Tri-iodothyronine supplement protects gut barrier in septic rats

Causal association between thyroid dysfunction and sepsis: a two-sample mendelian randomization study

Background

The causal association between thyroid dysfunction (including hyperthyroidism and hypothyroidism) and sepsis is controversial in previous studies. Therefore, we used Mendelian randomization (MR) to explore the causal association between hyperthyroidism or hypothyroidism and the susceptibility to four distinct subtypes of sepsis (streptococcal sepsis, puerperal sepsis, asthma-associated pneumonia or sepsis, and other sepsis).

Methods

In our research, we conducted two-sample Mendelian randomization (MR) analyses utilizing publicly available genome-wide association studies (GWAS) data from Sakaue et al. and the Finnish database to investigate the potential causal associations between hyperthyroidism, hypothyroidism, and each of the four distinct subtypes of sepsis, in addition to reverse MR analyses of the positive results to examine the existence of reverse causality.

Results

Genetic hypothyroidism was causally related to the development of asthma-associated pneumonia or sepsis (ORIVW: 1.097, 95% CI: 1.024 to 1.174, P = 0.008); hypothyroidism was significantly associated with the development of other sepsis (ORIVW: 1.070, 95% CI: 1.028 to 1.115, P < 0.001). In addition, sensitivity analysis substantiated the robustness of these two MR findings, with no evidence of horizontal pleiotropy observed (P > 0.05). MR Egger regression analysis demonstrated no heterogeneity between instrumental variables (IVs). Inverse MR results confirmed no reverse causality between hypothyroidism and asthma-associated pneumonia or sepsis, or between hypothyroidism and other sepsis. The findings of this study also unveiled that there is no evidence of a causal link between hypothyroidism and the development of streptococcal sepsis or puerperal sepsis. Additionally, the research provided evidence indicating the absence of a causal relationship between hyperthyroidism and streptococcal sepsis, puerperal sepsis, asthma-associated pneumonia or sepsis, and other sepsis.

Conclusions

This study identified a causal link between hypothyroidism and the occurrence of asthma-associated pneumonia or sepsis, and other sepsis, but not with the development of streptococcal sepsis and puerperal sepsis. Moreover, our findings did not reveal any causal association between hyperthyroidism and streptococcal sepsis, puerperal sepsis, asthma-associated pneumonia or sepsis, and other sepsis.

Thyroid Hormones in Critical Illness

Thyroid hormone is integral for normal function, yet during illness, circulating levels of the most active form (triiodothyronine [T3]) decline. Whether this is an adaptive response in critical illness or contributes to progressive disease has remained controversial. This review outlines the basis of thyroid hormone changes during critical illness and considers the evidence regarding T3 replacement.

Triiodothyronine Administration in a Model of Septic Shock: A Randomized Blinded Placebo-Controlled Trial

OBJECTIVES

Triiodothyronine concentration in plasma decreases during septic shock and may contribute to multiple organ dysfunction. We sought to determine the safety and efficacy of administering triiodothyronine, with and without hydrocortisone, in a model of septic shock.

DESIGN

Randomized blinded placebo-controlled trial.

SETTING

Preclinical research laboratory.

SUBJECTS

Thirty-two sheep rendered septic with IV Escherichia coli and receiving protocol-guided sedation, ventilation, IV fluids, and norepinephrine infusion.

INTERVENTIONS

Two hours following induction of sepsis, 32 sheep received a 24-hour IV infusion of 1) placebo + placebo, 2) triiodothyronine + placebo, 3) hydrocortisone + placebo, or 4) triiodothyronine + hydrocortisone.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was the total amount of norepinephrine required to maintain a target mean arterial pressure; secondary outcomes included hemodynamic and metabolic indices. Plasma triiodothyronine levels increased to supraphysiological concentrations with hormonal therapy. Following 24 hours of study drug infusion, the amount of norepinephrine required was no different between the study groups (mean ± SD μg/kg; placebo + placebo group 208 ± 392; triiodothyronine + placebo group 501 ± 370; hydrocortisone + placebo group 167 ± 286; triiodothyronine + hydrocortisone group 466 ± 495; p = 0.20). There was no significant treatment effect on any hemodynamic variable, metabolic parameter, or measure of organ function.

CONCLUSIONS

A 24-hour infusion of triiodothyronine, with or without hydrocortisone, in an ovine model of septic shock did not markedly alter norepinephrine requirement or any other physiological parameter.

Rebamipide suppresses diclofenac-induced intestinal permeability via mitochondrial protection in mice

AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice.

METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity.

RESULTS: Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling.

CONCLUSION: Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.