AUB ScholarWorks

Low-quality protein modulates inflammatory markers and the response to lipopolysaccharide insult: The case of lysine

Show simple item record

dc.contributor.advisor Obeid, Omar
dc.contributor.advisor Eid, Assaad El Mallah, Carla 2023-01-17T06:21:57Z 2023-01-17T06:21:57Z 1/17/2023 1/16/2023
dc.description.abstract The relationship between non-communicable diseases (NCDs) and eating behavior has long been an area of interest. The literature largely attributes the association between NCDs and nutrition to a surplus of food and energy. However, a population observation brought to our attention a dietary factor that may explain the increase in the prevalence of NCDs among the least advantaged communities. Over the last couple of decades, the world has witnessed an increase in the prevalence of NCDs that has paralleled a major nutrition transition characterized by very high cereal intake among populations with low socioeconomic status (SES). Cereals contain low amounts of proteins, which naturally lack lysine, an essential amino acid, in adequate quantities. Lysine is a main component of the amino acid composition of both serum albumin and c-reactive protein (CRP), which concentrations were shown to change among people with low-grade inflammation, a hallmark of NCDs. Hence, it is thought that lysine deficiency might be a confounding factor explaining the association between nutrition and NCDs. In this work, we aim to study the effect of varied levels of lysine deficiency (60% and 30% deficiency) on body composition, inflammatory profile, and behavior of rats in the absence or presence of an inflammatory insult [lipopolysaccharide (LPS)]. For this purpose, two experiments were designed on five-week-old male Sprague Dawley rats to meet the objective of the work. Both experiments were identical and only differed in the level of lysine deficiency. In experiment 1, rats were randomly distributed into four groups: 1) control diet, 2) control diet+LPS, 3) 60% lysine-deficient diet, and 4) 60% lysine-deficient diet+LPS. Experiment 1 was followed by experiment 2, which held three experimental groups: 1) control diet, 2) 30% lysine-deficient diet, and 3) 30% lysine-deficient diet+LPS. Rats were only allowed their experimental diets for four weeks, during which LPS (50 µg/kg) or saline injections were administered intraperitoneally three times per week. The study showed that 60% lysine deficiency blunted growth and body compartments development, decreased albumin production, and raised hepatic c-reactive protein (CRP) expression, independently of interleukins 6 and 1β, the main precursors of CRP. Also, the 60% insufficient levels of lysine in the diet triggered hyperactivity and anxiety-like behavior. On the other hand, a marginal lysine deficiency of 30%, did not yield drastic changes in rats, suggesting dose-dependent alterations associated with the level of deficiency. LPS administration exacerbated outcomes related to body composition, metabolism, and behavior caused by 60% lysine deficiency but surprisingly did not worsen albumin and CRP expressions. This work presents evidence of varied physiological changes associated with insufficient amounts of lysine intake that can potentially increase risk factors for diseases. Thus, the increment in NCDs among the low SES populations, who heavily rely on cereals as a main source of protein may be blamed on low lysine availability in diets.
dc.language.iso en_US
dc.subject Lysine Deficiency
dc.subject Nutrition
dc.subject Rats
dc.subject C-reactive protein
dc.subject Anxiety-like behavior
dc.subject Albumin
dc.subject Body composition
dc.subject Energy efficiency
dc.subject Lipopolysaccharide
dc.subject Inflammation
dc.subject Amino acid
dc.title Low-quality protein modulates inflammatory markers and the response to lipopolysaccharide insult: The case of lysine
dc.type Dissertation
dc.contributor.department Department of Anatomy, Cell Biology, and Physiological Sciences
dc.contributor.faculty Faculty of Medicine
dc.contributor.institution American University of Beirut
dc.contributor.commembers Darwiche, Nadine
dc.contributor.commembers Toufeili, Imad
dc.contributor.commembers Abou-Kheir, Wassim
dc.contributor.commembers Obeid, Makram
dc.contributor.commembers Bassil, Maya
dc.contributor.commembers El Yazbi, Ahmed PhD
dc.contributor.AUBidnumber 201210420

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search AUB ScholarWorks


My Account