Subclinical Hypothyroidism Is Associated With Adverse Prognosis in Heart Failure Patients

Background

It is widely recognized that overt hyper- as well as hypothyroidism are potential causes of heart failure (HF). Additionally it has been recently reported that subclinical hypothyroidism (sub-hypo) is associated with atherosclerosis, development of HF, and cardiovascular death. We aimed to clarify the effect of sub-hypo on prognosis of HF, and underlying hemodynamics and exercise capacity.

Craniofacial anatomical risk factors in men with obstructive sleep apnea and heart failure: a pilot study

Purpose

Obstructive sleep apnea (OSA) is complicated with heart failure (HF); however, the reason for this is not well understood. Craniofacial anatomic risk factors may contribute to OSA pathogenesis in HF patients. However, there are no data about cephalometric findings among OSA patients with HF.

Methods

Consecutive patients with HF and OSA (defined as total apnea–hypopnea index (AHI) ≥15/h) were enrolled. As controls, OSA patients without HF but matching the test group in age, BMI, and obstructive AHI were also enrolled.

Results

Overall, 17 OSA patients with HF and 34 OSA patients without HF were compared. There are no significant differences in the characteristics or polysomnographic parameters between 2 groups. In the cephalometric findings, compared with patients without HF, patients with HF showed a significantly greater angle between the line SN to point “A” (SNA) and a longer inferior airway space and greater airway area. However, the tongue area of patients with HF was more than those without HF.

Conclusions

The craniofacial structures of OSA patients with HF were different from those without HF. OSA patients with HF had an upper airway anatomy that is more likely to collapse when sleeping while recumbent, despite having a larger airway space.     

Redox signal-mediated sensitization of transient receptor potential melastatin 2 (TRPM2) to temperature affects macrophage functions

The ability to sense temperature is essential for organism survival and efficient metabolism. Body temperatures profoundly affect many physiological functions, including immunity. Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive, Ca(2+)-permeable cation channel expressed in a wide range of immunocytes. TRPM2 is activated by adenosine diphosphate ribose and hydrogen peroxide (H(2)O(2)), although the activation mechanism by H(2)O(2) is not well understood. Here we report a unique activation mechanism in which H(2)O(2) lowers the temperature threshold for TRPM2 activation, termed "sensitization," through Met oxidation and adenosine diphosphate ribose production. This sensitization is completely abolished by a single mutation at Met-214, indicating that the temperature threshold of TRPM2 activation is regulated by redox signals that enable channel activity at physiological body temperatures. Loss of TRPM2 attenuates zymosan-evoked macrophage functions, including cytokine release and fever-enhanced phagocytic activity. These findings suggest that redox signals sensitize TRPM2 downstream of NADPH oxidase activity and make TRPM2 active at physiological body temperature, leading to increased cytosolic Ca(2+) concentrations. Our results suggest that TRPM2 sensitization plays important roles in macrophage functions.     

Specific mitochondrial DNA mutation in mice regulates diabetes and lymphoma development

It has been hypothesized that respiration defects caused by accumulation of pathogenic mitochondrial DNA (mtDNA) mutations and the resultant overproduction of reactive oxygen species (ROS) or lactates are responsible for aging and age-associated disorders, including diabetes and tumor development. However, there is no direct evidence to prove the involvement of mtDNA mutations in these processes, because it is difficult to exclude the possible involvement of nuclear DNA mutations. Our previous studies resolved this issue by using an mtDNA exchange technology and showed that a G13997A mtDNA mutation found in mouse tumor cells induces metastasis via ROS overproduction. Here, using transmitochondrial mice (mito-mice), which we had generated previously by introducing G13997A mtDNA from mouse tumor cells into mouse embryonic stem cells, we provide convincing evidence supporting part of the abovementioned hypothesis by showing that G13997A mtDNA regulates diabetes development, lymphoma formation, and metastasis--but not aging--in this model.