Neuronal Redevelopment and the Regeneration of Neuromodulatory Axons in the Adult Mammalian Central Nervous System.

One reason that many central nervous system injuries, including those arising from traumatic brain injury, spinal cord injury, and stroke, have limited recovery of function is that neurons within the adult mammalian CNS lack the ability to regenerate their axons following trauma. This stands in contrast to neurons of the adult mammalian peripheral nervous system (PNS). New evidence, provided by single-cell expression profiling, suggests that, following injury, both mammalian central and peripheral neurons can revert to an embryonic-like growth state which is permissive for axon regeneration. This "redevelopment" strategy could both facilitate a damage response necessary to isolate and repair the acute damage from injury and provide the intracellular machinery necessary for axon regrowth. Interestingly, serotonin neurons of the rostral group of raphe nuclei, which project their axons into the forebrain, display a robust ability to regenerate their axons unaided, counter to the widely held view that CNS axons cannot regenerate without experimental intervention after injury. Furthermore, initial evidence suggests that norepinephrine neurons within the locus coeruleus possess similar regenerative abilities. Several morphological characteristics of serotonin axon regeneration in adult mammals, observable using longitudinal in vivo imaging, are distinct from the known characteristics of unaided peripheral nerve regeneration, or of the regeneration seen in the spinal cord and optic nerve that occurs with experimental intervention. These results suggest that there is an alternative CNS program for axon regeneration that likely differs from that displayed by the PNS.

Neurology Morbidity and Mortality Conferences and Quality Improvement: Single-Center Experience and National Survey.

Background: Morbidity and Mortality (M&M) conferences are widespread but vary in goals and methodology. Some focus on clinical enigmas while an increasing number utilize quality improvement (QI) tools to effect systems change. Little is known about the current state of US Neurology M&Ms. Methods: We surveyed 56 US academic neurology departments regarding their M&Ms to understand the use of QI tools and assess variability. Additionally, we reviewed the evolution of M&Ms in our department. Results: The survey was completed by 44 (80%) departments; 68% reported quarterly frequency with 61% discussing 1-2 safety events per conference. The number of written guidelines or protocols resulting from M&Ms in 2 years varied from 0 (14% of departments), 1-2 (45%), to >5 (5%). Institutional culture regarding quality and safety and conference timing were cited by 71% as important in improving participation. In our own department, the M&M format changed in 2014 based on a sentinel patient event combined with improving safety culture across the hospital: neurology M&Ms transformed into thematic quarterly conferences utilizing QI tools. Attendance increased 3-fold, and in 7 years, we have generated 26 guidelines or pathways with corresponding decision-support tools, among other improvement efforts, resulting in specific systems changes. Based on survey results and our experience, suggested M&M "best practices" include the use of just culture, peer review protection, safety event analysis with QI methodology, trainee involvement, and logistical optimization. Conclusion: Structured M&Ms incorporating suggested QI-informed "best practices" can be highly effective in driving system change within neurology.

Immediate preoperative hyperglycemia correlates with complications in non-cardiac surgical cases.

STUDY OBJECTIVE: Assess for a relationship between immediate preoperative glucose concentrations and postoperative complications. DESIGN: Retrospective cohort study. SETTING: Single large, tertiary care academic medical center. PATIENTS: A five-year registry of all patients at our hospital who had a glucose concentration (plasma, serum, or venous/capillary/arterial whole blood) measured up to 6 h prior to a non-emergent surgery. INTERVENTIONS: The glucose registry was cross-referenced with a database from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). We applied an outcomes review to the subset of patients for whom we had data from both registries (n = 1774). MEASUREMENTS: Preoperative glucose concentration in the full population as well as the subgroups of patients with or without diabetes were correlated with adverse postsurgical outcomes using 1) univariable analysis and 2) full multivariable analysis correcting for 27 clinical factors available from the ACS NSQIP database. Logistic regression analysis was performed using glucose level either as a continuous variable or as a categorical variable according to the following classifications: mild (≥140 mg/dL; ≥7.8 mmol/L), moderate (≥180 mg/dL; ≥10 mmol/L), or severe (≥250 mg/dL; ≥13.9 mmol/L) hyperglycemia. A third analysis was performed correcting for 7 clinically important factors (age, BMI, predicted duration of procedure, sex, CKD stage, hypoalbuminemia, and diabetic status) identified by anesthesiologists and surgeons as immediately available and important for decision making. MAIN RESULTS: Univariable analysis of all patients and the subgroups of patients without diabetes or with diabetes showed that immediate preoperative mild or moderate hyperglycemia correlates with postoperative complications. Statistical significance was lost in most groups using full multivariable analysis, but not when correcting for the 7 factors available immediately preoperatively. However, for all patients with diabetes, moderate hyperglycemia (≥180 mg/dL; ≥10 mmol/L) continued to significantly correlate with complications even in the full multivariable analysis [odds ratio (OR) 1.79; 95% Confidence Intervals (CI) 1.10, 2.92], and with readmission/reoperation within 30 days [OR 1.93; 95% CI 1.18, 3.13]. CONCLUSIONS: Preoperative hyperglycemia within 6 h of surgery is a marker of adverse postoperative outcomes. Among patients with diabetes in our study, a preoperative glucose level ≥ 180 mg/dL (≥10 mmol/L) independently correlates with risk of postoperative complications and readmission/reoperation. These results should encourage future work to determine whether addressing immediate preoperative hyperglycemia can improve complication rates, or simply serves as a marker of higher risk.

How Do Treatment Priorities Differ Between Patients in HIV Care and Their Providers? A Mixed-Methods Study.

Evidence suggests priorities differ between patients in HIV care and their providers regarding topics most important to address in care. At five U.S. sites, we asked patients and providers to prioritize 25 potential topic areas to address during routine visits, and invited patients to discuss selection rationale. Patients (n = 206) and providers (n = 17) showed high discordance in rank order priorities (X2 (24, 223) = 71.12; p < 0.0001). Patients ranked social domains such as HIV stigma highly; a higher proportion of providers prioritized substance use domains. HIV stigma was a higher priority for patients in care fewer than 6 years (Fisher's exact p = 0.0062), nonwhite patients (Fisher's exact p = 0.0114), and younger patients (Fisher's exact p = 0.0281). Patients' priorities differed between men and women (X2 (24, 188) = 52.89; p < 0.0001), white race vs. other races (X2 (24, 206) = 48.32; p = 0.0023), and Latinos vs. non-Latinos (X2 (24, 206) = 48.65; p = 0.0021). Interviews (n = 79) revealed perceived impact of social context on health and health behaviors.

Catecholaminergic axons in the neocortex of adult mice regrow following brain injury.

Serotonin axons in the adult rodent brain can regrow and recover their function following several forms of injury including controlled cortical impact (CCI), a neocortical stab wound, or systemic amphetamine toxicity. To assess whether this capacity for regrowth is unique to serotonergic fibers, we used CCI and stab injury models to assess whether fibers from other neuromodulatory systems can also regrow following injury. Using tyrosine-hydoxylase (TH) immunohistochemistry we measured the density of catecholaminergic axons before and at various time points after injury. One week after CCI injury we observed a pronounced loss, across cortical layers, of TH+ axons posterior to the site of injury. One month after CCI injury the same was true of TH+ axons both anterior and posterior to the site of injury. This loss was followed by significant recovery of TH+ fiber density across cortical layers, both anterior and posterior to the site of injury, measured three months after injury. TH+ axon loss and recovery over weeks to months was also observed throughout cortical layers using the stab injury model. Double label immunohistochemistry revealed that nearly all TH+ axons in neocortical layer 1/2 are also dopamine-beta-hyroxylase+ (DBH+; presumed norepinephrine), while TH+ axons in layer 5 are a mixture of DBH+ and dopamine transporter+ types. This suggests that noradrenergic axons can regrow following CCI or stab injury in the adult mouse neocortex and leaves open the question of whether dopaminergic axons can do the same.

Development and content validation of the Multifactoral assessment of perceived social support (MAPSS), a brief, patient-reported measure of social support for use in HIV care.

Low perceived social support (SS) negatively impacts health outcomes. We developed a measure of perceived SS for use in HIV care. We sought and categorized legacy items, selecting strongest items within categories. We elicited SS concepts from patients in English/Spanish, coded transcripts to match item pool content, and developed new items for salient unrepresented content. In focus groups, patients prioritized highly-matched items. We conducted cognitive interviews on high-priority items, and validity testing on final items against two legacy measures. From interviews (n = 32), we matched the following concepts: sense of belonging/inclusion; communication; emotional support; feeling accepted by others as a person; companionship; and practical support. We identified a new concept: support from friends/family in remaining healthy. Focus groups (n = 23) prioritized emotional support, communication, and support to remain healthy. Cognitive interviews (n = 30) found items were well-understood. The final 8-item measure performed well with patients (n = 708), with good construct validity. We used an Item Response Theory program to create a 3-item Short Form version of the measure, which captures 96% of patients indicating low social support. We developed the Multifactoral Assessment of Perceived Social Support (MAPSS) and Short Form (MAPSS-SF); brief, clinically relevant, sufficiently unidimensional measures of SS for use in HIV care.

Serotonin axons in the neocortex of the adult female mouse regrow after traumatic brain injury.

It is widely held that injured neurons in the central nervous system do not undergo axonal regrowth. However, there is mounting evidence that serotonin axons are a notable exception. Serotonin axons undergo long-distance regrowth in the neocortex after amphetamine lesion, and, following a penetrating stab injury, they can regrow from cut ends to traverse the stab rift. Traumatic brain injury (TBI) is clinically prevalent and can lead to pathologies, such as depression, that are related to serotonergic dysfunction. Thus, whether serotonin axons can regrow after TBI is an important question. We used two models for TBI-a persistent open skull condition and controlled cortical impact-to evoke injury in adult female mouse neocortex, and assessed serotonin axon density 1 week, 1 month, and 3 months after injury by serotonin transporter immunohistochemistry. We found that after both forms of TBI, serotonin axon density is decreased posterior but not anterior to the injury site when measured in layer 1 at 1 week post surgery, and that serotonin axons are capable of regrowing into the distal zone to increase density by 1 month post surgery. This pattern is consistent with the anterior-to-posterior course of serotonin axons in the neocortex. TBI in these models is associated with significant reactive astrogliosis both anterior and posterior to the impact, but the degree of reactive astrogliosis is not correlated with serotonin axon density when measured 1 week after TBI. Microglial density remains constant following both types of injuries, but microglial condensation was detected 1 week after controlled cortical impact.

In Vivo Imaging of CNS Injury and Disease.

In vivo optical imaging has emerged as a powerful tool with which to study cellular responses to injury and disease in the mammalian CNS. Important new insights have emerged regarding axonal degeneration and regeneration, glial responses and neuroinflammation, changes in the neurovascular unit, and, more recently, neural transplantations. Accompanying a 2017 SfN Mini-Symposium, here, we discuss selected recent advances in understanding the neuronal, glial, and other cellular responses to CNS injury and disease with in vivo imaging of the rodent brain or spinal cord. We anticipate that in vivo optical imaging will continue to be at the forefront of breakthrough discoveries of fundamental mechanisms and therapies for CNS injury and disease.

Characterization and Correction of Olfactory Deficits in Kidney Disease.

Patients with CKD suffer from food aversion, anorexia, and malnutrition. Although olfaction has a significant role in determining food flavor, our understanding of olfactory impairment and of the olfaction-nutrition axis in patients with kidney disease is limited. We quantified odor identification, odor threshold, and subjective odor perception in a cohort (n=161) comprising 36 participants with CKD, 100 participants with ESRD, and 25 controls. We investigated olfaction-nutrition associations in these participants and examined a novel intervention to improve olfaction in ESRD. The mean odor identification score was lower in patients with CKD (75.6%±13.1%; P=0.02) and ESRD (66.8%±15.1%; P<0.001) than in controls (83.6%±11.4%). Patients with ESRD exhibited higher odor threshold than the remaining participants exhibited. All groups had similar scores for subjective smell assessment. In multivariable adjusted analyses, kidney disease associated with increased odds of odor identification deficits (odds ratio, 4.80; 95% confidence interval, 1.94 to 11.89). A reduction in odor identification score was associated with higher subjective global assessment score and lower serum total cholesterol, LDL cholesterol, and albumin concentrations. We found no associations between odor threshold and nutritional parameters. In a proof of concept, 6-week, open-label clinical trial, intranasal theophylline (an epithelial membrane transport and proton secretion activator) increased odor identification score in five out of seven (71%) patients with ESRD. In conclusion, patients with kidney disease have olfactory deficits that may influence their nutritional status. Our preliminary results regarding olfactory improvement using intranasal theophylline warrant confirmation in a randomized controlled trial.

Cerebral vascular structure in the motor cortex of adult mice is stable and is not altered by voluntary exercise.

The cerebral vasculature provides blood flow throughout the brain, and local changes in blood flow are regulated to match the metabolic demands of the active brain regions. This neurovascular coupling is mediated by real-time changes in vessel diameter and depends on the underlying vascular network structure. Neurovascular structure is configured during development by genetic and activity-dependent factors. In adulthood, it can be altered by experiences such as prolonged hypoxia, sensory deprivation and seizure. Here, we have sought to determine whether exercise could alter cerebral vascular structure in the adult mouse. We performed repeated in vivo two-photon imaging in the motor cortex of adult transgenic mice expressing membrane-anchored green fluorescent protein in endothelial cells (tyrosine endothelial kinase 2 receptor (Tie2)-Cre:mTmG). This strategy allows for high-resolution imaging of the vessel walls throughout the lifespan. Vascular structure, as measured by capillary branch point number and position, segment diameter and length remained stable over a time scale of months as did pericyte number and position. Furthermore, we compared the vascular structure before, during, and after periods of voluntary wheel running and found no alterations in these same parameters. In both running and control mice, we observed a low rate of capillary segment subtraction. Interestingly, these rare subtraction events preferentially remove short vascular loops.

Regrowth of Serotonin Axons in the Adult Mouse Brain Following Injury.

It is widely believed that damaged axons in the adult mammalian brain have little capacity to regrow, thereby impeding functional recovery after injury. Studies using fixed tissue have suggested that serotonin neurons might be a notable exception, but remain inconclusive. We have employed in vivo two-photon microscopy to produce time-lapse images of serotonin axons in the neocortex of the adult mouse. Serotonin axons undergo massive retrograde degeneration following amphetamine treatment and subsequent slow recovery of axonal density, which is dominated by new growth with little contribution from local sprouting. A stab injury that transects serotonin axons running in the neocortex is followed by local regression of cut serotonin axons and followed by regrowth from cut ends into and across the stab rift zone. Regrowing serotonin axons do not follow the pathways left by degenerated axons. The regrown axons release serotonin and their regrowth is correlated with recovery in behavioral tests.

Shear wave elastography in chronic kidney disease: a pilot experience in native kidneys.

BACKGROUND: There currently is a need for a non-invasive measure of renal fibrosis. We aim to explore whether shear wave elastography (SWE)-derived estimates of tissue stiffness may serve as a non-invasive biomarker that can distinguish normal and abnormal renal parenchymal tissue. METHODS: Participants with CKD (by estimated GFR) and healthy volunteers underwent SWE. Renal elasticity was estimated as Young's modulus (YM) in kilopascals (kPa). Univariate Wilcoxon rank-sum tests were used. RESULTS: Twenty-five participants with CKD (median GFR 38 mL/min; quartile 1, quartile 3 28, 42) and 20 healthy controls without CKD underwent SWE performed by a single radiologist. CKD was associated with increased median YM (9.40 [5.55, 22.35] vs. 4.40 [3.68, 5.70] kPa; p = 0.002) and higher median intra-subject inter-measurement estimated YM's variability (4.27 [2.89, 9.90] vs. 1.51 [1.21, 2.05] kPa; p < 0.001). CONCLUSIONS: SWE-derived estimates of renal stiffness and intra-subject estimated stiffness variability are higher in patients with CKD than in healthy controls. Renal fibrosis is a plausible explanation for the observed difference in YM. Further studies are required to determine the relationship between YM, estimated renal stiffness, and renal fibrosis severity.

PGC-1α provides a transcriptional framework for synchronous neurotransmitter release from parvalbumin-positive interneurons.

Accumulating evidence strongly implicates the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in the pathophysiology of multiple neurological disorders, but the downstream gene targets of PGC-1α in the brain have remained enigmatic. Previous data demonstrate that PGC-1α is primarily concentrated in inhibitory neurons and that PGC-1α is required for the expression of the interneuron-specific Ca(2+)-binding protein parvalbumin (PV) throughout the cortex. To identify other possible transcriptional targets of PGC-1α in neural tissue, we conducted a microarray on neuroblastoma cells overexpressing PGC-1α, mined results for genes with physiological relevance to interneurons, and measured cortical gene and protein expression of these genes in mice with underexpression and overexpression of PGC-1α. We observed bidirectional regulation of novel PGC-1α-dependent transcripts spanning synaptic [synaptotagmin 2 (Syt2) and complexin 1 (Cplx1)], structural [neurofilament heavy chain (Nefh)], and metabolic [neutral cholesterol ester hydrolase 1 (Nceh1), adenylate kinase 1 (Ak1), inositol polyphosphate 5-phosphatase J (Inpp5j), ATP synthase mitochondrial F1 complex O subunit (Atp5o), phytanol-CoA-2hydroxylase (Phyh), and ATP synthase mitrochondrial F1 complex α subunit 1 (Atp5a1)] functions. The neuron-specific genes Syt2, Cplx1, and Nefh were developmentally upregulated in an expression pattern consistent with that of PGC-1α and were expressed in cortical interneurons. Conditional deletion of PGC-1α in PV-positive neurons significantly decreased cortical transcript expression of these genes, promoted asynchronous GABA release, and impaired long-term memory. Collectively, these data demonstrate that PGC-1α is required for normal PV-positive interneuron function and that loss of PGC-1α in this interneuron subpopulation could contribute to cortical dysfunction in disease states.

Expansion and somatic hypermutation of B-cell clones in rejected human kidney grafts.

BACKGROUND: B-cell infiltrates are common in rejected kidney allografts, yet their composition is still unclear. The aim of our study was to characterize the clonal composition of B-cell infiltrates of rejected human kidney grafts. METHODS: We used a molecular approach to characterize the partial B-cell repertoires of 5 failed human kidney grafts with detectable B-cell infiltrates. A comparison between the intragraft and blood repertoire was also conducted for 1 case. RESULTS: Redundant sequences were observed in both blood and graft, although the level of clonal amplification was significantly higher for the graft. Somatic hypermutations (SHMs) were also more frequent in sequences found in the graft compared to the blood. The rate of nonsilent mutations was significantly higher in complementarity determining regions (CDRs) compared to framework regions in blood sequences as well as in graft sequences found at low frequency. In contrast, this preferential distribution was lost in sequences found at high frequency in the graft, suggesting a lack of affinity maturation in situ. Lastly, follicular dendritic cells were undetectable in CD20 infiltrates in all samples examined. CONCLUSIONS: We provide here evidence that B-cell clones expand and undergo SHMs in situ. However, the even distribution of nonsilent SHM in high-frequency graft sequences together with the absence of follicular dendritic cells do not support the view that infiltrating B cells are part of functional germinal centers.

Cerebellar transcriptional alterations with Purkinje cell dysfunction and loss in mice lacking PGC-1α.

Alterations in the expression and activity of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (ppargc1a or PGC-1α) have been reported in multiple movement disorders, yet it is unclear how a lack of PGC-1α impacts transcription and function of the cerebellum, a region with high PGC-1α expression. We show here that mice lacking PGC-1α exhibit ataxia in addition to the previously described deficits in motor coordination. Using q-RT-PCR in cerebellar homogenates from PGC-1α(-/-) mice, we measured expression of 37 microarray-identified transcripts upregulated by PGC-1α in SH-SY5Y neuroblastoma cells with neuroanatomical overlap with PGC-1α or parvalbumin (PV), a calcium buffer highly expressed by Purkinje cells. We found significant reductions in transcripts with synaptic (complexin1, Cplx1; Pacsin2), structural (neurofilament heavy chain, Nefh), and metabolic (isocitrate dehydrogenase 3a, Idh3a; neutral cholesterol ester hydrolase 1, Nceh1; pyruvate dehydrogenase alpha 1, Pdha1; phytanoyl-CoA hydroxylase, Phyh; ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, Uqcrfs1) functions. Using conditional deletion of PGC-1α in PV-positive neurons, we determined that 50% of PGC-1α expression and a reduction in a subset of these transcripts could be explained by its concentration in PV-positive neuronal populations in the cerbellum. To determine whether there were functional consequences associated with these changes, we conducted stereological counts and spike rate analysis in Purkinje cells, a cell type rich in PV, from PGC-1α(-/-) mice. We observed a significant loss of Purkinje cells by 6 weeks of age, and the remaining Purkinje cells exhibited a 50% reduction in spike rate. Together, these data highlight the complexity of PGC-1α's actions in the central nervous system and suggest that dysfunction in multiple cell types contribute to motor deficits in the context of PGC-1α deficiency.

Hunger strikers: ethical and legal dimensions of medical complicity in torture at Guantanamo Bay.

Physicians and other licensed health professionals are involved in force-feeding prisoners on hunger strike at the US Naval Base at Guantanamo Bay (GTMO), Cuba, the detention center established to hold individuals captured and suspected of being terrorists in the wake of September 11, 2001. The force-feeding of competent hunger strikers violates medical ethics and constitutes medical complicity in torture. Given the failure of civilian and military law to end the practice, the medical profession must exert policy and regulatory pressure to bring the policy and operations of the US Department of Defense into compliance with established ethical standards. Physicians, other health professionals, and organized medicine must appeal to civilian state oversight bodies and federal regulators of medical science to revoke the licenses of health professionals who have committed prisoner abuses at GTMO.

Point-of-Care HIV Testing and Linkage in an Urban Cohort in the Southern US.

The Southern states experience the highest rates of HIV and AIDS in the US, and point-of-care (POC) testing outside of primary care may contribute to status awareness in medically underserved populations in this region. To evaluate POC screening and linkage to care at an urban south site, analyses were performed on a dataset of 3,651 individuals from an integrated rapid-result HIV testing and linkage program to describe this test-seeking cohort and determine trends associated with screening, results, and linkage to care. Four percent of the population had positive results. We observed significant differences by test result for age, race and gender, reported risk behaviors, test location, and motivation for screening. The overall linkage rate was 86%, and we found significant differences for clients who were linked to HIV care versus persons whose linkage could not be confirmed with respect to race and gender, location, and motivation. The linkage rate for POC testing that included a comprehensive intake visit and colocated primary care services for in-state residents was 97%. Additional research on integrated POC screening and linkage methodologies that provide intake services at time of testing is essential for increasing status awareness and improving linkage to HIV care in the US.

Developmental alterations in motor coordination and medium spiny neuron markers in mice lacking pgc-1α.

Accumulating evidence implicates the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α) in the pathophysiology of Huntington Disease (HD). Adult PGC-1α (-/-) mice exhibit striatal neurodegeneration, and reductions in the expression of PGC-1α have been observed in striatum and muscle of HD patients as well as in animal models of the disease. However, it is unknown whether decreased expression of PGC-1α alone is sufficient to lead to the motor phenotype and striatal pathology characteristic of HD. For the first time, we show that young PGC-1α (-/-) mice exhibit severe rotarod deficits, decreased rearing behavior, and increased occurrence of tremor in addition to the previously described hindlimb clasping. Motor impairment and striatal vacuolation are apparent in PGC-1α (-/-) mice by four weeks of age and do not improve or decline by twelve weeks of age. The behavioral and pathological phenotype of PGC-1α (-/-) mice can be completely recapitulated by conditional nervous system deletion of PGC-1α, indicating that peripheral effects are not responsible for the observed abnormalities. Evaluation of the transcriptional profile of PGC-1α (-/-) striatal neuron populations and comparison to striatal neuron profiles of R6/2 HD mice revealed that PGC-1α deficiency alone is not sufficient to cause the transcriptional changes observed in this HD mouse model. In contrast to R6/2 HD mice, PGC-1α (-/-) mice show increases in the expression of medium spiny neuron (MSN) markers with age, suggesting that the observed behavioral and structural abnormalities are not primarily due to MSN loss, the defining pathological feature of HD. These results indicate that PGC-1α is required for the proper development of motor circuitry and transcriptional homeostasis in MSNs and that developmental disruption of PGC-1α leads to long-term alterations in motor functioning.