Vasa nervorum of epicardial nerves and valves of small veins investigated in porcine heart by two types of vascular injections

The morphology of the vascular supply of peripheral branches of cardiac nerves has not been systematically described until now. The aim of this study was to describe the architectonics of the vasa nervorum of epicardial nerves in porcine hearts by using two injection techniques. Twenty-three hearts from young healthy pigs were used. In 10 hearts India ink solution was injected into the origin of the anterior interventricular branch. In another 10 hearts India ink solution was injected retrogradely through the coronary sinus. The hearts were then analyzed using a magnifying glass and light microscopy. The arterial injection showed the entirety of the rich venous components of the vasa nervorum, which often consisted of paired veins accompanying the epicardial nerves. The thickness of the nerves ranged from 50 to 815 μm. The vasa nervorum drained into larger subepicardial veins. In seven of the hearts prepared with venous injections the vasa nervorum of epicardial nerves were visualized in the same detail as in the arterial preparations and India ink solution filled the right ventricle via the smallest cardiac veins. The histological analysis of these seven hearts showed complete dehiscence and functional insufficiency of small and larger veins valves. In the other three hearts prepared with venous injections the valves were competent, which prevented retrograde filling of larger and smaller veins. The results obtained expand the current knowledge on epicardial nerves vasa nervorum and provide anatomical evidence behind the mechanism of retrograde application of cardioplegic solutions in cardiac surgery.

Vitamin D as a Potential Agent for Ischemic Axonal Regeneration after Epineurial Devascularization of the Sciatic Nerve

BACKGROUND

Although vitamin D has several noncalcemic functions particularly on nervous system, its neuroregenerative roles on ischemic peripheral nerve injury has not been reported. In this study, it was aimed to investigate the effect of vitamin D3 after epineurial devascularization of the sciatic nerve.

METHODS

Forty adult female Wistar rats were randomly divided into four groups: Group 1 (Control), Group 2 (Sham-operated), Group 3 (Epineurial devascularization + vitamin D3 treatment), Group 4 (Epineurial devascularization + vehicle treatment). Recovery of the sciatic nerve was analyzed by functional (sciatic functional index, pinch test and biochemical analyses) and morphological (electron microscopic analysis and wet muscle weight analysis) methods.

RESULTS

Comparison of the data revealed that vitamin D3 administration had a beneficial effect on regeneration after epineurial devascularization.

CONCLUSION

We suggest that vitamin D3 is an effective agent in the prevention of ischemic peripheral nerve insults.

Vasa nervorum angiogenesis in prostate cancer with perineural invasion

BACKGROUND

Perineural invasion (PNI) is generally accepted as a major route of cancer dissemination in malignancies associated with highly enervated organs. However, the effect of cancer cells on vasa nervorum remains unknown. We studied this effect in locally advanced prostate cancer, a high-risk feature associated with approximately 20% of prostate cancer specific mortality.

METHODS

We used immunohistochemistry for CD34, fibroblast growth factor-2 (FGF-2), FSHR, podoplanin, vascular endothelial growth factor (VEGF), and VEGFR-2 as well as histochemical methods to examine the vasa nervorum of nerves invaded by cancer cells in tissue samples from 85 patients.

RESULTS

The percentage of the nerve area occupied by CD34-positive vasa nervorum endothelial cells in nerves with PNI was much higher than in nerves without PNI (7.3 ± 1.2 vs 1.9 ± 0.4; P < 0.001 and 5.8 ± 0.6 vs 1.23 ± 0.8; P < 0.001 in pT3a and pT3b prostate cancer specimens, respectively). In 19/85 of the patients the CD34-positive vasa nervorum microvessels have a thick basement membrane, similar to the vessels in diabetic microangiopathy. This subendothelial layer contains collagen fibers. Vasa nervorum endothelia and Schwann cells express FGF-2 (nuclear localization) and FSHR (plasma membrane and cytoplasmic staining). Prostate cancer cells invading nerves express VEGF, a critical cytokine in tumor angiogenesis. The vasa nervorum of prostatic nerves with PNI did not express detectable levels of VEGFR-2. No podoplanin-positive lymphatic vessels were seen in nerves.

CONCLUSION

In locally advanced prostate cancer, PNI of cancer cells is associated with formation of new endoneurial capillaries and changes of vasa nervorum morphology.

Microangiopathy-A Potential Contributing Factor to Idiopathic Polyneuropathy: A Mini Review

Chronic idiopathic axonal polyneuropathy (CIAP) is a slowly progressive predominantly sensory axonal polyneuropathy. The prevalence of CIAP increases with age. The pathogenic cause of CIAP is unknown although there are several prevailing etiological hypotheses. In this mini review, we focus on the hypothesis of disturbed microcirculation in the vasa nervorum of peripheral nerves as a pathogenic cause of CIAP. There is an association between CIAP and metabolic risk factors. Furthermore, the phenotype of CIAP resembles diabetic neuropathy both clinically and electrophysiologically. In sural nerve biopsies from patients with diabetes mellitus, structural abnormalities indicating microangiopathy in the endoneurial microvessels are well documented. Similarly, sural microvessel abnormalities have been shown in patients with atherosclerotic non-diabetic peripheral vascular disease. However, the reported histopathological alterations of microvasculature in sural nerves of CIAP patients are inconsistent. Two studies report microangiopathic changes in CIAP sural nerves comparable with those found in patients with diabetic neuropathy. Conversely, another recent study showed no significant differences in the microangiopathic parameters in the endoneurial microvessels in the sural nerve biopsies from CIAP patients compared to controls without polyneuropathy. However, this CIAP patient group was younger compared to the patient groups in the other two studies. A general limitation with the published morphological studies are that different methods have been used in the assessment of microangiopathy, and there is also a risk of subjectivity in the results. Immunohistochemistry studies of sural nerves with verification of microangiopathy using specific biomarkers would be of great interest to develop.

Facial palsy after embolization of dural arteriovenous fistula: A case report and literature review

Background

Dural arteriovenous fistulas (DAVF) are unusual intracranial vascular malformations consisting of anomalous connections between meningeal arteries and dural sinuses or the veins that pass through them. They have variable clinical presentation and prognosis, which depend on their location and venous hemodynamics. Treatment is based on the closure of the abnormal connections, which is usually conducted via arterial and/or transvenous endovascular techniques.

Case Description

We present a male patient who complained of headaches and left-sided pulsatile tinnitus due to DAVF from the external carotid artery branches draining directly into the ipsilateral sigmoid sinus. Embolization with Onyx^® was successful, obtaining angiographic occlusion and symptom remission. However, on postoperative day 4, the patient presented with left facial palsy and spontaneous regression.

Conclusion

Although embolization is an effective and safe procedure, complications may occur. Reflux of the embolic agent to the vasa nervorum of the cranial nerve may lead to ischemic neuropathy. Here, we reported a case of embolized DAVF presenting with a postoperative peripheral facial palsy where the two embolized pedicles were branches of the middle meningeal and occipital arteries involved in the vascularization of the extratemporal segment of the facial nerve. We discuss the etiopathogenic, anatomical, and pathophysiological aspects of this complication.

Non-Systemic Vasculitic Neuropathy: An Enigmatic Clinical Entity

BACKGROUND

Non-systemic vasculitic peripheral neuropathy is a rare condition characterized by necrotizing inflammation resulting in luminal narrowing of the vasa nervorum, leading to ischemic injury to peripheral nerves. Here, we present the case of 63-year-old woman with subacute onset of severe hyperesthesia of the lower extremities accompanied by foot drop.

CASE REPORT

A 63-year-old woman with prolonged history of uncontrolled diabetes mellitus presented with subacute onset of severe bilateral lower extremity hyperesthesia and motor weakness along with left-sided foot drop. She had multiple emergency room visits with no relief of her symptoms. High doses of analgesics were insufficient to control pain. Laboratory tests were positive only for high erythrocyte sedimentation rate and C-reactive protein. A skin biopsy obtained 5 cm above the left lateral malleolus revealed medium-sized dermal vasculitis with dense mononuclear infiltrate. Electromyography showed peripheral neuropathy. A nerve biopsy was needed to reveal the exact diagnosis.

CONCLUSIONS

Diagnosis of non-systemic vasculitic peripheral neuropathy can be delayed or missed in patients with uncontrolled diabetes mellitus, leading to significant morbidity. Elevated markers of inflammation in the absence of a possible explanation should prompt the clinician to perform a nerve biopsy; however, it is an invasive procedure and is associated with complications of post-neuropathic pain and delayed wound healing. Magnetic resonance angiography of the lower limbs, if combined with skin biopsy, can save the patient from undergoing nerve biopsy.

Label-free 3D optical microangiography imaging of functional vasa nervorum and peripheral microvascular tree in the hind limb of diabetic mice

Diabetic neuropathy (DN) is, at least in part, associated with the functional attenuation of vasa nervorum, the microvascular structure of peripheral nerves. Microvascular imaging options for vasa nervorum still remain limited. In this work, Optical micro-angiography (OMAG), a volumetric, label-free imaging technique is utilized for characterizing, with high resolution, blood perfusion of peripheral nerve in diabetic mice. We demonstrate that OMAG is able to visualize the structure of microvasculature and to quantify the changes of dynamic blood flow and vessel diameters during administration of vessel stimulator in both diabetic and normal mice. The results indicate the potential of OMAG to assess the blood supply of nerve involved in the pathology and treatment of DN.