Nerve distribution in hemangiomas depends on the proliferative state of the microvasculature

Analysis of Mechanoreceptors and Free Nerve Endings of the Transverse Carpal Ligament

Background: The treatment of carpal tunnel syndrome (CTS) by sectioning the transverse carpal ligament (TCL) is not exempt from complications. Some nerve branches may be damaged by the incision. The aim of this study is to identify and map the TCL nerve endings, serving as a guide for sectioning this structure in a zone with less nerve ending density. Methods: Ten TCLs were obtained from fresh frozen cadavers. The TCLs were measured, divided into 3 equal bands (radial, central, and ulnar), and submitted to cryostat sectioning. The sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 and confocal microscopy analysis. Results: All the specimens contained type I and type IV mechanoreceptors. Neural elements occupied 0.695 ± 0.056% of the ligament area. The density of the neural elements was greater in the radial, followed by the ulnar and central bands, with 0.730 ± 0.083%, 0.686 ± 0.009%, and 0.669 ± 0.031%, respectively. Conclusion: The present findings suggest that the region with the least potential for neural element injury during TCL release is the central third near the transition with the ulnar third. When performed distally to proximally with a slight inclination from the radial to the ulnar, this release compromises the lowest nerve element density. Topographically, the proximal limit of the release is the distal wrist crease, while the distal limit is the intersection of Kaplan cardinal line and the axis of the third webspace.

Study of the Nerve Endings and Mechanoreceptors of the Anterolateral Ligament of the Knee

PURPOSE

To describe the morphology and distribution of the anterolateral ligament of the knee (ALL) nerve endings, aiming to understand the interaction between the proprioceptive system and knee mechanics.

METHODS

Twenty ALLs were obtained from fresh frozen cadavers. The ligaments were measured, weighed, and cut. Sections (10 μm) were prepared in hematoxylin and eosin-stained slides to analyze tissue integrity, and 50-μm sections were subjected to immunofluorescence with the protein gene product 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis.

RESULTS

The ALL was identified in 100% of the dissections, exhibiting a mean (± standard deviation) length of 4.0 ± 0.4 cm, a mean width of 5.5 ± 0.8 mm, and a mean weight of 0.9 ± 0.2 g. The histological sections in hematoxylin and eosin showed dense, well-organized collagen and the presence of vascular tissue. All the specimens analyzed contained type I (Ruffini-like) mechanoreceptors and free nerve endings (type IV), varying from parallel to intertwined fibers. Unclassified nerve endings with different irregular shapes were also found. The neural elements occupied 0.6% ± 0.3% of the ligament area, and most were observed near the origin of ALL insertions.

CONCLUSION

The ALL exhibits a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the ALL is important for the proprioception and anterolateral stabilization of the knee.

CLINICAL RELEVANCE

It is important to understand ALL innervation and infer how an injury could compromise the proprioceptive role of the lateral compartment, as the ligaments contribute dynamically to stability through proprioceptive control of muscle forces. The findings confirm that the ALL is highly innervated by mechanoreceptors and may have a proprioceptive role in conjunction with the lateral collateral ligament in the lateral region of the knee.

The use of propranolol in the treatment of infantile haemangiomas: an update on potential mechanisms of action

Currently, propranolol is the preferred treatment for problematic proliferating infantile haemangiomas (IHs). The rapid action of propranolol has been shown to be especially dramatic in IHs involving dyspnoea, haemodynamic compromise, palpebral occlusion or ulceration. Another remarkable aspect of propranolol treatment revealed that the growth of the IHs was not only stabilized, but also that the improvement continued until complete involution was achieved, leading to a considerable shortening of the natural course of IH. However, the mechanisms underlying the effects of propranolol have not been fully elucidated. Recent studies have offered evidence of a variety of mechanisms. These include the promotion of pericyte-mediated vasoconstriction, the inhibition of vasculogenesis and catecholamine-induced angiogenesis, the disruption of haemodynamic force-induced cell survival, and the inactivation of the renin-angiotensin system. This review summarizes these mechanisms and the new concepts that are emerging in this area of research. Moreover, several molecular mechanisms by which propranolol may modify neovascularization in IH have also been proposed. The antihaemangioma effect of propranolol may not be attributable to a single mechanism, but rather to a combination of events that have not yet been elucidated or understood. Further studies are needed to evaluate and verify these mechanisms to gain a greater understanding of the effects of the intake of propranolol on haemangioma involution.

Neuronal control of metabolism through nutrient-dependent modulation of tracheal branching

During adaptive angiogenesis, a key process in the etiology and treatment of cancer and obesity, the vasculature changes to meet the metabolic needs of its target tissues. Although the cues governing vascular remodeling are not fully understood, target-derived signals are generally believed to underlie this process. Here, we identify an alternative mechanism by characterizing the previously unrecognized nutrient-dependent plasticity of the Drosophila tracheal system: a network of oxygen-delivering tubules developmentally akin to mammalian blood vessels. We find that this plasticity, particularly prominent in the intestine, drives—rather than responds to—metabolic change. Mechanistically, it is regulated by distinct populations of nutrient- and oxygen-responsive neurons that, through delivery of both local and systemic insulin- and VIP-like neuropeptides, sculpt the growth of specific tracheal subsets. Thus, we describe a novel mechanism by which nutritional cues modulate neuronal activity to give rise to organ-specific, long-lasting changes in vascular architecture.

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The Drosophila tracheal system exhibits nutrient-dependent plasticity

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Tracheal plasticity is organ specific and metabolically significant

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Nutrient- and hypoxia-responsive neurons drive adaptive tracheation

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Distinct insulin-like and Pdf neuropeptides control organ-specific tracheal branching

Recent progress in studies of infantile hemangioma

A hallmark of infantile hemangioma, the most common tumor of infancy, is its dramatic growth after birth, by diffuse proliferation of immature endothelial cells, followed by spontaneous regression. The growth and involution of infantile hemangioma is quite different from other vascular anomalies, which do not regress and can occur at any time during life. Some hemangioma lesions can be extremely disfiguring and destructive to normal tissue and may even be life-threatening. Unfortunately, existing therapeutic approaches have limited success and significant adverse effects of some treatment modalities limit their use. Better understanding of the pathogenesis of hemangioma will enable the development of better therapeutic strategies. Here, we review recent studies and new hypotheses on the pathogenesis of the tumor. Detailed mechanisms of activated vascular endothelial growth factor signaling in tumor cells, identification of their origin and characterization of multipotent stem cells that can give rise to infantile hemangioma are shedding new light on this intriguing vascular tumor.

Fluorescence immunohistochemistry and confocal scanning laser microscopyA protocol for studies of joint innervation

We have developed a reliable technique for labeling and examining neural structures in soft tissues associated with articular joints and have tested it in human wrist joints under various specimen-related conditions. The labeling protocol employs an immunohistochemical process with a panneuronal marker (PGP 9.5) as the primary antibody and Alexa Fluor 488 as the fluorescing secondary antibody. Imaging was done using a confocal laser scanning microscope, which produced exceptionally detailed three-dimensional images of nerve endings and transiting nerve fibers from thick sections of wrist joint ligaments obtained from human cadavers. The protocol provided a practical postmortem window for specimen acquisition and processing without significant apparent worsening of image quality. The images produced are resistant to fading with repeated exposure to a fluorescent light source, which gives many opportunities for observation. Background staining is minimal, producing high contrast labeling of target tissues, which, in turn, enhances image analysis.

Vasculogenesis in infantile hemangioma

Infantile hemangioma is a vascular tumor that occurs in 5-10% of infants of European descent. A defining feature of infantile hemangioma is the dramatic growth and development into a disorganized mass of blood vessels. Subsequently, a slow spontaneous involution begins around 1 year of age and continues for 4-6 years. The growth and involution of infantile hemangioma is very different from other vascular tumors and vascular malformations, which do not regress and can occur at any time during childhood or adult life. Much has been learned from careful study of the tissue morphology and gene expression patterns during the life-cycle of hemangioma. Tissue explants and tumor-derived cell populations have provided further insight to unravel the cellular and molecular basis of infantile hemangioma. A multipotent progenitor cell capable of de novo blood vessel formation has been isolated from infantile hemangioma, which suggests that this common tumor of infancy, long considered to be a model for pathologic angiogenesis, may also represent pathologic vasculogenesis. Whether viewed as angiogenesis or vasculogenesis, infantile hemangioma represents a vascular perturbation during a critical period of post-natal growth, and as such provides a unique opportunity to decipher mechanisms of human vascular development.

Epidural Neurostimulation of Posterior Funiculi for the Treatment of Buerger's Disease

Background.  Buerger disease is a nonatherosclerotic, segmental, occlusive and recurrent inflammatory vascular disorder that affects small and medium-sized arteries and veins of the upper and lower extremities. Case reports.  We report two cases of Buerger disease. Medical History.  Smoking habit. No autoimmune diseases. No diabetes mellitus. Intermittent vascular claudication at 100-150 m. Several hospital admissions for amputations. Prior Medical Treatment.  Antiplatelet agents, vasodilators, nonsteroidal anti-inflammatory drugs, third-step analgesics, fibrinolytic treatment and lumbar sympathectomies. Following all of the above treatments, Synergy(®) spinal cord (ECP) stimulator with two electrodes (Quad PISCES(©) ) placed at the level of T9-T10. Results.  There has been a reduction in pain of about 80% and an improvement of intermittent claudication (one of the patients no longer claudicates, whereas the other patient claudicates at 400 m). Conclusion.  Neurostimulation of the posterior funiculi could be considered not only as palliative care but also as a therapeutic option.

Decreased nerve distribution in mixed venous-lymphatic malformation

In order to investigate the nerve distribution in mixed venous-lymphatic malformations (MVLMs), 57 postoperative patients diagnosed with MVLMs of the tongue were selected. Immunohistochemistry staining for neurofilament (NF) was used to detect sensory nerve fibers. Distribution of NF in samples from MVLMs was compared with distribution of NF in normal tongue tissue, venous malformations, lymphatic malformations and venular malformations. Results showed that the number of NF-positive nerve fibers in MVLMs was comparable to that in venous malformations and lymphatic malformations. The number of nerve fibers in MVLMs was significantly lower than in normal tissues. NF distribution in MVLMs was not affected by the patient's age or the coexistence of infection. These data suggest that the decreased distribution of sensory nerve fibers in MVLMs may be involved in the pathogenesis of MVLM of the tongue.

Putative mechanisms behind effects of spinal cord stimulation on vascular diseases: a review of experimental studies

Spinal cord stimulation (SCS) is a widely used clinical technique to treat ischemic pain in peripheral, cardiac and cerebral vascular diseases. The use of this treatment advanced rapidly during the late 80's and 90's, particularly in Europe. Although the clinical benefits of SCS are clear and the success rate remains high, the mechanisms are not yet completely understood. SCS at lumbar spinal segments (L2-L3) produces vasodilation in the lower limbs and feet which is mediated by antidromic activation of sensory fibers and decreased sympathetic outflow. SCS at thoracic spinal segments (T1-T2) induces several benefits including pain relief, reduction in both frequency and severity of angina attacks, and reduced short-acting nitrate intake. The benefits to the heart are not likely due to an increase, or redistribution of local blood flow, rather, they are associated with SCS-induced myocardial protection and normalization of the intrinsic cardiac nervous system. At somewhat lower cervical levels (C3-C6), SCS induces increased blood flow in the upper extremities. SCS at the upper cervical spinal segments (C1-C2) increased cerebral blood flow, which is associated with a decrease in sympathetic activity, an increase in vasomotor center activity and a release of neurohumoral factors. This review will summarize the basic science studies that have contributed to our understanding about mechanisms through which SCS produces beneficial effects when used in the treatment of vascular diseases. Furthermore, this review will particularly focus on the antidromic mechanisms of SCS-induced vasodilation in the lower limbs and feet.

The potential role of Calcitonin Gene-Related Peptide (CGRP) in breast carcinogenesis and its correlation with 99mTc-(V)DMSA scintimammography

OBJECTIVES

Experimental data suggest a role for calcitonin gene-related peptide (CGRP) in normal breast development and angiogenesis. This pilot study correlated CGRP with neoangiogenesis and the uptake of the tumor-seeking, proliferation-imaging radiotracer pentavalent technetium-99m dimercaptosuccinate (99mTc-(V)DMSA) in invasive and preinvesive breast lesions.

METHODS

Among women evaluated preoperatively by 99mTc-(V)DMSA scintimammography, 29 invasive ductal carcinomas (IDCs) were retrospectively studied: 15 isolated (Group I); 14 mixed with preinvasive pathologies (ductal carcinoma in situ [DCIS] and/or epithelial hyperplasia [EH]; Group M). CGRP staining and neoangiogenesis were compared between invasive and DCIS/EH regions and were correlated. 99mTc-(V)DMSA displayed a diffusely increased uptake pattern corresponding to DCIS/EH; its lesion-to-background (L/B) ratio was compared between images acquired at 10 and 60 minutes and its retention ratio (RR) was correlated with CGRP.

RESULTS

Seven of 15 group I and 10 of 14 group M patients (58.6% of the population) were CGRP-positive. CGRP was prevalent in the DCIS/EH component of mixed-lesions (even in the surrounding normal epithelium of nearly half), with declining intensity as advancing from DCIS/EH to high-grade IDC. Similarly, neoangiogenesis was considerably higher in DCIS/EH than in group I pure IDCs. A significant CGRP-neoangiogenesis correlation was verified only in group I. The diffuse 99mTc-(V)DMSA uptake exhibited significant, time-related L/B increase and a RR positively correlating with CGRP.

CONCLUSIONS

CGRP expression and neoangiogenesis are intensified in mixed invasive-preinvasive breast lesions; an underlying relation may exist, requiring further investigation. CGRP also appears associated with 99mTc-(V)DMSA's propensity to depict preinvasive pathologies. This relationship could denote an additional proliferative role for CGRP.

Hemangioma versus vascular malformation: presence of nerve bundle is a diagnostic clue for vascular malformation

CONTEXT

Arteriovenous vascular malformations and hemangiomas are benign vascular lesions that are difficult to distinguish from one another clinically. Also, they may be confused with each other at histopathology. Therefore, histochemical stains for the presence of an artery are frequently used to distinguish between the two.

OBJECTIVE

Because it is clinically relevant to differentiate between arteriovenous vascular malformations and hemangiomas, this study was carried out to explore additional diagnostic clues that may help in the diagnosis and differentiation of these lesions.

DESIGN

A total of 167 cases of benign extracranial vascular lesions were retrieved from the anatomic pathology file of our institution. These comprised 66 cases diagnosed as arteriovenous vascular malformations and 101 cases previously diagnosed as hemangiomas. The hematoxylin-eosin-stained glass slides were reviewed, Movat pentichrome histochemical stain was used to identify elastic vessels (arteries/arterioles), and S100 immunostain was used to identify nerves within these vascular lesions. For immunohistochemistry, the avidin-biotin detection method was used.

RESULTS

With Movat stain, the presence of thick-walled elastic arteries was detected in 12 of the 101 cases previously diagnosed as hemangiomas, and these cases were therefore reclassified as vascular malformations. Using the same criterion, 2 of the 66 cases originally diagnosed as arteriovenous vascular malformations were reclassified as hemangiomas because they lacked arterial structures. Thus, with this strict criterion, we ended up with 91 cases of hemangiomas and 76 cases of arteriovenous vascular malformations. Intralesional nerves were identified in 91% (69/76) of cases of arteriovenous vascular malformations, including all the 12 arteriovenous vascular malformations previously diagnosed as hemangiomas. In contrast, no intralesional nerve was detected in any of the 91 hemangiomas.

CONCLUSIONS

These results show that nerve bundles are consistently present in vascular malformations and absent in hemangiomas and so can be used as a diagnostic clue to differentiate between these lesions. Also, in addition to describing a previously unreported component of vascular malformations, these data further confirm the hamartomatous nature of these lesions.

Tumor-induced mechanical hyperalgesia involves CGRP receptors and altered innervation and vascularization of DsRed2 fluorescent hindpaw tumors

Functional and anatomical relationships among primary afferent fibers, blood vessels, and cancers are poorly understood. However, recent evidence suggests that physical and biochemical interactions between these peripheral components are important to both tumor biology and cancer-associated pain. To determine the role of these peripheral components in a mouse model of cancer pain, we quantified the change in nerve and blood vessel density within a fibrosarcoma tumor mass using stereological analysis of serial confocal optical sections of immunostained hind paw. To this end we introduced the Discoma coral-derived red fluorescent protein (DsRed2) into the NCTC 2472 fibrosarcoma line using the Sleeping Beauty transposon methodology, thus providing a unique opportunity to visualize tumor-nerve-vessel associations in context with behavioral assessment of tumor-associated hyperalgesia. Tumors from hyperalgesic mice are more densely innervated with calcitonin gene related peptide (CGRP)-immunoreactive nerve fibers and less densely vascularized than tumors from non-hyperalgesic mice. As hyperalgesia increased from Day 5 to 12 post-implantation, the density of protein gene product 9.5 (PGP9.5)-immunoreactive nerves and CD31-immunoreactive blood vessels in tumors decreased, whereas CGRP-immunoreactive nerve density remained unchanged. Importantly, intra-tumor injection of a CGRP1 receptor antagonist (CGRP 8-37) partially blocked the tumor-associated mechanical hyperalgesia, indicating that local production of CGRP may contribute to tumor-induced nociception through a receptor-mediated process. The results describe for the first time the interaction among sensory nerves, blood vessels and tumor cells in otherwise healthy tissue, and our assessment supports the hypothesis that direct tumor cell-axon communication may underlie, at least in part, the occurrence of cancer pain.

Endothelial cell tumors

Historically, there has been much debate on the nature of infantile hemangiomas as either congenital malformations or benign neoplasms. Some vascular lesions that are present at birth and evidence no proliferative growth are considered to be congenital malformations; other post-natal vascular tumors pursue aggressive and possibly lethal clinical courses. The literature of the last two decades has been reviewed with a hope of clarifying the pathogenesis and underlying molecular lesions of this diverse set of lesions. Genetic investigations of two diseases associated with vascular tumors and abnormalities, von Hippel-Lindau disease, and Hereditary Hemorrhagic Telangiectasia have greatly added to our knowledge of vascular proliferation and provided a tantalizing clue to the pathogenesis of hemangioblastomas. Mutations have also been described in infantile hemangiomas. All of the entities considered, vascular neoplasms as well as malformations, have been examined for the expression of vascular growth factors, their receptors, and factors that appear to promote cell proliferation. Similarly, factors that either block or promote apoptosis have also been examined in various vascular lesions. These studies have in large confirmed our expectations about proliferating tumors that show upregulation of growth promoting factors and inhibition of those that promote apoptosis. In conclusion, although much has been learned about vascular physiology and the control of endothelial proliferation, and while understanding about the molecular pathogenesis of the two inherited diseases mentioned above is detailed but not yet complete, understanding of the pathogenesis of benign and malignant endothelial tumors remains vague.

The pattern of neurovascular development in the forelimb of the quail embryo

Peripheral nerve and vascular patterns are congruent in the adult vertebrate, but this has been disputed in vertebrate embryos. The most detailed of these studies have used the avian forelimb as a model system, yet neurovascular anatomical relationships and critical vascular remodeling events remain inadequately characterized in this model. To address this, we have used a combination of intravascular marker injection, multilabel fluorescent stereomicroscopy, and confocal microscopy to analyze the spatiotemporal relationships between peripheral nerves and blood vessels in the forelimb of 818 quail embryos from E2 (HH13) to E15 (HH41). We find that the neurovascular anatomical relationships established during development are highly stereotypic and congruent. Blood vessels typically arise before their corresponding nerves, but there are several critical exceptions to this rule. The vascular pattern is extensively remodeled from the earliest stage examined (E2; HH13), whereas the peripheral nerves, the first of which enter the forelimb at E3.5-E4 (HH21-HH24), have a progressively unfolding pattern that, once formed, remains essentially unchanged. The adult neurovascular pattern is not established until E8 (HH34). Peripheral nerves are always found to track close and parallel to the vasculature. As they track distally, peripheral nerves always lie on the side of the vasculature away from the center of the forelimb. Neurovascular patterns have a hierarchy of congruence that is highest in the dorsoventral plane, followed by the anteroposterior, and lastly the proximodistal planes.