Dong H. Kim

Mutations in Smooth Muscle Alpha-Actin (ACTA2) Cause Coronary Artery Disease, Stroke, and Moyamoya Disease, Along with Thoracic Aortic Disease

The vascular smooth muscle cell (SMC)-specific isoform of alpha-actin (ACTA2) is a major component of the contractile apparatus in SMCs located throughout the arterial system. Heterozygous ACTA2 mutations cause familial thoracic aortic aneurysms and dissections (TAAD), but only half of mutation carriers have aortic disease. Linkage analysis and association studies of individuals in 20 families with ACTA2 mutations indicate that mutation carriers can have a diversity of vascular diseases, including premature onset of coronary artery disease (CAD) and premature ischemic strokes (including Moyamoya disease [MMD]), as well as previously defined TAAD. Sequencing of DNA from patients with nonfamilial TAAD and from premature-onset CAD patients independently identified ACTA2 mutations in these patients and premature onset strokes in family members with ACTA2 mutations. Vascular pathology and analysis of explanted SMCs and myofibroblasts from patients harboring ACTA2 suggested that increased proliferation of SMCs contributed to occlusive diseases. These results indicate that heterozygous ACTA2 mutations predispose patients to a variety of diffuse and diverse vascular diseases, including TAAD, premature CAD, ischemic strokes, and MMD. These data demonstrate that diffuse vascular diseases resulting from either occluded or enlarged arteries can be caused by mutations in a single gene and have direct implications for clinical management and research on familial vascular diseases.

Rebleeding leads to poor outcome in ultra-early craniotomy for intracerebral hemorrhage

Background: A modest benefit was previously demonstrated for hematoma evacuation within 12 hours of intracerebral hemorrhage onset. Perhaps surgery within 4 hours would further improve outcome. Methods: Adult patients with spontaneous supratentorial intracerebral hemorrhage were prospectively enrolled. Craniotomy and clot evacuation were commenced within 4 hours of symptom onset in all cases. Mortality and functional outcome were assessed at 6 months. This group of patients was compared with patients treated within 12 hours of symptom onset using the same surgical and medical protocols. Results: The study was stopped after a planned interim analysis of 11 patients in the 4-hour surgery arm. Median time to surgery was 180 minutes; median hematoma volume was 40 mL; median baseline NIH Stroke Scale score was 19 and Glasgow Coma Scale score was 12. Six-month mortality was 36% and median Barthel score was 75 in survivors. Postoperative rebleeding occurred in four patients, three of whom died. A relationship between postoperative rebleeding and mortality was apparent (p = 0.03). Rebleeding occurred in 40% of the patients treated within 4 hours, compared with 12% of the patients treated within 12 hours (p = 0.11). There was a clear correlation between improved outcome and smaller postsurgical hematoma volume (p = 0.04). Conclusions: Surgical hematoma evacuation within 4 hours of symptom onset is complicated by rebleeding, indicating difficulty with hemostasis. Maximum removal of blood remains a predictor of good outcome.

Transplantation of ciliary neurotrophic factor-expressing adult oligodendrocyte precursor cells promotes remyelination and functional recovery after spinal cord injury.

Demyelination contributes to the dysfunction after traumatic spinal cord injury (SCI). We explored whether the combination of neurotrophic factors and transplantation of adult rat spinal cord oligodendrocyte precursor cells (OPCs) could enhance remyelination and functional recovery after SCI. Ciliary neurotrophic factor (CNTF) was the most effective neurotrophic factor to promote oligodendrocyte (OL) differentiation and survival of OPCs in vitro. OPCs were infected with retroviruses expressing enhanced green fluorescent protein (EGFP) or CNTF and transplanted into the contused adult thoracic spinal cord 9 d after injury. Seven weeks after transplantation, the grafted OPCs survived and integrated into the injured spinal cord. The survival of grafted CNTF-OPCs increased fourfold compared with EGFP-OPCs. The grafted OPCs differentiated into adenomatus polyposis coli (APC+) OLs, and CNTF significantly increased the percentage of APC+ OLs from grafted OPCs. Immunofluorescent and immunoelectron microscopic analyses showed that the grafted OPCs formed central myelin sheaths around the axons in the injured spinal cord. The number of OL-remyelinated axons in ventrolateral funiculus (VLF) or lateral funiculus (LF) at the injured epicenter was significantly increased in animals that received CNTF-OPC grafts compared with all other groups. Importantly, 75% of rats receiving CNTF-OPC grafts recovered transcranial magnetic motor-evoked potential and magnetic interenlargement reflex responses, indicating that conduction through the demyelinated axons in VLF or LF, respectively, was partially restored. More importantly, recovery of hindlimb locomotor function was significantly enhanced in animals receiving grafts of CNTF-OPCs. Thus, combined treatment with OPC grafts expressing CNTF can enhance remyelination and facilitate functional recovery after traumatic SCI.

Analysis of multigenerational families with thoracic aortic aneurysms and dissections due to TGFBR1 or TGFBR2 mutations

Background: Mutations in the transforming growth factor β receptor type I and II genes (TGFBR1 and TGFBR2) cause Loeys–Dietz syndrome (LDS), characterised by thoracic aortic aneurysms and dissections (TAAD), aneurysms and dissections of other arteries, craniosynostosis, cleft palate/bifid uvula, hypertelorism, congenital heart defects, arterial tortuosity, and mental retardation. TGFBR2 mutations can also cause TAAD in the absence of features of LDS in large multigenerational families, yet only sporadic LDS cases or parent–child pairs with TGFBR1 mutations have been reported to date. Methods: The authors identified TGFBR1 missense mutations in multigenerational families with TAAD by DNA sequencing. Clinical features of affected individuals were assessed and compared with clinical features of previously described TGFBR2 families. Results: Statistical analyses of the clinical features of the TGFBR1 cohort (n = 30) were compared with clinical features of TGFBR2 cohort (n = 77). Significant differences were identified in clinical presentation and survival based on gender in TGFBR1 families but not in TGFBR2 families. In families with TGFBR1 mutations, men died younger than women based on Kaplan–Meier survival curves. In addition, men presented with TAAD and women often presented with dissections and aneurysms of arteries other than the ascending thoracic aorta. The data also suggest that individuals with TGFBR2 mutations are more likely to dissect at aortic diameters <5.0 cm than individuals with TGFBR1 mutations. Conclusion: This study is the first to demonstrate clinical differences between patients with TGFBR1 and TGFBR2 mutations. These differences are important for the clinical management and outcome of vascular diseases in these patients.

De novo ACTA2 mutation causes a novel syndrome of multisystemic smooth muscle dysfunction

Smooth muscle cells (SMCs) contract to perform many physiological functions, including regulation of blood flow and pressure in arteries, contraction of the pupils, peristalsis of the gut, and voiding of the bladder. SMC lineage in these organs is characterized by cellular expression of the SMC isoform of α‐actin, encoded by the ACTA2 gene. We report here on a unique and de novo mutation in ACTA2, R179H, that causes a syndrome characterized by dysfunction of SMCs throughout the body, leading to aortic and cerebrovascular disease, fixed dilated pupils, hypotonic bladder, malrotation, and hypoperistalsis of the gut and pulmonary hypertension.

Astrocytes from the contused spinal cord inhibit oligodendrocyte differentiation of adult oligodendrocyte precursor cells by increasing the expression of bone morphogenetic proteins

Promotion of remyelination is an important therapeutic strategy to facilitate functional recovery after traumatic spinal cord injury (SCI). Transplantation of neural stem cells (NSCs) or oligodendrocyte precursor cells (OPCs) has been used to enhance remyelination after SCI. However, the microenvironment in the injured spinal cord is inhibitory for oligodendrocyte (OL) differentiation of NSCs or OPCs. Identifying the signaling pathways that inhibit OL differentiation in the injured spinal cord could lead to new therapeutic strategies to enhance remyelination and functional recovery after SCI. In the present study, we show that reactive astrocytes from the injured rat spinal cord or their conditioned media inhibit OL differentiation of adult OPCs with concurrent promotion of astrocyte differentiation. The expression of bone morphogenetic proteins (BMP) is dramatically increased in the reactive astrocytes and their conditioned media. Importantly, blocking BMP activity by BMP receptor antagonist, noggin, reverse the effects of active astrocytes on OPC differentiation by increasing the differentiation of OL from OPCs while decreasing the generation of astrocytes. These data indicate that the upregulated bone morphogenetic proteins in the reactive astrocytes are major factors to inhibit OL differentiation of OPCs and to promote its astrocyte differentiation. These data suggest that manipulation of BMP signaling in the endogenous or grafted NSCs or OPCs may be a useful therapeutic strategy to increase their OL differentiation and remyelination and enhance functional recovery after SCI.

Genetic analysis of glioblastoma multiforme provides evidence for subgroups within the grade

We analyzed 72 primary and 25 recurrent glioblastoma multiforme (GBM) samples for DNA sequence copy number abnormalities (CNAs) by comparative genomic hybridization (CGH). The number of aberrations per tumor ranged from 2 to 23 in primary GBM and 5 to 25 in recurrent GBM. There were 26 chromosome regions with CNAs in more than 20% of tumors. 7q22‐36 was the most common gain and 10q25‐26 was the most common loss; each occurred in more than 70% of tumors. Of 27 amplification sites, epidermal growth factor receptor (EGFR) was the most common; it was observed in 25% of primary GBMs. Statistical analysis based on pairwise correlation of CNAs indicated that there is more than one class of primary GBM. Genes Chromosomes Cancer 21:195–206, 1998.

Morphine analgesia and acute physical dependence: rapid onset of two opposing, dose-related processes

Enhanced responsiveness to noxious stimulation is a reliable sign of opioid withdrawal and is therefore a measure of physical dependence. In lightly anesthetized rats, naloxone, given i.v. 15 min following i.v. morphine, caused a significant shortening of tail flick latency (hyperalgesia). At each dose of naloxone (0.1, 1.0 or 2.0 mg/kg), the magnitude of the observed hyperalgesia was a function of the preceding dose of morphine (0.5, 1.0 or 2.0 mg/kg). Thus morphine rapidly induces two dose-related opposing processes: one results in antinociception and the other in the potential for hyperalgesia.

Utility of Outcome Measures After Treatment for Intracranial Aneurysms. A Prospective Trial Involving 520 Patients

Background and Purpose— As different intracranial aneurysm treatments are compared in upcoming trials, complete characterization of patient outcomes will be critical. Currently, graded scales such as the Glasgow Outcome Score (GOS) or the Rankin scale are commonly used. Our objective was to test the utility of different outcome instruments in patients after aneurysm treatment. Methods— A prospective trial comparing 6 outcome instruments at 3 to 12 months after aneurysm treatment: the Rankin and GOS, the Barthel Index (activities of daily living), the National Institutes of Health Stroke Score (NIHSS) (neurological examination), the Short Form-36 (subjective experience of recovery), and the Mini-Mental Status Examination (MMSE) (cognitive recovery). All tests were administered to each patient at the same time by an independent grader. The Spearman correlation coefficient was calculated between instruments (with 1 representing complete correlation). Results— In 4 years, 520 patients with 618 ruptured or unruptured aneurysms were enrolled: 385 surviving patients were tested. The resulting scores showed a wide distribution for the MMSE and the SF-36, but almost no variability for the Barthel Index and NIHSS. Correlations between scores were poor: 0.15 when the GOS was compared with the MMSE; 0.27 compared with the SF-36. Many patients given the highest GOS or Rankin scores showed significant cognitive deficits. Conclusions— These data indicate that a single graded scale does not address all aspects of recovery after aneurysm treatment, particularly cognitive dysfunction and the patient’s perception of health. The implications of these findings are discussed.

Induction of heme oxygenase-1 (HO-1) in the contused spinal cord of the rat

The induction of heme oxygenase-1 (HO-1) was studied in intact spinal cords and injured spinal cords after a moderate, thoracic contusion injury. HO-1 was immunolocalized in the normal cord and along the axis of the cord at 1, 2, 3 and 4 days after contusion. Induction of this enzyme in astrocytes and microglia/macrophages was evaluated using immunofluorescent double labeling with monoclonal antibodies to HO-1 and either glial fibrillary acidic protein or the complement C3bi receptor. HO-1 was expressed in neurons in the normal spinal cord. After contusion, HO-1 was induced in both gray and white matter at the impact site. In segments of cord that were 1 cm proximal or distal to the injury, HO-1 was primarily induced in the dorsal columns and occasionally in the lateral white matter. This pattern of induction was noted at all time points. The HO-1 was induced primarily in microglia/macrophages. The distribution of the HO-1 positive cells closely correlated with the pattern of intraparenchymal hemorrhage. These findings demonstrate acute induction of HO-1 in non-neuronal cells in the injured spinal cord. Induction of HO-1 in glia may be a consequence of multiple factors including exposure to heme proteins, hypoxia and oxidative stress.