Hypoxia has been associated with cognitive impairment. Many studies have investigated the role of mTOR signalling pathway in cognitive functions but its role in hypoxia-induced cognitive impairment remains controversial. This review aimed to elucidate the role of mTOR in the mechanisms of cognitive impairment that may pave the way towards the mechanistic understanding and therapeutic intervention of hypoxia-induced cognitive impairment. mTORC1 is normally regulated during mild or acute hypoxic exposure giving rise to neuroprotection, whereas it is overactivated during severe or chronic hypoxia giving rise to neuronal cells death. Thus, it is worth exploring the possibility of maintaining normal mTORC1 activity and thereby preventing cognitive impairment during severe or chronic hypoxia.
Familial hypercholesterolemia is a genetic disorder mainly caused by defects in the low-density lipoprotein receptor gene. Few and limited analyses of familial hypercholesterolemia have been performed in Malaysia, and the underlying mutations therefore remain largely unknown.We studied a group of 154 unrelated FH patients from a northern area of Malaysia (Kelantan). The promoter region and exons 2-15 of the LDLR gene were screened by denaturing high-performance liquid chromatography to detect short deletions and nucleotide substitutions, and by multiplex ligation-dependent probe amplification to detect large rearrangements.
DNA methylation, a major regulator of epigenetic modifications has been shown to alter the expression of genes that are involved in aspects of glucose metabolism such as glucose intolerance, insulin resistance, β-cell dysfunction and other conditions, and it ultimately leads to the pathogenesis of type 2 diabetes mellitus (T2DM). Current evidences indicate an association of DNA methylation with T2DM. This review provides an overview of how various factors play crucial roles in T2DM pathogenesis and how DNA methylation interacts with these factors. Additionally, an update on current techniques of DNA methylation analysis with their pros and cons is provided as a basis for the adoption of suitable techniques in future DNA methylation research towards better management of T2DM. To elucidate the mechanistic relationship between vital environmental factors and the development of T2DM, a better understanding of the changes in gene expression associated with DNA methylation at the molecular level is still needed.
Although type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) are two independent diseases, evidences from epidemiological, pathophysiological and animal studies have indicated a close pathophysiological relationship between these diseases. Due to the pathophysiological similarity of T2DM and AD, which includes insulin resistance and deficiency, protein aggregation, oxidative stress, inflammation, autophagocytosis and advanced glycation end products; AD is often referred to as "type 3 diabetes". In addition to the targeted regimens usually used for treating T2DM and AD individually, currently, anti-diabetic drugs are successfully used to reduce the cognitive decline in AD patients. Therefore, if a common pathophysiology of T2DM and AD could be clearly determined, both diseases could be managed more efficiently, possibly by shared pharmacotherapy in addition to understanding the broader spectrum of preventive strategies. The aim of this review is to discuss the pathophysiological bridge between T2DM and AD to lay the foundation for the future treatment strategies in the management of both diseases.
Stunting is defined by height of more than two standard deviations below the World Health Organization's (WHO) child growth standard median. It is a significant nutritional problem in developing countries, where in 2021, Indonesia recorded a stunting prevalence at 24.4%, slightly higher than the global prevalence (22%). Reducing the prevalence of stunting has been the focus of the current administration in the Indonesian government, as delineated in the 2020-2024 National Medium-Term Development Plan. Globally, many studies have addressed parental stature as a risk factor of stunting. However, systematic reviews that summarized and critically appraised the relationship between parental stature and the incidence of stunting in Indonesia was scarce. This systematic review aimed to assess parental stature as a risk factor for stunting among Indonesian toddlers. Studies were searched through PubMed (MEDLINE), Google Scholar and Mendeley. Studies on Indonesian toddlers under five years old living in Indonesia were included. The quality of the included studies was assessed using Joanna Briggs Institute (JBI) critical appraisal tool. Data were extracted using a standardized data extraction form and were analyzed using Cochrane's RevMan 5.3. Twenty-seven prospective and retrospective cohort, case-control and cross-sectional studies were included with a total 4041 children. Out of 27 included studies, eight were found to be of low, seven of moderate and twelve of high quality. The result showed that parental stature was associated with the incidence of stunting among toddlers in Indonesia, either the mother only (odds ratio (OR) 1.92; 95% confidence interval (95%CI: 1.71-2.15), the father only (OR 5.21; 95%CI: 1.71-15.86) or both parents (OR 3.01; 95%CI: 2.41-3.75). However, studies on father and both parental statures suffered from substantial heterogeneity, imprecision and mixed qualities, therefore, they should be cautiously interpreted.
Nonsense mutations contribute to approximately 10-30% of the total human inherited diseases via disruption of protein translation. If any of the three termination codons (UGA, UAG and UAA) emerges prematurely [known as premature termination codon (PTC)] before the natural canonical stop codon, truncated nonfunctional proteins or proteins with deleterious loss or gain-of-function activities are synthesized, followed by the development of nonsense mutation-mediated diseases. In the past decade, PTC-associated diseases captured much attention in biomedical research, especially as molecular therapeutic targets via nonsense suppression (i.e. translational readthrough) regimens. In this review, we highlighted different treatment strategies of PTC targeting readthrough therapeutics including the use of aminoglycosides, ataluren (formerly known as PTC124), suppressor tRNAs, nonsense-mediated mRNA decay, pseudouridylation and CRISPR/Cas9 system to treat PTC-mediated diseases. In addition, as thrombotic disorders are a group of disease with major burdens worldwide, 19 potential genes containing a total of 705 PTCs that cause 21 thrombotic disorders have been listed based on the data reanalysis from the 'GeneCards® - Human Gene Database' and 'Human Gene Mutation Database' (HGMD®). These PTC-containing genes can be potential targets amenable for different readthrough therapeutic strategies in the future.
Globally, thrombosis-associated disorders are one of the main contributors to fatalities. Besides genetic influences, there are some acquired and environmental risk factors dominating thrombotic diseases. Although standard regimens have been used for a long time, many side effects still occur which can be life threatening. Therefore, natural products are good alternatives. Although the quest for antithrombotic natural products came to light only since the end of last century, in the last two decades, a considerable number of natural products showing antithrombotic activities (antiplatelet, anticoagulant and fibrinolytic) with no or minimal side effects have been reported. In this review, several natural products used as antithrombotic agents including medicinal plants, vegetables, fruits, spices and edible mushrooms which have been discovered in the last 15 years and their target sites (thrombogenic components, factors and thrombotic pathways) are described. In addition, the side effects, limitations and interactions of standard regimens with natural products are also discussed. The active compounds could serve as potential sources for future research on antithrombotic drug development. As a future direction, more advanced researches (in quest of the target cofactor or component involved in antithrombotic pathways) are warranted for the development of potential natural antithrombotic medications (alone or combined with standard regimens) to ensure maximum safety and efficacy.
Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by a persistently high titer of antiphospholipid antibodies (aPLs). In addition to pregnancy morbidity, arterial and/or venous thrombosis is another clinical feature of APS. Regardless of the type of APS, the thrombi formed by the induction of aPLs can lead to deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke and gangrene. Although the concept of APS was introduced approximately 32 years ago, its thrombogenic pathophysiology is still unclear. Therefore, patients are treated with anticoagulant and/or antiplatelet regimens just as in other thrombotic disorders even though the thrombotic pathophysiology is mainly aPLs-mediated. In this review, we provided an update of the cellular, auto-immune and genetic factors known to play important roles in the generation of thrombi. Current successful regimens are also outlined along with potential emerging treatment strategies that may lead to the optimum management of thrombotic APS patients.
Here we present a case report of three familial primary antiphospholipid syndrome (PAPS) patients from Malaysia. The three familial patients comprised two females and one male with a mean age of 26.3 years. The first diagnosis was made between 2005 and 2009, and all patients demonstrated deep vein thrombosis, high levels of IgM and IgG anticardiolipin antibodies, and received warfarin treatment international normalized ratio (INR) 2.0-3.0. The patients ceased to show clinical symptoms after treatment. Recently (August 2014), we investigated whether the levels of antiphospholipid antibodies remained elevated, and we found that seronegativity occurred in the patients. We suspect that prolonged anticoagulant treatment might be one of the causes of reduced levels of antiphospholipid antibodies in these familial PAPS patients.
BACKGROUND: Autoimmunity is believed to play an important causative role in the pathogenesis of epilepsy. There are evidences for the presence of autoantibodies in patients with epilepsy. To date, many studies have assessed the presence of antiphospholipid antibodies (aPLs) in epilepsy patients, though the relationship has been inconclusive.
AIMS: The aim of this systematic review and meta-analysis was to evaluate the presence of aPLs in epileptic patients as compared to healthy controls.
METHODS: Five electronic databases (PubMed, Web of Science, Embase, Scopus and Google Scholar) were searched systematically. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. Quality assessment was carried out by using the modified 9-star Newcastle-Ottawa Scale (NOS). L'Abbé plots were generated to visually inspect heterogeneity while publication bias was evaluated via visualization of contour- enhanced funnel plots, and Begg's and Egger's tests.
RESULTS: Based on the inclusion criteria, 14 studies were selected involving 1248 epilepsy patients and 800 healthy controls. The majority of epilepsy was categorised as generalised or partial and none had comorbidity with autoimmune diseases. Significant presence of both anticardiolipin (aCL) antibodies (OR: 5.16, 95% CI: 3.21-8.28, p
Neurological manifestations or disorders associated with the central nervous system are among the most common and important clinical characteristics of antiphospholipid syndrome (APS). Although in the most recently updated (2006) APS classification criteria, the neurological manifestations encompass only transient ischemic attack and stroke, diverse 'non-criteria' neurological disorders or manifestations (i.e., headache, migraine, bipolar disorder, transverse myelitis, dementia, chorea, epileptic seizures, multiple sclerosis, psychosis, cognitive impairment, Tourette's syndrome, parkinsonism, dystonia, transient global amnesia, obsessive compulsive disorder and leukoencephalopathy) have been observed in APS patients. To date, the underlying mechanisms responsible for these abnormal neurological manifestations in APS remain unclear. In vivo experiments and human observational studies indicate the involvement of thrombotic events and/or high titers of antiphospholipid antibodies in the neuro-pathogenic cascade of APS. Although different types of neurologic manifestations in APS patients have successfully been treated with therapies involving anti-thrombotic regimens (i.e., anticoagulants and/or platelet antiaggregants), antineuralgic drugs (i.e., antidepressants, antipsychotics and antiepileptics) and immunosuppressive drugs alone or in combination, evidence-based guidelines for the management of the neurologic manifestations of APS remain unavailable. Therefore, further experimental, clinical and retrospective studies with larger patient cohorts are warranted to elucidate the pathogenic linkage between APS and the central nervous system in addition to randomized controlled trials to facilitate the discovery of appropriate medications for the 'non-criteria' neurologic manifestations of APS.
BACKGROUND: Antiphospholipid syndrome (APS) is an autoimmune disorder characterised by thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies (aPLs) based on the Sydney criteria. We aimed to explore the clinico-laboratory features and treatment strategies of APS patients retrospectively.
METHODOLOGY: The medical records of APS patients registered under Hospital Universiti Sains Malaysia (Kelantan state) between 2000 and 2015 were reviewed.
RESULTS: A total of 17 APS subjects (age 40.7 ± 12.8 years) including 11 primary (64.7%) and six secondary APS (35.3%) patients were identified. The follow-up period was 9.5 ± 6.7 years with male:female ratio of 1.0:4.7. Pregnancy morbidity was the most common clinical manifestation (11/14; 78.6%) followed by recurrent venous thrombosis (10/17; 58.8%). For other clinical features, menorrhagia was the most frequently observed manifestation (4/14; 28.6%) followed by aPLs-associated thrombocytopenia (4/17; 23.5%) and ovarian cyst (3/14; 21.4%). LA and aCL were positive in 94.1% (16/17) and 81.8% (9/11) of the patients, respectively. APTT value (76.7 ± 17.0 sec) was significantly high (p < 0.05). Low intensity warfarin alone was successful to maintain target INR (2.0 - 3.0) and prevent recurrence of thrombosis.
CONCLUSION: The tendency of pregnancy morbidity in this cohort of Malaysian Kelantanese APS patients was high compared to other previously reported APS cohorts. Low intensity warfarin was successful in preventing recurrence of thrombosis, however, APS women receiving long-term anticoagulants should be monitored for possible occurrence of menorrhagia and ovarian cysts.
Growing evidences are supporting towards the involvement of antiphospholipid antibodies [aPLs e.g., lupus anticoagulant (LA), anticardiolipin (aCL) and anti-β2-glycoprotein I (anti-β2-GPI) antibodies] in various neurological manifestations including migraine, epilepsy and dementia in the presence or absence of autoimmune diseases such as antiphospholipid syndrome or systemic lupus erythematosus. The aim of this systematic review and meta-analysis was to assess the presence of aPLs in dementia patients without a diagnosis of any autoimmune disease. Electronic databases (e.g., PubMed, Web of Science, Scopus, ScienceDirect and Google Scholar) were searched without any year or language restrictions and based on the inclusion criteria, nine prospective case-control studies assessing only aCL were included involving 372 dementia patients and 337 healthy controls. No studies were found to assess the presence of both LA or anti-β2-GPI. The study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects model. We observed the prevalence of aCL in dementia was higher (32.80%) than that of controls (9.50%) e.g., 3.45 times higher risk of presenting with dementia than the controls, and significant presence of aCL antibodies was detected in dementia patients compared to controls (OR: 4.94, 95% CI: 2.66 - 9.16, p < 0.00001; I2 = 32%, p = 0.16). Publication bias was not observed from Egger's (p = 0.081) and Begg's tests (p = 0.180). Based on the study quality assessment using modified Newcastle-Ottawa Scale for case-control studies, seven of nine studies were of high methodological quality scoring ≥ 7 (median value). In summary, aCL antibodies were significantly present in dementia patients suggesting that aCL antibodies are generated due to the autoimmune-derived effects of dementia or there might be a potential causative role of this autoantibody in dementia pathogenesis.
Tuberous sclerosis complex is an autosomal dominant neurocutaneous disorder affecting multiple organs. Tuberous sclerosis complex is caused by mutation in either one of the two disease-causing genes, TSC1 or TSC2, encoding for hamartin and tuberin, respectively. TSC2/PKD1 contiguous gene deletion syndrome is a very rare condition due to deletion involving both TSC2 and PKD1 genes. Tuberous sclerosis complex cannot be easily diagnosed since there is no pathognomonic feature, although there are consensus diagnostic criteria for that. Mutation analysis is useful and plays important roles. We report here two novel gross deletions of TSC2 gene in Malay patients with tuberous sclerosis complex and TSC2/PKD1 contiguous gene deletion syndrome, respectively.
Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous disorder characterized by tumor growth in multiple organs and caused by mutations in either TSC1 or TSC2 genes. Because of their relatively large genomic sizes, absence of hotspots, and common type of mutations, mutation detection in TSC1 and TSC2 genes has been challenging. We devised a combination of multiple ligation-dependent probe amplification (MLPA) and amplicon sequencing (AS) to simplify the detection strategy, yet we come up with reasonably high detection rate. Thirty-four Malaysian patients diagnosed with TSC were referred to Human Genome Center, Universiti Sains Malaysia. We used a combination of MLPA to detect large copy number changes and AS to detect smaller mutations. TSC1 pathogenic or likely pathogenic mutations were found in 6 patients (18%) and TSC2 in 21 patients (62%), whereas 6 patients (18%) show no mutations and 1 patient (2%) showed only TSC2 missense variant with uncertain significance. Six of the mutations are novel. Our detection strategy costs 81% less and require 1 working week less than the conventional strategy. Confirmatory sequencing using Sanger method on a few representative mutations showed agreement with results of the AS. Combination of MLPA and Illumina MiSeq AS provides a simplified strategy and reasonably high detection rate for TSC1/TSC2 mutation, which suggested application of the strategies into clinical molecular diagnostics.
Genetic diagnosis of spinal muscular atrophy (SMA) is complicated by the presence of SMN2 gene as majority of SMA patients show absence or deletion of SMN1 gene. PCR may amplify both the genes non selectively in presence of high amount of DNA. We evaluated whether allele-specific PCR for diagnostic screening of SMA is reliable in the presence of high amount of genomic DNA, which is commonly used when performing diagnostic screening using restriction enzymes.
Several histone deacetylase inhibitors (HDACis) are known to increase Survival Motor Neuron 2 (SMN2) expression for the therapy of spinal muscular atrophy (SMA). We aimed to compare the effects of suberoylanilide hydroxamic acid (SAHA) and Dacinostat, a novel HDACi, on SMN2 expression and to elucidate their acetylation effects on the methylation of the SMN2. Cell-based assays using type I and type II SMA fibroblasts examined changes in transcript expressions, methylation levels and protein expressions. In silico methods analyzed the intermolecular interactions between each compound and HDAC2/HDAC7. SMN2 mRNA transcript levels and SMN protein levels showed notable increases in both cell types, except for Dacinostat exposure on type II cells. However, combined compound exposures showed less pronounced increase in SMN2 transcript and SMN protein level. Acetylation effects of SAHA and Dacinostat promoted demethylation of the SMN2 promoter. The in silico analyses revealed identical binding sites for both compounds in HDACs, which could explain the limited effects of the combined exposure. With the exception on the effect of Dacinostat in Type II cells, we have shown that SAHA and Dacinostat increased SMN2 transcript and protein levels and promoted demethylation of the SMN2 gene.
Histone acetylation plays an important role in regulation of transcription in eukaryotic cells by promoting a more relaxed chromatin structure necessary for transcriptional activation. Histone deacetylases (HDACs) remove acetyl groups and suppress gene expression. HDAC inhibitors (HDACIs) are a group of small molecules that promote gene transcription by chromatin remodeling and have been extensively studied as potential drugs for treating of spinal muscular atrophy. Various drugs in this class have been studied with regard to their efficacy in increasing the expression of survival of motor neuron (SMN) protein. In this review, we discuss the current literature on this topic and summarize the findings of the main studies in this field.
Hyperargininemia is a very rare progressive neurometabolic disorder caused by deficiency of hepatic cytosolic arginase I, resulting from mutations in the ARG1 gene. Until now, some mutations were reported worldwide and none of them were of Southeast Asian origins. Furthermore, most reported mutations were point mutations and a few others deletions or insertions.
In Duchenne muscular dystrophy (DMD), identification of one nonsense mutation in the DMD gene has been considered an endpoint of genetic diagnosis. Here, we identified two closely spaced nonsense mutations in the DMD gene. In a Malaysian DMD patient two nonsense mutations (p.234S>X and p.249Q>X, respectively) were identified within exon 8. The proband's mother carried both mutations on one allele. Multiple mutations may explain the occasional discrepancies between genotype and phenotype in dystrophinopathy.