Inhibition of poly(ADP-ribose) polymerase attenuates cerebral vasospasm after subarachnoid hemorrhage in rabbits

BACKGROUND AND PURPOSE

Poly(ADP-ribose) polymerase (PARP) is important in modulating inflammation, which has been implicated in cerebral vasospasm after subarachnoid hemorrhage (SAH). We investigated the role of PARP in vasospasm using 3-aminobenzamide (3-AB), a PARP inhibitor, in a rabbit model.

METHODS

Twenty-four New Zealand White rabbits were divided into 4 groups: (1) no treatment (control group, n=6); (2) blood injection without pretreatment (SAH-only group, n=6); (3) blood injection with pretreatment by vehicle (SAH+vehicle group, n=6); and (4) blood injection with pretreatment by 3-AB (SAH+3-AB group, n=6). We used the single-hemorrhage model of SAH, injecting autologous arterial blood into the cisterna magna. Angiography was performed before (baseline) and after (day 2) SAH, and the diameter of the basilar artery (BA) was measured. Animals were euthanatized after the second angiogram. After perfusion and fixation, the brains were cut into sections for hematoxylin and eosin and immunohistochemical staining for poly(ADP-ribosyl)ation.

RESULTS

In the control group, there were no differences in the BA lumen caliber between baseline and day 2 (96.8+/-10.4%). Cerebral vasospasm in the SAH+3-AB group (88.2+/-6. 2%) was remarkably attenuated in comparison with that in the SAH-only group (64.9+/-8.0%) and the SAH+vehicle group (65.6+/-10. 8%). The BA in the SAH+3-AB group showed less corrugation of the tunica elastica interna than that in the SAH-only and SAH+vehicle groups. Staining for poly(ADP-ribosyl)ation was markedly inhibited in smooth muscle and adventitial cells of the BA in the SAH+3-AB group compared with other groups.

CONCLUSIONS

Inhibiting ADP-ribosylation attenuates cerebral vasospasm after SAH in rabbits, and PARP activation may play an important role in the development of cerebral vasospasm.

Antivasospastic and antiinflammatory effects of caspase inhibitor in experimental subarachnoid hemorrhage

Object

Inflammation in the subarachnoid space and apoptosis of arterial endothelial cells have been implicated in the development of delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). The authors investigated mechanisms of possible antivasospastic effects of N-benzyl-oxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK), a caspase inhibitor that can inhibit both inflammatory and apoptotic systems, in animal models of SAH.

Methods

Rabbits were assigned to three groups of eight animals each and were subjected to SAH by injection of blood into the cisterna magna. The experiments were performed in the following groups: SAH only, SAH + vehicle, and SAH + Z-VAD-FMK. The Z-VAD-FMK (1 mg) or vehicle (5% dimethyl sulfoxide) was intrathecally administered before SAH induction. Diameters of the basilar artery (BA) were measured on angiograms obtained before and 2 days after SAH. The BA diameter on Day 2 was expressed as a percentage of that before SAH. Interleukin (IL)–1β in the cerebrospinal fluid (CSF) was examined using Western blotting, and brains were immunohistochemically examined for caspase-1 and IL-1β. In a separate experiment, 20 rats were subjected to SAH and their brains were immunohisto-chemically assessed for caspase-1, IL-1β, and macrophages.

Results

In rabbits, Z-VAD-FMK significantly attenuated cerebral vasospasm (the BA diameter on Day 2 in SAH-only, SAH + vehicle, and SAH + Z-VAD-FMK groups was 66.6 ± 3.2%, 66.3 ± 3.7%, and 82.6 ± 4.9% of baseline, respectively), and suppressed IL-1β release into the CSF and also suppressed immunoreactivities of caspase-1 and IL-1β in macrophages infiltrating into the subarachnoid space. Immunoreactivities for caspase-1 and IL-1β were observed in immunohistochemically proven infiltrating macrophages in rats.

Conclusions

These results indicate that caspase activation may be involved in the development of SAH-induced vasospasm through inflammatory reaction.

Effect of vasodilation by milrinone, a phosphodiesterase III inhibitor, on vasospastic arteries after a subarachnoid hemorrhage in vitro and in vivo: effectiveness of cisternal injection of milrinone

OBJECTIVE

Cerebral vasospasm remains a major cause of morbidity and mortality. Milrinone, a bipyridine phosphodiesterase III inhibitor, is a potent member of the inodilator class of cardiac agents for vasospasm and is injected intra-arterially or intracisternally. There have been no studies investigating the duration of action (context-sensitive half-life) of milrinone for vasospasm or the most effective route of administration (intra-arterial versus intracisternal). We examined the effects of intracisternal and intra-arterial injection of milrinone on chronic cerebral vasospasm in dogs.

METHODS

A double-hemorrhage canine model was used. In a preliminary isometric tension study of canine vasospastic basilar arteries, the vasodilatory effects of milrinone were examined 7 days after an initial injection of blood. Milrinone was injected intracisternally (0.1 mg, 0.47 mmol/L) or intra-arterially (0.3 mg/kg, 1.2 mmol/L), and angiograms were performed 30, 60, 120, 180, 240, 300, and 360 minutes later on day 7.

RESULTS

Milrinone produced concentration-dependent vasodilation and was effective intracisternally, resulting in significant dilation until 180 minutes after injection and a tendency for dilation until 240 minutes. The effect of intra-arterial injection was not as significant compared with an intracisternal injection, resulting in significant dilation only at 180 minutes after intra-arterial injection.

CONCLUSION

Intracisternal injection of milrinone was more effective than intra-arterial injection for chronic cerebral vasospasm in dogs because intracisternal injection produced a higher concentration in vasospastic arteries (0.034-0.068 mmol/L intracisternally versus 0.016 mmol/L intra-arterially).

Surgical correction of trigonocephaly: theoretical basis and operative procedures

Trigonocephaly involves premature fusion of both the metopic suture and the sutures in the skull base. Surgical treatment by opening of the prematurely fused metopic suture and expansion of the anterior cranial base by creating "neosutures" was used to treat three children with trigonocephaly. The combination of lateral canthal advancement and radical forehead remodeling achieved excellent results. These procedures can also prevent the development of midface hypoplasia such as hypotelorism. The two younger patients, aged 0 and 6 months, achieved rapid bone growth in the defects and normalization of intercanthal and interpupillary distances. The older patient, aged 8 years, retained some skull defects at follow-up. The optimal age for surgery is 3-6 months, which allows good cosmetic results and minimizes visual repercussions with relatively low perioperative risks.

Application and Advantages of the Trans-Unco-Discal (TUD) Approach for Cervical Spondylotic Myelopathy and Radiculopathy: Classification and Modification of Surgical Technique Based on the Location of Spinal Cord and/or Nerve Root Compression

Purpose: We assess the application and advantages of modifying the trans-unco-discal (TUD) approach which we underwent for cervical myelo-radiculopathy. We present the surgical techniques of the modified TUD approach. Materials and Methods: The material was 180 cases where anterior cervical decompression (ACD) was performed by the modified TUD approach. We classified the material into four groups based on the location of the nerve root and/or spinal cord compression: I, compression of the root at intervertebral foramen (IVF); II, compression of the posterior margin of the vertebral body; III, compression of the IVF and posterior margin of the vertebral body; IV, compression of the bilateral IVF and posterior margin of the vertebral body. We applied the modified TUD approach to these four types. We present the surgical procedures and techniques for the modified TUD approach. The Japanese orthopedic association (JOA) score and neuroradiological alignment were examined. Results: The improvement rate of the JOA score was 78.4% at 6 months post-surgery and 77.5% in the most recent examinations. By the modified TUD approach, compressive lesions of the spinal cord and/or nerve roots were removed, and good alignment was acquired and sustained. Conclusions: ACD by the modified TUD approach safely achieved appropriate decompression for the spinal cord and/or nerve roots, and the patients had a high improvement rate and good alignment. Complications were less common than with other surgical procedures. If the TUD approach and endoscopic approaches can be combined, their application to new area is anticipated.

Indication of C2-C7 Cervical Laminoplasty with Muscle and Ligament Preservation in Patients with Kyphosis

OBJECTIVE

Cervical laminoplasty is generally not indicated in patients with kyphosis because of poor outcomes. Therefore, data on the effectiveness of posterior structure-preserving techniques in patients with kyphosis are limited. This study investigated how laminoplasty with muscle and ligament preservation can benefit patients with kyphosis via risk factor analyses of postoperative complications.

METHODS

Clinicoradiological outcomes of 106 consecutive patients, including patients with kyphosis, who had undergone C2-C7 laminoplasty in a muscle- and ligament-preserving fashion, were retrospectively analyzed. Surgical outcomes, including neurological recovery, were assessed, and sagittal parameters were measured on radiographs.

RESULTS

Surgical outcomes of patients with kyphosis were comparable to outcomes of other patients except for axial pain (AP), which was significantly more frequent in patients with kyphosis. Moreover, AP was significantly associated with alignment loss (AL) >0°. Substantial local kyphosis (local kyphosis angle >10°) and greater value of range of motion (ROM) during flexion minus ROM during extension were identified as risk factors for AP and AL >0°, respectively. Receiver operating characteristic curve analysis indicated ROM during flexion minus ROM during extension cutoff value of 0.7° for predicting AL >0° in patients with kyphosis (sensitivity: 77%; specificity: 84%). Substantial local kyphosis combined with ROM during flexion minus ROM during extension >0.7° had 56% sensitivity and 84% specificity for predicting AP in patients with kyphosis.

CONCLUSIONS

Although patients with kyphosis had a significantly higher incidence of AP, C2-C7 cervical laminoplasty with muscle and ligament preservation may not be contraindicated in selected patients with kyphosis by risk stratification for AP and AL using newly identified risk factors.