Assessment using serum insulin-like growth factor-I and bone mineral density is useful for detecting prevalent vertebral fractures in patients with type 2 diabetes mellitus

Bone mineral density (BMD) is less useful for evaluating fracture risk in type 2 diabetes. This study showed for the first time that combined evaluation by serum insulin-like growth factor-I and BMD is useful to assess the risk of vertebral fracture in postmenopausal women and men with type 2 diabetes.

INTRODUCTION

BMD is less useful for evaluating fracture risk in type 2 diabetes mellitus (T2DM). We aimed to examine the usefulness of combined evaluation by BMD and serum insulin-like growth factor-I (IGF-I) to assess the risk of vertebral fracture (VF) in T2DM.

METHODS

In this cross-sectional study, 412 postmenopausal women and 582 men with T2DM, whose BMD, bone turnover markers, and serum IGF-I were measured, were enrolled. The association of BMD alone, serum IGF-I alone, and combined assessment by BMD and IGF-I with the presence of VF was examined.

RESULTS

Multiple logistic regression analyses showed that IGF-I as well as BMD T-score at lumbar (L) and femoral neck (FN) were significantly associated with VF except for IGF-I in men, respectively. Receiver operating characteristic curves showed that the cutoff values of IGF-I, L T-score and FN T-score were 127 ng/mL, - 1.78, and - 2.02 in postmenopausal women and 127 ng/mL, - 1.67, and - 1.24 in men. Based on the cutoff vales, the subjects were divided into four categories. The category of lower IGF-I and lower T-scores had a significant increased risk of VF compared to higher IGF-I and higher T-scores both in postmenopausal women and in men. The sensitivity and specificity of the combined assessment to detect VF were better compared to using BMD alone or IGF-I alone.

CONCLUSIONS

This is the first study to show that in addition to BMD measurement, the assessment using serum IGF-I is useful to estimate the prevalence of VF in patients with T2DM.

Elevated Serum Pentosidine and Decreased Serum IGF-I Levels are Associated with Loss of Muscle Mass in Postmenopausal Women with Type 2 Diabetes Mellitus

Advanced glycation end-products (AGEs) play important roles in the progression of diabetic complications. Although sarcopenia is recently recognized as another complication associated with diabetes mellitus, its mechanism still remains unclear. In this study, we investigated the relationship between serum levels of pentosidine, which is one of AGEs, and insulin-like growth factor-I (IGF-I) vs. skeletal muscle mass by whole body dual-energy x-ray absorptiometry in 133 postmenopausal women with type 2 diabetes. Relative skeletal muscle mass index (RSMI) was calculated by following formula; appendicular skeletal muscle mass divided by height in meters squared. Simple correlation analyses showed that serum pentosidine levels were significantly and negatively correlated with muscle mass of legs (r=-0.21, p=0.017) and RSMI (r=-0.18, p=0.022), and that IGF-I was significantly and positively correlated with muscle mass of arms and legs (r=0.23, p=0.008 and r=0.30, p=0.001, respectively) as well as RSMI (r=0.20, p=0.022). Moreover, after adjusting for age, duration of diabetes, serum creatinine, HbA1c, and IGF-I, pentosidine was significantly and negatively associated with RSMI (β=-0.27, p=0.018) and marginally with muscle mass of legs (β=-0.18, p=0.071). The associations between IGF-I and indices of muscle mass such as arms, legs and RSMI were still significant after additional adjustment for pentosidine (p=0.016, 0.019 and 0.021, respectively). These findings indicate that increased serum pentosidine and decreased IGF-I are independent risk factors for loss of muscle mass in postmenopausal women with type 2 diabetes.

Serum osteocalcin levels are inversely associated with abdominal aortic calcification in men with type 2 diabetes mellitus

We found that serum osteocalcin (OC) and undercarboxylated OC (ucOC) levels were negatively associated with abdominal aortic calcification in type 2 diabetes mellitus (T2DM) men. This finding suggests that circulating OC and ucOC are not only related to glucose or fat metabolism but also to arteriosclerosis.

INTRODUCTION

Recent studies revealed that serum osteocalcin levels were associated with not only bone metabolism but also glucose and fat metabolism. However, the relationship between serum OC levels and arteriosclerosis remains controversial. We examined whether or not bone metabolic markers including OC are associated with abdominal aortic calcification in patients with type 2 diabetes mellitus.

METHODS

We recruited 118 men and 100 postmenopausal women with T2DM. We evaluated the abdominal aortic calcification score (ACS) on a lateral lumbar radiograph and examined the association between serum OC or undercarboxylated OC levels and ACS.

RESULTS

The ACS of 3 and greater, which corresponded well to the highest quartile, was significantly and negatively associated with serum OC and ucOC levels in men by logistic regression analyses after adjusting for age, BMI, serum levels of creatinine and LDL cholesterol, radial bone mineral density, smoking, duration of DM, hemoglobin A1c, and the index of insulin resistance [odds ratio (OR) 0.36, 95 % confidence interval (CI) 0.19-0.70, P < 0.005, and OR 0.28, 95 % CI 0.12-0.69, P < 0.01, per standard deviation increase in OC and ucOC, respectively]. These observations were still significant after an additional adjustment for other bone markers. In contrast, there were no significant relationships with serum OC or ucOC levels and ACS in women.

CONCLUSIONS

These findings suggest that serum OC and ucOC levels are associated with not only bone metabolism but also arteriosclerosis in men, but not in women with type 2 diabetes mellitus.

Adiponectin in metabolic bone disease

Adiponectin has attracted widespread attention because of its pivotal role in glucose metabolism and energy homeostasis. Adiponectin and its receptor are shown to be expressed in osteoblasts, suggesting that adiponectin might affect bone metabolism. A number of clinical studies have shown that serum adiponectin is negatively associated with bone mineral density (BMD) and positively with biochemical markers of bone turnover, suggesting that adiponectin may be a negative regulator of bone mass. However, most in vitro studies demonstrate that adiponectin stimulates the differentiation and mineralization of osteoblasts as well as the expression of osteocalcin. Adiponectin indirectly stimulates osteoclast differentiation via receptor activator for nuclear factor κB ligand and osteoprotegerin expression in osteoblasts, while adiponectin directly inhibits osteoclast activity and bone resorption. These in vitro findings suggest that adiponectin stimulates bone formation and remodeling as well as inhibits bone resorption. In contrast, previous in vivo studies using overexpression and knockout mice of adiponectin have produced controversial results. On the other hand, recent studies have shown that osteocalcin derived form osteoblasts acts as a hormone regulating glucose metabolism and fat mass. Osteocalcin could decrease fat pads and stimulate the expression of adiponectin in adipocytes, suggesting that bone metabolism is associated with fat metabolism through adiponectin and osteocalcin. In this review, I summarize the effect of adiponectin on osteoblasts and osteoclasts in vitro and in vivo, the association of adiponectin with BMD and bone markers in humans, and the role of adiponectin in the endocrine loop between bone and fat metabolism.

Undercarboxylated osteocalcin is positively associated with free testosterone in male patients with type 2 diabetes mellitus

Although a recent study showed that undercarboxylated osteocalcin (ucOC) is important for male fertility and testosterone production by testes, little is known about the relationship between ucOC and testosterone in humans. We found for the first time that ucOC is positively associated with free testosterone in men with type 2 diabetes.

INTRODUCTION

The ucOC has been shown to play a key role in energy metabolism as an endocrine hormone. Although a recent animal study demonstrated that ucOC is also important for male fertility and testosterone production by the testes, association between serum osteocalcin and testosterone levels has not been understood in humans.

METHODS

Sixty-nine male patients with type 2 diabetes were recruited and chemical bone markers [total osteocalcin (TOC), ucOC, bone-specific alkaline phosphatase (BAP), and urinary N-terminal cross-linked telopeptide of type I collagen (uNTX)], gonadotropic hormones [luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], and free testosterone (FT) were measured.

RESULTS

Multiple regression analysis showed that ucOC and ucOC/TOC ratio were associated positively with FT and negatively with LH (for ucOC, β = 0.30, p = 0.042 and β = -0.52, p = 0.048; for ucOC/TOC ratio, β = 0.31, p = 0.031 and β = -0.54, p = 0.036, respectively) independently of age, duration of diabetes, body mass index, and hemoglobin A1c. ucOC and ucOC/TOC ratio were significantly associated with FT even after adjusting for LH and FSH (β = 0.24, p = 0.042 and β = 0.25, p = 0.031, respectively). However, neither TOC, BAP, nor uNTX was associated with the gonadotropic hormones or FT levels.

CONCLUSIONS

The present study indicates for the first time that ucOC is associated positively with FT and negatively with LH in type 2 diabetes. These findings support the recent evidence that ucOC is involved in testosterone production in male subjects.

Effects of intensive glycemic control on serum levels of insulin-like growth factor-I and dehydroepiandrosterone sulfate in Type 2 diabetes mellitus

BACKGROUND

Although accumulating evidence shows that aging hormones are involved in glucose metabolism, effects of glycemic control on serum IGF-I and DHEAS levels are still unclear.

OBJECTIVE AND METHODS

To investigate the effects of glycemic control on these hormone levels, we conducted a 1-month longitudinal study of 49 Japanese patients with Type 2 diabetes mellitus. We measured serum levels of IGF-I and DHEA-S before and after 1-month glycemic control and analyzed the association of changes in IGF-I and DHEA-S with glycated hemoglobin (HbA1c).

RESULTS

HbA1c was decreased at 1 month with mean changes of -1.2% (p<0.001). Serum IGF-I was increased with mean changes of 11 ng/ml (p<0.05), while serum DHEA-S was decreased with mean changes of -19 μg/dl (p<0.05). Multiple regression analysis showed that changes in DHEA-S were inversely associated with changes in fasting plasma glucose (β=-0.36, p=0.027) and HbA1c (β=-0.33, p=0.028), while changes in IGF-I were not.

CONCLUSION

The present longitudinal study showed that intensive glycemic control for 1 month increased serum IGF-I level and decreased serum DHEA-S level in Japanese patients with poorly controlled Type 2 diabetes. Further studies are needed to clarify the hormonal changes in IGF-I and DHEA-S after intensive glycemic control would affect diabetic complications.

Effects of metformin and pioglitazone on serum pentosidine levels in type 2 diabetes mellitus

OBJECTIVE

Accumulation of advanced glycation end products (AGEs) is associated with age- and diabetes-related disease. The aim of the present study is to investigate the effects of metformin or pioglitazone on serum pentosidine levels, a well-defined AGE, in type 2 diabetes.

RESEARCH DESIGN AND METHODS

66 Japanese patients were enrolled in this 6 months open-label study. In the metformin (n=22), the pioglitazone (n=22), and the control (optimal diet therapy, sulfonylurea and/or insulin) groups (n=22), serum levels of HbA (1c) and pentosidine were measured at baseline and 6 months after each treatment.

RESULTS

HbA (1c) and pentosidine levels were not different at baseline among 3 groups, and HbA(1c) was significantly decreased at 6 months in each group. In the metformin and the pioglitazone groups, serum pentosidine levels were significantly decreased at 6 months after treatments (p=0.039 and p=0.031, respectively). Percent changes in pentosidine levels in the metformin and the pioglitazone groups were significantly lower than that in the control group (p=0.012 and p=0.019, respectively).

CONCLUSION

6 months treatments with metformin or pioglitazone in clinical doses decreased serum pentosidine levels which resulted in greater %change of serum pentosidine levels than the control group, suggesting that these agents may prevent the diabetic complications associated with AGEs accumulation.

Serum insulin-like growth factor-I is a marker for assessing the severity of vertebral fractures in postmenopausal women with type 2 diabetes mellitus

Although previous studies indicated that serum insulin-like growth factor-I (IGF-I) was inversely associated with the presence of vertebral fractures (VFs), little is known whether serum IGF-I is associated with multiple VFs. We report that serum IGF-I could be clinically useful for assessing the severity of VFs in type 2 diabetic postmenopausal women.

INTRODUCTION

The number of VFs is associated with the mobility and mortality of the elderly people. Although serum IGF-I is inversely associated with the presence of VFs, little is known about the relationship between serum IGF-I and multiple VFs.

METHODS

In this cross-sectional study, we recruited 479 men and 334 postmenopausal women with type 2 diabetes mellitus and measured serum IGF-I, bone mineral density, and bone turnover markers. Lateral X-ray films of the thoracic and lumbar spine were taken to diagnose the VF.

RESULTS

In postmenopausal women, serum IGF-I level was decreased when the number of VFs was increased [no VFs; 138 ± 51 ng/ml (mean ± SD) vs. one VF; 119 ± 42 (p = 0.006), two VFs; 103 ± 39 (p = 0.002), and three and more VFs; 91 ± 40 (p < 0.001)]. Multiple logistic regression analysis adjusted for age, duration of diabetes, body mass index, serum creatinine, and HbA(1c) showed that serum IGF-I level was inversely associated with the presence of one VF [odds ratio (OR) = 0.67, p = 0.029], two VFs (OR = 0.40, p = 0.017), as well as three and more VFs (OR = 0.27, p = 0.005). These associations were still significant after the additional adjustment for BMD at the lumbar spine. In contrast, no significant association of serum IGF-I level with VFs was found in men.

CONCLUSIONS

Serum IGF-I level was inversely associated with the number of prevalent VFs in postmenopausal women with type 2 diabetes, suggesting that serum IGF-I could be clinically useful for assessing the severity of VFs in the population.

Serum undercarboxylated osteocalcin was inversely associated with plasma glucose level and fat mass in type 2 diabetes mellitus

Although recent animal studies have shown that undercarboxylated osteocalcin acts as a hormone regulating glucose metabolism and fat mass, little is known about the relationships in humans. We reported here for the first time that undercarboxylated osteocalcin were associated with glucose/fat metabolism in patients with type 2 diabetes.

INTRODUCTION

Recent studies have shown that undercarboxylated osteocalcin (ucOC) acts as a hormone regulating glucose metabolism and fat mass. We investigated the relationship between ucOC as well as other bone turnover markers [serum OC, bone-specific alkaline phosphatase (BAP), and urinary N-terminal cross-linked telopeptide of type-I collagen] versus serum levels of glucose, fasting serum C-peptide, and adiponectin as well as the amount of fat mass in type 2 diabetes.

METHODS

A total of 180 men and 109 postmenopausal women were consecutively recruited, and radiographic and biochemical characteristics were collected. Fat mass was measured by dual X-ray absorptiometry (DXA) and computed tomography (CT).

RESULTS

In men, ucOC negatively correlated with percent trunk fat (%trunk fat; by DXA) and visceral/subcutaneous fat ratio (by CT) as well as fasting plasma glucose and HbA(1c) (at least p < 0.05). Multiple regression analysis showed that these associations were still significant independent of age, duration of diabetes, body stature, and renal function as well as glucose or fat metabolism, whereas BAP, another bone formation marker, did not correlate with any variable. On the other hand, although ucOC also negatively correlated with %fat and %trunk fat as well as HbA(1c) (at least p < 0.05) in postmenopausal women, we found no significant association in multiple regression analysis.

CONCLUSIONS

These findings suggest that ucOC is associated with plasma glucose level and fat mass in men with type 2 diabetes.

Baseline atherosclerosis parameter could assess the risk of bone loss during pioglitazone treatment in type 2 diabetes mellitus

SUMMARY

We found that serum osteocalcin, femoral bone mineral density (F-BMD), and 1/3R-BMD were decreased during pioglitazone treatment in patients with type 2 diabetes. Moreover, baseline atherosclerosis parameter, serum insulin-like growth factor-I (IGF-I), and urinary N-terminal cross-linked telopeptide of type I collagen (uNTX) values were associated with changes in bone mineral density (BMD). Therefore, these parameters could assess the risk of BMD reduction in patients treated with pioglitazone.

INTRODUCTION

The aim of this study was to investigate the effects of pioglitazone or metformin on bone mass and atherosclerosis in patients with type 2 diabetes.

METHODS

A total of 55 Japanese patients were enrolled in this 1-year open-label study and randomized to either pioglitazone (n = 22, 15-30 mg/day) or metformin (n = 23, 500-750 mg/day) groups. BMD at the lumbar spine, femoral neck (F), and one third of the radius (1/3R), bone markers, and atherosclerosis parameters were measured.

RESULTS

In the pioglitazone group, serum osteocalcin significantly decreased at 6 months (p < 0.05), although it almost recovered to baseline level at 12 months. F-BMD significantly decreased at 6 months (p < 0.05), and 1/3R-BMD significantly decreased at 6 and 12 months (p < 0.05), while bone markers or BMD at any site were not changed in the metformin group. Although atherosclerosis parameters were not changed in the pioglitazone group, intima-media thickness (IMT)-mean significantly increased at 6 months (p < 0.05) and plaque score significantly increased at 6 and 12 months (p < 0.01) in the metformin group. In the pioglitazone group, %changes in F-BMD were significantly and negatively correlated with baseline IMT-Max, IMT-mean, and plaque scores (r = -0.61, p < 0.01; r = -0.71, p < 0.01; and r = -0.68, p < 0.01, respectively), and %changes in 1/3R-BMD were significantly and negatively correlated with baseline uNTX and IMT-Max (r = -0.57, p < 0.01 and r = -0.48, p < 0.05, respectively) and positively with IGF-I (r = 0.45, p < 0.05).

CONCLUSIONS

Baseline IMT, uNTX, and IGF-I could assess the risk of BMD reduction in diabetic patients treated with pioglitazone.

Parathyroid hormone upregulates BMP-2 mRNA expression through mevalonate kinase and Rho kinase inhibition in osteoblastic MC3T3-E1 cells

It is well known that parathyroid hormone (PTH) possesses an anabolic effect on bone. However, the mechanisms are not fully elucidated. So far, it is unclear whether or not PTH could stimulate the expression of bone morphogenetic protein-2 (BMP-2), a strong mediator for bone formation. Growing evidence suggests that BMP-2 expression is regulated by the mevalonate pathway and Rho-associated protein kinase (ROK) activity. This study was performed to examine if PTH affects BMP-2 expression and to clarify its involvement of the mevalonate pathway. Osteoblastic MC3T3-E1 cells were treated with human PTH-(1-34) to determine BMP-2 mRNA expression levels by real-time PCR and to measure the ROK activity by the kinase assay. Incubation with 10 (-9)-10 (-8) M of hPTH-(1-34) for 6 h induced significant upregulation of BMP-2 mRNA levels in MC3T3-E1 cells. Short-term treatment of hPTH-(1-34) suppressed Rho kinase activity and mevalonate kinase mRNA levels. PTH-induced BMP-2 mRNA upregulation was selectively reversed by geranylgeranyl pyrophosphate (GGPP) pretreatment, but not by mevalonate pretreatment. These findings suggest that BMP-2 mRNA expression was upregulated by PTH in MC3T3-E1 cells mediated by mevalonate pathway suppression followed by ROK inhibition. We have now demonstrated for the first time that PTH stimulated BMP-2 mRNA expression via the mevalonate pathway and ROK in osteoblastic MC3T3-E1 cells.

Inhibition of the mevalonate pathway rescues the dexamethasone-induced suppression of the mineralization in osteoblasts via enhancing bone morphogenetic protein-2 signal

We used dexamethasone (DEX)-treated osteoblastic MC3T3-E1 cells, and investigated the effects of an AMP-activated protein kinase activator, 5-aminoimidazole-4-carboxamide-1-beta- D-ribonucleoside (AICAR), a Rho-associated protein kinase inhibitor, fasudil hydrochrolide, as well as HMG-CoA reductase inhibitors, simvastatin and pitavastatin, all of which inhibit the mevalonate pathway. DEX (10(-8) M) significantly enhanced mRNA expression of bone morphogenetic protein (BMP)-2 antagonists, follistatin and Dan, and addition of each of 10 (-4) M AICAR, 10 (-5) M fasudil, 10(-6) M simvastatin, and 10(-6) M pitavastatin significantly reversed the enhancement in mRNA expression of follistatin and Dan and stimulated that of BMP-2 in the cells (p<0.05). DEX (10(-8) M) also significantly suppressed mineralization in the cells, and addition of each of these agents significantly reversed the suppression of mineralization (p<0.05). These findings suggest that the mevalonate pathway was involved in glucocorticoid-induced osteoblast dysfunction, and that its inhibition might promote bone formation through BMP-2 and alleviate glucocorticoid-induced osteoporosis.

Serum insulin-like growth factor-I level is associated with the presence of vertebral fractures in postmenopausal women with type 2 diabetes mellitus

Multivariate logistic regression analysis showed that serum IGF-I level was significantly lower in postmenopausal diabetic women with vertebral fractures than in those without fractures. Serum IGF-I level could be clinically useful for assessing the risk of vertebral fractures independent of BMD in postmenopausal women with type 2 diabetes.

INTRODUCTION

We investigated the relationships among serum IGF-I and C-peptide levels, BMD, and vertebral fractures in postmenopausal women with type 2 diabetes.

METHODS

A total of 131 postmenopausal women with type 2 diabetes were consecutively recruited, and radiographic and biochemical characteristics were collected.

RESULTS

Either IGF-I or C-peptide was not correlated with BMD at any site or bone metabolic markers, such as osteocalcin (OC) and urinary N-terminal cross-linked telopeptide of type-I collagen (uNTX). However, serum IGF-I level was significantly lower in subjects with vertebral fractures than in those without fractures (mean +/- SD: 106.9 +/- 50.0 vs. 142.8 +/- 50.8 ng/ml, p = 0.0006). When multivariate logistic regression analysis was performed with the presence of vertebral fractures as a dependent variable and serum IGF-I adjusted for the parameters described above as independent variables, IGF-I was selected as an index affecting the presence of vertebral fractures [odds ratio = 0.436, 95% confidential interval 0.234-0.814 per SD increase, p = 0.0092]. This significance was almost the same after additional adjustment for lumbar BMD or C-peptide.

CONCLUSIONS

Serum IGF-I level could be clinically useful for assessing the risk of vertebral fractures independent of BMD in postmenopausal women with type 2 diabetes.

Abnormalities in muscarinic cholinergic receptors and their G-protein coupling systems in the cerebral frontal cortex in Alzheimer's disease

Receptor binding assays and in vitro macroautoradiography were used to analyze muscarinic cholinergic receptors (MCR) in the cerebral frontal cortex of Alzheimer's disease (AD), senile dementia of Alzheimer type (SDAT), and age-matched control brains at autopsy. Total MCR binding, detected by [(3)H]quiniclinidyl benzilate binding, did not differ significantly between the 3 groups. The concentrations of M1 subtype (M1-R), detected by [(3)H]pirenzepine binding, and high affinity state MCRs, however, were significantly lower in AD than in control and SDAT frontal cortices. No differences were detected in the affinity of these receptors for their ligands. The MCRs in AD frontal cortex were more sensitive to the agonist carbachol than were control MCRs. Autoradiography revealed a complete destruction of the laminar distribution of MCR and M1-R in AD and SDAT frontal cortices. Forskolin and phorbol ester binding sites, used to analyze second messenger systems, were significantly and markedly reduced in AD frontal cortex. In addition, coupling between MCR and second messenger systems was supersensitive in AD frontal cortex. Our findings that there are alterations in the structural distribution of MCR as well as reductions and abnormalities in second messenger systems in AD cerebral frontal cortex, suggest that drug therapy with acetylcholine precursors, choline esterase inhibitors and muscarinic agonists cannot eliminate symptoms in dementia patients. Furthermore, they point out the need for techniques to diagnose the disease prior to disintegration of the neuronal network, and the need for therapies to delay or prevent the progression of structural changes.

Japanese SCA families with an unusual phenotype linked to a locus overlapping with SCA15 locus

The authors identified two Japanese spinocerebellar ataxia (SCA) families characterized by postural and action tremor and a very slow progression rate. A genome-wide linkage analysis revealed linkage to chromosome 3p26.1-25.3 with the highest multipoint lod score at D3S3728 (Zmax = 3.31 at theta = 0.00). The candidate region was 14.7 cM flanked by D3S1620 and D3S3691, which was partly overlapping with the locus of SCA15 characterized by pure cerebellar ataxia. Despite the difference in phenotypes, there remains a possibility that the causative gene for these Japanese SCA is allelic to SCA15.

Distal myopathy with rimmed vacuoles (DMRV): new GNE mutations and splice variant

Study of the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase gene (GNE) revealed that almost all cases of distal myopathy with rimmed vacuoles were caused by GNE mutations. Seven new mutations were identified, including M712T, which is the most common mutation in Jewish hereditary inclusion body myopathy. In addition, a splice-variant characteristic of the skeletal muscle was found, whereas the difference of the expression level between GNE-mutated and -nonmutated patients was not apparent.

Anti-GQ1b antibody as a factor predictive of mechanical ventilation in Guillain-Barre syndrome

Compared with 87 unventilated patients with Guillain-Barré syndrome (GBS), 44 ventilated patients with GBS more frequently had multiple cranial nerve involvement (91 vs 50%; p < 0.001) and IgG anti-GQ1b antibody (27 vs 8%; p = 0.006). In GBS patients without ophthalmoparesis, the presence of IgG anti-GQ1b antibody was associated with respiratory failure (12 [3/25] vs 0% [0/67]; p = 0.04). The presence of the antibody may be a factor predictive of respiratory failure in GBS.

GalNAc-GD1a in human peripheral nerve: target sites of anti-ganglioside antibody

BACKGROUND

The authors previously reported that immunoglobulin G (IgG) antibody to the ganglioside N-acetylgalactosaminyl GD1a (GalNAc-GD1a) is associated with the pure motor variant of Guillain-Barré syndrome (GBS). Elucidation of the localization of GalNAc-GD1a in human peripheral nerve tissue may lead to understanding of the pathogenetic role of anti-GalNAc-GD1a antibody in GBS.

METHODS

IgG anti-GalNAc-GD1a-monospecific antibody was purified from anti-GalNAc-GD1a antibody-positive rabbit sera through an affinity column. Anti-neurofilament-200 monoclonal and anti-HNK-1 monoclonal antibodies were used as the markers for axon and myelin. Immunohistochemical study using double fluorescence labeling technique was conducted in human ventral roots (VR), dorsal roots (DR), intramuscular nerves, and sural nerves. Human teased ventral fibers also were studied.

RESULTS

Anti-GalNAc-GD1a antibody immunostained an inner part of compact myelin and additionally a periaxonal-axolemma-related portion in the VR, small-diameter DR fibers, and IM nerves. In sural nerves, small fibers were selectively stained. In VR, the staining was localized in the paranodal region.

CONCLUSION

Anti-GalNAc-GD1a antibodies in patients' sera may bind to those regions in the VR and IM nerves where GalNAc-GD1a is localized, and may function in the pathogenesis of pure motor type GBS. Further investigation is needed to explain the discrepancy between the immunolocalization of GalNAc-GD1a in sensory nerves and the absence of sensory disturbance in patients with GBS with IgG anti-GalNAc-GD1a antibodies.

Neurotoxicity of an endogenous brain amine, 1-benzyl-1,2,3,4-tetrahydroisoquinoline, in organotypic slice co-culture of mesencephalon and striatum

Organotypic slice co-culture of the ventromedial portion of the mesencephalon and striatum was used to evaluate the neurotoxicity of 1-benzyl-1,2,3,4-tetrahydroisoquinoline, an endogenous brain amine related to Parkinson's disease. 1-Benzyl-1,2,3,4-tetrahydroisoquinoline is specifically increased in the cerebrospinal fluid of patients with Parkinson's disease and induces parkinsonian features in the monkey and mouse. Here, it decreased the dopamine content of the cultured mesencephalon in both dose- (10-100 microM) and time- (24 h to 7 days) dependent manners. This result suggests that the neurotoxicity of 1-benzyl-1,2,3,4-tetrahydroisoquinoline is correlated with the overall exposure (concentration multiplied by exposure time). Culture with 100 microM 1-benzyl-1,2,3,4-tetrahydroisoquinoline for 24 h irreversibly reduced the dopamine content. Furthermore, culture with 100 microM 1-benzyl-1,2,3,4-tetrahydroisoquinoline for 10 days caused morphological changes, including cell body shrinkage and distortion of dendritic morphology, in tyrosine hydroxylase-positive cells in the mesencephalon and reduced the number of cells by half. The increase in lactate dehydrogenase activity in the media produced by 1-benzyl-1,2,3,4-tetrahydroisoquinoline was significant in culture of the mesencephalon alone or its co-culture with striatum, but not in cultures of other brain regions. We suggest that 1-benzyl-1,2,3,4-tetrahydroisoquinoline is toxic to tyrosine hydroxylase-positive cells in the ventral mesencephalon and that it is correlated with the integral of the concentration by time of exposure. Thus a low concentration of 1-benzyl-1,2,3,4-tetrahydroisoquinoline may first induce a decrease in the dopamine content then shrinkage of the cell body, followed by the slow death of dopaminergic neurons over a long period. This is the first report that indicates 1-benzyl-1,2,3,4-tetrahydroisoquinoline exerts neurotoxicity at the cellular level, and reveals in part the character of its neurotoxicity.

Benefit of IVIG for long-standing ataxic sensory neuronopathy with Sjögren's syndrome. IV immunoglobulin

Ataxic sensory neuronopathy with Sjögren's syndrome is a devastating neurologic complication for which there is no established treatment. IV immunoglobulin (IVIG) was given to five patients with severe disabilities for an average of 12 years. Four patients showed remarkable improvement, two of whom responded after the first course. The authors conclude that IVIG is safe and effective to treat even chronically debilitated patients who have the disease, presumably because it ameliorates smoldering inflammation.

Distal myopathy with rimmed vacuoles: novel mutations in the GNE gene

The authors present three novel missense mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene, the causative gene for hereditary inclusion body myopathy, in Japanese patients with distal myopathy with rimmed vacuoles. Seven out of nine patients had homozygous V572L mutation, one was a compound heterozygote with C303V and V572L mutations, and the remaining patient bore homozygous A631V mutation.

PQBP-1 increases vulnerability to low potassium stress and represses transcription in primary cerebellar neurons

PQBP-1 is a polyglutamine tract binding protein implicated in transcription. We previously reported that PQBP-1 and mutant ataxin-1, product of the spinocerebellar atrophy type 1 (SCA1) causative gene, cooperatively induce cell death in culture cells. Simultaneously, we showed that mutant ataxin-1 promoted interaction between PQBP-1 and RNA polymerase II and enhanced repression of the basal transcription by PQBP-1. In this study, we have examined the effects of overexpression of PQBP-1 to the primary-cultured cerebellar neurons. Our results indicate that overexpression of PQBP-1 inhibits the basal transcription in cerebellar neurons and increases their vulnerability to low potassium conditions.

Hemiparkinsonism associated with a mesencephalic tumor

A 66-year-old woman presented with a 3-year history of progressive right-sided hemiparkinsonism manifested by a right-hand resting tremor and right-sided bradykinesia. Magnetic resonance imaging (MRI) of the brain revealed a non-enhanced polycystic mass in the left midbrain. (11)C-methylspiperone ((11)C-NMSP) and (18)F-fluorodopa ((18)F-DOPA) positron emission tomography (PET) revealed a striatal hypometabolism that was restricted to the left side. These findings are consistent with a dysfunction in the left nigrostriatal dopaminergic pathway that is presumably induced by the cystic mass in the left midbrain. This case is significant due to the paucity of reports regarding the occurrence of a relatively pure parkinsonism that is associated with a mesencephalic space-occupying lesion.

In vitro formation of corticospinal synapses in an organotypic slice co-culture

In order to study biological properties of the corticospinal tract, we have reconstructed this system in an in vitro slice culture preparation. Motor cortex and spinal cord slices, prepared from newborn rats, were co-cultured on pored membranes for 16-24 days. Anterograde labeling with biocytin showed that substantial neural connections had formed between the cortex and spinal cord slices. Retrograde labeling with horseradish peroxidase or 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate demonstrated that the parent cells were located primarily in the deeper layer of the cortex, as is found in vivo. Stimulation of the deep layer of the cortex elicited extracellular postsynaptic responses and intracellular excitatory postsynaptic potentials (EPSPs) in the co-cultured spinal cord that were mediated by the 1-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/ kainate-type glutamate receptor. The intracellular injection of biocytin after EPSPs were recorded showed that one-third of these cells were large stellate cells, which are thought to be motoneurons, while a large portion of the remaining labeled cells were bipolar cells of smaller sizes. Using this reconstructed in vitro preparation, we recorded field EPSPs (fEPSPs) along a 100-microm-interval lattice in the spinal gray matter, which allowed the quantitative evaluation of synapse formation. The fEPSP amplitudes were more than two-fold larger when the forelimb cortex was co-cultured with cervical cord rather than lumbar cord. However, hindlimb cortex did not show this preference. The fEPSP amplitudes were more than twice as large when the dorsal side of the spinal cord was adjacent to the cortex than the ventral side. In summary, we have reconstructed the corticospinal projection and synapses in vitro using cortical and spinal explants. This system allows for an efficient quantitative evaluation of synapse formation and for studies of postsynaptic cells. Our results suggest that synapse formation shows preferences along and perpendicular to the neuraxis of the spinal cord.

Linear and whorled naevoid hypermelanosis: a case with systemic involvement and trisomy 18 mosaicism

We describe a 20-year-old woman with trisomy 18 mosaicism, who presented with skeletal anomalies, epilepsy, mental retardation, and linear and whorled naevoid hypermelanosis.

The genomic structure and expression of MJD, the Machado-Joseph disease gene

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder that is clinically characterized by cerebellar ataxia and various associated symptoms. The disease is caused by an unstable expansion of the CAG repeat in the MJD gene. This gene is mapped to chromosome 14q32.1. To determine its genomic structure, we constructed a contig composed of six cosmid clones and eight bacterial artificial chromosome (BAC) clones. It spans approximately 300kb and includes MJD. We also determined the complete sequence (175,330bp) of B445M7, a human BAC clone that contains MJD. The MJD gene was found to span 48,240bp and to contain 11 exons. Northern blot analysis showed that MJD mRNA is ubiquitously expressed in human tissues, and in at least four different sizes; namely, 1.4, 1.8, 4.5, and 7.5kb. These different mRNA species probably result from differential splicing and polyadenylation, as shown by sequences of the 21 independent cDNA clones isolated after the screening of four human cDNA libraries prepared from whole brain, caudate, retina, and testis. The sequences of these latter clones relative to the MJD gene in B445M7 indicate that there are three alternative splicing sites and eight polyadenylation signals in MJD that are used to generate the differently sized transcripts.

Homozygous Machado-Joseph disease presenting as REM sleep behaviour disorder and prominent psychiatric symptoms

A male patient carrying the homozygous gene for Machado-Joseph disease (MJD) presented at age 43 with sleep disturbances and psychiatric symptoms followed by ataxic speech and gait. A polysomnogram (PSG) showed decreased rates of sleep time and stage rapid eye movement (REM) and an increased rate of 'stage 1-REM with tonic EMG' (Tachibana et al., 1975); all compatible with REM sleep behaviour disorder (RBD). Molecular gene analysis at age 59 showed that the CAG repeat units in the MJD gene were 60 and 60, smaller than the reported lengths for homozygous MJD patients (63-70 and 66-72). In addition to sleep disturbances, in particular RBD, psychiatric symptoms may be important clinical features in both heterozygous and homozygous MJD.

Stiff-person syndrome associated with invasive thymoma: a case report

We report a case of a 40-year-old female with continuous muscle stiffness and painful muscle spasms. The symptoms worsened over a two-week period after onset. Electrophysiological examinations revealed continuous muscle discharge, which was markedly reduced by intravenous administration of diazepam. High levels of anti-glutamic acid decarboxylase (GAD) antibodies were detected in both serum and cerebrospinal fluid, suggesting that the patient suffered from stiff-person syndrome. Steroid pulse therapy and immunoadsorption therapy alleviated the clinical symptoms and decreased the anti-GAD antibody titer. A chest CT revealed the presence of an invasive thymoma. Neither anti-acetylcholine receptor (AChR) antibodies nor symptoms of myasthenia gravis (MG) were observed. The patient underwent a thymectomy and postoperative radiotherapy. These treatments further alleviated the clinical symptoms. The present case is the first that associates stiff-person syndrome with invasive thymoma, and not accompanied by MG. The autoimmune mechanism, in this case, may be triggered by the invasive thymoma.

[On what I learned from researches on Huntington's disease]

In the Presidential Lecture, I looked back my 28 years' history of researches on Huntington's disease (HD). In the first 3-4 years, I worked predominantly in the field of the neuro-anatomy, elucidating the fine distribution of the inhibitory neurotransmitter, GABA, in the human substantia nigra, elucidating the existence of a hitherto unknown subthalamo-nigral pathway in rat, and demonstrating the presence of the excitatory substance P-ergic striatonigral pathway in rat. In the middle 16-17 years, I preferentially worked in the field of neurochemical pharmacology, suggesting a mechanism of chorea in HD to be a result of hyperactivity of remaining presynaptic dopaminergic system in the striatum by making a 'choreic' model in monkey using excitotoxic kainic acid and levodopa. In the last 7-8 years, we began to be involved in the analysis of huntington gene of patients and protein chemistry of intranuclear inclusion bodies appeared in culture cells, based on the concept that HD is a CAG repeat disease. We found that the forming process of inclusion bodies was unexpectedly rapid. In addition, we found that inclusion bodies not only contain huntington itself but also contain histones, splicosomes, and ubiquitin. The recruitment of those biologically important proteins into the inclusion bodies could give neurons serious damages for living normally, even if not directly to a catastrophe, a neuronal death.

Zonisamide has beneficial effects on Parkinson's disease patients

Zonisamide (ZNS) is a generally well tolerated anticonvulsant that has beneficial effects on Parkinson's disease (PD). ZNS (300 mg/day) given to a patient with PD who incidentally had convulsive attacks, ameliorated the attacks and, surprisingly, his parkinsonian symptoms. We, therefore, carried out an open trial of ZNS on nine patients with PD. Patients were given 50-200 mg/day ZNS in addition to their anti-PD drugs. Seven clearly showed lessening of symptoms, especially wearing-off. We speculate that long lasting activation of dopamine synthesis by ZNS ameliorates parkinsonian symptoms, in particular wearing-off.

alpha-Synuclein affects the MAPK pathway and accelerates cell death

Insoluble alpha-synuclein accumulates in Parkinson's disease, diffuse Lewy body disease, and multiple system atrophy. However, the relationship between its accumulation and pathogenesis is still unclear. Recently, we reported that overexpression of alpha-synuclein affects Elk-1 phosphorylation in cultured cells, which is mainly performed by mitogen-activated protein kinases (MAPKs). We further examined the relationship between MAPK signaling and the effects of alpha-synuclein expression on ecdysone-inducible neuro2a cell lines and found that cells expressing alpha-synuclein had less phosphorylated MAPKs. Moreover, they showed significant cell death when the concentration of serum in the culture medium was reduced. Under normal serum conditions, the addition of the MAPK inhibitor U0126 also caused cell death in alpha-synuclein-expressing cells. Transfection of constitutively active MEK-1 resulted in MAPK phosphorylation in alpha-synuclein-expressing cells and improved cell viability even under reduced serum conditions. Thus, we conclude that alpha-synuclein regulates the MAPK pathway by reducing the amount of available active MAPK. Our findings suggest a mechanism for pathogenesis and thus offer therapeutic insight into synucleinopathies.

Upregulation of the pro-apoptotic BH3-only peptide harakiri in spinal neurons of amyotrophic lateral sclerosis patients

DNA fragmentation and activation of caspase-1, implicating involvement of apoptosis, have been reported in the spinal cord of amyotrophic lateral sclerosis (ALS) patients and transgenic mouse models of ALS. Because BH3-only members of the Bcl-2 family have pro-apoptotic activity, we examined the expression of the BH3-only peptide harakiri (Hrk) in the spinal cord of ALS patients. In situ expression of Hrk mRNA and immunoreactivity against the Hrk peptide were verified in the spinal neurons. In the immunoblot analysis, upregulated Hrk protein migrated at 16 kDa. Heterodimerization of Hrk with Bcl-2 was detected by immunoprecipitation, which suggests the competition of Hrk and anti-apoptotic Bcl-2. These findings suggest that Hrk plays a role in apoptotic events in ALS pathogenesis.

Decreased sensory cortical excitability after 1 Hz rTMS over the ipsilateral primary motor cortex

OBJECTIVES

To study changes in the excitability of the sensory cortex by repetitive transcranial magnetic stimulation (rTMS) in humans.

METHODS

Somatosensory evoked potentials (SEPs) and antidromic sensory nerve action potentials (SNAPs) were elicited by right median nerve stimulation at the wrist before and after low frequency (1 Hz) rTMS over the left motor cortex, lateral premotor cortex, sensory cortex, and also after sham stimulation. The intensity of rTMS was fixed at 1.1 times the active motor threshold at the hand area of motor cortex.

RESULTS

N20 peak (N20p)-P25 and P25-N33 amplitudes were suppressed after rTMS over the motor cortex, whereas the N20 onset (N20o)-N20p and SNAP amplitudes were not affected. They recovered to the baseline about 100 min after the rTMS. rTMS over the premotor cortex or sensory cortex or sham stimulation had no suppressive effect on SEPs.

CONCLUSIONS

The reduction of N20p-P25 and P25-N33 components without any changes of N20o-N20p amplitude suggests that the suppression occurs in the sensory cortex. rTMS (1 Hz) of the motor cortex induces a long-lasting suppression of the ipsilateral sensory cortex even at an intensity as low as 1.1 times the active motor threshold, probably via cortico-cortical pathways between motor and sensory cortex.

A new splicing variant for human tyrosine hydroxylase in the adrenal medulla

It has been reported that several mRNA isoforms of tyrosine 3-monooxygenase (tyrosine hydroxylase; TH) occur only in primates. New TH isoforms produced by skipping of exon 3 in the adrenal medulla of patients with progressive supranuclear palsy (PSP) have recently been reported, J. Neurochem. 67 (1996) 19. Here, we looked for the presence of new TH isoforms in control brains and adrenal medulla and in brains from patients with PSP. We found a novel type of TH mRNA in the adrenal medulla from one of the control subjects. The mRNA lacked exon 4, resulting in a premature stop codon at amino acid 147. This result suggests the importance of alternative splicing in the regulation of TH activity.

Recurrence of convexity meningiomas: tumor cells in the arachnoid membrane

BACKGROUND

It remains open to debate why totally removed benign meningiomas recur. Two recurrent cases forced us to reconsider something corresponding to their recurrence that we had overlooked during Simpson grade I surgery.

METHODS

This study is based on 24 recent and 9 earlier cases in which benign convexity meningiomas were totally removed by Simpson's grade I surgery. Tough or thick arachnoid membranes continuing to normal arachnoid membranes and contiguous to meningiomas but different from dura mater were encountered in 11 recent and at least 2 earlier cases. Such thick arachnoid membranes were left in place or only partially resected in two earlier cases but extensively resected in all recent cases.

RESULTS

Light microscopy showed clusters of meningioma cells not in the removed dura mater but in the thick arachnoid membranes of an earlier case and 10 out of the 11 recent cases. Six and twelve years after initial surgery, recurrence of the 2 earlier cases was confirmed at subsequent surgery or diagnosed by neuro-imaging. By contrast, neuro-imaging from 30 to 132 months after initial surgery showed no recurrence in the 10 recent cases. A follow-up study over 5 years showed a significant difference in recurrence between Simpson's grade I surgery with and without extensive removal of surrounding thick arachnoid membranes (Fisher's exact test: p < 0.05).

CONCLUSION

This study emphasizes the possibility that thick arachnoid membranes contiguous to meningiomas and continuous to normal arachnoid membranes, involving clusters of tumor cells, may relate to meningioma recurrence.

Expression of the alpha1D subunit of the L-type voltage gated calcium channel in human liver

Calcium channel blocker is useful for a variety of purposes and is effective for preventing hepatitis elicited by different inducers, suggesting its possible clinical application for treating hepatitis. The alpha1-subunit of the dihydropyridine-sensitive L-type calcium channel is a target of calcium channel blocker. For clinical application of calcium channel blocker, it is important to analyze the expression of the L-type calcium channel in the liver. However, the subtype of the L-type calcium channel alpha1-subunit expressed in the liver was not known. In the present study, the alpha1-subunit of the calcium channel expressed in human liver was systematically analyzed. The alpha1D subunit of the dihydropyridine-sensitive L-type voltage gated calcium channel is expressed relatively strongly in the liver and may play an important role in the liver.

Single cell analysis of CAG repeat in brains of dentatorubral-pallidoluysian atrophy (DRPLA)

Somatic mosaicism of an expanded repeat is present in tissues of patients with triplet repeat diseases. Of the spinocerebellar ataxias associated with triplet repeat expansion, the most prominent heterogeneity of the expanded repeat is seen in dentatorubral-pallidoluysian atrophy (DRPLA). The common feature of this somatic mosaicism is the difference in the repeat numbers found in the cerebellum as compared to other tissues. The expanded allele in the cerebellum shows a smaller degree of expansion. We previously showed by microdissection analysis that the expanded allele in the granular layer in DRPLA cerebellum has less expansion than expanded alleles in the molecular layer and white matter. Whether this feature of lesser expansion in granule cells is common to other types of neurons is yet to be clarified. We used a newly developed excimer laser microdissection system to analyze somatic mosaicism in the brains of two patients, one with early- and another with late-onset DRPLA, and used single cell PCR to observe the cell-to-cell differences in repeat numbers. In the late onset patient, repeat expansion was more prominent in Purkinje cells than in granule cells, but less than that in the glial cells. In the early onset patient, repeat expansion in Purkinje cells was greater than in granule cells but did not differ from that in glial cells. These findings suggest that there is a difference in repeat expansion among neuronal subgroups and that the number of cell division cycles is not the only determinant of somatic mosaicism.

[Skeletal muscle pathology of chronic graft versus host disease accompanied with myositis, affecting predominantly respiratory and distal muscles, and hemosiderosis]

We report the muscle pathology in a 43-year-old woman who died of chronic graft versus host disease (GVHD) complicated by myositis and systemic transfusional hemosiderosis, after an allogeneic bone marrow transplantation and a donor leukocyte transfusion for acute myelogenous leukemia. Despite cyclosporin A treatment, fatal ventilatory failure progressed while she was still ambulant. Autopsy revealed the presence of chronic GVHD mildly involving the liver, skin, pericardium, pancreas, and salivary glands, in addition to skeletal muscles. Myopathic changes with mild inflammation and prominent iron deposition were found in the tibialis anterior muscle and, to a lesser degree, in the diaphragm and the intercostal muscle. There were iron deposits in both macrophages and sarcoplasm in the tibialis anterior. The iliopsoas and pectoralis major muscles showed prominent type 2 fiber atrophy; inflammation and iron deposition were minimal in the iliopsoas, but none in the pectoralis. Although we ascribed respiratory failure largely to GVHD myositis, weakness of the lower leg appeared to be aggravated by iron deposition superimposing the underlying GVHD myositis.