Anemia in older adults as a geriatric syndrome: A review

Anemia, a frequently occurring condition in older patients, has no standard definition; however, in most studies, it is defined as hemoglobin level <12 and <13 g/dL in women and men, respectively. Approximately 10% of older adults living in the community have anemia. The prevalence of anemia is significantly correlated with advanced age and male sex. Anemia is associated with falls, frailty and other negative outcomes, including early mortality. However, there remains little consensus regarding whether anemia treatment favorably affects these adverse outcomes. Therefore, this article reviews the prevalence of anemia, and provides updates on its common causes and treatments in older adults. While excluding well-established hematopoietic diseases, the etiology of anemia in older adults has been grouped into four categories: (i) nutritional deficiency; (ii) inflammation; (iii) clonal hematopoiesis; and (iv) “unexplained anemia,” when there is no clear mechanism to account for the anemia. Recently, clonal leukocytes were detected in a considerable number of older individuals. The number of somatic mutations in blood leukocytes increases with age; however, single mutations of DNMT3A, TET2 and ASXL1 are not correlated with the presence of unexplained anemia in older adults. With an increased understanding of anemia etiology and the availability of innovative anti-anemic drugs, future studies that evaluate the causes and benefits of treatment are required. Geriatr Gerontol Int 2021; 21: 549–554 .     

Acquisition of antimicrobial-resistant variants in repeated infections caused by Pseudomonas aeruginosa revealed by whole genome sequencing

Pseudomonas aeruginosa, responsible for serious nosocomial-acquired infections, possesses intrinsic antibiotic resistance mechanisms and commonly exhibits multidrug resistance. Here, we report the evolving resistance profiles of strains isolated from the sputum of a patient being treated for repeated P. aeruginosa infections following cancer resection. Whole genome sequencing of six isolates obtained over a 2-month period revealed two key single nucleotide polymorphisms in the mexR and gyrB genes that affected efflux pump expression and antimicrobial resistance.     

Serum autotaxin measurement in haematological malignancies: a promising marker for follicular lymphoma

Autotaxin (ATX) is a tumour cell motility-stimulating factor originally isolated from melanoma cell supernatants. ATX is identical to lysophospholipase D, which produces a bioactive lipid mediator, lysophosphatidic acid (LPA), from lysophosphatidylcholine. ATX is overexpressed in various malignancies, including Hodgkin lymphoma, and ATX may stimulate tumour progression via LPA production. The present study measured the serum ATX antigen levels in patients with haematological malignancies using a recently developed automated enzyme immunoassay. The serum ATX antigen levels in patients with B-cell neoplasms, especially follicular lymphoma (FL), were higher than those in healthy subjects. Serum ATX antigen levels in FL patients were associated with tumour burden and changed in parallel with the patients' clinical courses. The serum ATX antigen levels were little affected by inflammation, unlike the soluble interleukin-2 receptor and beta2-microglobulin levels. As expected, the plasma LPA levels in FL patients were correlated with the serum ATX antigen levels. Given that leukaemic tumour cells from FL patients expressed ATX, the shedding of ATX from lymphoma cells probably leads to the elevation of serum ATX antigen levels. Our results suggest that the serum ATX antigen level may be a promising and novel marker for FL.     

Single coronary artery with anomalous origin of the right coronary artery from the left anterior descending artery with a unique proximal course

A 62-year-old man with hypertension and hypercholesterolemia was referred to our unit for evaluation of chest pain. A very rare variant of single coronary artery, in which the anomalous right coronary artery originated as a separate branch from the left anterior descending artery, was incidentally found on his coronary angiography. The anomalous right coronary artery in our case appears to be unique in that it courses intraseptally rather than rightwards proximally and has obstructive atherosclerotic lesions resulting in inferior ischemia. Moreover, the acute angle made by the anomalous right coronary artery to turn toward the atrioventricular groove may have reduced the flow velocity and contributed to the development of inferior ischemia.     

Targeted gene expression without a tissue-specific promoter: Creating mosaic embryos using laser-induced single-cell heat shock

We have developed a method to target gene expression in the Drosophila embryo to a specific cell without having a promoter that directs expression in that particular cell. Using a digitally enhanced imaging system to identify single cells within the living embryo, we apply a heat shock to each cell individually by using a laser microbeam. A 1- to 2-min laser treatment is sufficient to induce a heat-shock response but is not lethal to the heat-shocked cells. Induction of heat shock was measured in a variety of cell types, including neurons and somatic muscles, by the expression of β-galactosidase from an hsp26-lacZ reporter construct or by expression of a UAS target gene after induction of hsGAL4. We discuss the applicability of this technique to ectopic gene expression studies, lineage tracing, gene inactivation studies, and studies of cells in vitro. Laser heat shock is a versatile technique that can be adapted for use in a variety of research organisms and is useful for any studies in which it is desirable to express a given gene in only a distinct cell or clone of cells, either transiently or constitutively, at a time point of choice.     

Aromatase-knockout mouse carrying an estrogen-inducible enhanced green fluorescent protein gene facilitates detection of estrogen actions in vivo

Aromatase is an enzyme that converts androgen to estrogen in the gonads and also at extragonadal sites, including the brain. In this study we developed a transgenic mouse that carries an enhanced green fluorescent protein (EGFP) gene inducible by estrogen through an estrogen response element to facilitate detection of estrogen actions in vivo. The expression of EGFP in aromatase-deficient (Ar(-/-)) female mice was significantly suppressed at the pituitary gland, ovary, uterus, and gonadal fat pad and was induced by dietary 17beta-estradiol to wild-type (Ar(+/+)) levels or higher. These results demonstrate that the expression of the EGFP gene is tissue selective and estrogen dependent in vivo. Employing this transgenic mouse, we examined whether estrogen synthesis in the extragonadal sites is necessary for reproduction in female mice. When ovaries of Ar(-/-) mice were replaced with Ar(+/+) ovaries, a significant induction of EGFP expression in the pituitary gland and uterus was observed. Histological examinations showed the presence of antral follicles in the replaced ovaries, indicating that the transplants are functional in Ar(-/-) mice. After crossing with males, three of 10 Ar(-/-)females with Ar(+/+) ovaries became pregnant and fed their pups. Collectively, these observations indicate that estrogen synthesis in the ovary is sufficient for supporting female reproduction, and that infertility of Ar(-/-) females is primarily due to a defect in estrogen synthesis in the ovary.