Zi Xiang Lim
Email Address
bchlzx@nus.edu.sg
Organizational Units
YONG LOO LIN SCH OF MEDICINE
faculty
BIOCHEMISTRY
dept
4 results
Publication Search Results
Now showing 1 - 4 of 4
Publication Alpha-Ketoglutarate dietary supplementation to improve health in humans(ELSEVIER SCIENCE LONDON, 2022-02-01) Gyanwali, Bibek; Lim, Zi Xiang; Soh, Janjira; Lim, Clarissa; Guan, Shou Ping; Goh, Jorming; Maier, Andrea B; Kennedy, Brian K; Dr Jor Ming Goh; MEDICINE; PHYSIOLOGY; BIOCHEMISTRYAlpha-ketoglutarate (AKG) is an intermediate in the Krebs cycle involved in various metabolic and cellular pathways. As an antioxidant, AKG interferes in nitrogen and ammonia balance, and affects epigenetic and immune regulation. These pleiotropic functions of AKG suggest it may also extend human healthspan. Recent studies in worms and mice support this concept. A few studies published in the 1980s and 1990s in humans suggested the potential benefits of AKG in muscle growth, wound healing, and in promoting faster recovery after surgery. So far there are no recently published studies demonstrating the role of AKG in treating aging and age-related diseases; hence, further clinical studies are required to better understand the role of AKG in humans. This review will discuss the regulatory role of AKG in aging, as well as its potential therapeutic use in humans to treat age-related diseases.Publication The potential benefits of assessing post-cardiopulmonary exercise testing (CPET) in aging: a narrative review.(Springer Science and Business Media LLC, 2023-05-01) Lim, Zi Xiang; Gyanwali, Bibek; Soh, Janjira; Koh, Angela S; Goh, Jorming; Dr Jorming Goh; PHYSIOLOGY; DUKE-NUS MEDICAL SCHOOL; BIOCHEMISTRYCardiopulmonary exercise testing (CPET) is an important tool to measure the cardiopulmonary fitness of an individual and has been widely used in athletic, clinical and research settings. Most CPET focus on analyzing physiological responses during exercise. We contend that the post-CPET recovery physiological responses offer further diagnostic and prognostic information about the health of the cardiopulmonary and metabolic systems, especially when testing apparently healthy middle-aged and older adults. However, there are limited studies that investigate physiological responses during the post-CPET recovery, and even less so in middle-aged and older adults. Therefore, this current review is aimed at discussing the contribution of post-CPET recovery parameters to cardiopulmonary health and their potential applications in aging populations. In addition to the existing methods, we propose to examine the aerobic and anaerobic recovery threshold post-CPET as novel potential diagnostic and/or prognostic tools.Publication Alpha-ketoglutarate supplementation and BiologicaL agE in middle-aged adults (ABLE)-intervention study protocol(SPRINGER, 2023-01-01) Sandalova, Elena; Goh, Jorming; Lim, Zi Xiang; Lim, Zhi Meng; Barardo, Diogo; Dorajoo, Rajkumar; Kennedy, Brian K; Maier, Andrea B; Dr Elena Sandalova; DEAN'S OFFICE (MEDICINE); MEDICINE; PHYSIOLOGY; DEAN'S OFFICE (DUKE-NUS MEDICAL SCHOOL); BIOCHEMISTRYTargeting molecular processes of aging will enable people to live healthier and longer lives by preventing age-related diseases. Geroprotectors are compounds with the potential to increase healthspan and lifespan. Even though many of them have been tested in animal models, the translation to humans is limited. Alpha-Ketoglutarate (AKG) has been studied widely in model animals, but there are few studies testing its geroprotective properties in humans. ABLE is a double blinded placebo-controlled randomized trial (RCT) of 1 g sustained release Ca-AKG versus placebo for 6 months of intervention and 3 months follow up including 120 40–60-year-old healthy individuals with a higher DNA methylation age compared to their chronological age. The primary outcome is the decrease in DNA methylation age from baseline to the end of the intervention. A total of 120 participants will be randomized to receive either sustained release Ca-AKG or placebo. Secondary outcomes include changes in the inflammatory and metabolic parameters in blood, handgrip strength and leg extension strength, arterial stiffness, skin autofluorescence, and aerobic capacity from baseline to 3 months, 6 months, and 9 months. This study will recruit middle-aged participants with an older DNA methylation age compared to their chronological age, and test whether supplementation with Ca-AKG can reduce DNA methylation age. This study is unique in its inclusion of biologically older participants.Publication Effects of blood flow restriction (BFR) with resistance exercise on musculoskeletal health in older adults: a narrative review(SPRINGER HEIDELBERG, 2022-12-01) Lim, Zi Xiang; Goh, Jorming; Dr Jor Ming Goh; PHYSIOLOGY; BIOCHEMISTRYBackground: Aging leads to a number of structural and physiological deficits such as loss of muscle mass and strength. Strength training at ~ 70% of 1 repetition max (RM) is recommended to prevent age-related loss of muscle mass and strength. However, most older adults may not be able to perform 70% of 1RM or higher intensity. An alternative exercise training program combining low intensity resistance exercise with blood flow restriction (BFR) can result in similar acute and chronic benefits to skeletal muscles in older adults. Main body and short conclusion: The potential mechanisms involved are discussed, and include reactive hyperaemia, metabolic stress, and hypoxia. Key issues and safety with the use of BFR in older adults, especially those with chronic conditions are also discussed. Although there has been no reported evidence to suggest that BFR elevates the risk of clinical complications any more than high intensity exercise, it is recommended for individuals to be medically cleared of any cardiovascular risks, prior to engaging in BFR exercise.