The discovery of a new type of innervation in lymphoid organs.

It is well known that the main forms of innervation are synapses and free nerve endings, while other forms of innervation have not been reported. Here, we explore a new way of innervating lymphoid organs. Male Sprague-Dawley rats were used for studying the innervation of sympathetic nerve fibers in lymph nodes by means of anterograde tracking, immunoelectron microscopy, three-dimension reconstruction analysis, and immunofluorescence labeling. The results showed that the Fluoro-Ruby labeled nerve endings targeted only a group of cells in the lymph nodes and entered the cells through the plasma membrane. The electron microscopy showed that the biotinylated glucan amine reaction elements were distributed in the cytoplasm, and most of the biotinylated glucan amine active elements were concentrated on the microtubule and microfilament walls. Birbeck particles with rod-shaped and/or tennis racket like structures can be seen in the labeled cells at high magnification, and Birbeck particles contain biotinylated glucan amine-reactive elements. The immunofluoresence results showed that the Fluoro-Ruby-labeled nerve innervating cells expressed CD207 and CD1a protein. This result confirmed that the labeled cells were Langerhans cells. Our findings suggested that Langerhans cells might serve as a "bridge cell" for neuroimmune cross-talking in lymph organs, which play an important role in transmitting signals of the nervous system to immune system. This study also opened up a new way for further study of immune regulation mechanism.

The discovery of the lymphatic system in the seventeenth century. Part V: an ode to the nerves.

The English anatomists Francis Glisson and Thomas Wharton introduced theories on the use of recently discovered lymphatic system in the1650s. Their main idea was that membranous tissues were supplied by nerves with a vital fluid produced within nutritive glands, to be carried to the brain and thence from the brain to all membranous tissues, including glands. They stated that the distribution of the vital fluid was based on the similarity between its ingredients and the needs of the recipient tissues, and not on the weight, size or location of pores encountered, as maintained by Descartes. Lymph, a mixture of waste from the consumed vital fluid and moisture transuded by arterial capillaries, was absorbed by the lymphatic vessels to be excreted via excretory glands, or to be diverted to the venous system by reductive glands. The theories of Glisson and Wharton were very soon rejected to be replaced by a mechanistic philosophy, a legacy of Descartes' theories.

Neural reflex pathways in intestinal inflammation: hypotheses to viable therapy.

Studies in neuroscience and immunology have clarified much of the anatomical and cellular basis for bidirectional interactions between the nervous and immune systems. As with other organs, intestinal immune responses and the development of immunity seems to be modulated by neural reflexes. Sympathetic immune modulation and reflexes are well described, and in the past decade the parasympathetic efferent vagus nerve has been added to this immune-regulation network. This system, designated 'the inflammatory reflex', comprises an afferent arm that senses inflammation and an efferent arm that inhibits innate immune responses. Intervention in this system as an innovative principle is currently being tested in pioneering trials of vagus nerve stimulation using implantable devices to treat IBD. Patients benefit from this treatment, but some of the working mechanisms remain to be established, for instance, treatment is effective despite the vagus nerve not always directly innervating the inflamed tissue. In this Review, we will focus on the direct neuronal regulatory mechanisms of immunity in the intestine, taking into account current advances regarding the innervation of the spleen and lymphoid organs, with a focus on the potential for treatment in IBD and other gastrointestinal pathologies.

S100+ cells: a new neuro-immune cross-talkers in lymph organs.

Up to now, the 'hardwired' neural pathway of the neuro-immune regulation is not fully understood. Here we reported a new neural pathway which links sympathetic nerves with immune cells of the lymphoid tissues. Our results demonstrated that nerve fibers derived from superior cervical ganglion directly targeted only S100(+) cells in the cervical lymph nodes. Moreover, we found co-expression of neurotransmitters such as norepinephrine, vasoactive intestinal polypeptide and neuropeptide Y in the postganglionic sympathetic nerve endings that innervate S100(+) cells. Our findings suggested that S100(+) cells serve as a neuro-immune cross-talker in lymph organs that may play a significant role in transmitting signals of nervous cells to targeted immune cells. The new findings provide better understanding of the cross-talk mechanism between the nervous system and the immune system.

Lymph heart in chick--somitic origin, development and embryonic oedema.

The lymph heart is a sac-like structure on either side of avian tail. In some adult birds, it empties the lymph from the copulatory organ; however, during embryonic development, it is thought to circulate extra-embryonic lymph. Very little is known about the origin, innervation and the cellular changes it undergoes during development. Using immunohistochemistry and gene expression profiling we show that the musculature of the lymph heart is initially composed solely of striated skeletal muscle but later develops an additional layer composed of smooth myofibroblasts. Chick-quail fate-mapping demonstrates that the lymph heart originates from the hypaxial compartments of somites 34-41. The embryonic lymph heart is transiently innervated by somatic motoneurons with no autonomic input. In comparison to body muscles, the lymph heart has different sensitivity to neuromuscular junction blockers (sensitive only to decamethonium). Furthermore, its abundant bungarotoxin-positive acetylcholinesterase receptors are unique as they completely lack specific acetylcholinesterase activity. Several lines of evidence suggest that the lymph heart may possess an intrinsic pacing mechanism. Finally, we assessed the function of the lymph heart during embryogenesis and demonstrate that it is responsible for preventing embryonic oedema in birds, a role previously thought to be played by body skeletal muscle contractions.

Evaluation of Chapman's neurolymphatic reflexes via applied kinesiology: a case report of low back pain and congenital intestinal abnormality.

OBJECTIVE: To describe the applied kinesiologic evaluation of Chapman's neurolymphatic (NL) reflexes in the management of a person with an unusual congenital bowel abnormality and its role in the manifestation of low back pain. The theoretical foundations of these reflexes will be elaborated on and practical applications discussed. CLINICAL FEATURES: A 29-year-old man had chronic low back pain. Radiographs of the patient's lumbar spine and pelvis were normal. Magnetic resonance imaging (MRI) demonstrated a mild protrusion of the fifth lumbar disk. Oral anti-inflammatory agents, cortisone injections, and chiropractic manipulative therapy provided little relief. Though generally in robust health, the patient was aware of a congenital intestinal abnormality diagnosed when he was a child; it was thought to be of no consequence with regard to his current back condition. INTERVENTION AND OUTCOME: The patient's history, combined with applied kinesiology examination, indicated a need to direct treatment to the large bowel. The essential diagnostic indicators were the analysis of the Chapman's neurolymphatic reflexes themselves, coupled with an evaluation of the traditional acupuncture meridians. The primary prescribed therapy was the stimulation of these reflexes by the patient at home. This intervention resulted in the resolution of the patient's musculoskeletal symptomatology, as well as improved bowel function. CONCLUSION: The rather remarkable outcome from the application of this relatively simple, yet valuable, diagnostic and therapeutic procedure represents a thought-provoking impetus for future study and clinical application.

Glucocorticoid inhibition of neuropathic limb edema and cutaneous neurogenic extravasation.

Sciatic nerve section in rats evokes chronic limb edema, pain behavior, and hindpaw hyperalgesia, a syndrome resembling the complex regional pain syndrome type II (CRPS II or causalgia) in man. Glucocorticoids such as methylprednisolone (MP) have been used as analgesic and anti-edematous agents in patients suffering from CRPS, and interestingly these therapeutic effects appear to persist in some patients after stopping the medication. Similar to the CRPS clinical response to glucocorticoids, we now demonstrate that chronic hindpaw edema in the sciatic transection CRPS model is reversed by a continuous infusion of MP (3 mg/kg/day over 21 days), and this anti-edematous effect persists for at least 1 week after discontinuing MP. Furthermore, there is a chronic increase in spontaneous protein extravasation in the hindpaw skin of rats after sciatic transection, similar to the increased protein extravasation observed in the edematous hands of CRPS patients. A 2-week infusion of MP (3 mg/kg/day) reduced spontaneous protein extravasation in the hindpaw skin by 80%. We postulated that increased spontaneous neurogenic extravasation resulted in development of limb edema in both the animal model and the CRPS patient, and that the anti-edematous effects of MP are due to an inhibition of spontaneous extravasation. Additional experiments examined the inhibitory effects of MP infusion on electrically-evoked neurogenic extravasation in the hindpaw skin of normal rats. MP inhibition was dose- and time-dependent, with an ED(50) of 1.2 mg/kg/day for a 14-day continuous infusion of MP, and a maximum inhibitory effect requiring 17 days of MP infusion (3 mg/kg/day). MP (3 mg/kg/day for 14 days) also blocked both capsaicin- and SP-evoked neurogenic extravasation, indicating a post-junctional inhibitory effect. Our interpretation is that increased spontaneous neurogenic extravasation in this CRPS model contributed to the development and maintenance of hindpaw edema, and that chronic MP administration dose- and time-dependently blocked neurogenic extravasation at a post-junctional level, thus reversing spontaneous extravasation and limb edema in this model.

Sympathetic innervation of lymphoreticular organs is rate limiting for prion neuroinvasion.

Transmissible spongiform encephalopathies are commonly propagated by extracerebral inoculation of the infectious agent. Indirect evidence suggests that entry into the central nervous system occurs via the peripheral nervous system. Here we have investigated the role of the sympathetic nervous system in prion neuroinvasion. Following intraperitoneal prion inoculation, chemical or immunological sympathectomy delayed or prevented scrapie. Prion titers in spinal cords were drastically reduced at early time points after inoculation. Instead, keratin 14-NGF transgenic mice, whose lymphoid organs are hyperinnervated by sympathetic nerves, showed reduction in scrapie incubation time and, unexpectedly, much higher titers of prion infectivity in spleens. We conclude that sympathetic innervation of lymphoid organs is rate limiting for prion neuroinvasion and that splenic sympathetic nerves may act as extracerebral prion reservoirs.

Autonomic regulation of lymphatic flow in the lower extremity demonstrated on lymphoscintigraphy in patients with reflex sympathetic dystrophy.

PURPOSE: Nuclear medicine techniques were used to show that the peripheral lymphatics are under autonomic control in much the same way as the blood vessels that supply the same anatomic region. METHODS: Three patients with complex regional pain syndrome type 1 (reflex sympathetic dystrophy) involving a lower extremity were evaluated using three-phase bone scintigraphy and peripheral lymphoscintigraphy. Each patient was treated with ipsilateral chemical lumbar sympathectomy, and lymphoscintigraphy was repeated within several days of the procedure. RESULTS: All three patients had evidence of decreased flow (compared with the contralateral extremity) to normal flow after ipsilateral sympathectomy. Bone scintigraphy, before and after sympathectomy, was difficult to interpret because of the effects of altered weight bearing. Two patients who had unilateral peripheral edema showed marked improvement after sympathectomy and increased lymphatic flow. CONCLUSIONS: Peripheral lymphatic function is controlled by the autonomic nervous system. In reflex sympathetic dystrophy, peripheral edema may be caused by an increased sympathetic stimulus to the lymphatics. Further study of this phenomenon may show that nuclear medicine studies, such as bone scintigraphy and lymphoscintigraphy, can be used to distinguish patients who will benefit from sympathectomy from those who will not, thereby obviating invasive testing and unnecessary invasive treatment.

Noradrenergic and peptidergic innervation of lymphoid organs.

It now is evident that extensive neural-immune anatomical connections exist between the nervous and immune systems, with close contacts of nerves with lymphocytes and macrophages. The presence of receptors for catecholamines and neuropeptides on these cells, coupled with functional evidence that these neural signals can modulate immune responses, brings these putative neurotransmitters to the forefront as a class of immunomodulatory molecules that can be investigated for possible benefit of disorders resulting from enhanced or suppressed activity of specific aspects of immune function. Furthermore, feedback from the immune system (cytokines) can act locally on lymphoid organ innervation to modulate transmitter release, and can act on the central nervous system via the vagus nerve to alter central pathways relevant to the immune system. It certainly is very clear that extensive bidirectional interactions occur between the nervous and immune systems, and that one system cannot be considered functionally without taking into account the state of activity of the other system.

An examination of the close relationship between lymphatic vessels and nerve fibers containing calcitonin gene-related peptide and substance P in rat skin.

The distribution of nerve fibers containing either calcitonin gene-related peptide (CGRP) and substance P (SP) was investigated in rat skin with special reference to their relationship to the lymphatic vessels. These nerve fibers exhibited a similar distribution pattern but the former were more numerous than the latter. In the dermis and subcutaneous layers, thin nerve fibers containing CGRP or SP were in abundance, and were observed running along the blood vessels as well as freely in the tissue. Nerve fibers with these peptides were often located close to lymphatic capillaries, and innervated lymphatic vessels in the subcutaneous layer, reaching smooth muscles of the tunica media. These findings suggest that some CGRP and SP may directly drain into lymphatic vessels when released under noxious stimulation from nerve fibers around the lymphatic vessels. When discharged from nerve fibers in the vicinity of blood vessels, both peptides may also drain into the lymphatic vessels after causing blood vascular dilation and an increase in permeability producing edema. These peptides may then be transported to the draining lymph nodes where they can modulate the functions of the immune system.

[The intramural neural apparatus of the mesenteric lymphangion of the small intestine]. / Intramural'nyi nervnyi apparat limfangiona bryzheiki tonkoi kishki.

Concentration of nerve structures in the lymphangion wall directly correlates with myocyte number in its different regions. Maximal adrenergic and cholinergic fibres concentration was defined in valvular torus muscular cuff of the lymphangion and minimal--in the valvular sinus wall. Besides, as structural organization of adrenergic plexus does not differ from that of antichollinaestherase-positive one and electron microscopic photos display diverse cholinergic and monoaminergic mediator vesicles in same fibres a suggestion is made on the mixed mediator nature of intramural plexuses of the lymphangion.

Studies of the lymphatic vessel-associated neurons in the intestine of the guinea pig.

A unique group of neurons in the submucous plexus of the gastrointestinal tract in guinea pigs was studied using (1) Nissl staining and an enzyme histochemical technique for acetylcholinesterase (AChE), (2) immunohistochemical methods for the localisation of neuron specific enolase (NSE) and neuropeptides, including vasoactive intestinal peptide (VIP), substance P (SP), somatostatin (SOM), calcitonin gene-related peptide (CGRP), leu-enkephalin (leu-ENK), neuropeptide (NPY) and cholecystokinin (CCK), (3) a fluorescence tracer technique involving the intraperitoneal (i.p.) injection of fluorogold, and (4) normal electron microscopy. The results showed that these neurons were distributed singly or in groups in the submucosa. They were closely adherent to the outer walls of lymphatic vessels, some appearing to protrude into the lumen. Ultrastructurally, only a thin layer of basal lamina and some collagen fibrils intervened between the endothelia of the lymphatic vessels and these neurons. Based on their synaptic contacts and the features of their content of synaptic vesicles, at least 4 types of axon terminal forming synaptic contacts with the 'lymphatic vessel-associated neurons' (LV-AN) were identified. The sources of origin of these terminals remains uncertain although it is speculated that they may be derived from vagal efferents or of intrinsic origin from the neighbouring neurons. All the LV-AN showed AChE and NSE positive reactions, but only a varying number were positive for VIP, SP, SOM, ENK, CGRP, CCK or NPY. The LV-AN were labelled with fluorogold injected i.p.(ABSTRACT TRUNCATED AT 250 WORDS)

Subendothelial nerve fibers in bovine mesenteric lymphatics: an ultrastructural and immunohistochemical study.

In the lymphatic vessels of man and most animals the nerve fibers are confined to the adventitia. However, immunohistochemical studies suggest that acetylcholinesterase-positive and monoamine-containing fibers reach as far as the endothelium in bovines. The aim of this study was to verify the presence of subendothelial nerve fibers by transmission electron microscopy (TEM) in bovine mesenteric lymphatics and to determine whether typical sensory neurotransmitters such as Substance P (SP) and calcitonin gene related peptide (CGRP) could be detected in these fibers. TEM revealed numerous unmyelinated nerve fibers in the subendothelial connective environment in close association with endothelial cells. Their axons were devoid of Schwann cell sheath on the endothelial side and contained small clear vesicles and large nerve fibers were demonstrated to be SP and CGRP-immunoreactive with mouse monoclonal antibodies against SP and rabbit polyclonal antibodies against CGRP. It is hypothesized that these fibers act as mechanoceptors capable of detecting intraluminal pressure and vessel wall tension variations and of locally releasing SP and CGRP. Since SP, potentiated by CGRP, is known to be a vasoconstrictor in lymphatics, we propose that the contraction of bovine mesenteric lymphatics may also be neurogenic.

Direct innervation of lymphoid organs: substrate for neurotransmitter signaling of cells of the immune system.

The nervous system can generate outflow capable of signaling cells of the immune system via two routes: (1) hormonal influences via hypothalamopituitary-target organ activation, and (2) neurotransmitter influences via direct innervation of the parenchyma of both primary and secondary lymphoid organs. Both noradrenergic and neuropeptidergic nerve fibers are found directly adjacent to cells of the immune system in bone marrow, thymus, spleen, lymph nodes, and other sites. These neurotransmitters can modulate immune responsiveness at several levels, including individual cellular functions, collective cellular interactions and immune responses, and overall host immunological response to a challenge by bacteria, viruses, tumor cells, or other sources. The ability of neural signals to modulate immune responsiveness is influenced by such factors as co-localization with other neurotransmitters, synergistic or dual signaling by neurotransmitters and cytokines, hormonal influences on ligand availability or receptor responsiveness, extent of catabolism and inactivation of the neural signal, and unique chemical and morphological aspects of the specific compartmentation of the lymphoid organ in which signaling is taking place. Thus, neural-immune signaling is a complex and dynamic process, with bidirectional interactions in a complex microenvironment.

Influence of spontaneous contractions of the lymphatic vessels on the lymphatic absorption rate of the peritoneal cavity in CAPD.

The lymphatic vessels have sympathetic innervation. Noradrenaline increases the number of spontaneous contractions of the lymphatic vessels, whereas isoprenaline slows these contractions. The purpose of this study was to analyze the influence of the blockade of spontaneous contractions of the lymphatic vessels on the lymphatic absorption rate (LAR) in 6 patients on continuous ambulatory peritoneal dialysis (CAPD) by using 0.12 mg of isoprenaline added to 2 L of 2.5% dextrose dialysis solution. This dose of isoprenaline has been shown to inhibit bovine mesenteric lymphatic contractions. The LAR was measured by the quantification of the intraperitoneal disappearance of dextran 70 added to this same dialysis solution during a 4-hour dwell. All patients were submitted to a control test without isoprenaline. The LAR was 0.57 +/- 0.19 and 0.65 +/- 0.38 mL/minute (p > 0.05), with and without isoprenaline, respectively. We conclude that spontaneous contractions of the lymphatic vessels do not play an important role in the lymphatic drainage mechanism of the peritoneal cavity. The diaphragmatic contractions seem to be more important, since drugs that interfere with such diaphragmatic mechanisms alter the LAR.

[Neurologic principles of edema in inactivity]. / Neurologische Grundlagen des Inaktivitätsödems.

The complete immobilisation of a limb alone can lead to the formation of oedema. Whereas the oedema secondary to inactivity induced by immobilisation is completely reversible, and will only lead to tissue damage in the longterm, neglect of oedema secondary to inactivity in the presence of central and peripheral paresis (apoplectic insult, paraplegia, damage to the plexus brachialis) may entail serious consequences due to the danger of tissue fibrosis. With paresis of an extremity, the lymphovenous return is impaired by two decisive factors: increased hydrostatic pressure in the distal limb segment, and absence of the muscle pump. In flaccid paresis, where there is low muscle tone and no muscle pump action, there is also a low venous tone and the resultant hydrostatic pressure is especially high. Venous stasis in the sub- and prefascial veins leads to increased protein loss from the venous limb of the capillaries and the venules. Compensation initially occurs in the prefascial lymph outflow region (latent oedema) which becomes decompensated if overloaded (visible oedema). Fibrosis of the subcutis and trophic skin changes are the result. In spastic paresis the regional subfascial lymphatic system responds with lymphangiospasm. Where the sympathetic innervation is interrupted (e.g. brachial plexus paralysis) there is passive hyperaemia of the terminal vessels with vascular dilatation and lymphangioparalysis. Insufficiency of the vascular walls results in an accumulation of protein in the tissues, which ultimately ends in fibrosis with ankylosis and shortening of the tendons and muscles. The early administration of complex physical decongestion therapy with manual lymphatic drainage can prevent this state.