mcLARO: Multi-contrast learned acquisition and reconstruction optimization for simultaneous quantitative multi-parametric mapping

PURPOSE

To develop a method for rapid sub-millimeter T1 , T2 ,T 2 * $$ {\mathrm{T}}_2^{\ast } $$ , and QSM mapping in a single scan using multi-contrast learned acquisition and reconstruction optimization (mcLARO).

METHODS

A pulse sequence was developed by interleaving inversion recovery and T2 magnetization preparations and single-echo and multi-echo gradient echo acquisitions, which sensitized k-space data to T1 , T2 ,T 2 * $$ {\mathrm{T}}_2^{\ast } $$ , and magnetic susceptibility. The proposed mcLARO optimized both the multi-contrast k-space under-sampling pattern and image reconstruction based on image feature fusion using a deep learning framework. The proposed mcLARO method withR = 8 $$ R=8 $$ under-sampling was validated in a retrospective ablation study and compared with other deep learning reconstruction methods, including MoDL and Wave-MoDL, using fully sampled data as reference. Various under-sampling ratios in mcLARO were investigated. mcLARO was also evaluated in a prospective study using separately acquired conventionally sampled quantitative maps as reference standard.

RESULTS

The retrospective ablation study showed improved image sharpness of mcLARO compared to the baseline network without the multi-contrast sampling pattern optimization or image feature fusion module. The under-sampling ratio experiment showed that higher under-sampling ratios resulted in blurrier images and lower precision of quantitative values. The prospective study showed that small or negligible bias and narrow 95% limits of agreement on regional T1 , T2 ,T 2 * $$ {\mathrm{T}}_2^{\ast } $$ , and QSM values by mcLARO (5:39 mins) compared to reference scans (40:03 mins in total). mcLARO outperformed MoDL and Wave-MoDL in terms of image sharpness, noise suppression, and artifact removal.

CONCLUSION

mcLARO enabled fast sub-millimeter T1 , T2 ,T 2 * $$ {\mathrm{T}}_2^{\ast } $$ , and QSM mapping in a single scan.

Hereditary causes of hypertension due to increased sodium transport

PURPOSE OF REVIEW

Hypertension, commonly known as high blood pressure, is a widespread health condition affecting a large number of individuals across the globe. Although lifestyle choices and environmental factors are known to have a significant impact on its development, there is growing recognition of the influence of genetic factors in the pathogenesis of hypertension. This review specifically focuses on the hereditary causes of hypertension that are associated with increased sodium transport through the thiazide-sensitive NaCl cotransporter (NCC) or amiloride-sensitive epithelial sodium channel (ENaC), crucial mechanisms involved in regulating blood pressure in the kidneys. By examining genetic mutations and signaling molecules linked to the dysregulation of sodium transport, this review aims to deepen our understanding of the hereditary causes of hypertension and shed light on potential therapeutic targets.

RECENT FINDINGS

Liddle syndrome (LS) is a genetic disorder that typically manifests early in life and is characterized by hypertension, hypokalemic metabolic alkalosis, hyporeninemia, and suppressed aldosterone secretion. This condition is primarily caused by gain-of-function mutations in ENaC. In contrast, Pseudohypoaldosteronism type II (PHAII) is marked by hyperkalemia and hypertension, alongside other clinical features such as hyperchloremia, metabolic acidosis, and suppressed plasma renin levels. PHAII results from overactivations of NCC, brought about by gain-of-function mutations in its upstream signaling molecules, including WNK1 (with no lysine (K) 1), WNK4, Kelch-like 3 (KLHL3), and cullin3 (CUL3).

SUMMARY

NCC and ENaC are integral components, and their malfunctions lead to disorders like LS and PHAII, hereditary causes of hypertension. Current treatments for LS involve ENaC blockers (e.g., triamterene and amiloride) in conjunction with low-sodium diets, effectively normalizing blood pressure and potassium levels. In PHAII, thiazide diuretics, which inhibit NCC, are the mainstay treatment, albeit with some limitations and potential side effects. Ongoing research in developing alternative treatments, including small molecules targeting key regulators, holds promise for more effective and tailored hypertension solutions.

Commentaries: Lecanemab: pioneering the way as the first approved drug for Alzheimer's disease treatment

Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline and neuronal abnormalities. Current therapies address symptoms without altering disease progression. Lecanemab, an anti-amyloid antibody, binds to amyloid-beta (Aβ) protofibrils. Phase II trials revealed dose-dependent amyloid clearance and reduced clinical decline. Phase III trials demonstrated cognitive benefits with potential adverse events. Full FDA approval was granted for lecanemab due to its ability to eliminate toxic brain amyloids. However, longer trials are needed to assess its efficacy and safety. While lecanemab marks a significant advancement, further breakthroughs are essential for effective AD treatment.

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Exosomes derived from hypoxic endometrial epithelial cells are pivotal in cellular communication and tissue repair, offering new perspectives on reproductive health. This manuscript highlights the study by Zhang et al, which investigates the effects of miR-214-5p and miR-21-5p in hypoxic cell-derived exosomes on human umbilical cord mesenchymal stem cells. The study reveals that low levels of these microRNAs activate the signal transducer and activator of transcription 3 signaling pathway, enhancing human umbilical cord mesenchymal stem cell migration and differentiation. These findings provide novel insights into therapeutic strategies for improving endometrial health and addressing infertility linked to thin endometrium.

Role of 1,25-dihydroxyvitamin D3 in alleviating hepatic steatosis: Targeting M1 macrophage polarization in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), a critical global health concern, continues to challenge medical researchers with limited treatment options. This letter examines on the study by Luo et al, demonstrating that vitamin D 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] improves hepatic steatosis in NAFLD by inhibiting M1 macrophage polarization via the vitamin D receptor-peroxisome proliferator-activated receptor gamma signaling pathway. This letter critically appraises these findings, comparing them to similar studies, and discusses their potential implications for treating NAFLD. Furthermore, we highlight future directions, including dose optimization and mechanistic studies.

Genetic intersection of human leukocyte antigen-DP/DQ and hepatitis B virus-related liver disease: Insights from a multi-clustering study

Hepatitis B virus infection remains a significant global health challenge, particularly in endemic regions like Vietnam. This article examines the groundbreaking study by Nguyen et al, which investigates the relationship between human leukocyte antigen-DP/DQ polymorphisms and hepatitis B virus-related liver disease progression. Through advanced multi-clustering analysis, the study reveals that the A-A-A haplotype (rs2856718-rs3077-rs9277535) provides protection against disease progression, while the G-G-G haplotype correlates with increased hepatocellular carcinoma susceptibility. The integration of machine learning approaches with genetic data offers promising avenues for refined disease prediction and personalized therapeutic strategies. This article discusses the implications for expanding study populations, implementing longitudinal cohort studies, and leveraging artificial intelligence for improved patient outcomes.

Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK, Zhang J. Oral Paclovid Significantly Reduces Hospitalization and Mortality in Non-hospitalized Elderly Patients with COVID-19

The development of antiviral drugs against coronavirus has proceeded at an unprecedented pace. In December 2021, the US FDA has successively approved two oral drugs against coronavirus pneumonia (COVID-19), namely PAXLOVID™ (PF-07321332) developed by Pfizer and Molnupiravir developed by Merck by targeting papain-like protease (PLpro) and RNA-dependent RNA polymerase (RdRp), respectively. PLpro and RdRp are important for the normal life cycle of coronaviruses. Inhibition of their activities could impair the synthesis of viral RNA and aid therapeutic treatments. However, little is known about the real-world effectiveness of oral antivirals against the severe acute respiratory syndrome (SARS)-CoV-2 omicron (B.1.1.529) variant. Recent studies have shown that Paxlovid can lead to a marked reduction hospitalization or death among unvaccinated outpatients with early COVID-19, whereas it was found no significant benefit for patients aged 64 and younger. In comparison, Molnupiravir did not reduce the risk of hospitalization or death after infection in high-risk groups who had been vaccinated against the coronaviruses, but only accelerated their recovery.