. For 11 of 12 metrics, the NCI was the significantly more efficient model. CONCLUSIONS: The NCI outperforms the CCI and ECI by providing more appropriate and efficient risk stratification of patients regarding death, outcome, LOS, and cost. Given this finding, the NCI should be used for retrospective reviews of patient outcomes instead of the CCI or ECI.

CD70, a novel target of CAR T-cell therapy for gliomas.

Background: Cancer immunotherapy represents a promising treatment approach for malignant gliomas but is hampered by the limited number of ubiquitously expressed tumor antigens and the profoundly immunosuppressive tumor microenvironment. We identified cluster of differentiation (CD)70 as a novel immunosuppressive ligand and glioma target. Methods: Normal tissues derived from 52 different organs and primary and recurrent low-grade gliomas (LGGs) and glioblastomas (GBMs) were thoroughly evaluated for CD70 gene and protein expression. The association between CD70 and patients' overall survival and its impact on T-cell death was also evaluated. Human and mouse CD70-specific chimeric antigen receptors (CARs) were tested respectively against human primary GBMs and murine glioma lines. The antitumor efficacies of these CARs were also examined in orthotopic xenograft and syngeneic models. Results: CD70 was not detected in peripheral and brain normal tissues but was constitutively overexpressed by isocitrate dehydrogenase (IDH) wild-type primary LGGs and GBMs in the mesenchymal subgroup and recurrent tumors. CD70 was also associated with poor survival in these subgroups, which may link to its direct involvement in glioma chemokine productions and selective induction of CD8+ T-cell death. To explore the potential for therapeutic targeting of this newly identified immunosuppressive axis in GBM tumors, we demonstrate that both human and mouse CD70-specific CAR T cells recognize primary CD70+ GBM tumors in vitro and mediate the regression of established GBM in xenograft and syngeneic models without illicit effect. Conclusion: These studies identify a previously uncharacterized and ubiquitously expressed immunosuppressive ligand CD70 in GBMs that also holds potential for serving as a novel CAR target for cancer immunotherapy in gliomas.

CD4+ and Perivascular Foxp3+ T Cells in Glioma Correlate with Angiogenesis and Tumor Progression.

BACKGROUND: Angiogenesis and immune cell infiltration are key features of gliomas and their manipulation of the microenvironment, but their prognostic significance remains indeterminate. We evaluate the interconnection between tumor-infiltrating lymphocyte (TIL) and tumor blood-vasculatures in the context of glioma progression. METHODS: Paired tumor tissues of 44 patients from three tumor-recurrent groups: diffuse astrocytomas (DA) recurred as DA, DA recurred as glioblastomas (GBM), and GBM recurred as GBM were evaluated by genetic analysis, immunohistochemistry for tumor blood vessel density, TIL subsets, and clinical outcomes. These cells were geographically divided into perivascular and intratumoral TILs. Associations were examined between these TILs, CD34+ tumor blood vessels, and clinical outcomes. To determine key changes in TIL subsets, microarray data of 15-paired tumors from patients who failed antiangiogenic therapy- bevacizumab, and 16-paired tumors from chemo-naïve recurrent GBM were also evaluated and compared. RESULTS: Upon recurrence in primary gliomas, similar kinetic changes were found between tumor blood vessels and each TIL subset in all groups, but only CD4+ including Foxp3+ TILs, positively correlated with the density of tumor blood vessels. CD4 was the predominant T cell population based on the expression of gene-transcripts in primary GBMs, and increased activated CD4+ T cells were revealed in Bevacizumab-resistant recurrent tumors (not in chemo-naïve recurrent tumors). Among these TILs, 2/3 of them were found in the perivascular niche; Foxp3+ T cells in these niches not only correlated with the tumor vessels but were also an independent predictor of shortened recurrence-free survival (RFS) (HR = 4.199, 95% CI 1.522-11.584, p = 0.006). CONCLUSION: The minimal intratumoral T cell infiltration and low detection of CD8 transcripts expression in primary GBMs can potentially limit antitumor response. CD4+ and perivascular Foxp3+ TILs associate with tumor angiogenesis and tumor progression in glioma patients. Our results suggest that combining antiangiogenic agents with immunotherapeutic approaches may help improve the antitumor efficacy for patients with malignant gliomas.

The spectrum of hand dysfunction after hemodialysis fistula placement.

INTRODUCTION: Contemporary dogma has classically attributed hand dysfunction following hemodialysis arteriovenous fistula (AVF) placement to regional ischemia. We hypothesize that hemodynamic perturbations alone do not entirely explain the postoperative changes in hand function and, furthermore, that various elements of hand function are differentially affected following surgery. METHODS: Bilateral wrist and digital pressures and upper extremity nerve conduction tests were recorded preoperatively and at 6 weeks and 6 months following upper extremity AVF construction in 46 patients. Concurrently, biomechanical tests were administered to evaluate multiple limb functional domains including grip strength, dexterity, sensation and perception of hand function. RESULTS: Mean age was 59±14 years (75% male) and 48% were on hemodialysis at the time of access placement. 69% had a brachial-based AVF, and the remainder had radial-based accesses. Six weeks following AVF placement, a significant decrease in access side digital pressures was observed, with only partial recovery at 6 months (P<0.0001). Grip strength was significantly worse in the access side limb (P=0.0003), and Disability of Arm, Shoulder and Hand Questionnaire (DASH) score substantially worsened postoperatively (P=0.06). Digital sensation and limb dexterity did not differ between limb sides (P>0.1) or change significantly over time (P>0.1). Principal component analyses demonstrated that nerve conduction parameters tended to track the biomechanical parameters, yet both were relatively independent of the hemodynamic parameters. CONCLUSION: Our findings suggest that ischemia alone does not completely explain access-related hand dysfunction and that future study is needed to elucidate alternative mechanisms.

Tumor associated CD70 expression is involved in promoting tumor migration and macrophage infiltration in GBM.

Tumor migration/metastasis and immunosuppression are major obstacles in effective cancer therapy. Incidentally, these 2 hurdles usually coexist inside tumors, therefore making therapy significantly more complicated, as both oncogenic mechanisms must be addressed for successful therapeutic intervention. Our recent report highlights that the tumor expression of a TNF family member, CD70, is correlated with poor survival for primary gliomas. In this study, we investigated how CD70 expression by GBM affects the characteristics of tumor cells and the tumor microenvironment. We found that the ablation of CD70 in primary GBM decreased CD44 and SOX2 gene expression, and inhibited tumor migration, growth and the ability to attract monocyte-derived M2 macrophages in vitro. In the tumor microenvironment, CD70 was associated with immune cell infiltrates, such as T cells; myeloid-derived suppressor cells; and monocytes/macrophages based on the RNA-sequencing profile. The CD163+ macrophages were far more abundant than T cells were. This overwhelming level of macrophages was identified only in GBM and not in low-grade gliomas and normal brain specimens, implying their tumor association. CD70 was detected only on tumor cells, not on macrophages, and was highly correlated with CD163 gene expression in primary GBM. Additionally, the co-expression of the CD70 and CD163 genes was found to correlate with decreased survival for patients with primary GBM. Together, these data suggest that CD70 expression is involved in promoting tumor aggressiveness and immunosuppression via tumor-associated macrophage recruitment/activation. Our current efforts to target this molecule using chimeric antigen receptor T cells hold great potential for treating patients with GBM.

The effects of new or worsened postoperative neurological deficits on survival of patients with glioblastoma.

OBJECTIVE An increased extent of resection (EOR) has been shown to improve overall survival of patients with glioblastoma (GBM) but has the potential for causing a new postoperative neurological deficit. To investigate the impact of surgical neurological morbidity on survival, the authors performed a retrospective analysis of the clinical data from patients with GBM to quantify the impact of a new neurological deficit on the survival benefit achieved with an increased EOR. METHODS The data from all GBM patients who underwent resection at the University of Florida from 2010 to 2015 with postoperative imaging within 72 hours of surgery were included in the study. Retrospective analysis was performed on clinical outcomes and tumor volumes determined on postoperative and follow-up imaging examinations. RESULTS Overall, 115 patients met the inclusion criteria for the study. Tumor volume at the time of presentation was a median of 59 cm3 (enhanced on T1-weighted MRI scans). The mean EOR (± SD) was 94.2% ± 8.7% (range 59.9%-100%). Almost 30% of patients had a new postoperative neurological deficit, including motor weakness, sensory deficits, language difficulty, visual deficits, confusion, and ataxia. The neurological deficits had resolved in 41% of these patients on subsequent follow-up examinations. The median overall survival was 13.1 months (95% CI 10.9-15.2 months). Using a multipredictor Cox model, the authors observed that increased EOR was associated with improved survival except for patients with smaller tumor volumes (≤ 15 cm3). A residual volume of 2.5 cm3 or less predicted a favorable overall survival. Developing a postoperative neurological deficit significantly affected survival (9.2 months compared with 14.7 months, p = 0.02), even if the neurological deficit had resolved by the first follow-up. However, there was a trend of improved survival among patients with resolution of a neurological deficit by the first follow-up compared with patients with a permanent neurological deficit. Any survival benefit from achieving a 95% EOR was abrogated by the development of a new neurological deficit postoperatively. CONCLUSIONS Developing a new neurological deficit after resection of GBM is associated with a decrease in overall survival. A careful balance between EOR and neurological compromise needs to be taken into account to reduce the likelihood of neurological morbidity from surgery.

Macrophage index predicts short-term renal allograft function and graft survival.

The ability to predict renal allograft dysfunction in the short term and predict graft survival by quantifying the macrophage infiltrate in allograft renal biopsies is described. Renal allograft biopsies performed for cause in 41 consecutive patients were scored for macrophages (macrophage index, MI) by use of a modified Banff score of inflammation (BSI), and the impact of the MI on serum creatinine (SCr) levels 3 months post-biopsy (post-Bx) and on graft survival was quantified. Biopsies were stained for macrophages, individual lesions semiquantified and MI, BSI and chronic allograft damage index (CADI) obtained. The effects of pathologic indices on 3 month post-Bx SCr and graft survival were quantified by multivariate analysis and Cox regression. Glomerular and interstitial macrophage scores correlated inversely with graft survival. MI predicted an increase in SCr 3 months post-Bx (P=0.02). MI >3 (hazard ratio 23.13, P=0.003) also had a powerful negative predictive value on graft survival.