The autonomic nerves around the vein of Marshall: a postmortem study with clinical implications

This study aims to analyze the vein of Marshall (VOM) in human autopsy hearts and its correlation with clinical data to elucidate the morphological substrates of atrial fibrillation (AF) and other cardiac diseases. Twenty-three adult autopsy hearts were studied, assessing autonomic nerves by immunohistochemistry with tyrosine hydroxylase (sympathetic nerves), choline acetyltransferase (parasympathetic nerves), growth-associated protein 43 (neural growth), and S100 (general neural marker) antibodies. Interstitial fibrosis was assessed by Masson trichrome staining. Measurements were conducted via morphometric software. The results were correlated with clinical data. Sympathetic innervation was abundant in all VOM-adjacent regions. Subjects with a history of AF, cardiovascular cause of death, and histologically verified myocardial infarction had increased sympathetic innervation and neural growth around the VOM at the mitral isthmus. Interstitial fibrosis increased with age and heart weight was associated with AF and cardiovascular cause of death. This study increases our understanding of the cardiac autonomic innervation in the VOM area in various diseases, offering implications for the development of new therapeutic approaches targeting the autonomic nervous system.

Quantification of the intrinsic neural plexus of the heart - The missing link in histological tissue analysis

BACKGROUND AND OBJECTIVE

The heart is under strict regulation of the autonomic nervous system, during which, in a healthy state, the effects of sympathetic and parasympathetic branches are balanced. In recent years, there has been increasing interest in pathological remodeling and outgrowth of cardiac autonomic nerves in relation to arrhythmogenesis. However, the small size of the cardiac nerves in relatively large tissues renders research using histological quantification of these nerves extremely challenging and usually relies on quantification of the nerve density in selected regions of interest only. Our aim was to develop a method to be able to quantify the histological nerve density in transmural tissue sections.

METHODS

Here we describe a novel workflow that enables visualization and quantification of variable innervation types and their heterogeneity within transmural myocardial tissue sections. A custom semiautomatic workflow for the quantification of cardiac nerves involving Python, MATLAB and ImageJ is provided and described in this protocol in a stepwise and detailed manner.

REPRESENTATIVE RESULTS

The results of two example tissue sections are represented in this paper. An example tissue section taken from the infarction core with a high heterogeneity value of 0.20, 63.3% normal innervation, 12.2% hyperinnervation, 3.6% hypoinnervation and 21.0% denervation. The second example tissue section taken from an area of the left ventricle remote from the infarction showed a low heterogeneity value of 0.02, 95.3% normal innervation, 3.8% hyperinnervation, 0.5% hypoinnervation and 0.5% denervation.

CONCLUSIONS

This approach has the potential to be broadly applied to any research involving high-resolution imaging of nerves in large tissues.

Nerves in cancer

The contribution of nerves to the pathogenesis of malignancies has emerged as an important component of the tumour microenvironment. Recent studies have shown that peripheral nerves (sympathetic, parasympathetic and sensory) interact with tumour and stromal cells to promote the initiation and progression of a variety of solid and haematological malignancies. Furthermore, new evidence suggests that cancers may reactivate nerve-dependent developmental and regenerative processes to promote their growth and survival. Here we review emerging concepts and discuss the therapeutic implications of manipulating nerves and neural signalling for the prevention and treatment of cancer.

Targeting Ligands Deliver Model Drug Cargo into the Central Nervous System along Autonomic Neurons

While biologic drugs such as proteins, peptides, or nucleic acids have shown promise in the treatment of neurodegenerative diseases, the blood-brain barrier (BBB) severely limits drug delivery to the central nervous system (CNS) after systemic administration. Consequently, drug delivery challenges preclude biological drug candidates from the clinical armamentarium. In order to target drug delivery and uptake into to the CNS, we used an in vivo phage display screen to identify peptides able to target drug-uptake by the vast array of neurons of the autonomic nervous system (ANS). Using next-generation sequencing, we identified 21 candidate targeted ANS-to-CNS uptake ligands (TACL) that enriched bacteriophage accumulation and delivered protein-cargo into the CNS after intraperitoneal (IP) administration. The series of TACL peptides were synthesized and tested for their ability to deliver a model enzyme (NeutrAvidin-horseradish peroxidase fusion) to the brain and spinal cord. Three TACL-peptides facilitated significant active enzyme delivery into the CNS, with limited accumulation in off-target organs. Peptide structure and serum stability is increased when internal cysteine residues are cyclized by perfluoroarylation with decafluorobiphenyl, which increased delivery to the CNS further. TACL-peptide was demonstrated to localize in parasympathetic ganglia neurons in addition to neuronal structures in the hindbrain and spinal cord. By targeting uptake into ANS neurons, we demonstrate the potential for TACL-peptides to bypass the blood-brain barrier and deliver a model drug into the brain and spinal cord.

Cutaneous somatic and autonomic nerve TDP-43 deposition in amyotrophic lateral sclerosis

OBJECTIVE

To evaluate the involvement of the sensory and autonomic nervous system in amyotrophic lateral sclerosis (ALS) and to determine whether TDP-43/pTDP-43 deposits in skin nerve fibers signify a valuable biomarker for ALS.

METHODS

Eighteen patients with ALS and 18 age- and sex-matched control subjects underwent physical examinations, in addition to donating skin biopsies from the distal leg. The density of epidermal, Meissner's corpuscle (MC), sudomotor, and pilomotor nerve fibers were measured. Confocal microscopy was used to determine the cutaneous somatic and autonomic nerve fiber density and TDP-43/pTDP-43 deposition.

RESULTS

Intraepidermal nerve fiber density (IENFD) was reduced in individuals with ALS (P < 0.001). MC density (MCD) (P = 0.001), sweat gland nerve fiber density (SGNFD) (P < 0.001), and pilomotor nerve fiber density (PNFD) (P < 0.001) were all reduced in ALS patients. The SGNFD correlated with the small-fiber neuropathy Symptoms Inventory Questionnaire (SFN-SIQ), VAS and age. The SFN-SIQ was higher in ALS with sensory symptoms than without sensory symptoms (P = 0.000). Furthermore, the SFN-SIQ was higher in ALS with autonomic symptoms than without autonomic symptoms (P = 0.002). SFN-SIQ was higher in ALS patients that were pTDP-43 positive than pTDP-43 negative (P = 0.04), respectively.

CONCLUSIONS

We established in the peripheral nervous system that higher SFN-SIQ and VAS was involved in ALS, indicating the loss of SGNF. The deposition of TDP-43/pTDP-43 in ALS nerve fibers may indicate an important role in the underlying pathogenesis of ALS. This observation might be used as a potential biomarker for diagnosing ALS.

Long-Term Improvement of Neurological Signs and Metabolic Dysfunction in a Mouse Model of Krabbe's Disease after Global Gene Therapy

We report a global adeno-associated virus (AAV)9-based gene therapy protocol to deliver therapeutic galactosylceramidase (GALC), a lysosomal enzyme that is deficient in Krabbe's disease. When globally administered via intrathecal, intracranial, and intravenous injections to newborn mice affected with GALC deficiency (twitcher mice), this approach largely surpassed prior published benchmarks of survival and metabolic correction, showing long-term protection of demyelination, neuroinflammation, and motor function. Bone marrow transplantation, performed in this protocol without immunosuppressive preconditioning, added minimal benefits to the AAV9 gene therapy. Contrasting with other proposed pre-clinical therapies, these results demonstrate that achieving nearly complete correction of GALC's metabolic deficiencies across the entire nervous system via gene therapy can have a significant improvement to behavioral deficits, pathophysiological changes, and survival. These results are an important consideration for determining the safest and most effective manner for adapting gene therapy to treat this leukodystrophy in the clinic.

In vivo corneal confocal microscopy as a novel non-invasive tool to investigate cardiac autonomic neuropathy in Type 1 diabetes

AIMS

To investigate whether small nerve fibre degeneration detected using corneal confocal microscopy is associated with cardiac autonomic neuropathy in people with Type 1 diabetes.

METHODS

Thirty-six people with Type 1 diabetes and 20 age- and sex-matched healthy control subjects were enrolled. Tests to determine heart rate response to deep-breathing (expiratory-to-inspiratory ratio), heart rate response to lying-to-stand test (30:15 ratio) and blood pressure response to standing were performed to detect cardiac autonomic neuropathy. Corneal confocal microscopy was performed to assess: corneal nerve density and corneal nerve beadings; branching pattern; and nerve fibre tortuosity.

RESULTS

Compared with control participants, participants with Type 1 diabetes had fewer (mean ± SD 45.4 ± 20.2 vs 92.0 ± 22.7 fibres/mm²; P < 0.001) and more tortuous corneal nerve fibres (20 participants with Type 1 diabetes vs four control participants had nerve tortuosity grade 2/3; P = 0.022) and fewer beadings (mean ± SD 15.1 ± 3.5 vs 20.6 ± 5.0; P < 0.001). Of the participants with Type 1 diabetes, 11 met the criteria for the diagnosis of cardiac autonomic neuropathy. Corneal nerve density was significantly lower in participants with cardiac autonomic neuropathy than in those without (mean ± SD 32.8 ± 16.4 vs 51.7 ± 18.9 fibres/mm²; P = 0.008). This difference remained significant after adjustment for age (P = 0.02), gender (P = 0.04), disease duration (P = 0.005), insulin requirement (P = 0.02) and neuropathy disability score (P = 0.04).

CONCLUSION

This study suggests that corneal confocal microscopy could represent a new and non-invasive tool to investigate cardiac autonomic neuropathy in people with Type 1 diabetes. Larger studies are required to define the role of corneal confocal microscopy in the assessment of cardiac autonomic neuropathy.

Oxidative stress predicts progression of peripheral and cardiac autonomic nerve dysfunction over 6 years in diabetic patients

Oxidative stress is implicated in the pathogenesis of experimental diabetic neuropathy, but prospective studies in diabetic patients are lacking. We aimed to evaluate whether the plasma levels of various biomarkers of oxidative stress predict the progression of diabetic neuropathy and mortality over 6 years. We followed 89 diabetic patients aged 54 ± 14 years (59 % with polyneuropathy), 72 of whom underwent nerve function reassessment after 6.2 ± 0.8 years, whereas 17 died after 4.2 ± 1.0 years. Plasma markers of oxidative stress at baseline included superoxide anion, hypochlorous acid, peroxynitrite, 8-iso-prostaglandin F2α, vitamin E/lipid ratio, and vitamin C. Neuropathy was assessed by symptoms and deficits, motor and sensory nerve conduction velocity (MNCV, SNCV), vibration perception thresholds (VPT), thermal detection thresholds, and heart rate variability (HRV). Despite a reduction in HbA1c by 1.4 ± 1.6 % (p < 0.001), median SNCV, sural SNCV, peroneal MNCV, malleolar VPT, and warm TDT deteriorated after 6 years (all p < 0.05). In multivariate models, increased superoxide generation was associated with a decline in median SNCV (β = -0.997; p = 0.036) and deterioration in HRV at rest (OR 1.63 [95 % CI 1.09-2.44]; p = 0.017) over 6 years. Low vitamin E/lipid ratio tended to predict a decrease in peroneal MNCV (β = 0.781; p = 0.057) and an increase in malleolar VPT (β = -0.725; p = 0.077). Plasma superoxide generation was associated with an increased risk of mortality (HR 23.2 [95 % CI 1.05-513]; p = 0.047). In conclusion, increased plasma superoxide generation predicted the decline in sensory and cardiac autonomic nerve function and mortality over 6 years in diabetic patients, but larger studies are required for confirmation.

Exposure to traffic pollution, acute inflammation and autonomic response in a panel of car commuters

BACKGROUND

Exposure to traffic pollution has been linked to numerous adverse health endpoints. Despite this, limited data examining traffic exposures during realistic commutes and acute response exists.

OBJECTIVES

We conducted the Atlanta Commuters Exposures (ACE-1) Study, an extensive panel-based exposure and health study, to measure chemically-resolved in-vehicle exposures and corresponding changes in acute oxidative stress, lipid peroxidation, pulmonary and systemic inflammation and autonomic response.

METHODS

We recruited 42 adults (21 with and 21 without asthma) to conduct two 2-h scripted highway commutes during morning rush hour in the metropolitan Atlanta area. A suite of in-vehicle particulate components were measured in the subjects' private vehicles. Biomarker measurements were conducted before, during, and immediately after the commutes and in 3 hourly intervals after commutes.

RESULTS

At measurement time points within 3h after the commute, we observed mild to pronounced elevations relative to baseline in exhaled nitric oxide, C-reactive-protein, and exhaled malondialdehyde, indicative of pulmonary and systemic inflammation and oxidative stress initiation, as well as decreases relative to baseline levels in the time-domain heart-rate variability parameters, SDNN and rMSSD, indicative of autonomic dysfunction. We did not observe any detectable changes in lung function measurements (FEV1, FVC), the frequency-domain heart-rate variability parameter or other systemic biomarkers of vascular injury. Water soluble organic carbon was associated with changes in eNO at all post-commute time-points (p<0.0001).

CONCLUSIONS

Our results point to measureable changes in pulmonary and autonomic biomarkers following a scripted 2-h highway commute.

Screening for the high-risk foot of ulceration: tests of somatic and autonomic nerve function

Diabetic foot ulcers affect almost 5% of the patients with diabetes and carry a huge physical, emotional, and financial burden. Almost 80% of amputations in patients with diabetes are preceded by a foot ulcer. The need for simple screening methods for prevention of foot ulcers and amputations is indisputable. Simple tests such as monofilament, tuning fork, vibration perception threshold determination, ankle reflexes, and pinprick sensation alone or in combination have been studied prospectively and can be used for identification of patients at risk. Newer tests examining sudomotor dysfunction and skin dryness have been introduced in recent years. In cross-sectional studies sudomotor dysfunction assessed by either sympathetic skin response or NEUROPAD™ (Miro Verbandstoffe GmbH, Wiehl-Drabenderhöhe, Germany) testing has been consistently associated with foot ulceration. In addition, NEUROPAD™ testing is simple, reproducible, and widely available and has a high sensitivity for the diagnosis of clinical or subclinical diabetic polyneuropathy. Prospective studies are required to establish whether sudomotor dysfunction can predict foot ulcers and if simple methods assessing sudomotor dysfunction (eg, NEUROPAD™ testing) can be included in the screening tests for the prevention of this complication.

A neuroanatomical dissociation for emotion induced by music

Does feeling an emotion require changes in autonomic responses, as William James proposed? Can feelings and autonomic responses be dissociated? Findings from cognitive neuroscience have identified brain structures that subserve feelings and autonomic response, including those induced by emotional music. In the study reported here, we explored whether feelings and autonomic responses can be dissociated by using music, a stimulus that has a strong capacity to induce emotional experiences. We tested two brain regions predicted to be differentially involved in autonomic responsivity (the ventromedial prefrontal cortex) and feeling (the right somatosensory cortex). Patients with damage to the ventromedial prefrontal cortex were impaired in their ability to generate skin-conductance responses to music, but generated normal judgments of their subjective feelings in response to music. Conversely, patients with damage to the right somatosensory cortex were impaired in their self-rated feelings in response to music, but generated normal skin-conductance responses to music. Control tasks suggested that neither impairment was due to basic defects in hearing the music or in cognitively recognizing the intended emotion of the music. The findings provide evidence for a double dissociation between feeling emotions and autonomic responses to emotions, in response to music stimuli.

Small-fiber involvement in spinobulbar muscular atrophy (Kennedy's disease)

We assessed the involvement of cutaneous innervation in two subjects with a molecularly confirmed diagnosis of spinobulbar muscular atrophy (SBMA) using antidromic nerve conduction studies, quantitative sensory testing, and sweat tests, as well as immunohistochemical techniques and confocal microscopy of glabrous and hairy skin biopsy. Both patients showed a marked reduction in amplitude of sensory action potentials and moderate or severe abnormalities of tactile thresholds and mechanical pain perception. A severe reduction of sweat drops on the Silastic imprint test and a widespread loss of small myelinated and unmyelinated fibers in hairy skin were also observed. Fiber loss involved either somatic or autonomic fibers and did not show any distal-proximal gradient. These results, together with loss of Meissner corpuscles and their large myelinated afferent fibers in glabrous skin, confirmed the extensive involvement of sensory neurons of large and small size and revealed an autonomic skin denervation in SBMA.

The cardiac R-R variation and sympathetic skin response in the intensive care unit

BACKGROUND AND PURPOSE

The central and peripheral nervous systems are often affected in intensive care unit (ICU) patients, especially those with prolonged assisted ventilation and sepsis or systemic inflammatory response syndrome (SIRS). The autonomic nervous system, however, has been under-investigated in such patients. We evaluated autonomic nervous system (ANS) function in 29 ICU patients with various neurological disorders.

METHODS

Testing involved cardiac R-R variation (CRRV) as an index of parasympathetic function and the sympathetic skin response (SSR) for sympathetic assessment.

RESULTS

Only those 8 patients with sepsis-related neuropathy or encephalopathy had abnormal CRRV, while the SSR was absent in all but 2 patients.

CONCLUSIONS

Our preliminary study revealed a high incidence of autonomic dysfunction in ICU patients with various neurological disorders.

Morphological substrate of autonomic failure and neurohormonal dysfunction in multiple system atrophy: impact on determining phenotype spectrum

Autonomic failure is a prominent clinical feature of patients with multiple system atrophy (MSA). Neurohormonal dysfunction is also a frequent accompaniment in patients with MSA. The determination of the pathological involvement of the autonomic neurons, which are responsible for circadian rhythms and responses to stress, provides new insight into autonomic failure and neurohormonal dysfunction in MSA. The disruptions of circadian rhythms and responses to stress may underlie the impairment of homeostatic integration responsible for cardiovascular and respiratory failures. These notions lead to the hypothesis that a pathological involvement of autonomic neurons is a significant factor of the poor prognosis of MSA. Beyond this perspective, endeavors to find the morphological phenotype that represents a predominant loss of autonomic neurons may elucidate the full spectrum of pathological involvements in MSA.

Patient-reported autonomic symptoms in Parkinson disease

OBJECTIVE

There is a wide range of autonomic symptoms (AS) in Parkinson disease (PD), but the full spectrum has never been evaluated with a validated instrument and in comparison with control subjects. In this study a reliable and valid instrument, the SCOPA-AUT, was used to evaluate the occurrence of AS in a large cohort of patients with PD and control subjects and to assess the relations with demographic, disease-related, and clinical variables.

METHODS

A cohort of 420 patients with PD was evaluated for the occurrence of AS, motor and nonmotor symptoms, as well as for demographic and disease-related characteristics. Results were compared with those of 150 control subjects. Associations between AS and demographic and clinical characteristics were also studied.

RESULTS

For all autonomic domains, patients with PD reported more symptoms compared to control subjects, with the greatest differences in the gastrointestinal and urinary domain. Higher age, greater disease severity, and higher doses of dopaminergic medication were related to more autonomic problems. Autonomic symptom severity was associated with more motor dysfunction, depressive symptoms, cognitive dysfunction, psychiatric complications, nighttime sleep disturbances, and excessive daytime sleepiness (all p values < 0.01).

CONCLUSIONS

Autonomic symptoms (AS) are an important feature of Parkinson disease (PD) and increase with age, disease severity, and medication use. The prominent presence of AS warrants increased clinical awareness and highlights the need for efficacious therapies for the wide spectrum of problems related to this domain of PD.

Evaluation of cutaneous autonomic innervation in idiopathic sensory small-fiber neuropathy

To evaluate the loss of autonomic nerve fibers in patients with clinical pure small-fiber sensory neuropathy, we performed skin punch biopsies in 17 and 15 age- and sex-matched controls. Biopsies were taken 10 cm above the lateral malleolus, and 5-mum sections were stained with hematoxylin and eosin and the panaxonal marker protein gene product (PGP) 9.5. Positively stained fibers, represented as dots, innervating the erector pili muscles, arterioles, and sweat glands (SG) were counted. The ratios between the number of nerve fibers and nuclei of each structure were calculated. The autonomic innervation was significantly reduced in the patients' group compared with controls in all the examined autonomic-innervated structures: SG (0.27 +/- 0.15 vs. 0.66 +/- 0.37, p = 0.001), arterioles (0.38 +/- 0.32 vs. 0.86 +/- 0.45, p=0.002), and the erector pili muscle (0.58 +/- 0.27 vs. 1.23 +/- 0.87, p = 0.036). Our results suggest that autonomic involvement occurs in patients with sensory small-fiber neuropathy and that punch skin biopsy using thin sections is a simple and convenient method to detect these dermal autonomic small-fiber abnormalities.

Vesicouterine ligament contains abundant autonomic nerve ganglion cells: the distribution in histology concerning nerve-sparing radical hysterectomy

The aim of this study is to describe the histologic architecture of the tissues corresponding to the surgically developed connective tissue bundle commonly referred to as the posterior leaf of the vesico-uterine ligament (VUL), and to examine distribution of ganglion cells. Serial macroscopic slices, each 15-20 mm in thickness, were made from eight specimens (obtained from six female elderly cadavers). In these macroslices, the location of the deep uterine vein was used to identify the deep leaf of the VUL. The specimens were trimmed and semi-serial histologic sections in thickness were prepared at 1 mm intervals. Vesical veins and the associated nerve elements were enclosed by fascia and formed a common pedicle. The base of the pedicle contained the deep uterine vein trunk. The fascia encircling the pedicle varied in thickness and connective intensity between specimens. This vesical neurovascular bundle contained abundant ganglion cells. On average, 48.0% of the ganglion cells along the vesical tributaries of the deep uterine vein were located on the medial or vaginal side of the veins, 19.2% were located between veins, 13.0% on the lateral side of the veins, and 19.8% on the dorsal side. The interindividual variability was greatest on the dorsal side of vesical veins and ranged 11-202 cells. We conclude that in order to achieve maximal preservation of the ganglion cells during the surgical dissection of the posterior leaf of the VUL, care must be taken when the medial or vesical aspect of the ligament is separated. The standard nerve-sparing radical hysterectomy should be modified to reflect differences in the distribution of ganglion cells and in connective intensity between ganglions and veins.

The progression of Parkinson disease

Recent neuropathologic studies suggest that Parkinson disease (PD) does not begin in the substantia nigra compacta (SNc) but only involves this region later in the course of the disease. It is proposed that once the SNc is affected by the original pathobiological process (for example, protein aggregation), additional processes more specific to dopaminergic neurons are triggered (including sources of oxidative stress such as increased dopamine turnover, reduced levels of reduced glutathione, increased iron, and the presence of neuromelanin, as well as altered calcium homeostasis and excitotoxicity). This results in an acceleration of cell loss in the SNc, causing nigrostriatal degeneration to both reach a threshold for symptoms in advance of earlier affected brain areas and progress more rapidly than other aspects of the disease. Neuroprotective therapy directed solely at more general biologic processes may not have sufficient effects on this accelerated degeneration in the SNc, while neuroprotective therapy designed exclusively to slow the progression of dopaminergic cell loss will not alter the progression of the nondopaminergic symptoms that contribute the greatest disability in the later stages of the disease. Effective disease-modifying therapy may require a cocktail combining treatments designed to address the basic mechanisms of the neurodegeneration and the additional biologic processes specific to the dopaminergic SNc. This hypothesis has implications for the development of disease-modifying therapy and the interpretation of endpoints of clinical trials evaluating the efficacy of such treatments.

Fatal familial insomnia and agrypnia excitata

This review summarizes the pioneering steps culminating in the identification of a novel disease, fatal familial insomnia (FFI), a hereditary prion disease. Together with Morvan's chorea and delirium tremens, FFI is characterized by an inability to sleep associated with motor and autonomic overactivation. We named this pattern agrypnia excitata, a syndrome caused by a dysfunction in thalamolimbic circuits. This review highlights the strategic role of the limbic thalamus in the central autonomic network running from the limbic cortex to the lower brainstem and regulating sleep and wakefulness.

Age-related changes in myocardial nerve and collagen networks of the auricle of the right atrium

OBJECTIVE

The objective of this study was to analyse age-related changes in human myocardial nerve plexuses and collagen networks of the auricle of the right atrium in subjects in whom no cardiac diseases or pathology had been diagnosed.

METHODS AND RESULTS

Morphometric analysis of acetylcholinesterase (AChE)-stained nerve plexuses and picrosirius-stained cardiac collagen networks from 17 persons of both genders aged 20-94 years was performed using video microscopy and a digital video camera. It was found that with age linear regression of nerve plexuses occurred.Atrial collagen content increases lifelong.

CONCLUSION

Aging of human atrial myocardium is accompanied by a decrease of nerve plexuses and an increase in fibrosis.

Effects of spinal cord injury on synaptic inputs to sympathetic preganglionic neurons

Spinal cord injuries often lead to disorders in the control of autonomic function, including problems with blood pressure regulation, voiding, defecation and reproduction. The root cause of all these problems is the destruction of brain pathways that control spinal autonomic neurons lying caudal to the lesion. Changes induced by spinal cord injuries have been most extensively studied in sympathetic preganglionic neurons, cholinergic autonomic neurons with cell bodies in the lateral horn of thoracic and upper lumbar spinal cord that are the sources of sympathetic outflow. After an injury, sympathetic preganglionic neurons in mid-thoracic cord show plastic changes in their morphology. There is also extensive loss of synaptic input from the brain, leaving these neurons profoundly denervated in the acute phase of injury. Our recent studies on sympathetic preganglionic neurons in lower thoracic and upper lumbar cord that regulate the pelvic viscera suggest that these neurons are not so severely affected by spinal cord injury. Spinal interneurons appear to contribute most of the synaptic input to these neurons so that injury does not result in extensive denervation. Since intraspinal circuitry remains intact after injury, drug treatments targeting these neurons should help to normalize sympathetically mediated pelvic visceral reflexes. Furthermore, sympathetic pelvic visceral control may be more easily restored after an injury because it is less dependent on the re-establishment of direct synaptic input from regrowing brain axons.

[Innervation of adrenal glands in some types of cardiovascular pathology]

We examined adrenal glands obtained at early autopsy of 56 men aged 21-70 years. According to the age five groups of cases were distinguished. The study was performed with the use of methods of silver impregnation of nerve plexuses and planimetric pointcounting. Density of nerve plexuses in adrenal medulla was significantly increased by 30 years of age due to the development of nervous relations in this organ. After age of 30 years density of nerve plexuses in adrenal medulla remained relatively stable providing high morphofunctional activity of adrenal glands. Morphological and morphometrical changes in nervous plexuses of adrenal medulla of patients were associated with cardiovascular diseases.

Gastrointestinal symptoms related to autonomic dysfunction following spinal cord injury

The impact of spinal cord injury on an individual's gastrointestinal tract function is often poorly understood by the general public and also by those involved with persons with spinal cord injury. This chapter reviews the anatomy, physiology and function of the gastrointestinal tract, with particular emphasis on neurological control mechanisms. In turn, it relates the effect that spinal cord injury has on the neurological control of the gastrointestinal tract. The symptoms that are encountered by patients in the acute phase following injury, and by individuals in the months/years after injury, with particular reference to the effect of altered autonomic nervous system control of the gastrointestinal tract, are discussed. Together with a following summary of current bowel management regimens and techniques, this chapter aims to provide an overall view of the effect that autonomic dysfunction due to spinal cord injury has on gastrointestinal function.

Cardiotoxicity of digitalis glycosides: roles of autonomic pathways, autacoids and ion channels

1 Cardiac glycosides have been used for centuries as therapeutic agents for the treatment of heart diseases. In patients with heart failure, digoxin and the other glycosides exert their positive inotropic effect by inhibiting Na(+)-K(+)-ATPase, thereby increasing intracellular sodium, which, in turn, inhibits the Na(+)/Ca(2+) exchanger and increases intracellular calcium levels. As the therapeutic index of digitalis is narrow, arrhythmias are common problems in clinical practice. The mechanisms and mediators of these arrhythmias, however, are not completely understood. 2 The involvement of the sympathetic and parasympathetic nervous system in digitalis cardiac toxicity is reviewed. 3 Receptors, channels, exchange systems or other cellular components involved in digitalis-induced cardiotoxicity are also reviewed. 4 Possible mediators of digitalis-induced cardiac toxicity are discussed. 5 Management of digitalis toxicity in patients is summarized. 6 The determination of the possible mediators of digitalis-induced cardiac toxicity will enhance our knowledge and lead to the development of new therapeutic strategies to treat these lethal arrhythmias.

Sexual function after rectal excision

BACKGROUND

Rectal excision is associated with a risk of autonomic nerve damage and associated sexual dysfunction (SD). The evolution of our understanding of the anatomy and physiology of sexual function together with continual refinement of surgery for both benign and malignant disease has led to a decrease in the incidence of SD after rectal surgery. A knowledge of the degree of risk of postoperative SD is important both for the patient and as a benchmark for audit of individual colorectal practice.

METHODS

The available literature on the anatomy, physiology and surgical aspects of this topic has been researched through the Medline database. The more recently available data are reviewed in the context of the historical evolution of surgery for benign and malignant rectal disease.

RESULTS AND CONCLUSIONS

In the best hands, permanent impotence occurs in less than 2% of patients following restorative proctocolectomy and at a similarly low rate after proctocolectomy and ileostomy. Isolated ejaculatory dysfunction is also numerically a minor problem post operation for benign disease. Patient age is the most important predictor of SD after surgery for rectal cancer. The incidence of permanent impotence remains high (>40%) after abdomino-perineal excision of the rectum (APE) but the continued decline in the use of this operation in favour of low anterior resection (LAR), which carries about half the risk of impotence compared to sphincter ablating surgery, is likely to have resulted in a fall in the absolute number of patients rendered impotent as a result of rectal cancer surgery. Anatomical dissection of the pelvis with preservation of the named autonomic fibres results in a low and predictable rate of sexual morbidity. Surgeons could profitably spend more time with their patients discussing the possible effects of surgery on sexual function. Further research is required to determine the effects of adjuvant therapy for rectal cancer on sexual function.

Brainstem in multiple system atrophy: clinicopathological correlations

1. Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder that manifests with parkinsonism, cerebellar ataxia, and autonomic failure in various combinations. 2. Orthostatic hypotension, neurogenic bladder, laryngeal stridor and sleep apnea, and rapid eye movement (REM) sleep behavior disorder are prominent manifestations of MSA. 3. In MSA, there is severe depletion of catecholaminergic neurons of the C1 and A1 areas in the ventrolateral medulla, and this may contribute to orthostatic hypotension and endocrine disturbances in this disorder, respectively. 4. Loss of corticotrophin-releasing factor (CRF) neurons in the pontine micturition area may contribute to neurogenic bladder dysfunction. 5. Respiratory abnormalities may reflect loss of cholinergic neurons in the arcuate nucleus of the ventral medulla. 6. Loss of cholinergic mesopontine neurons, in the setting of loss of locus ceruleus neurons and preservation of rostral raphe neurons, may contribute to REM sleep abnormalities in MSA.

Prospective evaluation of somatic and autonomic small fibers in selected autonomic neuropathies

BACKGROUND

There are a number of distal and generalized small-fiber neuropathies. The neuropathologic basis is poorly understood as somatic and autonomic C fibers are not usually studied in the same region of the body.

OBJECTIVE

To evaluate prospective somatic and autonomic C-fiber function in 11 healthy control subjects and 38 patients with different clinical patterns of neuropathy.

METHODS

Distal small-fiber neuropathy (DSFN), peripheral neuropathy (PN), diabetic neuropathy (DN), neuropathic postural tachycardia syndrome (POTS), and idiopathic autonomic neuropathy (IAN) were evaluated. Intraepidermal nerve fiber density was used to evaluate distal somatic C fibers. Both quantitative sudomotor axon reflex test and skin norepinephrine content were measured for the biopsy site to assess distal autonomic C-fiber function. Postganglionic sudomotor, adrenergic, and cardiovagal functions were evaluated by autonomic reflex testing and quantified using a Composite Autonomic Severity Scale.

RESULTS

Skin norepinephrine concentration was significantly related to CASS. DN was associated with somatic and autonomic C-fiber impairment with good agreement. POTS was associated with selective distal autonomic deficit. DSFN had combined distal somatic and C-fiber impairment. IAN showed combined and selective distal and generalized autonomic C-fiber impairment. The somatic neuropathies had C-fiber impairment affecting both populations to varying degrees.

CONCLUSION

Although a general agreement exists between the loss of somatic C fibers and autonomic deficits, selective involvement occurs for specific autonomic neuropathies.

Autonomic and motor neuron death is progressive and parallel in a lumbosacral ventral root avulsion model of cauda equina injury

Injuries to the cauda equina of the spinal cord result in autonomic and motor neuron dysfunction. We developed a rodent lumbosacral ventral root avulsion injury model of cauda equina injury to investigate the lesion effect in the spinal cord. We studied the retrograde effects of a unilateral L5-S2 ventral root avulsion on efferent preganglionic parasympathetic neurons (PPNs) and pelvic motoneurons in the L6 and S1 segments at 1, 2, 4, and 6 weeks postoperatively in the adult male rat. We used Fluoro-Gold-prelabeling techniques, immunohistochemistry, and quantitative stereologic analysis to show an injury-induced progressive and parallel death of PPNs and motoneurons. At 6 weeks after injury, only 22% of PPNs and 16% of motoneurons remained. Furthermore, of the neurons that survived at 6 weeks, the soma volume was reduced by 25% in PPNs and 50% in motoneurons. Choline acetyltransferase (ChAT) protein was expressed in only 30% of PPNs, but 80% of motoneurons remaining at 1 week postoperatively, suggesting early differential effects between these two neuronal types. However, all remaining PPNs and motoneurons were ChAT positive at 4 weeks postoperatively. Nuclear condensation and cleaved caspase-3 were detected in axotomized PPNs and motoneurons, suggesting apoptosis as a contributing mechanism of the neural death. We conclude that lumbosacral ventral root avulsions progressively deplete autonomic and motor neurons. The findings suggest that early neuroprotection will be an important consideration in future attempts of treating acute cauda equina injuries.

Reduced number of intrinsic pulmonary nitrergic neurons in Fawn-Hooded rats as compared to control rat strains

The Fawn-Hooded rat (FHR) strain reveals a congenital predisposition to primary (idiopathic) pulmonary hypertension (PPH), and can therefore be regarded as an animal model in which to study possible mechanisms underlying an inherited susceptibility to pulmonary hypertension. Pulmonary hypertension can be induced in FHRs after a short exposure to mild hypoxia, presumably because of an altered peripheral oxygen sensitivity. Given the presence of pulmonary nitrergic neurons in rat lungs, the observed link between airway hypoxia and the expression of pulmonary neuronal nitric oxide synthase (nNOS), and the fact that nNOS appears to be involved in peripheral chemoreceptor sensitivity, we examined the intrinsic pulmonary nitrergic innervation in the FHR. In the present study the number of intrapulmonary nitrergic nerve cell bodies, detected by NADPH diaphorase (NADPHd) histochemistry, was quantified in the FHR and three control rat strains. Compared to the control rat strains, the FHR lungs revealed a highly significantly lower number of intrinsic nitrergic neurons, while no apparent differences were found in the number of enteric nitrergic neurons in the esophagus. In conclusion, the possible links between neuronal NO, hypersensitivity to airway hypoxia, and the development of PPH clearly deserve further investigation.

From physiology to pathology: arousal deficiency theory in sudden infant death syndrome (SIDS)--with reference to apoptosis and neuronal plasticity

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age (including 26 infant victims of sudden infant death syndrome (SIDS), 5 with congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 with a prolonged seizure, 1 from prolonged neonatal hypoxemia, 1 from meningitis and brain infarction). The frequency and duration of sleep apneas recorded some 3-12 weeks before the infants' death were analyzed. Brainstem material from these 38 infants was studied in an attempt to elucidate the relationship between sleep apnea and neuronal pathological changes in the arousal pathway. Immunohistochemical analyses included the evaluation of growth-associated phosphoprotein 43 (GAP43) as a marker for synaptic plasticity. The terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used to identify apoptosis. The positive pathological reactions were quantitatively analyzed. The pathological and physiological data were linked for each infant. Akaike Information Criterion (AIC) statistics was calculated to elucidate the relationship between the physiological and the pathological data in the SIDS victims. The findings illustrated the possibility of an organic fragility within the arousal pathway, particularly in the midbrain periaqueductal gray matter, which is associated with the "visceral alerting response". This autonomic response occurs within an acetylcholine afferent system and pedunculopontine tegmental nucleus (PPTN). The finding is, in future SIDS infants, associated with repetitive sleep apnea.

Complex genetic alterations in gastrointestinal stromal tumors with autonomic nerve differentiation

Gastrointestinal stromal tumors (GISTs) with neurogenic differentiation, also referred to as "gastrointestinal autonomic nerve tumors (GANTs)," form an ultrastructurally distinctive subgroup of mesenchymal neoplasms of gastrointestinal tract. Cytogenetic and molecular data of these tumors are limited. In the current study, c-KIT gene sequenc-ing analysis, comparative genomic hybridization (CGH), and interphase fluorescence in situ hybrid- ization (FISH) analysis, utilizing chromosome 14- and 22-specific probes, were performed on five primary ultrastructurally confirmed GANTs. FISH and CGH analysis revealed loss of a whole or part of chromosome 14q in two tumors and of chromo- some 22q, with the common overlapping area of loss at q13, in all five tumors evaluated. c-KIT mu- tations were found in all cases; three tumors carried point mutation and/or deletions of exon 11, and in two tumors, insertion in exon 9 was found. These findings suggest that accumulated genetic changes contribute to the pathogenesis of GANTs and that 22q13 loss may be a characteristic feature of these tumors.

Quantitative assessment of the innervation of epineurial arteries in the peripheral nerve by immunofluorescence: differences between controls and patients with peripheral arterial disease

The peripheral nerve is supplied by the vasa nervorum. The epi- and perineurial vessels are innervated by an autonomic plexus, which plays a role in regulation of the endoneurial blood flow. This innervation is decreased in diabetes and alcohol polyneuropathy and seems to precede the development of diabetic polyneuropathy. A decreased innervation may therefore play a role in the development of polyneuropathy. In peripheral arterial disease (PAD) clinical and morphological features are present, related to severity of ischemia. To investigate the innervation of the vasa nervorum in severe ischemia, we performed immunofluorescence staining with the general neural marker protein gene product (PGP) 9.5 in whole mount preparations of epineurial vessels of nine sural nerves taken from patients with legs amputated because of severe PAD (59+/-15 years, mean +/- SD) and ten age-matched controls (61+/-24 years). In patients with PAD the nerve density of the perivascular plexus was decreased in comparison with controls (mean intercept density/mm +/- SD) 26.0+/-6.9 in PAD and 39.9+/-10.7 in controls, area% 6.0+/-1.6 in PAD and 9.9+/-2.6 in controls, both P<0.01, t-test). A decreased perivascular plexus may result in a diminished regulation of the endoneurial blood flow in patients with severe PAD.

Differential effects of neurotoxic destruction of descending noradrenergic pathways on acute and persistent nociceptive processing

Although many pharmacological studies indicate that bulbospinal noradrenergic projections contribute to antinociception, lesions of the major brainstem noradrenergic cell groups have provided conflicting evidence. Here we used a new immunotoxin, anti-dopamine beta-hydroxylase-saporin, to re-examine the contribution of noradrenergic pathways to nociception and to morphine analgesia. We treated rats intrathecally by lumbar puncture with the immunotoxin and examined dopamine beta-hydroxylase (DbetaH) immunoreactivity seven and 14 days after treatment. There was no change in DbetaH staining at 7 days; however, 14 days after treatment we demonstrated significant destruction of noradrenergic neurons in the locus coeruleus and in the A5 and A7 cell groups. There was a concomitant loss of noradrenergic axons in the dorsal and ventral horns of the lumbosacral and cervical cord. Consistent with the lack of anatomical changes, we found no difference in nociceptive responses in the hot-plate, tail-flick or formalin tests one week post-toxin. On day 14 we examined the behavioral response to injection of formalin into the hindpaw and found that responses during the second phase of pain behavior were significantly reduced. There was no change during the first phase. Formalin-evoked fos expression in the spinal cord was also reduced. We also evaluated morphine analgesia in the formalin test and found that toxin-treated animals exhibited enhanced morphine analgesia. These results establish the utility of using this immunotoxin to selectively destroy subpopulations of noradrenergic cell groups and provide evidence that acute and persistent nociception are differentially regulated by descending noradrenergic pathways.

[Neural infiltration in benign gallbladder lesions. Description of a case]

Neural infiltration is considered a very useful marker of malignancy in the biliary tract. Aim of this study is to report a case of benign epithelium of the gallbladder with neural infiltration and to review the literature.

Effect of steroid therapy on parameters of peripheral autonomic dysfunction in leprosy patients with acute neuritis

Recent electrophysiological studies on peripheral autonomic dysfunction in leprosy patients show a high prevalence of autonomic dysfunction as measured by abnormal vasomotor reflexes (VMR) and absent sympathetic skin response (SSR). Nothing is known about the reversibility of these autonomic parameters with treatment. Since there is evidence that small fiber function may be the most reversible component in neuropathies, we measured the effect of steroid treatment on autonomic parameters together with motor and sensory functions in leprosy patients with acute neuritis. Control subjects were investigated for repeatability testing of autonomic function. Due to a relatively high variability on repeat VMR testing in the controls, we defined a change in VMR testing as a change of > 30%. With this definition, the VMR of 14.8% of the patients improved, 75% remained unchanged, and 10.2% worsened. Absent SSR became positive in 16.6% and remained unchanged in 83.4%. Improvement in sensory motor functions was seen in 21.2% and 1.3% of the patients, respectively.

Autonomic nervous system as a model of neuronal aging: the role of target tissues and neurotrophic factors

The aim of this study was to determine the role of target tissues and neurotrophic factors in the growth and atrophy of autonomic neurons during development and aging. Using quantitative neuroanatomical techniques, it is shown that, although axonal and dendritic growth is apparent throughout postnatal development, different patterns of growth are found in autonomic neurons innervating different target tissues. For example, sympathetic neurons innervating the submandibular gland continue to grow well into maturity, but those innervating the iris cease net growth early in postnatal development. Similarly, although neuronal atrophy was observed in aged autonomic ganglia, this was not a general phenomenon but was specific to neurons innervating particular target tissues. Sympathetic neurons innervating the middle cerebral artery showed significant axonal and dendritic atrophy in old age, whereas neurons innervating the iris were morphologically unchanged. The trophic influence of peripheral target tissues on their innervating neurons has been shown to decline in old age possibly as a result of decreased availability of target-derived neurotrophic factors such as nerve growth factor (NGF) [Gavazzi et al. (1992) Neuroreport, 3:717-720]. Therefore, in an attempt to reverse neuronal atrophy where it occurred, NGF was infused via miniosmotic pumps over the peripheral axons of aged neurons. NGF induced increases in soma size, dendritic length and axonal arborization. However, in contrast to young adult neurons, no increase in the number of dendritic branch points or primary dendrites was observed, suggesting that some aspects of neuronal plasticity are impaired in old age. In sum, these results show a range of age- and target-specific differences in the axonal and dendritic morphology of autonomic neurons that may result from differing trophic interactions with their target tissues.