Cell-based assays for IGF-I bioactivity measurement: overview, limitations and current trends

Ramadhin, Charlotte; Pillay, Balakrishna; Olaniran, Ademola O.

doi:10.3109/08977194.2014.939806

Cited by 5 publications

(6 citation statements)

References 96 publications

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“…This reflects the fact that, in contradistinction to animal studies, circulating levels of total IGF-1 and bioactive IGF-1 (determined by measuring IGF-binding proteins 1,2 and 3) are poor markers of the effects of energy restriction and weight loss in humans (Byers and Sedjo, 2011), and do not relate well to IGF-1 bioactivity at the tissue level (Ramadhin et al, 2014). We reported no change in total circulating IGF-1 alongside weight loss with IF or CER in either of our studies (Harvie et al, 2011, 2013a).…”

Section: If In Humansmentioning

confidence: 99%

Impact of intermittent fasting on health and disease processes

Mattson

Longo

Harvie

2017

Ageing Research Reviews

762

621

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Humans in modern societies typically consume food at least three times daily, while laboratory animals are fed ad libitum. Overconsumption of food with such eating patterns often leads to metabolic morbidities (insulin resistance, excessive accumulation of visceral fat, etc.), particularly when associated with a sedentary lifestyle. Because animals, including humans, evolved in environments where food was relatively scarce, they developed numerous adaptations that enabled them to function at a high level, both physically and cognitively, when in a food-deprived/fasted state. Intermittent fasting (IF) encompasses eating patterns in which individuals go extended time periods (e.g., 16–48h) with little or no energy intake, with intervening periods of normal food intake, on a recurring basis. We use the term periodic fasting (PF) to refer to IF with periods of fasting or fasting mimicking diets lasting from 2 to as many as 21 or more days. In laboratory rats and mice IF and PF have profound beneficial effects on many different indices of health and, importantly, can counteract disease processes and improve functional outcome in experimental models of a wide range of age-related disorders including diabetes, cardiovascular disease, cancers and neurological disorders such as Alzheimer’s disease Parkinson’s disease and stroke. Studies of IF (e.g., 60% energy restriction on 2 days per week or every other day), PF (e.g., a 5 day diet providing 750–1100 kcal) and time-restricted feeding (TRF; limiting the daily period of food intake to 8 h or less) in normal and overweight human subjects have demonstrated efficacy for weight loss and improvements in multiple health indicators including insulin resistance and reductions in risk factors for cardiovascular disease. The cellular and molecular mechanisms by which IF improves health and counteracts disease processes involve activation of adaptive cellular stress response signaling pathways that enhance mitochondrial health, DNA repair and autophagy. PF also promotes stem cell-based regeneration as well as long-lasting metabolic effects. Randomized controlled clinical trials of IF versus PF and isoenergetic continuous energy restriction in human subjects will be required to establish the efficacy of IF in improving general health, and preventing and managing major diseases of aging.

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Section: If In Humansmentioning

confidence: 99%

Impact of intermittent fasting on health and disease processes

Mattson

Longo

Harvie

2017

Ageing Research Reviews

762

621

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“…Antioxidant drugs that could change cellular NAD(P)H concentrations have been effective in diseases such as aging, inflammation, neural degeneration, and cancer [73,74]. Many tetrazolium compounds can be reduced by NADH and NADPH to produce colored formazin and have been developed commercially for cell vitality assay, as shown in Table 4 [75].…”

Section: Nadh and Nadph Production Of Live Cellmentioning

confidence: 99%

“…Continuously tracking the cell growth is important for accurate assessment of drug effects and/or growth condition changes. Even though various endpoint assays [75,82,83] can be terminated at various time point to obtain the time-dependent cell proliferation curve, the procedures are labor-intensive and have high experimental error. Therefore, a nondestructive continuous assay is highly desirable and critical for the precise evaluation of drug potency and efficacy.…”

Section: Continuous Assaymentioning

confidence: 99%

Cell Growth Measurement

Chen¹,

Rui²,

Yu³

et al. 2020

Cell Growth

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The cell is the basic structural and functional unit of all living organisms. As the smallest unit and building blocks of life, cells differ in size, shape, metabolism, reproduction, and growth requirements. Cells reproduce through cell division involving a four-phase (G1, S, G2, M) cell cycle, which is tightly regulated at multiple checkpoints. The resulting growth curve demonstrates that cell population increases in three sequential steps: incubation, exponential hyperplasia, and stagnation/death phases. Cell growth is subject to changes in disease state and/or environmental conditions. This chapter will focus on methods for cell growth measurement, which are grouped into five sections: cell cycle, apoptosis, growth curve, druginduced proliferation (DIP), and continuous assays. Among the continuous assays, the EZMTT dye allows for long-term tracking of cell growth under various conditions and shows promise in precision medicine by early detection of drug resistance.

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“…Serum IGF-I often increases alongside weight loss, ER, and exercise (65), and is inversely linked to general adiposity and hepatic fat (66). Serum IGF-I concentrations do not relate well to IGF-I bioactivity within tissues, which is notoriously difficult to assess in humans (67).…”

Section: Studies Of Ier and If In Obese And Overweight Humansmentioning

confidence: 99%

Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence

Harvie

Howell

2016

Advances in Nutrition

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Animal studies and human observational data link energy restriction (ER) to reduced rates of carcinogenesis. Most of these studies have involved continuous energy restriction (CER), but there is increasing public and scientific interest in the potential health and anticancer effects of intermittent energy restriction (IER) or intermittent fasting (IF), which comprise periods of marked ER or total fasting interspersed with periods of normal eating. This review summarizes animal studies that assessed tumor rates with IER and IF compared with CER or ad libitum feed consumption. The relevance of these animal data to human cancer is also considered by summarizing available human studies of the effects of IER or IF compared with CER on cancer biomarkers in obese, overweight, and normal-weight subjects. IER regimens that include periods of ER alternating with ad libitum feed consumption for 1, 2, or 3 wk have been reported to be superior to CER in reducing tumor rates in most spontaneous mice tumor models. Limited human data from short-term studies (≤6 mo) in overweight and obese subjects have shown that IER can lead to greater improvements in insulin sensitivity (homeostasis model assessment) than can CER, with comparable reductions in adipokines and inflammatory markers and minor changes in the insulin-like growth factor axis. There are currently no data comparing IER or IF with CER in normal-weight subjects. The benefits of IER in these short-term trials are of interest, but not sufficient evidence to recommend the use of IER above CER. Longer-term human studies of adherence to and efficacy and safety of IER are required in obese and overweight subjects, as well as normal-weight subjects.

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Cell-based assays for IGF-I bioactivity measurement: overview, limitations and current trends

Cited by 5 publications

References 96 publications

Impact of intermittent fasting on health and disease processes

Impact of intermittent fasting on health and disease processes

Cell Growth Measurement

Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence

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