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Genetic variants in corneal dystrophy genes : a Maltese cohort study : inhibition of TGFBI as a treatment modality

Mon, 01 Jan 2024 00:00:00 GMT

Title: Genetic variants in corneal dystrophy genes : a Maltese cohort study : inhibition of TGFBI as a treatment modality Abstract: The three aims of this study were to a) establish which worldwide populations have a corneal dystrophy (CD) genetic makeup closest to that of the Maltese; b) identify mutations present in a Maltese family that exhibit granular corneal dystrophy 1 (GCD1), a subtype of TGFBI CDs; c) explore TGFBI inhibition as a treatment modality. Genetic prevalence of CD subtypes and fixation index (FST) values for Maltese single nucleotide polymorphisms (SNPs) were calculated and compared to global cohorts. Clinical exome sequencing was performed on mouthwash samples from Maltese GCD1 phenotype individuals. A scoping literature review to identify compounds that decrease corneal TGFBIp (protein) levels was conducted to explore their potential to be used as a cost-effective approach via drug repurposing. Human corneal epithelial cells (HCECs) were cultured and shRNA mediated knockdown (KD) of TGFBI was effectively performed. HCECs were also exposed to lithium (Li) and mitomycin C (MMC). RNA extraction and sequencing revealed gene expression levels in control, TGFBI KD, Li and MMC treated HCECs. Differential expression (DE) and enrichment analysis (ORA) were performed on these samples. FST values showed least differentiation with Puerto Rican, Mexican, and Colombian cohorts. The mutation in the GCD1 phenotype patients was identified as R555W (TGFBI gene). 16 compounds that can theoretically reduce the levels of mutant TGFBIp in corneal cells were identified. ORA of TGFBI KD DE genes showed enrichment of adhesion and signalling proteins. Surprisingly, TGFBI expression was found to be upregulated in the Li and MMC groups at 72hours. Identifying the Hispanic cohorts as those with a CD genome closest to the Maltese implies that when no comparable Maltese data is available, research in these cohorts can be used to guide future treatment strategies for Maltese CD individuals. The clinical exome sequencing study is the first CD genetic study that has ever been carried out on GCD1 Maltese individuals, generating new data about the previously unknown genetic pool. This project is also the first of its kind to explore the DE of genes in KD, Li and MMC treated HCECs, leading to further understanding of TGFBI related molecular pathways in HCECs. Surgical treatment of TGFBI CDs can be associated with serious complications and recurrence is almost universal. The introduction of gene therapy as a treatment option would be a breakthrough. Description: Ph.D.(Melit.)

Achilles tendon rupture : epidemiology, outcomes after treatment and an analysis of plantar foot pressures

Mon, 01 Jan 2024 00:00:00 GMT

Title: Achilles tendon rupture : epidemiology, outcomes after treatment and an analysis of plantar foot pressures Abstract: The influence of socioeconomic deprivation status (SEDS) on the epidemiology of primary Achilles tendon rupture (ATR) has not been explored, while the general epidemiology of Achilles tendon re-ruptures (ATRR) is poorly understood. The optimal management of ATR remains controversial and recent trends towards functional rehabilitation are not supported by robust evidence. The studies comprising this thesis sought to define the epidemiology of primary ATR, with particular focus on the influence of SEDS; to describe the epidemiology and risk factors for ATRR; to report on comparative outcomes from randomised controlled trials comparing long-term outcomes after traditional operative and non-operative management and short-term outcomes after traditional and functional non-operative rehabilitation; and to report on changes in static plantar loading patterns, physical and patient reported parameters after functional nonoperative treatment of ATR. ATR and ATRR were commoner in males and individuals with lower levels of socioeconomic deprivation. The nature of ATR varied with variations in SEDS. Risk factors for ATRR were identified, including younger age and immobilising treatment of ATR. Patients treated surgically did not report superior long-term outcomes to those treated non-operatively. Functional rehabilitation was found to be a safe alternative to immobilising treatment, giving better early outcomes, albeit with a higher incidence of minor skin complications. There was no difference in outcomes beyond one year after injury. Functional, non-operative rehabilitation was associated with reduced forefoot loading and increased rearfoot loading. These changes reduced with time but persisted nine months after injury and were accompanied by progressive changes in uninjured foot loading. Description: Ph.D.(Melit.)

Identifying young adults at high risk of prediabetes and diabetes using the German diabetes risk score and fasting plasma glucose

Sat, 01 Jan 2022 00:00:00 GMT

Title: Identifying young adults at high risk of prediabetes and diabetes using the German diabetes risk score and fasting plasma glucose Abstract: Background: Prediabetes, the leading risk factor for type two diabetes mellitus, represents the intermediate glycaemic stage between normal glycaemia and clinical diabetes. Since the prevalence of type two diabetes mellitus has been increasing, importance is given to monitor the prevalence of prediabetes especially in the younger segment. Aim: To quantify the risk of prediabetes by using a risk tool incorporating its risk factors. This study also sought to assess the validity and reliability of a risk tool on the local population. Fasting plasma glucose was collected to further assess prediabetes risk and compared to the risk score. Research Design and Method: A cross-sectional, correlational, study was conducted. Convenience sampling was used with a target sample size of 374. 176 young adults aged 18-35 years attending either the University of Malta or the Malta College of Arts, Science and Technology had their data collected from the 22 nd of December, 2020 up until the 30th of April, 2021. 57 of these participants also attended for fasting plasma glucose tests after fasting for at least 8 hours. Data analysis was carried out using IBM® SPSS® Statistics Version 27. The Kolmogorov-Smirnov and Shapiro-Wilk test, Mann-Whitney U test, Pearson and Spearman correlation, Fisher’s exact test, Univariate General Linear Model and the receiver operating characteristic analysis were all used to analyse the data. Results: 5.3% (n=3) of participants obtained an abnormal fasting plasma glucose value (≥5.6 mmol/L), signifying prediabetes. One of these three participants also satisfied the criteria for type 2 diabetes mellitus (8.57 mmol/L). The participants who obtained an abnormal fasting plasma glucose value were all male, thus suggesting a higher prevalence of prediabetes in males. The risk factors mostly associated with prediabetes as shown by the German Diabetes Risk Score were sibling history of diabetes, the occurrence of high blood pressure, waist circumference and smoking status. The area under the ROC curve of the German Diabetes Risk Score resulted in 0.787, with a sensitivity of 66.6% and a specificity of 78.0% when scoring 30 points. Conclusion: The utilisation of the German Diabetes Risk Score in young adults in a south European high risk population identified was not shown to be useful in the identification of those subjects with prediabetes or indeed diabetes. The low respondent rate and resultant small sample size undoubtedly contributed to this. The utilisation of fasting plasma glucose to identify such subjects appears to be superior and further studies are needed to investigate the feasibility of nationwide screening in this high risk Maltese population. Description: M.Sc.(Melit.)

The effect of regional anaesthesia and genetic factors on the development of chronic pain following total knee arthroplasty

Sun, 01 Jan 2023 00:00:00 GMT

Title: The effect of regional anaesthesia and genetic factors on the development of chronic pain following total knee arthroplasty Abstract: Background: Chronic Post Surgical Pain (CPSP) is common after Total Knee Arthroplasty (TKA). Factors, including demographic, genetic and possibly anaesthetic techniques, that may modify the risk of developing CPSP are still being investigated. Aim and Objectives: The aims of this study were to show how anaesthetic techniques may influence CPSP and to evaluate potential polymorphisms in six genes that may also affect CPSP. Furthermore, this research studied the genomic variation of these genes in a sample of the local population. The genes investigated were COMT, GCH1, SCN9A, KCNS1, OPRM1 and OPRK1. Methods: Patients scheduled for a TKA were enrolled. Baseline characteristics were obtained, with a blood sample collected for genotyping. Patients were randomized to a spinal anaesthetic alone or to a general anaesthetic with femoral nerve block. Genotyping was performed using TaqManTM SNP Genotyping assays. Patients were followed up at three and at six months with a telephone questionnaire that included a WOMAC® and S-LANSS score. The primary outcome was the WOMAC® score at six months. Secondary outcomes were the acute postoperative pain scores, the WOMAC® Pain score, the S-LANSS score and the incidence of chronic post-surgical pain (CPSP) at six months. Results: 199 patients participated in the study. Patients who received a spinal anaesthetic had better function (WOMAC®: GA: 16.9 vs SP: 14.4, p-value 0.015) and less pain (WOMAC® pain: GA: 3.04 vs SP: 2.69, p-value 0.02) at three months, but not at six months. Overall, 11% of patients had chronic post-surgical pain (CPSP), with Group GA having a higher incidence of (CPSP) at 6 months (OR 4.07, 95CI: 1.33 – 14.59, p-value 0.019). Neuropathic pain was strongly associated with CPSP. Genotyping revealed that most SNPs had a frequency distribution similar to that found in European samples, except for rs998259 and rs3783641 (GCH1) and for rs495491 and rs533586 (OPRM1). Preoperative pain scores were lower in patients who carried the minor allele of rs2075572(OPRM1) (9 vs 11, p-value: <0.001), rs609148 (OPRM1) (9 vs 10, p-value: 0.028) and rs734784 (KCNS1) (9 vs 11, p-value: 0.046). Patients being homozygous for rs495491 (OPRM1) reported lower pain scores at rest (0 vs 2, p-value: 0.05). On multivariate analysis, patients homozygous for rs4633 (COMT) had lower WOMAC® pain scores at six months (Estimate -1.78, 95CI: -2.98 – -0.58, p-value: 0.004). Patients who carried the rs2075572 (OPRM1) had higher pain scores at three months (Estimate: +7.30, 95CI:2.64 – 11.96, p-value: 0.002). Patients who had two copies of rs734784 (KCNS1) had lower WOMAC® scores throughout the study period (Estimate3.94, 95CI: -6.97 – -0.91, p-value: 0.011). Conclusion: Spinal anaesthesia appears to reduce CPSP when compared to general anaesthesia with a femoral block. Genetic polymorphisms may also play a role in the development of CPSP. Description: Ph.D.(Melit.)