This study examined the patterns of epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) deposition in the small intestine and colon to evaluate the association between histopathological severity of EFEMP1 deposition and constipation and determine if amyloid transthyretin (ATTR) and EFEMP1 deposits can colocalize. In 40 older cases (≥80 years of age), EFEMP1 deposition in the small intestine initiated in the submucosal and subserous vessels, subserous interstitium, and serosa (early stage); progressing to the muscularis propria and peri-Auerbach plexus area (intermediate stage); and finally, spreading diffusely to areas, excluding the mucosa and muscularis mucosa (advanced stage). The colon had a similar pattern of progression. During the middle-to-advanced stages, amyloid formation was observed in some vascular and serous deposits. We identified a subgroup of cases in which EFEMP1 deposition was the only presumed cause of constipation. Additionally, we demonstrated the colocalization of ATTR and EFEMP1 deposition. Apple-green birefringence was detected under polarized light only in approximately one-half of the cases in the small intestine and one-third of the cases in the colon. These findings emphasize that EFEMP1 deposits may be associated with lower gastrointestinal pathological conditions. Given the challenges of histopathological diagnosis on Congo red-stained specimens, we recommend the combined use of elastic fiber staining and immunohistochemistry for EFEMP1 to prevent overlooking this deposition.

Left-to-right differences in the histopathologic patterns of transthyretin-derived amyloid (ATTR) deposition in the atria of older adults have not yet been investigated. Hence, this study evaluated heart specimens from 325 serial autopsy subjects. The amount of ATTR deposits in the seven cardiac regions, including both sides of atria and atrial appendages, was evaluated semiquantitatively. Using digital pathology, we quantitatively evaluated the immunohistochemical deposition burden of ATTR in the myocardium. We identified 20 sporadic ATTR cardiac amyloidosis cases (9 males). All patients had ATTR deposition in the left atrial regions of the myocardium. In the semiquantitative analysis, 14 of the 20 cases showed more severe ATTR deposition on the left atrial regions than on the right side, with statistically significant differences in the pathology grading (p < 0.01 for both the atrium and atrial appendage). Quantitative analysis further supported the difference. Moreover, six had ATTR deposition in the epineurium and/or neural fibres of the atria. Cluster analysis revealed that ATTR deposition in the myocardium was significantly more severe in males than in females. The heterogeneous distribution of amyloid deposits between atria revealed in this study may impair the orderly transmission of the cardiac conduction system and induce arrhythmias, which may be further aggravated by additional neuropathy in the advanced phase. This impairment could be more severe among males. These findings emphasise that atrial evaluation is important for individuals with sporadic ATTR cardiac amyloidosis, particularly for early detection.

Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adult, it is rare in early infant. Methods: Clinical testing was performed as part of medical evaluation and management. Next gene se-quencing (NGS) was performed for a patient with TIC. Literature review about TIC was con-ducted. Results: The case was a 5-month-old infant referred the hospital due to symptoms with heart failure at least lasting two months. Heart rate was 200 beats per minute, left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardiover-sion, there was no recurrence of atrial flutter, and cardiac function was improved at 98 days after tachycardia arrest. There were no pathogenic variants identified according to NGS. Literature review identified 8 early infantile cases with TIC reported. However, there were no previous re-ports such as our case with longer duration of TIC. Conclusions: Improvement of cardiac function depends on the duration of TIC. TIC should be considered in all patients with a dilated cardiomyopathy of uncertain origin and who have tachycardias such as atrial flutter.

This study aimed to elucidate the similarities and differences between amyloid-forming corpora amylacea (CA) in the prostate and lung, examine the nature of CAs in cystic tumors of the atrioventricular node (CTAVN), and clarify the distinctions between amyloid-forming CA and spheroid-type amyloid deposition. We conducted proteomics analyses using liquid chromatography–tandem mass spectrometry with laser microdissection and immunohistochemistry to validate the characteristics of CAs in the lung and prostate. Our findings revealed that CAs in these organs primarily consist of common proteins (β2-microglobulin and lysozyme) and locally produced proteins. Moreover, we observed a discrepancy between the histopathological and proteomic analysis results in CTAVN-associated CAs. In addition, while the histopathological appearance of amyloid-forming CAs and spheroid-type amyloid deposits were nearly identical, the latter deposition lacked β2-microglobulin and lysozyme, and exhibited evident destruction of surrounding tissue. A literature review further supported these findings. These results suggest that amyloid-forming CAs in the lung and prostate are formed through a shared mechanism, serving as waste containers (wasteosomes) and/or storage for excess proteins (functional amyloids). In contrast, we hypothesize that while amyloid-forming CA and spheroid-type amyloid deposits are formed, in part, through common mechanisms, the latter are pathological.