Sexually dimorphic differences in angiogenesis markers predict brain aging trajectories

Aberrant angiogenesis could contribute to cognitive impairment, representing a therapeutic target for preventing dementia. However, most angiogenesis studies focus on model organisms. To test the relevance of angiogenesis to human cognitive aging, we evaluated associations of circulating blood markers of angiogenesis with brain aging trajectories in two deeply phenotyped human cohorts (n=435, age 74 + 9) with longitudinal cognitive assessments, biospecimens, structural brain imaging, and clinical data. Machine learning and traditional statistics revealed sex dimorphic associations of plasma angiogenic growth factors with brain aging outcomes. Specifically, angiogenesis is associated with higher executive function and less brain atrophy in younger women (not men), a directionality of association that reverses around age 75. Higher levels of basic fibroblast growth factor, known for pleiotropic effects on multiple cell types, predicted favorable cognitive trajectories. This work demonstrates the relevance of angiogenesis to brain aging with important therapeutic implications for vascular cognitive impairment and dementia.

Body composition in patients with primary neuromuscular disease assessed by dual energy X-ray absorptiometry (DXA) and three different bioimpedance devices

BACKGROUND

Patients with primary neuromuscular disease have reduced muscle mass, and use of body mass index to assess nutritional status and body composition can therefore be questioned. Dual emission X-ray absorptiometry (DXA) can estimate muscle mass, but is not always readily available. Bioimpedance is a simple, portable and "easy to use" method for the assessment of body composition.

OBJECTIVES

To assess muscle mass by DXA in 143 patients with primary neuromuscular disease and validate three bioimpedance devices; Impedimed SFB7, (BIS_IMPEDIMED), Xitron4200 (BIS_XITRON) and Tanita MC180MA (MFBIA_TANITA).

METHODS

Body composition was assessed by DXA in 143, by BIS_IMPEDIMED in 116, by MFBIA_TANITA in 104 and by BIS_XITRON in 35 patients.

RESULTS

Muscle mass assessed by DXA, and phase angle (PhA) were below reference values in all female and 96% of male patients. BIS_IMPEDIMED underestimated muscle mass by 6.5 ± 14.2 kg (p < 0.001), but this could be corrected after exclusion of resistance (Ri) values > 3500 Ohm (p = 0.84). MFBIA_TANITA overestimated muscle mass by 30.8 ± 9.1 kg (p < 0.001) with systematic bias, whereas BIS_XITRON was in agreement with DXA, and without systematic bias. Muscle mass was strongly correlated to PhA (r_PEARSON = 0.75, p < 0.01).

CONCLUSION

Patients with primary neuromuscular disease have proportionally more fat and less muscle mass than the population in general, despite normal BMI. Muscle mass can be assessed by bioimpedance in these patients, but performance and bias depends on device. Phase angle by bioimpedance correlates to muscle mass, and could therefore potentially be used a surrogate measure of muscle mass during follow up.

Search for Pompe disease among patients with undetermined myopathies

OBJECTIVE

Pompe disease is a rare treatable glycogen storage disease with in adults - a limb-girdle muscle weakness. Muscle biopsy may fail to show the typical vacuolar myopathy. We asked if we had un-diagnosed patients with Pompe disease in western Sweden.

MATERIAL AND METHODS

We searched the muscle biopsy registry during the time period 1986 until 2006 including 3665 biopsies and included patients at our Neuromuscular Center with unspecified myopathy or limb-girdle muscular dystrophy. The dry blood spot test was used to identify patients with Pompe disease.

RESULTS

A total of 82 patients (46 from the biopsy register and 36 from our center) were seen and dry blood spot test was obtained. No patient with Pompe disease was found. The dry blood spot test was low in three cases (11, 16, and 18% of normal) but a second blood sample showed a normal result based on GAA enzyme activity in lymphocytes in all three patients. In one patient with low normal result of the analysis in lymphocytes a genetic test showed no pathogenic mutations. Further investigation gave a definite diagnose of another myopathy in 12 patients.

CONCLUSIONS

The prevalence of Pompe disease in western Sweden (3 in 1.27 million or 0.24 per 100.000 inhabitants) is lower than in the Netherlands and New York. Re-evaluation of patients with myopathies but without definite diagnosis is rewarding since 12 of 82 patients in our study had a definite molecular diagnosis after workup.

Facial memory deficits in myotonic dystrophy type 1

OBJECTIVES

To evaluate facial memory ability (FMA) in patients with myotonic dystrophy type 1 (DM1). We also explored the relationship between FMA and neuropsychological data, disease-related factors, and CTG repeat expansion size.

MATERIALS AND METHODS

Patients with DM1 (n = 33) and healthy subjects (n = 30) were tested with the faces task of the Rivermead Behavioural Memory Test - Extended version (RBMT-E) and an additional set of neuropsychological tests. Clinical data were collected, and CTG repeat size was quantified in blood lymphocytes.

RESULTS

Low results on the faces task were more common in patients with DM1 compared with healthy subjects (P < 0.05), with 36% of the patients showing a poor/impaired performance. DM1 patients with deficits in FMA performed significantly worse on tests measuring visual-construction ability and memory. Furthermore, these patients more often falsely recognised unknown faces as known. Deficits in FMA were not associated with any disease-related factor, including CTG repeat expansion size.

CONCLUSIONS

These findings revealed deficits in FMA in the DM1 group, which was associated with reduced construction- and visual memory ability.

Prognosis and prognostic factors in sporadic inclusion body myositis

OBJECTIVES

To describe the course of change in muscle strength sporadic inclusion body myositis (IBM) patients.

MATERIAL AND METHODS

We have studied a cohort of 66 IBM pateints using a hand-held dynamometer.

RESULTS

Follow-up during a mean of 61.1 months showed a deterioration of on average -0.79% per month. The 'natural course' without immunosuppressive treatment (IS), analyzed in 43 patients (mean 46.4 months) was mean -1.03% per month. Loss of muscle power was most rapid in knee extension -1.12% (P < 0.001 when compared with elbow flexion, elbow extension and hip flexion). There was a tendency towards a more rapid decline in males than females and over the first 5 years after onset, while the level of serum creatine kinase (CK), age, or region affected at onset did not predict the prognosis. The mean change during periods with any IS treatment was -0.76% per month which was significantly lower compared to the total of untreated periods -1.03% (P < 0.05). Patients (n = 13) treated with mykofenolatmofetil showed a better prognosis of -0.67% per month (P < 0.05). In this group elbow flexion and extension and hip flexion showed a positive response, while knee extension was seemingly unaffected.

CONCLUSIONS

There is a mean of 1% loss in power per month in the untreated IBM patient - the rate of loss was greater in the quadriceps muscle and in untreated compared with IS-treated patients.

Episodes of exercise-induced dark urine and myalgia in LGMD 2I

BACKGROUND

Mutations in the fukutin-related protein gene FKRP (MIM *606596) cause a form of congenital muscular dystrophy (MDC1C) and also limb girdle muscular dystrophy type 2I (LGMD2I). Exercise-induced myoglobinuria, frequently occurring in metabolic myopathies, has been described in Becker muscular dystrophy and in a few cases of LGMD.

OBJECTIVES

To describe that episodes with myoglobinuria, often associated with exercise-induced myalgia, may be common and a presenting symptom in patients with LGMD2I.

METHODS

Data on episodes of suspected myoglobinuria and myalgia were collected from the patient records on 14 patients with a diagnosis of LGMDI.

RESULTS

Five LGMD2I patients reported recurrent episodes of dark urine and myalgia after exercise, and in three of them, this was the only symptom for several years.

CONCLUSIONS

We conclude that episodes compatible with exercise-induced myoglobinuria may be frequent in LGMD2I.

Laboratory medicine: the precursors strike back

Laboratory Medicine represents a major component of healthcare and nowadays it is involved in more than seventy percent of medical decisions. The value of any innovative laboratory test will depend on its clinical sensitivity and specificity. This clinical value is of course influenced by the analytical performance and reliability of the assay. Some spectacular advances in the understanding of circulating forms were recently accomplished with an emphasis place on prohormones and analytes precursors. Release of prohormones in the blood flow may be of major impact to improve diagnosis and risk stratification but may also influence the analytical specificity of some commercial assays. The goal of this short review is to discuss some perspectives related to some analytes' precursors that have recently been evidenced to affect assay specificity or increase assay discriminatory power.

Rituximab for severe myasthenia gravis--experience from five patients

BACKGROUND

Rituximab (RTX), a monoclonal antibody directed against CD20+ B cells, is used in the treatment of several autoimmune disorders including severe generalized myasthenia gravis (MG).

AIMS OF THE STUDY

To describe the experience with RTX in five MG patients treated at our Neuromuscular Centre.

METHODS

Effect of RTX treatment was monitored by quantitative MG score (QMG score), forced vital capacity (FVC) and records of clinical parameters. Three patients had thymoma. Duration of MG prior to the first course of RTX was 3, 7, 26, 26 and 38 years.

RESULTS

We found favourable response to RTX treatment in all five patients. QMG score was markedly lower after RTX and in the three patients with respiratory muscle affection the FVC was increased. A good relief of bulbar, respiratory or extremity MG weakness was thus also found in the three patients who had long-standing severe MG. Repeated RTX treatment was needed in four patients.

CONCLUSIONS

We conclude that RTX is effective in recent onset MG as well as in long-standing cases. As thymoma is prevalent in patients with severe MG, further studies are needed to evaluate the risk of thymoma recurrence following RTX treatment.

MELAS syndrome in a patient with a point mutation in MTTS1

BACKGROUND, OBJECTIVE AND METHODS: We describe a female patient with a mitochondrial encephalopathy, lactic acidosis and stroke-like episodes syndrome. As a child, she developed epilepsy and stroke-like episodes giving cognitive impairment and ataxia but no hearing impairment. At the age of 44 years, she suffered a cerebral sinus thrombosis which was warfarin treated. One month later, she developed an episode of severe acidosis associated with encephalopathy and myelopathy.

RESULTS

She was found to harbour a 7512T>C mutation in the mitochondrial encoded tRNA(Ser(UCN)) gene (MTTS1). The mutation load was 91% in muscle and 24% in blood. Enzyme histochemical analysis of the muscle tissue showed numerous cytochrome c oxidase (COX)-negative fibres. Restriction fragment length polymorphism (RFLP) analysis of single muscle fibres showed significantly higher level (median 97%, range: 94-99%) of the mutation in the COX-negative fibres compared with COX-positive fibres (median 36%, range: 12-91%), demonstrating the pathogenic effect of the mutation. Different levels of heteroplasmy (range 34-61%) were detected in hair shafts analysed by RFLP.

CONCLUSION

This case adds to the spectrum of clinical presentations, i.e. sinus thrombosis, in patients having MTTS1 mutations.

Raised troponin T in inclusion body myositis is common and serum levels are persistent over time

Cardiac Troponin T (cTnT), creatine kinase (CK) and creatine kinase isoenzyme MB (CKMB) were measured in 42 consecutive patients with sporadic inclusion body myositis (s-IBM). 26 patients (62%) had a cTnT level >0.05 microg/L, the cut off used in the diagnosis of myocardial infarction. The cTnT levels correlated somewhat more closely to CKMB (rho=0.83, p<0.0001) than to CK (rho=0.60, p<0.0001). Patients on immunosuppressive treatment had lower cTnT levels than untreated, while there were no significant differences according to age, disease duration or gender. Repeated samples in 26 patients showed that the cTnT levels were essentially unchanged over time up to 17 months. None of the patients had signs of myocardial damage or renal failure at time of sampling. It may be of value to analyse cTnT at some occasion(s) in s-IBM patients.

Facial emotion recognition in myotonic dystrophy type 1 correlates with CTG repeat expansion

OBJECTIVE

To investigate the ability of patients with myotonic dystrophy type 1 to recognise basic facial emotions. We also explored the relationship between facial emotion recognition, neuropsychological data, personality, and CTG repeat expansion data in the DM-1 group.

METHODS

In total, 50 patients with DM-1 (28 women and 22 men) participated, with 41 healthy controls. Recognition of facial emotional expressions was assessed using photographs of basic emotions. A set of tests measured cognition and personality dimensions, and CTG repeat size was quantified in blood lymphocytes.

RESULTS

Patients with DM-1 showed impaired recognition of facial emotions compared with controls. A significant negative correlation was found between total score of emotion recognition in a forced choice task and CTG repeat size. Furthermore, specific cognitive functions (vocabulary, visuospatial construction ability, and speed) and personality dimensions (reward dependence and cooperativeness) correlated with scores on the forced choice emotion recognition task.

CONCLUSION

These findings revealed a CTG repeat dependent facial emotion recognition deficit in the DM-1 group, which was associated with specific neuropsychological functions. Furthermore, a correlation was found between facial emotional recognition ability and personality dimensions associated with sociability. This adds a new clinically relevant dimension in the cognitive deficits associated with DM-1.

No association between the -399 C > T polymorphism of the neuropeptide Y gene and schizophrenia, unipolar depression or panic disorder in a Danish population

OBJECTIVE

A polymorphism in the promoter region of the NPY gene at position -399 C > T was recently reported to be associated with schizophrenia in a Japanese population and with treatment refractory unipolar depression in a Swedish population. The objective of this study was to investigate potential associations between the polymorphism and three psychiatric disorders in a Danish population.

METHOD

We investigated the occurrence of the polymorphism in patients with schizophrenia (n = 291), unipolar depression (n = 256) and panic disorder (n = 142) compared with controls (n = 716).

RESULTS

We detected the polymorphism -399 C > T at a frequency of 48% in controls. No significant differences were found between genotype or allele frequencies in controls vs. the patient groups.

CONCLUSION

The lack of association between the -399 C > T polymorphism and schizophrenia, unipolar depression or panic disorder, respectively, suggests that the polymorphism is not involved in the etiology of these disorders in the Danish population.

Mitochondrial abnormalities in inclusion-body myositis

Mitochondrial changes are frequently encountered in sporadic inclusion-body myositis (s-IBM). Cytochrome c oxidase (COX)-deficient muscle fibers and large-scale mitochondrial DNA (mtDNA) deletions are more frequent in s-IBM than in age-matched controls. COX deficient muscle fibers are due to clonal expansion of mtDNA deletions and point mutations in segments of muscle fibers. Such segments range from 75 microm to more than 1,000 microm in length. Clonal expansion of the 4977 bp "common deletion" is a frequent cause of COX deficient muscle fiber segments, but many other deletions also occur. The deletion breakpoints cluster in a few regions that are similar to what is found in human mtDNA deletions in general. Analysis in s-IBM patients of three nuclear genes associated with multiple mtDNA deletions, POLG1, ANT1 and C10orf2, failed to demonstrate any mutations. In s-IBM patients with high number of COX-deficient fibers, the impaired mitochondrial function probably contribute to muscle weakness and wasting. Treatment that has positive effects in mitochondrial myopathies may be tried also in s-IBM.

Temperament and character in patients with classical myotonic dystrophy type 1 (DM-1)

This study was designed to investigate personality in classical Myotonic Dystrophy (DM-1). Forty-six patients with DM-1 (25 women and 21 men), 31 healthy controls and 37 subjects in a contrast group, consisting of patients with other muscle disorders (spinal muscular atrophy, facioscapulohumeral dystrophy and limb girdle muscular dystrophy), completed the Temperament and Character Inventory (TCI) (Cloninger, 1994). We aimed to establish whether CTG triplet repeat size correlated with ratings of personality dimensions in the TCI. The DM-1 patients scored significantly higher on the TCI dimension Harm avoidance and lower on Persistence, Self-directedness and Cooperativeness. Signs of a personality disorder were found in 20% of the DM-1 patients. No correlation was found between the number of CTG repeats and scores in the TCI. This study indicates deviant personality in classical DM-1 regarding temperament and character, both in comparison to healthy controls and to patients with other muscle disorders with no known brain disorder.

Myopathies associated with myosin heavy chain mutations

Myosin, a molecular motor, converts chemical energy into mechanical force. The motor domain of myosin heavy chain (MyHC) includes an ATP binding region with ATPase activity and an actin-binding region. Motor function is achieved by conformational changes, at hydrolysis, of ATP causing a shift in the angle between the actin binding head and the rod region of the molecule. The elongated alpha-helical coiled-coil rod region of MyHC molecules constitutes the major part of the thick filaments of the sarcomere. Three major MyHC isoforms are expressed in human skeletal muscle (type I, MYH7, expressed in type 1 fibres; IIa, MYH2, expressed in 2A fibres; IIx, MYH1, expressed in 2B fibres). While mutations in slow/beta cardiac MyHC (MYH7) are a common cause of familial hypertrophic cardiomyopathy, no skeletal myopathies have, until recently, been associated with mutations in MyHC. A heterozygous mutation, Glu706Lys, in the core of the head of MyHC IIa is associated with a familial congenital myopathy, which, in most instances, has shown mild phenotypic expression in children but progressive course in some adults. There is a relationship between the level of expression of mutated MyHC IIa and muscle pathology. Some adults with a progressive course show muscle fibres with rimmed vacuoles and filaments of the type seen in inclusion body myositis/myopathy (IBM). Endurance training in a group of affected patients caused a shift in the expression of myosin from fast (IIx) to slow (I) isoforms but no reduction in the expression of MyHC IIa. A heterozygous mutation, Arg1845Trp, in the distal rod region of slow myosin (type I, MYH7) is associated with familial congenital myopathy, with large deposits of MyHC I in the subsarcolemmal region of type 1 muscle fibres, "Myosin storage myopathy". These patients showed slowly progressive muscle weakness but no overt cardiomyopathy. These two muscle diseases, which are caused by mutations in MyHC, form the basis of a novel entity: "Myosin myopathies".

A novel mutation in the mitochondrial tRNAPhe gene associated with mitochondrial myopathy

We report a novel heteroplasmic T-->C mutation at nt position 582 within the mitochondrial tRNA(Phe) gene of a 70-year-old woman with mitochondrial myopathy. No other family members were affected, suggesting that our patient was a sporadic case. The muscle showed frequent ragged red fibers and 43% cytochrome c oxidase deficient fibers. The mutation alters a conserved base pairing in the aminoacyl acceptor stem. The mutation load was 70% in muscle homogenate and varied from 0 to 95% in individual muscle fiber segments. Cytochrome c oxidase-negative fibers showed significantly higher levels of mutated mtDNA (>75%) than Cytochrome c oxidase-positive fibers (<55%). This mutation adds to the previously described four pathogenic mutations in the tRNA(Phe) gene.

Inclusion body myositis: clonal expansions of muscle-infiltrating T cells persist over time

Inclusion body myositis (IBM) is a chronic inflammatory myopathy. The muscle histology is characterized by infiltration of T cells, which invade and apparently destroy muscle fibres. This study was performed to investigate whether predominant clones of muscle-infiltrating T cells are identical in different muscles and whether they persist over time in IBM. By reverse transcriptase-polymerase chain reaction, 25 T-cell receptor (TCR) variable beta (Vbeta) chain families and the complementarity-determining region 3 (CDR3) of the TCR were analysed in two different muscle biopsies of four patients with IBM. In two of the patients, the muscle biopsies were obtained from different muscles at one time point, whereas in two patients, the second biopsy was obtained 9 years after the first biopsy. T cells expressing predominant Vbeta families were analysed for clonality by fragment length analysis of the CDR3. Predominant Vbeta families were analysed by DNA sequencing to identify identical clones. Immunohistochemical staining of Vbeta families was performed to study the distribution of T cells expressing identified predominant Vbeta families. The muscle-infiltrating lymphocytes showed restricted expression of TCR Vbeta families. DNA sequencing proved that clonally expanded T cells were identical in different muscles and persisted 9 years after the first biopsy. Immunohistochemical analysis with Vbeta family-specific antibodies demonstrated the endomysial localization of these T cells in inflammatory cell infiltrates. Our results show that in IBM there is clonal restriction of TCR expression in muscle-infiltrating lymphocytes. Identical T-cell clones predominate in different muscles, and these clones persist for many years. These results indicate an important, continuous, antigen-driven inflammatory reaction in IBM.

Anti-T-lymphocyte globulin treatment in inclusion body myositis: a randomized pilot study

The authors performed an open, randomized trial in patients with inclusion body myositis comparing 1) 12-month treatment with oral methotrexate 7.5 mg/week alone (MTX group) with 2) 12-month MTX treatment preceded by 7 days of IV anti-T-lymphocyte immunoglobulin treatment (ATG group). Eleven patients were randomized; 10 patients completed 12 months follow-up. Myometry showed that patients in the ATG group (n = 6) increased in mean muscle strength by 1.4% compared with the MTX group (n = 5), whose muscle strength decreased by 11.1% (p = 0.021).

Inclusion body myositis: morphological clues to correct diagnosis

The aim of this study was to investigate variability of morphological changes found in patients with sporadic inclusion body myositis, to assess the diagnostic value of muscle biopsy. The study included all 43 definite inclusion body myositis patients (86 biopsies) diagnosed at Sahlgrenska University Hospital, Gothenburg, Sweden, between 1984 and 2000. Invasion of mononuclear inflammatory cells in non-necrotic muscle fibres was found in 72 of 86 specimens, while all investigated biopsies showed up-regulation of major histocompatibility complex class I. Cytochrome c oxidase-negative muscle fibres were demonstrated in 84 of 86 biopsies. Rimmed vacuoles were present in all specimens from the vastus lateralis and tibialis muscles, and in 43 of 51 biopsies from the deltoid muscle. In cases with clinical suspicion of inclusion body myositis, where the muscle biopsy does not show inflammatory cell infiltration and rimmed vacuoles, inclusion body myositis should still be considered if there are cytochrome c oxidase-negative fibres and up-regulation of major histocompatibility complex class I. In such cases repeat muscle biopsy may be helpful.

Expression of Bcl-2 in inclusion body myositis

OBJECTIVES

On the background of the possible role of the anti-apoptotic protein Bcl-2 to inhibit apoptosis induced by the Fas/Fas ligand system in inflammatory myopathies we investigated the expression of Bcl-2 in inclusion body myositis (IBM).

MATERIAL AND METHODS

We examined muscle tissue from seven IBM patients and controls by immunocytochemistry using antibodies against Bcl-2, Fas (a member of the tumor necrosis factor receptor family) and the regeneration marker, neural cell adhesion molecule (N-CAM). We also investigated the occurrence of DNA fragmentation by the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL)-method.

RESULTS

Both Bcl-2 and Fas were up-regulated in muscle fibers in IBM and disease controls. Bcl-2 was expressed by regenerating muscle fibers while Fas was expressed by non-regenerating muscle fibers associated with inflammatory cell infiltrates. Bcl-2 and Fas were also expressed by inflammatory cells. There were scattered TUNEL positive nuclei and most of these appeared to be inflammatory cells.

CONCLUSION

The low occurrence of apoptotic myonuclei is not related to Bcl-2 expression, which is confined to regenerating muscle cells in IBM and other myopathies.