Response of the periodontal tissues to β-adrenergic stimulation

AUTHORS

Renata Mendonça Moraes, Florent Elefteriou, Ana Lia Anbinder

ABSTRACT

Aims

Stimulation of β-adrenergic receptors (βAR) in osteoblasts by isoproterenol (ISO) was shown to induce Vascular Endothelial Growth Factor (VEGF) and angiogenesis in long bones. We thus aimed to determine the vascular response of mandibular tissues to βAR stimulation regarding blood vessel formation.

Main methods

Six-week-old wild-type C57BL6 female mice received daily intraperitoneal injections of ISO or phosphate buffered saline (PBS) for 1 month. Hemimandibles and tibias were collected for immunolocalization of endomucin, tyrosine hydroxylase (TH), neuropeptide Y (NPY) and norepinephrine transporter (NET). Moreover, Vegfa, Il-1 β, Il-6, Adrb2 and Rankl mRNA expression was assessed in mandibles and tibias 2 h after PBS or ISO treatment.

Key findings

Despite similar sympathetic innervation and Adrb2 expression between mandibular tissues and tibias, with TH and NPY+ nerve fibers distributed around blood vessels, ISO treatment did not increase endomucin+ vessel area or the total number of endomucin+ vessels in any of the regions investigated (alveolar bone, periodontal ligament, and dental pulp). Consistent with these results, the expression of Vegfα, Il-6, Il-1β, and Rankl in the mandibular molar region did not change following ISO administration. We detected high expression of NET by immunofluorescence in mandible alveolar osteoblasts, osteocytes, and periodontal ligament fibroblasts, in addition to significantly higher Net expression by qPCR compared to the tibia from the same animals.

Significance

These findings indicate a differential response to βAR agonists between mandibular and tibial tissues, since the angiogenic potential of sympathetic outflow observed in long bones is absent in periodontal tissues.

Effects of Theranekron and alpha-lipoic acid combined treatment on GAP-43 and Krox-20 gene expressions and inflammation markers in peripheral nerve injury

AUTHORS

Leman Sencar, Gülfidan Coşkun, Dilek Şaker, Tuğçe Sapmaz, Samet Kara, Alper Çelenk, Sema Polat, Derviş Mansuri Yılmaz, Y. Kenan Dağlıoğlu & Sait Polat

ABSTRACT

Peripheral nerve injury (PNI) is a major health problem that results in loss of motor and sensory functions. In treatment of PNI, various methods such as anastomosis, nerve grafts, nonneural tissue grafts, and nerve conduits are applied. In the present study, it was aimed to investigate the effects of Theranekron and Alpha-lipoic acid (ALA) combined treatment on nerve healing in experimental PNI by using histomorphometric, electron microscopic, immunohistochemical and molecular biological methods. Sixty-two Wistar rats were divided into six groups; the normal control group, sham operation group, experimental control group having a crush type injury with no treatment, Theranekron treatment group, ALA treatment group and Theranekron+ALA combined treatment group. Sciatic nerve tissue samples were obtained on days 1, 7 and 14 following injury in all groups. GAP-43 expression was upregulated in all PNI received groups compared to the control group. Krox-20 expression was downregulated in all groups that received PNI compared to the control group. While intensely positive TNF-α and IL-6 expressions were observed up to the 1st to the 14th day for the experimental control group, these expressions were seen as “weakly positive” in the treatment groups from the 1st day to the 14th day. The number of myelinated fibers was higher in the control and sham operation groups. Additionally, the number of myelinated nerve fibers increased in the combined treatment group. In conclusion, these findings suggest that combined therapy of Theranekron and ALA promotes structural recovery and it should be considered as an effective treatment protocol following PNI.

The alarmin interleukin-1α triggers secondary degeneration through reactive astrocytes and endothelium after spinal cord injury

AUTHORS

Floriane Bretheau, Adrian Castellanos-Molina, Benoit Mailhot, Maxime Kusik, Dominic Belanger, Martine Lessard, Nicolas Vallières, Xiaoyu Liu, Ning Quan, Steve Lacroix

ABSTRACT

Spinal cord injury (SCI) triggers neuroinflammation, and subsequently secondary degeneration and oligodendrocyte (OL) death. We report that the alarmin interleukin (IL)-1α is released by damaged microglia after SCI. Intra-cisterna magna injection of IL-1α in mice rapidly induced neutrophil infiltration and OL death throughout the spinal cord, mimicking what is seen at sites of SCI. These effects were abolished by co-treatment with the IL-1R1 antagonist anakinra, as well as in IL-1R1-knockout mice which showed enhanced locomotor recovery after SCI. Conditional restoration of IL-1R1 expression in astrocytes or endothelial cells (ECs), but not in OLs or microglia, restored IL-1α-induced effects, while astrocyte- or EC-specific Il1r1 deletion reduced OL loss. Conditioned medium derived from IL-1α-stimulated astrocytes is toxic for OLs; further, IL-1α-stimulated astrocytes generate reactive oxygen species (ROS) and blocking ROS production in IL-1α-treated or SCI mice prevented OL loss. Thus, after SCI, microglia release IL-1α, which induces astrocyte- and EC-mediated OL degeneration.

Nerve transfer for restoration of lower motor neuron-lesioned bladder function. Part 2: correlation between histological changes and nerve evoked contractions

AUTHORS

Mary F. Barbe, Courtney L. Testa, Geneva E. Cruz, Nagat A. Frara, Ekta Tiwari, Lucas J. Hobson, Brian S. McIntyre, Danielle S. Porreca, Dania Giaddui, Alan S. Braverman, Emily P. Day, Mamta Amin, Justin M. Brown, Michael Mazzei, Michel A. Pontari, Ida J. Wagner, and Michael R. Ruggieri Sr.

ABSTRACT

We determined the effect of pelvic organ decentralization and reinnervation 1 yr later on urinary bladder histology and function. Nineteen canines underwent decentralization by bilateral transection of all coccygeal and sacral (S) spinal roots, dorsal roots of lumbar (L)7, and hypogastric nerves. After exclusions, eight were reinnervated 12 mo postdecentralization with obturator-to-pelvic and sciatic-to-pudendal nerve transfers, then euthanized 8-12 mo later. Four served as long-term decentralized only animals. Before euthanasia, pelvic or transferred nerves and L1–S3 spinal roots were stimulated and maximum detrusor pressure (MDP) recorded. Bladder specimens were collected for histological and ex vivo smooth muscle contractility studies. Both reinnervated and decentralized animals showed less or denuded urothelium, fewer intramural ganglia, and more inflammation and collagen, than controls, although percent muscle was maintained. In reinnervated animals, pgp9.5+ axon density was higher compared with decentralized animals. Ex vivo smooth muscle contractions in response to KCl correlated positively with submucosal inflammation, detrusor muscle thickness, and pgp9.5+ axon density. In vivo, reinnervated animals showed higher MDP after stimulation of L1–L6 roots compared with their transected L7–S3 roots, and reinnervated and decentralized animals showed lower MDP than controls after stimulation of nerves (due likely to fibrotic nerve encapsulation). MDP correlated negatively with detrusor collagen and inflammation, and positively with pgp9.5+ axon density and intramural ganglia numbers. These results demonstrate that bladder function can be improved by transfer of obturator nerves to pelvic nerves at 1 yr after decentralization, although the fibrosis and inflammation that developed were associated with decreased contractile function.

Key indicators of repetitive overuse-induced neuromuscular inflammation and fibrosis are prevented by manual therapy in a rat model

AUTHORS

Mary F. Barbe, Michele Y. Harris, Geneva E. Cruz, Mamta Amin, Nathan M. Billett, Jocelynne T. Dorotan, Emily P. Day, Seung Y. Kim & Geoffrey M. Bove

ABSTRACT

Background

We examined the effectiveness of a manual therapy consisting of forearm skin rolling, muscle mobilization, and upper extremity traction as a preventive treatment for rats performing an intensive lever-pulling task. We hypothesized that this treatment would reduce task-induced neuromuscular and tendon inflammation, fibrosis, and sensorimotor declines.

Methods

Sprague-Dawley rats performed a reaching and lever pulling task for a food reward, 2 h/day, 3 days/week, for 12 weeks, while simultaneously receiving the manual therapy treatment 3 times per week for 12 weeks to either the task-involved upper extremities (TASK-Tx), or the lower extremities as an active control group (TASK-Ac). Results were compared to similarly treated control rats (C-Tx and C-Ac).

Results

Median nerves and forearm flexor muscles and tendons of TASK-Ac rats showed higher numbers of inflammatory CD68+ and fibrogenic CD206+ macrophages, particularly in epineurium, endomysium and epitendons than TASK-Tx rats. CD68+ and CD206+ macrophages numbers in TASK-Tx rats were comparable to the non-task control groups. TASK-Ac rats had more extraneural fibrosis in median nerves, pro-collagen type I levels and immunoexpression in flexor digitorum muscles, and fibrogenic changes in flexor digitorum epitendons, than TASK-Tx rats (which showed comparable responses as control groups). TASK-Ac rats showed cold temperature, lower reflexive grip strength, and task avoidance, responses not seen in TASK-Tx rats (which showed comparable responses as the control groups).

Conclusions

Manual therapy of forelimbs involved in performing the reaching and grasping task prevented the development of inflammatory and fibrogenic changes in forearm nerves, muscle, and tendons, and sensorimotor declines.

A Cadaveric Study on the Utility of the Levator Scapulae Motor Nerve as a Donor for Brachial Plexus Reconstruction

AUTHORS

Eliana B.Saltzman, Karthik Krishnan, Mark J.Winston, Soumen Das DeM, Steve K.Lee, Scott W. Wolfe

ABSTRACT

Purpose

The purpose of the study was to evaluate the utility of the levator scapulae motor nerve (LSN) as a donor nerve for brachial plexus nerve transfer. We hypothesized that the LSN could be transferred to the suprascapular nerve (SSN) or long thoracic nerve (LTN) with a reliable tension-free coaptation and appropriate donor-to-recipient axon count ratio.

Methods

Twelve brachial plexus dissections were performed on 6 adult cadavers, bilaterally. We identified the LSN, spinal accessory nerve (SAN), SSN, and LTN. Each nerve was prepared for transfer and nerve redundancies were calculated. Cross-sections of each nerve were examined histologically, and axons counted. We transferred the LSN to target first the SSN and then the LTN, in a tension-free coaptation. For reference, we transferred the distal SAN to target the SSN and LTN and compared transfer parameters.

Results

Three cadavers demonstrated 2 LSN branches supplying the levator scapulae. The axon count ratio of donor-to-recipient nerve was 1:4.0 (LSN:SSN) and 1:2.1 (LSN:LTN) for a single LSN branch and 1:3.0 (LSN:SSN) and 1:1.6 (LSN:LTN) when 2 LSN branches were available. Comparatively, the axon count ratio of donor-to-recipient nerve was 1:2.5 and 1:1.3 for the SAN to the SSN and the LTN, respectively. The mean redundancy from the LSN to the SSN and the LTN was 1.7 cm (SD, 3.1 cm) and 2.9 cm (SD, 2.8 cm), and the redundancy from the SAN to the SSN and the LTN was 4.5 (SD, 0.7 cm) and 0.75 cm (SD, 1.0 cm).

Conclusions

These data support the use of the LSN as a potential donor for direct nerve transfer to the SSN and LTN, given its adequate redundancy and size match.