Role of nutrition in patients with coexisting chronic obstructive pulmonary disease and sarcopenia.

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic diseases in the elderly population and is characterized by persistent respiratory symptoms and airflow obstruction. During COPD progression, a variety of pulmonary and extrapulmonary complications develop, with sarcopenia being one of the most common extrapulmonary complications. Factors that contribute to the pathogenesis of coexisting COPD and sarcopenia include systemic inflammation, hypoxia, hypercapnia, oxidative stress, protein metabolic imbalance, and myocyte mitochondrial dysfunction. These factors, individually or in concert, affect muscle function, resulting in decreased muscle mass and strength. The occurrence of sarcopenia severely affects the quality of life of patients with COPD, resulting in increased readmission rates, longer hospital admission, and higher mortality. In recent years, studies have found that oral supplementation with protein, micronutrients, fat, or a combination of nutritional supplements can improve the muscle strength and physical performance of these patients; some studies have also elucidated the possible underlying mechanisms. This review aimed to elucidate the role of nutrition among patients with coexisting COPD and sarcopenia.

The protective effects of heat shock protein 22 in lung ischemia-reperfusion injury mice.

Lung ischemia-reperfusion injury (LIRI) often results in respiratory insufficiency after pulmonary embolism, lung transplantation, etc. To investigate the role of HSP22 in LIRI mice, ischemia-reperfusion injury was established in the left lung of an HSP22 overexpression transgenic mouse. Twelve HSP22 transgenic (TG) mice and twelve wild-type (WT) mice were randomly divided into 2 groups: the sham-operated group (SO: TG-SO, WT-SO) and the ischemia-reperfusion group (I/R: TG-I/R, WT-I/R), respectively. We tested the PaO2, W/D ratio, and MDA level; observed morphology changes; and calculated the index of alveolar damage. HSP22 expression was examined in lung tissues of TG and WT C57BL mice by immunohistochemistry. TUNEL assay was performed to measure apoptosis. We found that HSP22 was significantly overexpressed in TG mice. There was no difference in PaO2 among the four groups. In the I/R group, the W/D ratio, MDA and index of alveolar damage were higher than those in the SO group. Moreover, compared with WT-I/R group, the W/D ratio, MDA and index of alveolar damage in the TG-I/R group were significantly decreased. Apoptosis in the I/R groups was increased compared to that in the SO groups, while apoptosis in the TG-I/R groups was decreased compared to that in the WT-I/R groups. Our results showed that HSP22 TG mice and the LIRI model were successfully established. In addition, HSP22 overexpression has protective effects on LIRI by inhibiting lipid peroxidation and apoptosis.

A novel transgenic mouse model of Chinese Charcot-Marie-Tooth disease type 2L.

We previously found that the K141N mutation in heat shock protein B8 (HSPB8) was responsible for Charcot-Marie-Tooth disease type 2L in a large Chinese family. The objective of the present study was to generate a transgenic mouse model bearing the K141N mutation in the human HSPB8 gene, and to determine whether this (K141N)HSPB8 transgenic mouse model would manifest the clinical phenotype of Charcot-Marie-Tooth disease type 2L, and consequently be suitable for use in studies of disease pathogenesis. Transgenic mice overexpressing (K141N)HSPB8 were generated using K141N mutant HSPB8 cDNA cloned into a pCAGGS plasmid driven by a human cytomegalovirus expression system. PCR and western blot analysis confirmed integration of the (K141N)HSPB8 gene and widespread expression in tissues of the transgenic mice. The (K141N)HSPB8 transgenic mice exhibited decreased muscle strength in the hind limbs and impaired motor coordination, but no obvious sensory disturbance at 6 months of age by behavioral assessment. Electrophysiological analysis showed that the compound motor action potential amplitude in the sciatic nerve was significantly decreased, but motor nerve conduction velocity remained normal at 6 months of age. Pathological analysis of the sciatic nerve showed reduced myelinated fiber density, notable axonal edema and vacuolar degeneration in (K141N)HSPB8 transgenic mice, suggesting axonal involvement in the peripheral nerve damage in these animals. These findings indicate that the (K141N)HSPB8 transgenic mouse successfully models Charcot-Marie-Tooth disease type 2L and can be used to study the pathogenesis of the disease.

Investigation of TREM2, PLD3, and UNC5C variants in patients with Alzheimer's disease from mainland China.

Recently, 3 rare coding variants significantly associated with Alzheimer's disease (AD) risk have been identified in western populations using whole exome sequencing method, including p.R47H in TREM2, p.V232M in PLD3, and p.T835M in UNC5C. To examine whether these variants are genetic risk factors in patients with AD from mainland China, we sequenced exon 2 of TREM2, exon 9 of PLD3, and exon 15 of UNC5C in Chinese Han population including 360 patients with AD and 400 control individuals. As a result, none of these 3 variants were identified in all subjects, however, 1 novel variant (p.A130V) in TREM2 and 4 novel variants (p.Q860H, p.T837K, p.S843G, and p.V836V) in UNC5C were detected in unrelated patients with late-onset AD. These findings suggest the 3 rare coding variants might not play an important role in AD risk in mainland China.

Mutational analysis in early-onset familial Alzheimer's disease in Mainland China.

Mutations of 3 causative genes, namely presenilin 1 (PSEN1), presenilin 2 (PSEN2), and amyloid precursor protein (APP), have been identified as the major causes of early-onset familial Alzheimer's disease (EOFAD). Recently, a GGGGCC repeat expansion in the noncoding region of C9orf72 was also detected in some patients with clinically diagnosed familial Alzheimer's disease. The prevalence of causative gene mutations in patients with EOFAD has been reported in previous studies but their prevalence remains unclear in Mainland China. The aim of this study was to characterize the common causative gene mutation spectrum and genotype-phenotype correlations in Chinese patients with EOFAD. Genetic screening for mutations in PSEN1, PSEN2, and APP was conducted in a total of 32 families with clinical diagnoses of EOFAD from Mainland China. Subsequently, a hexanucleotide repeat expansion in C9orf72 was detected in all patients. Four novel mutations in PSEN1 (p.A434T, p.I167del, p.F105C, and p.L248P) were identified in 4 respective families, and 1 previously recognized pathogenic mutation in APP (p.V717I) was detected in another 2 unrelated families. The PSEN2 mutation and pathogenic repeat expansions of C9orf72 were not detected in all patients. To the best of our knowledge, this is the first cohort report of a causative gene screen in patients with EOFAD in Mainland China. The analysis of the genetic-clinical correlations in this cohort supports the idea that the clinical phenotype might be influenced by specific genetic defects.

Identification of CHIP as a novel causative gene for autosomal recessive cerebellar ataxia.

Autosomal recessive cerebellar ataxias are a group of neurodegenerative disorders that are characterized by complex clinical and genetic heterogeneity. Although more than 20 disease-causing genes have been identified, many patients are still currently without a molecular diagnosis. In a two-generation autosomal recessive cerebellar ataxia family, we mapped a linkage to a minimal candidate region on chromosome 16p13.3 flanked by single-nucleotide polymorphism markers rs11248850 and rs1218762. By combining the defined linkage region with the whole-exome sequencing results, we identified a homozygous mutation (c.493CT) in CHIP (NM_005861) in this family. Using Sanger sequencing, we also identified two compound heterozygous mutations (c.389AT/c.441GT; c.621C>G/c.707GC) in CHIP gene in two additional kindreds. These mutations co-segregated exactly with the disease in these families and were not observed in 500 control subjects with matched ancestry. CHIP colocalized with NR2A, a subunit of the N-methyl-D-aspartate receptor, in the cerebellum, pons, medulla oblongata, hippocampus and cerebral cortex. Wild-type, but not disease-associated mutant CHIPs promoted the degradation of NR2A, which may underlie the pathogenesis of ataxia. In conclusion, using a combination of whole-exome sequencing and linkage analysis, we identified CHIP, encoding a U-box containing ubiquitin E3 ligase, as a novel causative gene for autosomal recessive cerebellar ataxia.

C9orf72 mutation is rare in Alzheimer's disease, Parkinson's disease, and essential tremor in China.

GGGGCC repeat expansions in the C9orf72 gene have been identified as a major contributing factor in patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Given the overlapping of clinical phenotypes and pathological characteristics between these two diseases and Alzheimer's disease (AD), Parkinson's disease (PD), and essential tremor (ET), we speculated regarding whether C9orf72 repeat expansions also play a major role in these three diseases. Using the repeat-primed polymerase chain reaction method, we screened for C9orf72 in three groups of patients with PD (n = 911), AD (n = 279), and ET (n = 152) in the Chinese Han population. There were no pathogenic repeats (>30 repeats) detected in either the patients or controls (n = 314), which indicated that the pathogenic expansions of C9orf72 might be rare in these three diseases. However, the analysis of the association between the number of repeats (p = 0.001), short/intermediate genotype (short: <7 repeats; intermediate: ≥7 repeats) (odds ratio 1.37 [1.05, 1.79]), intermediate/intermediate genotype (Odds ratio 2.03 [1.17, 3.54]), and PD risks indicated that intermediate repeat alleles could act as contributors to PD. To the best of our knowledge, this study is the first to reveal the correlation between C9orf72 and Chinese PD, AD, or ET patients. Additionally, the results of this study suggest the novel idea that the intermediate repeat allele in C9orf72 is most likely a risk factor for PD.

[Roles of axonal transport affected by K141N mutant HSP22 in the pathogenesis of CMT2L].

OBJECTIVE: To compare the axonal transport of wild-type (WT) and K141N mutant HSP22 in transfected primary cultured cortical neurons. METHODS: The plasmid (pCAGGS-HA-wtHSP22 or pCAGGS-HA-K141NHSP22) with WT or K141N mutant HSP22 gene and a GFP-expressing plasmid (pEGFP-N1) were co-transfected respectively into primary cultured cortical neurons. The axonal transport of WT and K141N mutant HSP22 was observed. And the distance traveled by WT and K141N mutant HSP22 was analyzed. RESULTS: The WT HSP22 was transported within axons and uniformly present throughout the entire length of axons. K141N mutant HSP22 failed to be transported to the same extent and was present only in cell body and proximal portion of axons. Analysis of distance traveled revealed that WT HSP22 traveled significantly further than the K141N mutant HSP22. CONCLUSION: The axonal transport of K141N mutant HSP22 may play an important role in the pathogenesis of CMT2L.

[Mutation analysis of MFN2 gene in Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To analyze MFN2 gene mutation in Chinese patients Charcot-Marie-Tooth disease (CMT) and to establish a quick and effective diagnostic method. METHODS: Through denaturing high-performance liquid chromatography (DHPLC) combined with DNA sequencing, MFN2 gene mutation analysis was carried out in 35 Chinese CMT2 patients including 9 probands of CMT2 pedigree and 26 sporadic CMT2 patients. RESULTS: The investigators found three abnormal sequence variations in MFN2 gene: c.281G-->A, c.395G-->A and c.408A-->T. c.395G-->A (C132T) was a novel causative missense mutation firstly reported while c.281G-->A (R94Q) a hotspot mutation and c.408A-->T (V136V) a single nucleotide polymorphism (SNP). The accuracy and specificity of DHPLC detection reached up to 100%. CONCLUSION: Through DHPLC combined with DNA sequencing, MFN2 mutations are detected in Chinese CMT2 patients. There are two causative missense mutations: c.395G-->A (C132T) and c.281G-->A (R94Q) and one SNP c.408A-->T (V136V). Such a method is an effective and economic diagnostic screening tool of MFN2 gene in CMT patients on a large scale.

[Study on aggregate formation mechanism of HSPB8 gene mutation resulting in CMT2L].

OBJECTIVE: To study the possible mechanism of the intracellular aggregate formation of small heat shock protein HSPB8 (HSPB8)(K141N) mutation resulting in axonal Charcot-Marie-Tooth disease type 2L(CMT2L). METHODS: The cell models which transiently expressed pEGFPN1-HSPB8 and pEGFPN1-(K141N)HSPB8 were established. The immunofluorescent co-location study of EGFP-(K141N)HSPB8 and HSPB1, EGFP-(K141N)HSPB8 and neurofilament light chain (NEFL) was carried out in the SHSY5Y cell models. The aggregate formation of EGFP-(K141N)HSPB8 in cell models was investigated and the possible mechanism of cellular aggregate formation was analyzed by t test and analysis of variance between group(ANOVA). RESULTS: EGFP-(K141N)HSPB8 formed large aggregate which predominantly located around the nucleus in cell models. EGFP-(K141N)HSPB8 co-localized perfectly with HSPB1 and NEFL in the SHSY5Y cell models. The aggregate formation was different in different cell types, there were fewer aggregates formed in an sHSPs deficient milieu than in HEK293T cells. CONCLUSION: (K141N)HSPB8 formed aggregates predominantly locate around the nucleus in cells. (K141N)HSPB8 co-localizes perfectly with HSPB1 and NEFL. The aggregate formation may be due to (K141N)HSPB8 conformational change leading to self aggregation and its abnormal interaction with other sHSPs such as HSPB1.

[Analysis of the pathological features and gene mutations of Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To analyze the relationship of the pathological features and the gene mutations of Chinese patients with Charcot-Marie-Tooth disease. METHODS: The clinical manifestations and pathological investigations of 26 Chinese patients with Charcot-Marie-Tooth disease, 17 males and 9 females, aged 19.0 (4 - 49), with an average disease course of 0.5 - 30 years, 16 being with CMT1 type and 10 being with CMT2 type. Biopsy of sural nerve was conducted in 26 cases, and gene diagnosis was carried out in 13 cases. RESULTS: Five patients were with peripheral myelin protein-22 (PMP22) duplication, 4 of which showed demyelination, 4 of which showed incrassation of myelin sheath, and two of which showed "onion bulb" change without axonal denaturation. Four cases were with connexin 32 (Cx32) point mutations, 3 of which showed demyelination and one of which showed incrassation of myelin sheath and absence of axonal denaturation. The 2 patients with heat shock protein 22 (Hsp22) and heat shock protein 27 (Hsp27) point mutations both showed axonal atrophy, axonal loss and axonal regeneration. CONCLUSION: The pathological findings of the Chinese CMT patients performed by mutation screening were not completely consistent with the pathological features reported abroad. The results of the mutation screening are consistent with the pathological features; mutation screening has the character of high accuracy, little harm and helps diagnose early, so it is suggested to be performed widely clinically, especially to the patients who has family history or to their lineal relatives.

[Clinical, pathological and genetic studies in a Chinese Charcot-Marie-Tooth disease type 2 family].

OBJECTIVE: To report a Chinese Charcot-Marie-Tooth disease type 2 (CMT2) family. METHODS: All the members in the family were studied clinically,and 6 patients were studied electrophysiologically. Sural nerve biopsy was performed in the proband. PMP22 gene duplications were detected by highly polymorphic short tandem repeat. Point mutation analysis of PMP22, MPZ and NEFL gene was screened by PCR-SSCP combined with DNA direct sequencing. A genome-wide screening was carried out to the family. RESULT: Except 2 who had weakness and atrophy in both proximal and distal muscles of the lower limbs, all patients presented muscle wasting and a predominating weakness of distal parts of the lower limbs, and mild to moderate sensory impairments. In 6 patients who were subjected to elctrophysiological examinations, median-nerve conduction velocity (NCV) of the median nerve was normal. Electromyograms (EMGs) revealed signs of denervation with large motor unit potentials, fibrillation potentials and positive sharp waves. Sural nerve biopsy of the proband confirmed the presence of axonal neuropathy with an important loss of large myelinating fibers and a large number of clusters with mostly thinly myelinated axons. PMP22, MPZ and NEFL gene mutations were not found. The results of genome-wide screening revealed a linkage of CMT2 to a locus at chromosome 12q24. CONCLUSION: The results are consistent with the diagnosis of CMT2. This family represents a rare genetic type of CMT2 which can be designated as CMT2L.

[The characteristics of gene mutations in Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To study the characteristics of gene mutations in Chinese patients with Charcot-Marie-Tooth disease (CMT). METHODS: Real-time quantitative PCR, PCR-SSCP, and/or direct sequencing were used to analyze the mutation of the pathogenic genes PMP22, MPZ, CX32, EGR2, GDAP1, NEFL, HSP22 and HSP27 in 113 probands of CMT families, 45 of which had family history, from different provinces in China. The whole family members of the subjects with abnormal electrophoretic bands and 50 normal controls underwent the same examination. RESULTS: Thirty-six cases of PMP22 duplication, 7 cases of CX32 mutation, 1 case of HSP22 mutation, 1 case of HSP27 mutation, 1 case of MPZ mutation, and 1 case of GDAP1 mutation were found in the 113 CMT probands. No point mutation was found in PMP22, EGR2 and NEFL genes. CONCLUSION: Among the Chinese CMT patients 31.9% are caused by PMP22 duplication, 6.2% by CX32, and 0.9% by HSP22, HSP27, MPZ and GDAP1. Point mutations of PMP22, EGR2 and NEFL are rare.

[Mutation analysis of small heat shock protein 27 gene in Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To investigate the features of small heat shock protein 27 (HSP27) gene mutation in Chinese patients with Charcot-Marie-Tooth disease (CMT). METHODS: DNA samples from 114 CMT probands were screened for mutations in HSP27 gene by polymerase chain reaction and direct sequencing, and haplotype analysis was further carried out on the mutation detected families. RESULTS: One missense mutation C379T was detected in 4 autosomal dominant CMT2 families. Haplotype analysis indicated that the 4 families probably had a common ancestor. CONCLUSION: To the authors' knowledge, this is the first report of HSP27 gene mutation in Chinese patients with CMT, but it may be not common(0.90%). The C379T mutation in HSP27 gene also causes CMT2 except for distal hereditary motor neuropathy, thus providing further evidence that even the same mutation in the same gene may lead to distinct phenotypes.

[Detection of duplications or deletions of the PMP22 gene using real-time quantitative PCR].

OBJECTIVE: To detect the duplication or deletion of peripheral myelin protein 22(PMP22) gene in Chinese patients with Charcot-Marie-Tooth disease(CMT) or hereditary neuropathy with liability to pressure palsies(HNPP) using real-time quantitative polymerase chain reaction. METHODS: Duplications or deletions of PMP22 gene were detected in 113 CMT cases, 4 HNPP cases and 50 normal controls by using real-time quantitative PCR. RESULTS: Thirty-six of 113 CMT cases had the PMP22 duplication, 4 HNPP cases had the PMP22 deletion. No duplication or deletion was found in 50 normal controls. CONCLUSION: The PMP22 duplication rate in Chinese patients with CMT is 31.9%(36/113). PMP22 deletion is the common cause of HNPP.

Mutation analysis of small heat-shock protein 22 gene in Chinese patients with Charcot-Marie-Tooth disease.

OBJECTIVE: To study the characteristics of the mutation of small heat-shock protein 22 (HSP22) gene in Chinese patients with Charcot-Marie-Tooth (CMT) disease. METHODS: A CMT2L proband with 423(G--> T) mutation in HSP22 gene had been studied and reported by the present authors. In this study, mutation analysis of HSP22 gene was performed using polymerase chain reaction and DNA direct sequencing in 114 CMT probands. RESULTS: In the 114 CMT probands, a 582(C--> T)(T194T)samesense mutation was found in two unrelated families. CONCLUSION: The rate of HSP22 gene mutation in Chinese patients with CMT is as low as 0.87%(1/115).

Mutation analysis of the small heat shock protein 27 gene in chinese patients with Charcot-Marie-Tooth disease.

BACKGROUND: Charcot-Marie-Tooth (CMT) disease, the most common hereditary peripheral neuropathy, is highly clinically and genetically heterogeneous, and mutations in at least 18 genes have been identified. Recently, mutations in small heat shock protein 27 (Hsp27) were reported to cause CMT disease type 2F and distal hereditary motor neuropathy. OBJECTIVE: To investigate the frequency and phenotypic features of an Hsp27 mutation in Chinese patients with CMT disease. DESIGN: DNA samples from 114 unrelated patients with CMT disease were screened for mutations in Hsp27 by polymerase chain reaction and direct sequencing. A cosegregated study was performed using the MbiI restriction endonuclease, and 50 healthy control subjects were analyzed. Haplotype analysis was performed using 5 short tandem repeat markers to analyze whether the families with the same mutation probably had a common ancestor. RESULTS: One missense mutation, C379T, was detected in 4 autosomal dominant families with CMT disease type 2, and haplotype analysis indicated that the 4 families probably had a common founder. The frequency of the Hsp27 mutation is 0.9% (1/111) in Chinese patients with CMT disease in our study, and the phenotypes were characterized by later onset (age, 35-60 years) and mild sensory impairments. Electrophysiological findings showed moderately to severely slowed nerve conduction velocities in lower limb nerves but normal or mildly reduced velocities in upper limb nerves. CONCLUSIONS: To our knowledge, this is the first report of an Hsp27 mutation in the People's Republic of China. The C379T mutation in Hsp27 also causes CMT disease type 2, except for distal hereditary motor neuropathy, and the phenotypes are distinct from the family with CMT disease type 2F described previously. A mutation of Hsp27 may be uncommon in Chinese patients with CMT disease.

Mutation screening of Cx32 in Han Chinese patients with Charcot-Marie-Tooth disease.

OBJECTIVE: To investigate the Cx32 mutation features and the clinical manifestations of Chinese patients with Charcot-Marie-Tooth disease(CMT). METHODS: Twenty-four of 65 unrelated CMT patients were selected for Cx32 mutation screening after the exclusion of the CMT1A 1.5 Mb duplication and male-to-male transmission. The motor and sensory nerve conduction studies were performed in all probands and most of their affected family members to establish the clinical CMT1 ,CMT2 or CMT intermediate diagnosis. The presence of mutations in the coding region of Cx32 was detected by single-strand conformation polymorphism analysis combined with direct sequencing. RESULTS: We found 7 different point mutations in the coding region of Cx32 in a total of 7 families. All the patients were mildly to moderately affected with a clinical CMT1 or CMT intermediate diagnosis. The mutation Arg15Gln was inherited with X-linked recessive trait in family 1 involved in our study. The Arg75Trp mutation was detected in a family with X-linked dominant CMT and autosomal recessive nonsydromic hearing loss. The clinical phenotype of the Thr188Ala mutation was firstly reported. CONCLUSION: Seven different Cx32 point mutations were detected and the percentage of Chinese CMT families with Cx32 mutation is about 10% in our study. The inheritance model of CMT secondary to Cx32 mutation could be X-linked dominant, X-linked recessive or sporadic. Male patients are usually more severely affected than females with slower nerve conduction velocities. Cx32 mutation screening should be firstly performed in those CMT families without male-to-male transmission and CMT1A duplication.

Small heat-shock protein 22 mutated in autosomal dominant Charcot-Marie-Tooth disease type 2L.

Charcot-Marie-Tooth (CMT) disease is the most common inherited motor and sensory neuropathy. We have previously described a large Chinese CMT family and assigned the locus underlying the disease (CMT2L; OMIM 608673) to chromosome 12q24. Here, we report a novel c.423G-->T (Lys141Asn) missense mutation of small heat-shock protein 22-kDa protein 8 (encoded by HSPB8), which is also responsible for distal hereditary motor neuropathy type (dHMN) II. No disease-causing mutations have been identified in another 114 CMT families.