Endothelial dysfunction and diabetes: effects on angiogenesis, vascular remodeling, and wound healing

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia due to lack of or resistance to insulin. Patients with DM are frequently afflicted with ischemic vascular disease or wound healing defect. It is well known that type 2 DM causes amplification of the atherosclerotic process, endothelial cell dysfunction, glycosylation of extracellular matrix proteins, and vascular denervation. These complications ultimately lead to impairment of neovascularization and diabetic wound healing. Therapeutic angiogenesis remains an attractive treatment modality for chronic ischemic disorders including PAD and/or diabetic wound healing. Many experimental studies have identified better approaches for diabetic cardiovascular complications, however, successful clinical translation has been limited possibly due to the narrow therapeutic targets of these agents or the lack of rigorous evaluation of pathology and therapeutic mechanisms in experimental models of disease. This paper discusses the current body of evidence identifying endothelial dysfunction and impaired angiogenesis during diabetes.

Hydrogen sulfide chemical biology: pathophysiological roles and detection

Hydrogen sulfide (H2S) is the most recent endogenous gasotransmitter that has been reported to serve many physiological and pathological functions in different tissues. Studies over the past decade have revealed that H2S can be synthesized through numerous pathways and its bioavailability regulated through its conversion into different biochemical forms. H2S exerts its biological effects in various manners including redox regulation of protein and small molecular weight thiols, polysulfides, thiosulfate/sulfite, iron-sulfur cluster proteins, and anti-oxidant properties that affect multiple cellular and molecular responses. However, precise measurement of H2S bioavailability and its associated biochemical and pathophysiological roles remains less well understood. In this review, we discuss recent understanding of H2S chemical biology, its relationship to tissue pathophysiological responses and possible therapeutic uses.

Measurement of plasma hydrogen sulfide in vivo and in vitro

The gasotransmitter hydrogen sulfide is known to regulate multiple cellular functions during normal and pathophysiological states. However, a paucity of concise information exists regarding quantitative amounts of hydrogen sulfide involved in physiological and pathological responses. This is primarily due to disagreement among various methods employed to measure free hydrogen sulfide. In this article, we describe a very sensitive method of measuring the presence of H₂S in plasma down to nanomolar levels, using monobromobimane (MBB). The current standard assay using methylene blue provides erroneous results that do not actually measure H₂S. The method presented herein involves derivatization of sulfide with excess MBB in 100 mM Tris-HCl buffer (pH 9.5, 0.1 mM DTPA) for 30 min in 1% oxygen at room temperature. The fluorescent product sulfide-dibimane (SDB) is analyzed by RP-HPLC using an eclipse XDB-C18 (4.6 × 250 mm) column with gradient elution by 0.1% (v/v) trifluoroacetic acid in acetonitrile. The limit of detection for sulfide-dibimane is 2 nM and the SDB product is very stable over time, allowing batch storage and analysis. In summary, our MBB method is suitable for sensitive quantitative measurement of free hydrogen sulfide in multiple biological samples such as plasma, tissue and cell culture lysates, or media.

Hydrogen sulfide attenuates cardiac dysfunction after heart failure via induction of angiogenesis

BACKGROUND

Hydrogen sulfide (H2S) has been shown to induce angiogenesis in in vitro models and to promote vessel growth in the setting of hindlimb ischemia. The goal of the present study was to determine the therapeutic potential of a stable, long-acting H2S donor, diallyl trisulfide, in a model of pressure-overload heart failure and to assess the effects of chronic H2S therapy on myocardial vascular density and angiogenesis.

METHODS AND RESULTS

Transverse aortic constriction was performed in mice (C57BL/6J; 8-10 weeks of age). Mice received either vehicle or diallyl trisulfide (200 µg/kg) starting 24 hours after transverse aortic constriction and were followed up for 12 weeks using echocardiography. H2S therapy with diallyl trisulfide improved left ventricular remodeling and preserved left ventricular function in the setting of transverse aortic constriction. H2S therapy increased the expression of the proangiogenic factor, vascular endothelial cell growth factor, and decreased the angiogenesis inhibitor, angiostatin. Further studies revealed that H2S therapy increased the expression of the proliferation marker, Ki67, as well as increased the phosphorylation of endothelial NO synthase and the bioavailability of NO. Importantly, these changes were associated with an increase in vascular density within the H2S-treated hearts.

CONCLUSIONS

These results suggest that H2S therapy attenuates left ventricular remodeling and dysfunction in the setting of heart failure by creating a proangiogenic environment for the growth of new vessels.

Hydrogen sulfide stimulates ischemic vascular remodeling through nitric oxide synthase and nitrite reduction activity regulating hypoxia-inducible factor-1α and vascular endothelial growth factor-dependent angiogenesis

Background

Hydrogen sulfide (H₂S) therapy is recognized as a modulator of vascular function during tissue ischemia with the notion of potential interactions of nitric oxide (NO) metabolism. However, little is known about specific biochemical mechanisms or the importance of H₂S activation of NO metabolism during ischemic tissue vascular remodeling. The goal of this study was to determine the effect of H₂S on NO metabolism during chronic tissue ischemia and subsequent effects on ischemic vascular remodeling responses.

Methods and Results

The unilateral, permanent femoral artery ligation model of hind‐limb ischemia was performed in C57BL/6J wild‐type and endothelial NO synthase–knockout mice to evaluate exogenous H₂S effects on NO bioavailability and ischemic revascularization. We found that H₂S selectively restored chronic ischemic tissue function and viability by enhancing NO production involving both endothelial NO synthase and nitrite reduction mechanisms. Importantly, H₂S increased ischemic tissue xanthine oxidase activity, hind‐limb blood flow, and angiogenesis, which were blunted by the xanthine oxidase inhibitor febuxostat. H₂S treatment increased ischemic tissue and endothelial cell hypoxia‐inducible factor‐1α expression and activity and vascular endothelial growth factor protein expression and function in a NO‐dependent manner that was required for ischemic vascular remodeling.

Conclusions

These data demonstrate that H₂S differentially regulates NO metabolism during chronic tissue ischemia, highlighting novel biochemical pathways to increase NO bioavailability for ischemic vascular remodeling.

Relevance of Simpson grading system and recurrence-free survival after surgery for World Health Organization Grade I meningioma

OBJECTIVE The clinical significance of the Simpson system for grading the extent of meningioma resection and its role as a predictor of the recurrence of World Health Organization (WHO) Grade I meningiomas have been questioned in the past, echoing changes in meningioma surgery over the years. The authors reviewed their experience in resecting WHO Grade I meningiomas and assessed the association between extent of resection, as evaluated using the Simpson classification, and recurrence-free survival (RFS) of patients after meningioma surgery. METHODS Clinical and radiological information for patients with WHO Grade I meningiomas who had undergone resective surgery over the past 20 years was retrospectively reviewed. Simpson and Shinshu grading scales were used to evaluate the extent of resection. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression. RESULTS Four hundred fifty-eight patients were eligible for analysis. Overall tumor recurrence rates for Simpson resection Grades I, II, III, and IV were 5%, 22%, 31%, and 35%, respectively. After Cox regression analysis, Simpson Grade I (extensive resection) was revealed as a significant predictor of RFS (p = 0.003). Patients undergoing Simpson Grade I and II resections showed significant improvement in RFS compared with patients undergoing Grade III and IV resections (p = 0.005). Extent of resection had a significant effect on recurrence rates for both skull base (p = 0.047) and convexity (p = 0.012) meningiomas. Female sex and a Karnofsky Performance Scale score > 70 were also identified as independent predictors of RFS after resection of WHO Grade I meningioma. CONCLUSIONS In this patient cohort, a significant association was noted between extent of resection and rates of tumor recurrence. In the authors' experience the Simpson grading system maintains its relevance and prognostic value and can serve an important role for patient education. Even though complete tumor resection is the goal, surgery should be tailored to each patient according to the risks and surgical morbidity.

Emerging Concepts in Vascular Dementia: A Review

OBJECTIVE

Vascular dementia (VaD) is the second most common cause of dementia and a major health concern worldwide. A comprehensive review on VaD is warranted for better understanding and guidance for the practitioner. We provide an updated overview of the epidemiology, pathophysiological mechanisms, neuroimaging patterns as well as current diagnostic and therapeutic approaches.

MATERIALS AND METHODS

A narrative review of current literature in VaD was performed based on publications from the database of PubMed, Scopus and Google Scholar up to January, 2021.

RESULTS

VaD can be the result of ischemic or hemorrhagic tissue injury in a particular region of the brain which translates into clinically significant cognitive impairment. For example, a cerebral infarct in the speech area of the dominant hemisphere would translate into clinically significant impairment as would involvement of projection pathways such as the arcuate fasciculus. Specific involvement of the angular gyrus of the dominant hemisphere, with resultant Gerstman's syndrome, could have a pronounced effect on functional ability despite being termed a "minor stroke". Small vessel cerebrovascular disease can have a cumulate effect on cognitive function over time. It is unfortunately well recognized that "good" functional recovery in acute ischemic or haemorrhagic stroke, including subarachnoid haemorrhage, does not necessarily translate into good cognitive recovery. The victim may often be left unable to have gainful employment, drive a car safely or handle their affairs independently.

CONCLUSIONS

This review should serve as a compendium of updated information on VaD and provide guidance in terms of newer diagnostic and potential therapeutic approaches.

Emerging role of PKA/eNOS pathway in therapeutic angiogenesis for ischaemic tissue diseases

Although an abundant amount of research has been devoted to the study of angiogenesis, its precise mechanisms are incompletely understood. Numerous clinical trials focused on therapeutic angiogenesis for the treatment of tissue ischaemia have not been as successful as those of preclinical studies. Thus, additional studies are needed to better understand critical molecular mechanisms regulating ischaemic neovascularization to identify novel therapeutic agents. Nitric oxide (NO) plays a central role in ischaemic neovascularization through the generation of cyclic guanosine monophosphate (cGMP) and the activation of several other signalling responses. Accumulated evidence suggests that endothelial protein kinase A/endothelial NO synthase (PKA/eNOS) signalling may play an important role in ischaemic disorders by promoting neovascularization. This review highlights recent advances in the role of the PKA/eNOS and NO-cGMP-kinase cascade pathway in ischaemic neovascularization. We also discuss molecular relationships of PKA/eNOS with other angiogenic pathways and explore the possibility of activation of the NO/nitrite endocrine system as potential therapeutic targets for ischaemic angiogenesis.

Redox balance dynamically regulates vascular growth and remodeling

Vascular growth and remodeling responses entail several complex biochemical, molecular, and cellular responses centered primarily on endothelial cell activation and function. Recent studies reveal that changes in endothelial cell redox status critically influence numerous cellular events that are important for vascular growth under different conditions. It has been known for some time that oxidative stress actively participates in many aspects of angiogenesis and vascular remodeling. Initial studies in this field were largely exploratory with minimal insight into specific molecular mechanisms and how these responses could be regulated. However, it is now clear that intracellular redox mechanisms involving hypoxia, NADPH oxidases (NOX), xanthine oxidase (XO), nitric oxide and its synthases, and intracellular antioxidant defense pathways collectively orchestrate a redox balance system whereby reactive oxygen and nitrogen species integrate cues controlling vascular growth and remodeling. In this review, we discuss key redox regulation pathways that are centrally important for vascular growth in tissue health and disease. Important unresolved questions and issues are also addressed that requires future investigation.

Spinal meningiomas: clinicoradiological factors predicting recurrence and functional outcome

OBJECTIVE

Spinal meningiomas are benign tumors with a wide spectrum of clinical and radiological features at presentation. The authors analyzed multiple clinicoradiological factors to predict recurrence and functional outcome in a cohort with a mean follow-up of more than 4 years. The authors also discuss the results of clinical studies regarding spinal meningiomas in the last 15 years.

METHODS

The authors retrospectively reviewed the clinical and radiological details of patients who underwent surgery for spinal tumors between 2001 and 2015 that were histopathologically confirmed as meningiomas. Demographic parameters, such as age, sex, race, and association with neurofibromatosis Type 2, were considered. Radiological parameters, such as tumor size, signal changes of spinal cord, spinal level, number of levels, location of tumor attachment, shape of tumor, and presence of dural tail/calcification, were noted. These factors were analyzed to predict recurrence and functional outcome. Furthermore, a pooled analysis was performed from 13 reports of spinal meningiomas in the last 15 years.

RESULTS

A total of 38 patients were included in this study. Male sex and tumors with radiological evidence of a dural tail were associated with an increased risk of recurrence at a mean follow-up of 51.2 months. Ventral or ventrolateral location, large tumors, T2 cord signal changes, and poor preoperative functional status were associated with poor functional outcome at 1-year follow-up.

CONCLUSIONS

Spine surgeons must be aware of the natural history and risk factors of spinal meningiomas to establish a prognosis for their patients.

Cystathionine γ-lyase regulates arteriogenesis through NO-dependent monocyte recruitment

AIMS

Hydrogen sulfide (H2S) is a vasoactive gasotransmitter that is endogenously produced in the vasculature by the enzyme cystathionine γ-lyase (CSE). However, the importance of CSE activity and local H2S generation for ischaemic vascular remodelling remains completely unknown. In this study, we examine the hypothesis that CSE critically regulates ischaemic vascular remodelling involving H2S-dependent mononuclear cell regulation of arteriogenesis.

METHODS AND RESULTS

Arteriogenesis including mature vessel density, collateral formation, blood flow, and SPY angiographic blush rate were determined in wild-type (WT) and CSE knockout (KO) mice at different time points following femoral artery ligation (FAL). The role of endogenous H2S in regulation of IL-16 expression and subsequent recruitment of monocytes, and expression of VEGF and bFGF in ischaemic tissues, were determined along with endothelial progenitor cell (CD34/Flk1) formation and function. FAL of WT mice significantly increased CSE activity, expression and endogenous H2S generation in ischaemic tissues, and monocyte infiltration, which was absent in CSE-deficient mice. Treatment of CSE KO mice with the polysulfide donor diallyl trisulfide restored ischaemic vascular remodelling, monocyte infiltration, and cytokine expression. Importantly, exogenous H2S therapy restored nitric oxide (NO) bioavailability in CSE KO mice that was responsible for monocyte recruitment and arteriogenesis.

CONCLUSION

Endogenous CSE/H2S regulates ischaemic vascular remodelling mediated during hind limb ischaemia through NO-dependent monocyte recruitment and cytokine induction revealing a previously unknown mechanism of arteriogenesis.

Outcome of resection of WHO Grade II meningioma and correlation of pathological and radiological predictive factors for recurrence

This study investigated whether extent of surgical resection (Simpson and Shinshu grade) along with pathological and radiological factors influence the tumor control and recurrence-free survival (RFS) of patients with World Health Organization (WHO) grade II meningiomas. The clinical, radiological and surgical notes on the 59 patients with WHO grade II meningioma managed at our institution over 20years were retrospectively reviewed. In this study, median survival time was 41months. The overall recurrence rate in Simpson grades I and II resection was 31%. In grades III and IV, the overall recurrence rate was 73%, and this high recurrence rate in these groups was confined within 5years. In Cox regression analysis, combined data of grades (I and II)/complete resection showed a significant difference in RFS compared to grades (III and IV)/subtotal resection (p=0.0001). A similar trend of RFS (p=0.0001) was observed with the Shinshu grading system of resection. In addition, a Ki-67% marker for proliferation less than 15% (p=0.029), absence of certain radiological features including heterogeneous enhancement, cyst formation and peritumoral edema (p=0.006), and repeat surgery for recurrent meningioma was associated with better survival (p=0.014). However, radiosurgery did not have a beneficial role in the treatment of recurrence of atypical meningioma. The Simpson grading system is the primary predictor of recurrence of WHO grade II meningioma after resection. In addition, certain pathological and radiological features need to be considered as possible factors of recurrence after resection. Lastly, depending on the likely risks and surgical morbidity, repeat surgical resection should be performed for recurrent atypical meningioma.

Nitrite anion therapy protects against chronic ischemic tissue injury in db/db diabetic mice in a NO/VEGF-dependent manner

Nitrite anion has been demonstrated to be a prodrug of nitric oxide (NO) with positive effects on tissue ischemia/reperfusion injury, cytoprotection, and vasodilation. However, effects of nitrite anion therapy for ischemic tissue vascular remodeling during diabetes remain unknown. We examined whether sodium nitrite therapy altered ischemic revascularization in BKS-Lepr(db/db) mice subjected to permanent unilateral femoral artery ligation. Sodium nitrite therapy completely restored ischemic hind limb blood flow compared with nitrate or PBS therapy. Importantly, delayed nitrite therapy 5 days after ischemia restored ischemic limb blood flow in aged diabetic mice. Restoration of blood flow was associated with increases in ischemic tissue angiogenesis activity and cell proliferation. Moreover, nitrite but not nitrate therapy significantly prevented ischemia-mediated tissue necrosis in aged mice. Nitrite therapy significantly increased ischemic tissue vascular endothelial growth factor (VEGF) protein expression that was essential for nitrite-mediated reperfusion of ischemic hind limbs. Nitrite significantly increased ischemic tissue NO bioavailability along with concomitant reduction of superoxide formation. Lastly, nitrite treatment also significantly stimulated hypoxic endothelial cell proliferation and migration in the presence of high glucose in an NO/VEGF-dependent manner. These results demonstrate that nitrite therapy effectively stimulates ischemic tissue vascular remodeling in the setting of metabolic dysfunction that may be clinically useful.

Neuromodulation in intractable pain management: outcomes and predictors of revisions of spinal cord stimulators

OBJECTIVE Spinal cord stimulators (SCSs) appear to be safe and efficacious for chronic intractable back pain. Although there are many reports on percutaneous SCSs, there are very few studies on outcomes of paddle lead SCSs. In addition, the predictors of requirement for SCS revision have not been well established. Here, the authors review the outcome of a case series and attempt to identify the predictors of SCS revisions. METHODS The clinical and radiological information of 141 patients with intractable chronic pain who underwent SCS implantation within the past 20 years was retrospectively reviewed. Paddle lead SCSs were used in this series. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression. RESULTS Among 141 cases, 90 (64%) did not require any revision after SCS implantations. Removal of the SCS was required in 14 patients. The average pain score was significantly reduced (preimplantation score of 8 vs postimplantation score of 1.38; p < 0.0001). Younger age, male sex, obesity, a preimplantation pain score ≥ 8, and the presence of neuromuscular pain were identified as predictors of the overall requirement for SCS revision. However, only a preimplantation pain score ≥ 8 was identified as a predictor of early failure of the SCS. CONCLUSIONS Implantation of a paddle lead SCS is a relatively less invasive, safe, and effective procedure for patients with intractable back pain. Revision of the procedure depends on many factors, including younger age, male sex, associated neuromuscular pain, and severity of the pain. Therefore, patients with these factors, for whom implantation of an SCS is planned, should be closely followed for the possible requirement for revision.

Dipyridamole reverses peripheral ischemia and induces angiogenesis in the Db/Db diabetic mouse hind-limb model by decreasing oxidative stress

Dipyridamole anti-platelet therapy has previously been suggested to ameliorate chronic tissue ischemia in healthy animals. However, it is not known if dipyridamole therapy represents a viable approach to alleviating chronic peripheral tissue ischemia associated with type 2 diabetes. Here we examine the hypothesis that dipyridamole treatment restores reperfusion of chronic hind-limb ischemia in the murine B6.BKS-Lepr(db/db) diabetic model. Dipyridamole therapy quickly rectified ischemic hind-limb blood flow to near preligation levels within 3 days of the start of therapy. Restoration of ischemic tissue blood flow was associated with increased vascular density and endothelial cell proliferation observed only in ischemic limbs. Dipyridamole significantly increased total nitric oxide metabolite levels in tissue, which were not associated with changes in endothelial NO synthase expression or phosphorylation. Interestingly, dipyridamole therapy significantly decreased ischemic tissue superoxide and protein carbonyl levels, identifying a dominant antioxidant mechanistic response. Dipyridamole therapy also moderately reduced diabetic hyperglycemia and attenuated development of dyslipidemia over time. Together, these data reveal that dipyridamole therapy is an effective modality for the treatment of chronic tissue ischemia during diabetes and highlights the importance of dipyridamole antioxidant activity in restoring tissue NO bioavailability during diabetes.

Control of angiogenesis dictated by picomolar superoxide levels

Control of vascular insufficiencies due to various cardiovascular pathologies is important for developing specific and effective treatments. Fluctuations in oxidative stress significantly alter the progression of angiogenesis under physiological and pathological conditions. However, the precise amount of reactive oxygen species (ROS) required to influence subsequent signaling pathways for ischemic angiogenesis remains undefined. Here, we have determined the effect of ROS-mediated molecular mechanisms on angiogenesis in a murine model of peripheral artery disease using Gclm mutant mice (a model of compromised glutathione synthesis and therefore reduced antioxidant capacity). Left femoral artery ligation and excision were performed in Gclm WT (+/+), heterozygous (+/-), and null (-/-) mice. Blood flow (laser Doppler), angiogenic index (CD31/DAPI), and proliferation index (Ki67/DAPI) were significantly increased in Gclm(+/-) mice but not in Gclm(+/+) or Gclm(-/-) mice. Measurements of reactive oxygen species suggest that the amount of superoxide required to stimulate angiogenesis after the induction of ischemia is 9.82 pmol/mg of tissue. Protein carbonyl levels increased in a manner consistent with increasing oxidative stress. Superoxide and protein carbonyl levels were reduced by the addition of the nitroxide tempol, a known superoxide dismutase mimetic. Finally, restoration of blood flow in Gclm(+/-) mice was attenuated by a VEGF164 aptamer, verifying that slightly elevated levels of ROS restore blood flow by stimulating endothelial cell proliferation through a VEGF-dependent pathway. The results of this study reveal new information on the amount of ROS necessary for angiogenic activity and provide the foundation of critical redox parameters for vascular remodeling responses. The information obtained from this study on vascular ischemia, using a model of decreased antioxidant capacity, has provided insight into the control of revascularization and is a step forward in our ability to regulate angiogenic therapies.

A systematic review of overall survival in pediatric primary glioblastoma multiforme of the spinal cord

OBJECTIVE The incidence of primary spinal cord glioblastoma multiforme (GBM) in the pediatric age group is very rare. Only a few case series and case reports have been published in the literature; therefore, overall survival (OS) outcome and the as-yet poorly defined management options are not discussed in detail. The authors performed a cumulative survival analysis of all reported cases of pediatric spinal cord GBM to identify the predictive factors related to final survival outcome. METHODS A comprehensive search for relevant articles was performed on PubMed's electronic database MEDLINE for the period from 1950 to 2015 using the search words "malignant spinal cord tumor" and "spinal glioblastoma multiforme." This study was limited to patients younger than 18 years of age. Survival rates for children with various tumor locations and treatments were collected from the published articles and analyzed. RESULTS After an extensive literature search, 29 articles met the study inclusion criteria. From the detailed information in these articles, the authors found 53 children eligible for the survival analysis. The majority (45%) of the children were more than 12 years old. Thirty-four percent of the cases were between 7 and 12 years of age, and 21% were younger than 7 years. In the Kaplan-Meier survival analysis, children younger than 7 years of age had better survival (13 months) than the children older than 7 years (7-12 years: 10 months, > 12 years: 9 months; p = 0.01, log-rank test). Fifty-five percent of the children were female and 45% were male. A cervical tumor location (32%) was the most common, followed by thoracic (28.3%). Cervicothoracic (18.9%) and conus (18.8%) tumor locations shared the same percentage of cases. Cervical tumors had a worse outcome than tumors in other locations (p = 0.003, log-rank test). The most common presenting symptom was limb weakness (53%), followed by sensory disturbances (25%). Median OS was 10 months. The addition of adjuvant therapy (radiotherapy [RT] and/or chemotherapy [CT]) after surgery significantly improved OS (p = 0.01, log-rank test). Children who underwent gross-total resection and RT had better outcomes than those who underwent subtotal resection and RT (p = 0.04, log-rank test). Cerebrospinal fluid spread, hydrocephalus, brain metastasis, and spinal metastasis were not correlated with OS in primary spinal GBM. CONCLUSIONS Adjuvant therapy after surgery had a beneficial effect on overall outcome of spinal GBM in the pediatric age group. Gross-total resection followed by RT produced a better outcome than subtotal resection with RT. Further large-scale prospective study is required to establish the genetic and molecular factors related to OS in primary GBM of the spinal cord in pediatric patients.

Epidemiology of adult-onset hydrocephalus: institutional experience with 2001 patients

OBJECTIVE Adult-onset hydrocephalus is not commonly discussed in the literature, especially regarding its demographic distribution. In contrast to pediatric hydrocephalus, which is related to a primary CSF pathway defect, its development in adults is often secondary to other pathologies. In this study, the authors investigated the epidemiology of adult-onset hydrocephalus as it pertains to different etiologies and in reference to age, sex, and race distributions. METHODS The authors retrospectively reviewed the clinical notes of 2001 patients with adult-onset hydrocephalus who presented to Louisiana State University Health Sciences Center within a 25-year span. Significant differences between the groups were analyzed by a chi-square test; p < 0.05 was considered significant. RESULTS The overall mean (± SEM) incidence of adult hydrocephalus in this population was 77 ± 30 per year, with a significant increase in incidence in the past decade (55 ± 3 [1990-2003] vs 102 ± 6 [2004-2015]; p < 0.0001). Hydrocephalus in a majority of the patients had a vascular etiology (45.5%) or was a result of a tumor (30.2%). The incidence of hydrocephalus in different age groups varied according to various pathologies. The incidence was significantly higher in males with normal-pressure hydrocephalus (p = 0.03) or head injury (p = 0.01) and higher in females with pseudotumor cerebri (p < 0.0001). In addition, the overall incidence of hydrocephalus was significantly higher in Caucasian patients (p = 0.0002) than in those of any other race. CONCLUSIONS Knowledge of the demographic variations in adult-onset hydrocephalus is helpful in achieving better risk stratification and better managing the disease in patients. For general applicability, these results should be validated in a large-scale meta-analysis based on a national population database.

Surgical Outcomes and Predictors of Recurrence in Elderly Patients with Meningiomas

BACKGROUND

Meningiomas are more prevalent with increasing age, and there is no general consensus of surgical management for this group of tumors. The role of resection and the predictors of recurrence of meningiomas in elderly patients have not been well established. The authors reviewed their experience of surgical resection of these tumors in elderly patients and determined the factors for recurrence.

METHODS

Clinical and radiologic information of 81 elderly patients with meningiomas was retrospectively reviewed. Simpson grading scales were used to evaluate the extent of surgical resection. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional hazards regression.

RESULTS

In this study, the recurrence rate in the grades I-II resection group was 10%, whereas in the grades III-IV resection group, the recurrence rate was 46% (P < 0.001). In Cox regression analysis, Simpson grades I-II/complete resection was revealed as a significant predictor of recurrence-free survival (P = 0.002). The hazard ratio for recurrence after grades III-IV resection was 5 times higher than after grades I-II resection. Location, size of the tumor, medical comorbidities, Karnofsky Performance Status, Geriatric Scoring System (GSS) score >16, and repeated resection were identified as predictors of recurrence-free survival after resection of meningiomas.

CONCLUSIONS

Elderly patients with meningiomas having a GSS score >16 and undergoing Simpson grades I-II/gross total resection have low operative morbidity, mortality, and recurrence rates and are less likely to continue on antiepileptic medications. Although complete tumor resection is the goal, the surgical approach should be tailored to each patient depending on the patient's GSS score.

Utility of Neuronavigation in Intracranial Meningioma Resection: A Single-Center Retrospective Study

OBJECTIVE

In this study, we validate the utility of navigation in intracranial meningioma excision and evaluate the effectiveness of image guidance surgery based on clinical outcome, extent of resection, and recurrence-free survival (RFS).

METHODS

Information related to clinical history, use of neuronavigation, neuroimaging, microsurgical dissection, and outcomes of 517 consecutive cases with meningiomas between January 1995 and June 2015 was collected retrospectively. A Cox proportional hazards regression model was used to determine independent predictors of RFS.

RESULTS

In this study, overall recurrence rate after tumor excision with or without neuronavigation was 17.7% and 31.2%, respectively (P = 0.03). Based on neuronavigation use, RFS of the patients with meningiomas in different locations also varied significantly (skull base; with, 110 months vs. without, 157 months; P = 0.02). The median RFS for patients operated on with or without use of neuronavigation during resection of tumors was 167 and 97 months, respectively, (log-rank P =0.0001). In Cox regression multivariate analysis, use of neuronavigation (P = 0.0001), gross total resection (Simpson grade I-II; P = 0.001), and World Health Organization grade I tumor (P = 0.0001) were revealed as significant predictors of RFS. In addition, mean blood loss (P = 0.005) and average length of stay (P = 0.008) in the hospital were significantly reduced and performance status was improved using neuronavigation during resection of meningiomas.

CONCLUSIONS

Interactive surgical navigation is a useful tool in the operative management of intracranial meningiomas to decrease recurrence rate, blood loss, and length of stay, and to improve RFS and performance status. Therefore, use of neuronavigation should be ensured during resection of intracranial meningiomas.

Intraventricular Meningioma: Technical Nuances in Surgical Management

OBJECTIVE

Intraventricular meningiomas (IVMs) are rare tumors compared with intracranial meningiomas. Optimal surgical management of IVMs is controversial. The objective of this article was to review the outcomes and complications of meningiomas treated with various surgical approaches.

METHODS

We performed a retrospective review of 18 patients with IVMs who received different treatment strategies during the period 2000-2014. Of 18 patients, 17 underwent microsurgical resection, and 1 patient received Gamma Knife radiosurgery. The literature was reviewed to compare the present cohort with previously published series.

RESULTS

In our series, 12 (70%) patients underwent parieto-occipital craniotomy and a superior parietal gyrus approach, which was similar to procedures used in various series (74.4%) in the existing literature. Preoperatively, patients commonly presented with headache (65%) and neurologic deficits (70%). After surgical management, there was a significant reduction in symptoms, including headache (preoperative 65% vs. postoperative 6%, P = 0.0001), and neurologic deficits (preoperative 70% vs. postoperative 5.5%). Preoperatively, 2 patients experienced visual impairment, which was completely resolved after surgery. The Karnofsky performance scale was significantly improved after resection compared with before treatment (89 vs. 76, P = 0.003). In 4 patients with World Health Organization grade II tumor, redo surgery was required because of recurrence of tumor.

CONCLUSIONS

Based on a literature review and our experience, surgical approaches for patients with IVM vary according to size, location, and laterality of the meningioma. In addition, the growth pattern of the tumor (transependymal extension), vascular supply of the tumor, and brain function (particularly visual function) can affect surgical treatment and should be identified preoperatively.

Nitrite anion stimulates ischemic arteriogenesis involving NO metabolism

Nitric oxide (NO) is a potential regulator of ischemic vascular remodeling, and as such therapies augmenting its bioavailability may be useful for the treatment of ischemic tissue diseases. Here we examine the effect of administering the NO prodrug sodium nitrite on arteriogenesis activity during established tissue ischemia. Chronic hindlimb ischemia was induced by permanent unilateral femoral artery and vein ligation. Five days postligation; animals were randomized to control PBS or sodium nitrite (165 μg/kg) therapy twice daily. In situ vascular remodeling was measured longitudinally using SPY angiography and Microfil vascular casting. Delayed sodium nitrite therapy rapidly increased ischemic limb arterial vessel diameter and branching in a NO-dependent manner. SPY imaging angiography over time showed that nitrite therapy enhanced ischemic gracillis collateral vessel formation from the profunda femoris to the saphenous artery. Immunofluorescent staining of smooth muscle cell actin also confirmed that sodium nitrite therapy increased arteriogenesis in a NO-dependent manner. The NO prodrug sodium nitrite significantly increases arteriogenesis and reperfusion of established severe chronic tissue ischemia.

Factors predictive of improved overall survival following stereotactic radiosurgery for recurrent glioblastoma

The currently accepted standard of care for primary glioblastoma (GBM) consists of maximal surgical resection followed by fractionated external beam radiotherapy (EBRT) with concomitant temozolomide chemotherapy. The role of stereotactic radiosurgery (SRS) in the treatment of GBM is not well defined, but SRS has typically been applied as a salvage therapy for GBM recurrence. This paper reviews our single institution experience using gamma knife radiosurgery (GKRS) for the treatment of GBM. Thirty-six patients treated with GKRS for pathologically proven GBM at LSU Health in Shreveport from February 2000 to December 2013 were identified and analyzed. Patient characteristics, treatment variables, and survival were correlated. Seven patients received GKRS in the immediate postoperative period for an average tumor volume of 10.9 cm(3), and 29 patients were treated for a recurrent average tumor volume of 11.4 cm(3) with a prescribed dose ranging from 10 to 20 Gy at the 50 % isodose line. The median overall survival was significantly higher in recurrence group compared to up-front group [7.9 months (0.77-32.1 months) vs. 3.5 months (range 0.23-11.7 months) respectively, (p = 0.018)]. The predictive factors for improved survival in the patients with GBM were as follows: Karnofsky performance scale (KPS) > 70 (p = 0.026), age ≤ 50 years (p = 0.006), absence of neurodeficits (p = 0.01), and initial postoperative treatment with EBRT (p = 0.042). Adjuvant therapy with GKRS following GBM recurrence demonstrates statistical superiority over immediate postoperative boost therapy.