Age and sex related differences in subcortical brain iron concentrations among healthy adults.

Age and sex can influence brain iron levels. We studied the influence of these variables on deep gray matter magnetic susceptibilities. In 183 healthy volunteers (44.7 ± 14.2 years, range 20-69, ♀ 49%), in vivo quantitative susceptibility mapping (QSM) at 1.5T was performed to estimate brain iron accumulation in the following regions of interest (ROIs): caudate nucleus (Cd), putamen (Pt), globus pallidus (Gp), thalamus (Th), pulvinar (Pul), red nucleus (Rn), substantia nigra (Sn) and the cerebellar dentate nuclei (Dn). We gauged the influence of age and sex on magnetic susceptibility by specifying a series of structural equation models. The distributions of susceptibility varied in degree across the structures, conforming to histologic findings (Hallgren and Sourander, 1958), with the highest degree of susceptibility in the Gp and the lowest in the Th. Iron increase correlated across several ROIs, which may reflect an underlying age-related process. Advanced age was associated with a particularly strong linear rise of susceptibility in the striatum. Nonlinear age trends were found in the Rn, where they were the most pronounced, followed by the Pul and Sn, while minimal nonlinear trends were observed for the Pt, Th, and Dn. Moreover, sex related variations were observed, so that women showed lower levels of susceptibility in the Sn after accounting for age. Regional susceptibility of the Pul increased linearly with age in men but exhibited a nonlinear association with age in women with a leveling off starting from midlife. Women expected to be post menopause (+51 years) showed lower total magnetic susceptibility in the subcortical gray matter. The current report not only is consistent with previous reports of age related variations of brain iron, but also adds to the current knowledge by reporting age-related changes in less studied, smaller subcortical nuclei. This is the first in-vivo report to show lower total subcortical brain iron levels selectively in women from midlife, compared to men and younger women. These results encourage further assessment of sex differences in brain iron. We anticipate that age and sex are important co-factors to take into account when establishing a baseline level for differentiating pathologic neurodegeneration from healthy aging. The variations in regional susceptibility reported herein should be evaluated further using a longitudinal study design to determine within-person changes in aging.

In vivo detection of magnetic labeled oxidized multi-walled carbon nanotubes by magnetic resonance imaging.

Functionalized carbon nanotubes (f-CNTs) have been widely used in bio-medicine as drug carriers, bio-sensors, imaging agents and tissue engineering additives, which demands better understanding of their in vivo behavior because of the increasing exposure potential to humans. However, there are limited studies to investigate the in vivo biodistribution and elimination of f-CNTs. In this study, superparamagnetic iron oxides (SPIOs) were used to label oxidized multiwalled carbon nanotubes (o-MWCNTs) for in vivo distribution study of o-MWCNTs by magnetic resonance imaging (MRI). SPIO labeled o-MWCNTs (((SPIO))o-MWCNTs) were prepared by a hydrothermal reaction process, and characterized by TEM, XRD and magnetometer. ((SPIO))o-MWCNTs exhibited superparamagnetic property, excellent biocompatibility and stability. The intravenously injected ((SPIO))o-MWCNTs were observed in liver, kidney and spleen, while the subcutaneously injected ((SPIO))o-MWCNTs could be only detected in sub mucosa. Most of the intravenously injected ((SPIO))o-MWCNTs could be eliminated from liver, spleen, kidney and sub mucosa on 4 d post injection (P.I.). However, the residual o-MWCNTs could induce 30-40% MRI signal-to-noise ratio changes in these tissues even on 30 d P.I. This in vivo biodistribution and elimination information of o-MWCNTs will greatly facilitate the application of f-CNT based nanoproducts in biomedicine. In addition, the magnetic labeling method provides an approach to investigate the in vivo biodistribution and clearance of other nanomaterials.

The Correlation Between Aldosterone and Leukocyte-Related Inflammation: A Comparison Between Patients with Primary Aldosteronism and Essential Hypertension.

Background: Hypertension patients with primary aldosteronism (PA) have a higher risk of cardiovascular complications than blood pressure-matched essential hypertension (EH) patients. The cause may be closely related to inflammation. We explored the correlations between leukocyte-related inflammation parameters and plasma aldosterone concentration (PAC) in PA patients and clinical characteristics-matched EH patients. Methods: A total of 346 PA and 346 sex, age and 24-h blood pressure-matched EH patients at the 2nd Affiliated Hospital of Nanchang University from January 2020 to June 2021 were enrolled in this study. The differences and correlations of aldosterone and leukocyte parameters between the two groups were analyzed. Results: Compared with EH patients, the lymphocyte count was significantly lower (P = 0.004), the neutrophil-lymphocyte ratio (NLR) (P = 0.023) and the monocyte-lymphocyte ratio (MLR) (P = 0.037) were significantly higher in PA patients. Linear regression analysis and multivariate regression analysis identified that lymphocyte count, NLR and MLR were significantly and independently correlated with PAC in PA patients, and the correlations were stronger with increasing levels of aldosterone. However, in EH patients, only NLR maintained an independent correlation with PAC. Conclusion: Leukocyte-related inflammation parameters, including lymphocyte count, NLR, and MLR, were significantly and independently correlated with PAC in PA patients. The correlations were stronger with increasing levels of aldosterone. However, the above correlations were not always present in patients with EH matched for clinical characteristics.

Predictors of progression in rheumatoid arthritis-associated interstitial lung disease: A single-center retrospective study from China.

AIM: Interstitial lung disease (ILD) is a common extra-articular manifestation of rheumatoid arthritis (RA) and is associated with high mortality, especially in progressive ILD. We aimed to identify predictors of disease progression in the early stages of ILD in a large sample of patients with RA. METHOD: The medical records of 201 RA-ILD patients were retrospectively analyzed. According to changes in their pulmonary function tests, patients were divided into progressive disease and stable disease groups. Data were collected on clinical characteristics, laboratory findings, chest high-resolution computed tomography, and therapeutic agents. Univariate and multivariate analyses were performed to identify predictors of ILD progression. RESULTS: During a median follow up of 38 months, 105 (52.5%) patients were diagnosed with progressive ILD. These patients were mostly male, past or present smokers (P = 0.028, P = 0.021, respectively). Higher Health Assessment Questionnaire-Disability Index score and higher Disease Activity Score in 28 joints with erythrocyte sedimentation rate (DAS28-ESR) were observed in the ILD progression group (P = 0.003, P < 0.001, respectively). There were no significant differences in baseline respiratory symptoms, pulmonary function, or laboratory features. Multivariate analysis indicated that high DAS28-ESR, definite usual interstitial pneumonia pattern, fibrosis score, and less use of cyclophosphamide were independent risk factors for RA-ILD progression. Fifteen (7.46%) patients died during the follow up, and the most frequent cause of death was lung infection. CONCLUSION: Our results suggested that high disease activity, definite usual interstitial pneumonia pattern, fibrosis score, and less use of cyclophosphamide at the onset of ILD may indicate the progression of ILD in RA patients.