Theses (PHD)

Background: The number of people in Malaysia who are 60 years of age or over has grown dramatically in the last several years, and by 2030, when this demographic accounts for more than 15% of the total population, the nation is predicted to become an ageing nation. Age-related changes in physiological processes result in a number of morbidities requiring more frequent visits to primary care and long-term care facilities and institutionalised care. Older people with various medical diseases are more likely to use multiple medications to manage their conditions, and the use of many medications increases the risk of exposure to potentially inappropriate medications. Older people who take multiple medications are at high risk of adverse drug reactions, and there is an increased risk of poor sleep quality in frail older people, including those living in aged care settings. Many drugs are known to alter sleep in older people; however, there is a lack of evidence on how potentially inappropriate medications are associated with sleep quality in aged care home residents in Malaysia. Therefore, this study evaluated the effects of potentially inappropriate medications, medication burden, and frailty on sleep quality and quality of life of aged care home residents in Malaysia. Methods: A total of 151 Malaysian aged care home residents were eligible and consented to the study. All of them were included in the data collection process, which was conducted in three phases: baseline, first follow-up in the sixth month, and second follow-up in the twelfth month. Data were collected using a comprehensive questionnaire comprising demographic data about the study participants and instruments to assess physical activity, mental health, frailty, quality of life, and sleep quality. The last part of the questionnaire involved gathering information such as comorbidities, medications, and physical health measurements. The mental health of the population was assessed using the hospital anxiety and depression scale (HADS), frailty was assessed using the Groningen Frailty Index (GFI), quality of life was assessed using the older of Life (OPQoL) scale, and sleep quality was assessed using Pittsburgh Sleep Quality Index (PSQI). All these scales are validated for use in the Malaysian-aged population. In addition to the above well-recognised tools, this study designed and validated a novel Medication Adherence Tool for older people in Malaysia, which was used in this study to assess the medication adherence of aged care home residents. The tool had good reliability and internal consistency for use in aged care home residents. Beers Criteria (2015) for potentially inappropriate medications, a Screening Tool for Older Person's Prescriptions (STOPP), and the Medication Appropriateness Index (MAI) were used to identify potentially inappropriate medications. A longitudinal study design was employed in which individuals were followed up three times a year (baseline and at six and twelve months). The data collected were analysed using SPSS version 28. Descriptive statistics were used to calculate percentage frequencies, mean and standard deviations. The differences in mean were calculated using an independent t-test. Correlation between study variables was assessed using Pearson and Spearman correlation methods. Multiple linear regression models were used to assess the association of continuous dependent variables with other study characteristics. Multiple logistic regression models were used to analyse the relationship between categorical variables. Results: 151 participants were recruited for the study, and 138 remained in the study at the one-year follow-up. The mean age of the study population was 74.45±8.43; 98% of the study population were Chinese, and 51% of the population were females. About one-third of the study population was exposed to potentially inappropriate medication according to both Beers Criteria and STOPP Criteria. Drugs with possible anticholinergic burden were present in nearly half (46%) of the older people in this study. There was an increase in polypharmacy from 29% at baseline to 34% at the second follow-up. The study developed a new Medication Adherence Tool (MAT) to assess medication adherence in aged care home residents. The tool had acceptable content validity and reliability (Cronbach's alpha = 0.890). The tool was found to be clear, simple, reliable, and free from ambiguity, making it suitable for use in the older adult population without requiring the expenditures associated with utilising current adherence assessment instruments. The study used an internationally recognised tool (PSQI) to assess sleep quality in aged care home residents and found that most of the study population has poor sleep quality. To the best of my knowledge, this is the first study assessing the effects of potentially inappropriate medications and other health-related factors on sleep quality. Frailty score (<0.001), anxiety (<0.001), depression (<0.001), and OPQoL (<0.001) significantly and independently predicted the sleep quality. However, potentially inappropriate medications and anticholinergic drug burden were not significantly associated with sleep quality. Age, gender, smoking, alcoholism, number of chronic conditions, polypharmacy, and medication inappropriateness cumulatively contribute to an increase in the prediction of global sleep quality scores even if they are independently not associated with sleep quality. A fixed effect regression analysis found that polypharmacy (p = 0.010, -0.24 at six months and p = 0.020 -0.22 at one year), OPQoL (p = 0.000 -0.54 at six months and p = 0.000 -0.53 at one year), and frailty (p = 0.009 0.18 at six months and p = 0.002 0.18 at one year) were significantly associated with changes in sleep quality scores. The combined model was significantly associated with a 23% increase in sleep quality score (R2 = 0.23, F (6,271) = 24.75, p < 0.001). The findings suggest that medication reviews should be conducted at regular intervals to reduce inappropriate polypharmacy, which could improve the sleep quality of the aged care home residents. The study assessed the effects of sleep quality, frailty, and medication-related factors on the quality of life in older adults. Frailty, anxiety, depression, and sleep quality were independently and significantly associated with quality of life. A stepwise regression analysis was used to identify the strongest predictors of older people's quality of life. Global PSQI (p = 0.001 -0.28 at six months and p <0.001 -0.36 at one year) and depression (p = 0.006 -0.23 at six months and p <0.001 = -0.30 at one year) were most significantly associated with quality of life. Since sleep quality in the aged care home residents was the strongest predictor of quality of life, improving sleep quality could positively impact residents' general health and well-being. In addition to sleep quality and quality of life, the study assessed the factors influencing frailty in aged care home residents. Frailty was associated significantly with PIM (OR = 4.22, 95%CI [1.80-9.88]), STOPP criteria (OR = 2.95, 95% CI [1.426.16]), MAI (OR = 1.17, 95%CI [1.05-1.30]), anticholinergic burden (OR = 2.36, 95%CI [1.26-4.43]), and DBI (OR:3.92, 95%CI [1.43-10.76]) only at the first followup. More long-term studies are required to determine the effect of medication inappropriateness on frailty, as the other phases of the study could not find any significant association. However, frailty was significantly associated with anxiety (OR = 1.49, 95%CI [1.25-1.78], and OR = 1.72, 95%CI [1.38-2.15] respectively), depression (OR = 1.58, 95%CI [1.31-1.90] and OR = 1.57, 95%CI [1.29-1.90] respectively) and sleep quality (OR = 1.28, 95%CI [1.08-1.52] and OR = 1.34, 95%CI [1.13-1.59] respectively) in the first and second follow-ups (p <0.01in all cases). The most significant association was found between frailty and OPQoL scores, where the association was consistent in all three phases of the study (OR = 0.92, 95%CI [0.86-0.98], OR = 0.93, 95%CI [0.89-0.98] and OR = 0.96 95%CI [0.920.99] at baseline, six months and 12 months, respectively). Preliminary findings from this PhD study were published in PLOS One and MDPI Pharmacy. Other findings will be submitted for publication after the thesis has been submitted for examination to ensure that examination deadlines for this part-time thesis are met. Conclusion: This PhD study used a unique combination of internationally recognised instruments to determine the impact of medication inappropriateness, burden, and frailty on sleep quality and quality of life among older people in aged care homes. The novel Medication Adherence Tool was validated and used to assess the medication adherence of aged care home residents in Malaysia. The tool is simple, easy to use, less time-consuming and more economical compared to many existing medication adherence tools for use in the older population. Most of the study population had poor sleep quality, and the prevalence of potentially inappropriate medications was high enough to cause some concern. Even though there was no significant association between sleep quality, medication appropriateness parameters, and anticholinergic burden, the study suggests medication reviews to reduce drugrelated problems and improve health outcomes. Sleep quality was significantly associated with quality of life, polypharmacy, and frailty. These findings further support the need for medication reviews and highlight the need to assess the quality of life and frailty when conducting the reviews and/or designing interventions to reduce inappropriate polypharmacy. In addition, the study found a bidirectional relationship between sleep quality, quality of life, and frailty. Although frailty is nonmodifiable, this study highlights that adjusting the modifiable factors (medication appropriateness and medication burden) can potentially improve sleep quality and quality of life. Paying particular attention to addressing frailty and improving modifiable factors in older people residing in aged care homes could improve health outcomes and reduce healthcare costs to individuals and society. The generalisability of the present study to Malaysian aged care homes is restricted due to the significant proportion of the Chinese population in the study. A similar longitudinal study over a longer period in a larger population, which includes a cost-benefit component, would provide further insight into factors influencing sleep quality and quality of life. Keywords: Sleep quality, Potentially Inappropriate Medications, Older People's Quality of Life, Frailty, Aged care homes

To address gaps in the understanding of host-parasite interactions, this study employed a systems biology approach to investigate system biological responses in Balb/c mice infected with Toxoplasma gondii and Trypanosoma brucei brucei. The study found distinct histopathological changes in Balb/e mouse organs post- infection. Spleen hyperplasia, chronic inflammation, and immune cell infiltrations were apparent in both infected arms. Cytokine profiling identified key players like tumour necrosis factor alpha, interferon-gamma, interleukin-2 in T. gondii group interleukin-6, and interleukin-IO in T. b. brucei group, providing insights into their roles in host defence or immunomodulation. Nuclear magnetic resonance metabolomics profiling was used to identify potential parasitic infection biomarkers, revealing alterations in metabolic profiles indicative of metabolic adaptations and gut microbiota dynamics during infection. Notably, short-chain fatty acids like acetate and butyrate, aromatic amino acid derivatives like phenylacetylglycine and tyrosine, and metabolites such as sueeinate and creatine were implicated in immune regulation and host-parasite interactions. This study also explores interactions between the gut microbiota and parasitic pathogens, highlighting their impact on disease outcomes. Specifically, Lactobacillus species were identified as key players in modulating the host's immune response and metabolic processes during parasitic infections. In conclusion, the systems biology approach enhances our understanding of host-pathogen interactions in Balb,/c mice, revealing potential therapeutic targets. While the findings are specific to the mouse model, they offer valuable insights that could inform strategies for managing parasitic infections in humans. This study thus lays a strong foundation for future research aimed at developing targeted interventions across various host systems, potentially bridging the gap from animal models to human disease management.

6-Shogaol is a naturally occurring compound mainly present in Zingiber officinale rhizomes and belongs to the category of a class of compounds known as gingerols. It is synthesised in plants via dehydration of 6-gingerol, a principal bioactive constituent in Z. officinale rhizomes. 6-Shogaol is the most potent active compound among all the gingerols present in Z. officinale. Many bioactivities (in vitro and in vivo), such as anti-inflammatory, antioxidant, anticancer, antiobesity, antihyperlipidaemic, etc., have been reported for 6-shogaol in the literature. Few in vitro studies have suggested the possible protective role of 6-shogaol in atherosclerosis. However, there were no in vivo studies to ascertain the antiatherosclerotic activity of 6-shogaol in physiologically relevant animal models. Many animal models to study atherosclerosis are reported in the literature, including apolipoprotein E-deficient (ApoE-/-) mice, low-density lipoprotein receptor-deficient (LDL R-/-) mice, golden hamsters, rats, etc. This study evaluated the activity and molecular mechanism of 6-shogaol in HFD-induced atherosclerosis in ApoE-/- mice and golden hamsters. 6-Shogaol was purchased from commercial suppliers, and its purity is confirmed using LC-MS. The 6-shogaol was dissolved in 10% aqueous dimethylsulfoxide (DMSO) and administered intraperitoneally. In mice, the 6-shogaol was tested at three doses: 0, 20, and 40 mg/kg, whereas in hamsters, the activity was tested at only one dose: 40 mg/kg. Atorvastatin at 10 mg/kg was used as a reference standard. The ApoE-/- mice and hamsters were fed an HFD for 3 months, followed by intraperitoneal administration of 6-shogaol and Atorvastatin on alternative days for 3 months while maintaining the animals on an HFD. The antiatherosclerotic activity of 6-shogaol in APOE -/- mice and hamsters was preliminarily assessed by observing the changes in serum biochemical parameters (glucose, cholesterol, triglycerides, liver function markers, oxidative stress markers and kidney function markers). In the case of mice, the histological changes in the aorta and liver tissues were quantified using , followed by the quantification of genes and proteins of interest associated with atherosclerosis. In the hamsters' case, the liver's histological changes were quantified using H&E and Oil Red O staining, followed by lipidomics analysis of the liver and aorta tissues. The genes were quantified using RT-qPCR (Reverse transcription-quantitative polymerase chain reaction) following the 2- Ct method. The proteins were quantified using immunohistochemical studies. The lipidomics analysis was conducted using Waters Acquity HPLC, equipped with a Q-Extractive Orbitrap mass spectrometer. 6-Shogaol has shown a dose-dependent effect in ApoE (-/-) mice and reversed the dysregulated atherosclerosis-associated biochemical parameters, histological features, gene expression, and protein expression. The activity was further confirmed in golden hamsters through biochemical, histological and lipidomics studies. The mechanism of action of 6- shogaol is multi-folded and is mediated via the regulation of lipogenesis, inflammation and oxidative stress.

Introduction: The current standard for storing human cells involves using DMSO and liquid nitrogen, but this method requires specialized equipment and has associated toxicity. This study aims to develop a DMSO-free preservation protocol potentially through lyophilization. Methods: Trehalose and sucrose at 20-800 mM, hydroxyethyl starch (HES) at 25-350 mg/mL, poly(vinyl alcohol) (PVA) at 1-34 mg/mL and glycerol at 1-10%v/v were evaluated for its toxicity on fibroblasts (MRC5), kidney (HEK293) or mesenchymal stem cells (MSCs). Next, tri-excipients formulations were compared with 10% v/v DMSO during freezing and dehydration. The effect of freezing rate, primary drying duration or choice of reconstitution medium on the cell viability were assessed as well. Cell viability was determined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay or trypan blue staining. The optimized protocol was evaluated on other human cells and storage at -20 oC and -80 oC for ≤30 days. Molecular dynamics (MD) simulation was used to elucidate the molecular mechanisms of the sugar and polymer combination under freezing conditions. Results and Discussion: The formulations failed to provide adequate protection during lyophilization. However, (i) 100 mM trehalose, 150 mg/mL HES and 2% v/v glycerol, (ii) 100 mM sucrose, 150 mg/mL HES and 2% v/v glycerol and (iii) 50 mM trehalose, 50 mM sucrose, 150 mg/mL HES and 2% v/v glycerol showed similar or better cryoprotective capabilities than 10% v/v DMSO during freezing and storage. MD simulation showed the sugar-polymers exert cryoprotective effect through hygroscopicity and water redirection. Conclusion: The optimized formulations demonstrated great potential in replacing DMSO as a cryoprotective agent. However, further investigation is warranted in lyophilization. We hypothesized that intracellular damage was the cause of cell death.

Introduction: According to the National Oral Health Survey of Preschool Children (NOHPS) in 2015, in Malaysia, caries affects 71.3% of preschool children, most of which remain untreated. Caries is preventable; thus, the caries lesion formation and progression can be controlled. There is a need to find a cost-effective caries prevention intervention for 5-6-year-olds that is attractive to governmental and private investment. This study investigates the effectiveness and costeffectiveness of delivering 6-monthly Dental Home Visits (DHVs) and Education Leaflets (ELs) compared to delivering only ELs in caries prevention of 5-6-year-olds in Malaysia. Objectives: This study aimed to evaluate the cost-effectiveness of 6- monthly DHVs and ELs in preventing new caries development in 5– 6-year-olds compared to those receiving only ELs over 24 months. Methodology: The study design is a community-based randomized controlled trial with two arms. A nested sample of 5–6-year-olds attending government-funded kindergartens in the state of Selangor within the 2015 NOHPS was randomized to receive 6-monthly DHVs and ELs for the intervention group and only ELs delivered to the control group over 24 months. This study analyzed the costeffectiveness of each arm in preventing new caries development, OHRQoL, and potential dental treatment cost avoidance in 24 months. This study adopted a government or health provider perspective. The cost data of this study was the estimated cost data, and a conservative approach was adopted to perform sensitivity analysis. Results: Fourteen out of 100 5-6-year-olds in the intervention group, and 60 out of 100 5-6-year-olds in the control group developed new caries at the 24-month follow-up. The estimated cost avoidance of dental treatment on the dental chair of 5-6-year-olds in the intervention group for 24 months was RM 1,500.25, and RM 4,800.00 was the estimated cost avoidance of 5-6-year-olds in the control group for 24 months. The estimated cost avoidance of comprehensive dental treatment under GA of 5-6-year-olds in the intervention group for 24 months was RM 21,945.25, and RM 90,007.70 was the estimated cost avoidance of 5-6-year-olds in the control group for 24 months. ICER for dental treatment on the dental chair was RM -72.50, and RM – 1,492.60 was ICER for comprehensive dental treatment under GA. The sensitivity analysis demonstrated consistent negative results, after calculating with different values of total estimated intervention costs and the total estimated control costs with the range of 15.0-30.0%. 6- monthly DHVs and ELs remained at quadrant II in the costeffectiveness plane. Conclusions: Delivering 6-monthly DHVs and ELs resulted in fewer number of 5-6-year-olds developing new caries at 24-month followup. It would reduce the number of 5-6-year-olds that need dental treatment and potentially avoid expensive dental treatment due to caries. 6-monthly DHVs and ELs could reduce the economic burden of caries in 5-6-year-olds in Malaysia