title: Effects of oxytocin on feeding suppression and neuronal activity in aged mice

authors: Jervis, Robin

subjects: Oxytocin

abstract: Many studies have shown that, compared to younger adults, old individuals show a different sensitivity to various pharmacological treatments. This phenomenon stems from a plethora of physiological and pathophysiological changes associated with aging, from hormonal regulation to brain functioning. Yet, most animal and human studies do not focus on effects of experimental molecules in aged individuals. This includes drugs that affect appetite and body weight, among which, only a handful have been investigated in the context of aging. One appetite suppressant that has garnered recent attention is oxytocin (OT). In younger adult humans and laboratory animals, peripheral administration of OT reduces eating to satisfy hunger as well as the intake strictly for palatability (pleasure). The effects of OT on food intake in aged individuals are unknown. Thus, the current project was aimed at elucidating the effect of intraperitoneally (IP) injected OT on consumption of standard and palatable food in aged male mice.  This effect was compared to the outcome of the OT treatment in younger adults. In order to identify differences in central mechanisms triggered by OT treatment in aged versus adult mice, the feeding studies were followed by the analysis of OT-induced activity of brain sites involved in appetite control in these animals. Brain activation was assessed by an immunohistochemical detection of an immediate-early gene product, c-Fos, in relevant brain areas. IP OT decreased food consumption in aged and adult male mice. The lowest effective dose in supressing consumption of solid standard and palatable diets in aged animals was 0.3 mg/kg, whereas a higher dose of 1 mg/kg was required to elicit the same response in younger adults.  Furthermore, OT in aged mice supressed palatable sucrose solution intake at 1 mg/kg and milk at 0.1 mg/kg, whereas in young adults, sucrose and milk intakes were supressed by 1 mg/kg OT. The effective dose of 0.3 mg/kg OT in aged animals increased activation of the paraventricular nucleus, central nucleus of the amygdala, nucleus tractus solitarius, and arcuate nucleus and decreased activation of ventromedial nucleus of the hypothalamus and dorsomedial hypothalamus. On the other hand, the 0.3 mg/kg dose in adults resulted in increased c-Fos IR only in paraventricular nucleus, central nucleus of the amygdala, and nucleus tractus solitarius and a decrease only in the ventromedial nucleus of the hypothalamus. The results allow me to conclude that intraperitoneal OT is an effective appetite suppressant in aged individuals, however, a lower dose of the drug is sufficient to generate a decrease in consumption at an old age. This likely stems from a broader circuit of feeding-related brain sites activated by the low dose of OT in aged animals compared to the younger adults.

text: Effects of oxytocin on feeding suppression and neuronal activity in aged mice Many studies have shown that, compared to younger adults, old individuals show a different sensitivity to various pharmacological treatments. This phenomenon stems from a plethora of physiological and pathophysiological changes associated with aging, from hormonal regulation to brain functioning. Yet, most animal and human studies do not focus on effects of experimental molecules in aged individuals. This includes drugs that affect appetite and body weight, among which, only a handful have been investigated in the context of aging. One appetite suppressant that has garnered recent attention is oxytocin (OT). In younger adult humans and laboratory animals, peripheral administration of OT reduces eating to satisfy hunger as well as the intake strictly for palatability (pleasure). The effects of OT on food intake in aged individuals are unknown. Thus, the current project was aimed at elucidating the effect of intraperitoneally (IP) injected OT on consumption of standard and palatable food in aged male mice.  This effect was compared to the outcome of the OT treatment in younger adults. In order to identify differences in central mechanisms triggered by OT treatment in aged versus adult mice, the feeding studies were followed by the analysis of OT-induced activity of brain sites involved in appetite control in these animals. Brain activation was assessed by an immunohistochemical detection of an immediate-early gene product, c-Fos, in relevant brain areas. IP OT decreased food consumption in aged and adult male mice. The lowest effective dose in supressing consumption of solid standard and palatable diets in aged animals was 0.3 mg/kg, whereas a higher dose of 1 mg/kg was required to elicit the same response in younger adults.  Furthermore, OT in aged mice supressed palatable sucrose solution intake at 1 mg/kg and milk at 0.1 mg/kg, whereas in young adults, sucrose and milk intakes were supressed by 1 mg/kg OT. The effective dose of 0.3 mg/kg OT in aged animals increased activation of the paraventricular nucleus, central nucleus of the amygdala, nucleus tractus solitarius, and arcuate nucleus and decreased activation of ventromedial nucleus of the hypothalamus and dorsomedial hypothalamus. On the other hand, the 0.3 mg/kg dose in adults resulted in increased c-Fos IR only in paraventricular nucleus, central nucleus of the amygdala, and nucleus tractus solitarius and a decrease only in the ventromedial nucleus of the hypothalamus. The results allow me to conclude that intraperitoneal OT is an effective appetite suppressant in aged individuals, however, a lower dose of the drug is sufficient to generate a decrease in consumption at an old age. This likely stems from a broader circuit of feeding-related brain sites activated by the low dose of OT in aged animals compared to the younger adults.

year: 2022

title: Physical death, digital life, and post-self: That dragon, cancer as a digital memorial

authors: Schott, Gareth R.

abstract: That Dragon, Cancer represents one of the first notable biographical documentary games to address terminal illness and personal loss. This article highlights how the actionable properties of games are repeatedly reversed to generate a thoughtful reflection on the impact of medical jurisdiction over the dying and its regulation over the end of life. Liberating the medium’s reliance on certain commonplace and overused design principles, That Dragon, Cancer seeks to foster empathy, and urge care, hesitation and preservation rather than progression, advancement and winning states. The resultant game is a poignant digital commemoration of the game creator’s son, Joel, whose life was affected and curtailed by cancer. In addition to being a document of parental grief and loss that offers an emotionally resonant and candid articulation of the effect of disease on the trajectory of life and biography of a child, this article also reasons that the game comprises Joel’s constructed post-self, allowing his life to be extended post-mortem.

text: Physical death, digital life, and post-self: That dragon, cancer as a digital memorial That Dragon, Cancer represents one of the first notable biographical documentary games to address terminal illness and personal loss. This article highlights how the actionable properties of games are repeatedly reversed to generate a thoughtful reflection on the impact of medical jurisdiction over the dying and its regulation over the end of life. Liberating the medium’s reliance on certain commonplace and overused design principles, That Dragon, Cancer seeks to foster empathy, and urge care, hesitation and preservation rather than progression, advancement and winning states. The resultant game is a poignant digital commemoration of the game creator’s son, Joel, whose life was affected and curtailed by cancer. In addition to being a document of parental grief and loss that offers an emotionally resonant and candid articulation of the effect of disease on the trajectory of life and biography of a child, this article also reasons that the game comprises Joel’s constructed post-self, allowing his life to be extended post-mortem.

year: 2020

title: Investigation of in vitro diabetic inflammation and  treatment with Piper excelsum tea extract

authors: Harvey, Savannah

subjects: Piper excelsum

abstract: Induction of inflammation through hyperglycaemia and adiposity has been shown to contribute to the pathogenicity of type 2 diabetes (T2D). The pro-inflammatory cytokine, tumour necrosis factor α (TNF-α) was the first cytokine found to bridge the connection between the immune system and T2D. This was found due to its increased production in the disease state. TNF-α has specifically been linked to the onset of insulin resistance in T2D models. Evidence has shown that heat shock protein 60 (HSP60) may also play a role as a danger signal for the immune system as it can result in the induction of inflammation. Currently, there are no pharmaceutical options for T2D patients which target inflammation. Tea made from the leaves of kawakawa (Piper excelsum) has been used for many generations by Māori as a traditional rākau rongoā (traditional medicine) to treat a range of ailments including inflammation. The aim of this project was to investigate the modulation of inflammation using a commercially available kawakawa tea in human cancer cells in vitro. 

This project involved measuring the growth rate, cytotoxicity, TNF-α production and HSP60 expression upon exposure to three treatments: high glucose, lipopolysaccharide (LPS) or kawakawa tea extract (KTE).

This study showed that a high concentration of KTE (1000 µg/mL) inhibited cell growth in both HEPG2 and HeLa cell lines. Cells treated with this concentration also showed typical morphological signs of apoptosis. Cytotoxicity testing confirmed that there was a significant (p <0.05) decrease in mitochondrial dehydrogenase activity for this treatment which confirmed the cells were likely dying through apoptosis. Over a course of 24-hours three LPS treatments were found to be cytotoxic. These were the 10 ng/mL, 10 µg/mL, and 100 µg/mL concentrations of LPS. After 48-hours all treatments apart from 100 µg/mL KTE treatment were also found to be cytotoxic. The cytotoxicity for these treatments was either due to a reduction in mitochondrial dehydrogenase activity (infers mitochondrial stress) or increased lactate dehydrogenase (LDH) release from cells (infers necrotic cell death). These cytotoxicity experiments allowed for identification of which concentrations should be selected or removed for future experiments. 

Cytotoxicity levels were taken into consideration and experiments were run investigating the induction of TNF-α using enzyme-linked immunosorbent assays (ELISA). Issues regarding negative readings from samples arose which resulted in protocol changes and extensive trouble shooting. It was found that extended exposure times were required to attenuate a positive result from the positive control, LPS. 

HSP60 expression was also measured for human cells exposed to high glucose and KTE treatments. No change in HSP60 expression was detected. However, 24-hour LPS exposure resulted in a significant increase in HSP60 expression compared to the control for the 100 ng/mL LPS treatment. Two concentrations were investigated; 100 ng/mL LPS and 100 µg/mL LPS which resulted in 1.4- and 2.1-fold increases compared to the control, respectively.

Overall, no conclusion could be drawn regarding the modulation of inflammation by KTE. However, this study was able to identify the effect the tea has on human cancer cell growth and the nature of cytotoxicity the tea poses to the cells. It is recommended to continue this research exploring different kawakawa tea blends and using alternative in vitro cell lines and whole animal models.

text: Investigation of in vitro diabetic inflammation and  treatment with Piper excelsum tea extract Induction of inflammation through hyperglycaemia and adiposity has been shown to contribute to the pathogenicity of type 2 diabetes (T2D). The pro-inflammatory cytokine, tumour necrosis factor α (TNF-α) was the first cytokine found to bridge the connection between the immune system and T2D. This was found due to its increased production in the disease state. TNF-α has specifically been linked to the onset of insulin resistance in T2D models. Evidence has shown that heat shock protein 60 (HSP60) may also play a role as a danger signal for the immune system as it can result in the induction of inflammation. Currently, there are no pharmaceutical options for T2D patients which target inflammation. Tea made from the leaves of kawakawa (Piper excelsum) has been used for many generations by Māori as a traditional rākau rongoā (traditional medicine) to treat a range of ailments including inflammation. The aim of this project was to investigate the modulation of inflammation using a commercially available kawakawa tea in human cancer cells in vitro. 

This project involved measuring the growth rate, cytotoxicity, TNF-α production and HSP60 expression upon exposure to three treatments: high glucose, lipopolysaccharide (LPS) or kawakawa tea extract (KTE).

This study showed that a high concentration of KTE (1000 µg/mL) inhibited cell growth in both HEPG2 and HeLa cell lines. Cells treated with this concentration also showed typical morphological signs of apoptosis. Cytotoxicity testing confirmed that there was a significant (p <0.05) decrease in mitochondrial dehydrogenase activity for this treatment which confirmed the cells were likely dying through apoptosis. Over a course of 24-hours three LPS treatments were found to be cytotoxic. These were the 10 ng/mL, 10 µg/mL, and 100 µg/mL concentrations of LPS. After 48-hours all treatments apart from 100 µg/mL KTE treatment were also found to be cytotoxic. The cytotoxicity for these treatments was either due to a reduction in mitochondrial dehydrogenase activity (infers mitochondrial stress) or increased lactate dehydrogenase (LDH) release from cells (infers necrotic cell death). These cytotoxicity experiments allowed for identification of which concentrations should be selected or removed for future experiments. 

Cytotoxicity levels were taken into consideration and experiments were run investigating the induction of TNF-α using enzyme-linked immunosorbent assays (ELISA). Issues regarding negative readings from samples arose which resulted in protocol changes and extensive trouble shooting. It was found that extended exposure times were required to attenuate a positive result from the positive control, LPS. 

HSP60 expression was also measured for human cells exposed to high glucose and KTE treatments. No change in HSP60 expression was detected. However, 24-hour LPS exposure resulted in a significant increase in HSP60 expression compared to the control for the 100 ng/mL LPS treatment. Two concentrations were investigated; 100 ng/mL LPS and 100 µg/mL LPS which resulted in 1.4- and 2.1-fold increases compared to the control, respectively.

Overall, no conclusion could be drawn regarding the modulation of inflammation by KTE. However, this study was able to identify the effect the tea has on human cancer cell growth and the nature of cytotoxicity the tea poses to the cells. It is recommended to continue this research exploring different kawakawa tea blends and using alternative in vitro cell lines and whole animal models.

year: 2021