Daily Endocrinology Research Analysis
Three impactful studies in endocrinology and metabolic medicine stood out today: a preclinical study demonstrating pharmacologic induction of pancreatic α-to-β-cell conversion via mitochondrial complex I inhibition; a prospective diagnostic study showing AI-enhanced, super-resolution DCE MRI markedly improves detection of pituitary microadenomas; and clinical evidence that corneal confocal microscopy can non-invasively detect early and definite diabetic cardiac autonomic neuropathy with performa
Summary
Three impactful studies in endocrinology and metabolic medicine stood out today: a preclinical study demonstrating pharmacologic induction of pancreatic α-to-β-cell conversion via mitochondrial complex I inhibition; a prospective diagnostic study showing AI-enhanced, super-resolution DCE MRI markedly improves detection of pituitary microadenomas; and clinical evidence that corneal confocal microscopy can non-invasively detect early and definite diabetic cardiac autonomic neuropathy with performance comparable to CARTs.
Research Themes
- Beta-cell regeneration and diabetes therapeutics
- AI-enhanced endocrine imaging for pituitary microadenomas
- Non-invasive detection of diabetic cardiac autonomic neuropathy
Selected Articles
1. Mulberry twig (Sangzhi) alkaloids induce pancreatic α-to-β-cell phenotypic conversion in type 2 diabetic mice.
In db/db mice, Sangzhi alkaloids (SZ-A) improved glycemia and uniquely expanded β-cell area by inducing α-to-β-cell conversion, confirmed by lineage tracing and double immunostaining. Mechanistically, the main component 1-deoxynojirimycin (DNJ) promotes transdifferentiation by inhibiting mitochondrial complex I and reprogramming α- to β-cell gene expression.
Impact: This study reveals a drug-inducible route to β-cell regeneration via mitochondrial complex I inhibition, offering a mechanistic target and a clinically relevant compound (DNJ/SZ-A) for diabetes therapy development.
Clinical Implications: Although preclinical, targeting mitochondrial complex I to induce α-to-β-cell conversion could inspire regenerative therapies for type 2 diabetes and inform optimization of current SZ-A use.
Key Findings
- SZ-A improved glycemic control and increased islet and β-cell area in db/db mice, whereas acarbose did not enlarge β-cell area.
- Lineage tracing and double immunostaining confirmed α-to-β-cell conversion after SZ-A treatment.
- DNJ downregulated α-cell markers and upregulated β-cell markers in cultured α-cells.
- RNA-seq implicated mitochondrial protein complexes; DNJ inhibited mitochondrial complex I, and complex I inhibition induced α-to-β conversion.
Methodological Strengths
- Use of α-cell lineage tracing with corroborative double immunostaining for transdifferentiation.
- Integrated in vivo and in vitro validation with RNA-seq and mitochondrial complex activity assays.
Limitations
- Preclinical mouse and cell models without human islet or clinical validation.
- Potential off-target and safety concerns of mitochondrial complex I inhibition not addressed long-term.
Future Directions: Validate α-to-β conversion and functional insulin secretion in human islets, assess safety/efficacy in large animals, and explore combination regimens optimizing DNJ dosing and delivery.
BACKGROUND: Pancreatic β-cell regeneration represents a promising therapeutic strategy for diabetes, yet safe and effective treatments remain elusive. PURPOSE: We aimed to investigate whether and how mulberry twig (Sangzhi) alkaloids (SZ-A), a newly approved anti-diabetic Chinese medicine, promoted β-cell regeneration. METHODS: Diabetic db/db mice and pancreatic α-cell lineage-tracing mice were treated with SZ-A, acarbose, or vehicle daily via intragastric gavage. Blood glucose and plasma insulin levels were measured. The areas of islets, α-cells and β-cells were quantified. Cell transdifferentiation was assessed by double-immunostaining of glucagon or α-cell lineage-tracing marker with β-cell-specific markers. Mouse α-cells were incubated with SZ-A or its three main components, and the mRNA levels of cell transdifferentiation-related genes were detected. RNA-sequencing was performed to screen potential targets. The activities of five mitochondrial complexes were detected following treatment, and specific inhibitor was utilized to validate the involvement. RESULTS: Both SZ-A and acarbose improved glycemic control, but only SZ-A enlarged islet and β-cell areas in the diabetic mice. SZ-A induced α-to-β-cell conversion, as indicated by glucagon and insulin double-immunostaining and confirmed by α-cell lineage-tracing. In cultured α-cells, SZ-A and its main component 1-deoxynojirimycin (DNJ) downregulated the expressions of α-cell-specific markers, while upregulated the expressions of β-cell-specific markers. DNJ-induced differentially expressed genes were enriched in the mitochondrial protein complex term. DNJ inhibited mitochondrial complex I activity, and the complex inhibitor induced α-to-β-cell conversion. CONCLUSION: SZ-A, especially its main component DNJ, induces α-to-β-cell transdifferentiation via inhibiting mitochondrial complex I. Our finding provides a potential strategy for β-cell regeneration and diabetes treatment.
2. Evaluation of high-resolution pituitary dynamic contrast-enhanced MRI using deep learning-based compressed sensing and super-resolution reconstruction.
In a prospective cohort of 126 patients, 1.5-mm DLCS-SR DCE MRI achieved the highest inter-reader agreement (κ 0.746–0.848) and superior microadenoma detection (AUC 0.89–0.94) compared with DLCS alone, routine 1.5-mm, and 3-mm DLCS-SR images. AI-enhanced compressed sensing plus super-resolution overcame resolution limits, reducing false negatives in pituitary microadenoma diagnosis.
Impact: Demonstrates a practical, single-scan, AI-reconstructed protocol that significantly improves detection of pituitary microadenomas, a key challenge in endocrine imaging with direct implications for Cushing disease and hyperprolactinemia diagnostics.
Clinical Implications: Adopting 1.5-mm DLCS-SR DCE MRI can enhance diagnostic accuracy for suspected pituitary microadenomas, potentially expediting targeted therapy and avoiding repeat imaging.
Key Findings
- 1.5-mm DLCS-SR images showed highest inter-reader agreement (κ 0.746–0.848) among all reconstructions.
- Microadenoma detection AUC for 1.5-mm DLCS-SR was 0.89–0.94, outperforming 1.5-mm DLCS (0.83–0.87; p=0.042/0.011), 1.5-mm routine (0.76–0.78; p<0.001), and 3-mm DLCS-SR (0.72–0.74; p<0.001).
- Single-scan DCE MRI with AI-based compressed sensing and super-resolution reconstruction significantly improves image quality and diagnostic efficacy.
Methodological Strengths
- Prospective design with predefined diagnostic criteria integrating clinical, laboratory, imaging, and pathology.
- Blinded dual-reader assessment with κ statistics and robust intergroup comparisons (DeLong and McNemar tests).
Limitations
- Composite reference standard rather than uniform histopathology for all cases.
- Single-scan derived reconstructions without external, multi-center validation; generalizability needs confirmation.
Future Directions: External validation across centers and vendors, assessment of workflow/time/cost impacts, and evaluation of clinical outcomes (e.g., time to diagnosis, surgical yield).
OBJECTIVE: This study aims to assess diagnostic performance of high-resolution dynamic contrast-enhanced (DCE) MRI with deep learning-based compressed sensing and super-resolution (DLCS-SR) reconstruction for identifying microadenomas. MATERIALS AND METHODS: This prospective study included 126 participants with suspected pituitary microadenomas who underwent DCE MRI between June 2023 and January 2024. Four image groups were derived from single-scan DCE MRI, which included 1.5-mm slice thickness images using DLCS-SR (1.5-mm DLCS-SR images), 1.5-mm slice thickness images with deep learning-based compressed sensing reconstruction (1.5-mm DLCS images), 1.5-mm routine images, and 3-mm slice thickness images using DLCS-SR (3-mm DLCS-SR images). Diagnostic criteria were established by incorporating laboratory findings, clinical symptoms, medical histories, previous imaging, and certain pathologic reports. Two readers assessed the diagnostic performance in identifying pituitary abnormalities and microadenomas. Diagnostic agreements were assessed using κ statistics, and intergroup comparisons for microadenoma detection were performed using the DeLong and McNemar tests. RESULTS: The 1.5-mm DLCS-SR images (κ = 0.746-0.848) exhibited superior diagnostic agreement, outperforming 1.5-mm DLCS (κ = 0.585-0.687), 1.5-mm routine (κ = 0.449-0.487), and 3-mm DLCS-SR images (κ = 0.347-0.369) (p < 0.001 for all). Additionally, the performance of 1.5-mm DLCS-SR images in identifying microadenomas [area under the receiver operating characteristic curve (AUC), 0.89-0.94] surpassed that of 1.5-mm DLCS (AUC, 0.83-0.87; p = 0.042 and 0.011, respectively), 1.5-mm routine (AUC, 0.76-0.78; p < 0.001), and 3-mm DLCS-SR images (AUC, 0.72-0.74; p < 0.001). CONCLUSION: The findings revealed superior diagnostic performance of 1.5-mm DLCS-SR images in identifying pituitary abnormalities and microadenomas, indicating the clinical-potential of high-resolution DCE MRI. KEY POINTS: Question What strategies can overcome the resolution limitations of conventional dynamic contrast-enhanced (DCE) MRI, and which contribute to a high false-negative rate in diagnosing pituitary microadenomas? Findings Deep learning-based compressed sensing and super-resolution reconstruction applied to DCE MRI achieved high resolution while improving image quality and diagnostic efficacy. Clinical relevance DCE MRI with a 1.5-mm slice thickness and high in-plane resolution, utilizing deep learning-based compressed sensing and super-resolution reconstruction, significantly enhances diagnostic accuracy for pituitary abnormalities and microadenomas, enabling timely and effective patient management.
3. Corneal confocal microscopy identifies early and definite diabetic cardiac autonomic neuropathy.
Among 238 people with diabetes and 37 controls, corneal nerve metrics (CNFD, CNBD, CNFL) progressively declined with increasing CAN severity. CCM’s ROC AUC and sensitivity/specificity were comparable to CARTs for identifying early and definite CAN, supporting CCM as a rapid, non-invasive diagnostic alternative.
Impact: Provides clinical evidence that CCM can detect early and definite CAN with diagnostic performance comparable to CARTs, offering a scalable, non-invasive screening pathway.
Clinical Implications: CCM could be integrated into diabetic complications screening to identify CAN earlier, enabling timely risk factor modification and potentially reducing morbidity.
Key Findings
- Corneal nerve metrics (CNFD, CNBD, CNFL) and autonomic measures (DB-HRV, E:I, 30:15) decline progressively with increasing CAN severity.
- CCM demonstrated ROC AUC and sensitivity/specificity comparable to CARTs for early and definite CAN detection.
- Includes both type 1 and type 2 diabetes with healthy controls, supporting generalizability across diabetes types.
Methodological Strengths
- Direct comparison with CARTs using ROC analysis and multiple corneal and autonomic indices.
- Mixed cohort of T1D and T2D plus healthy controls enabling stratified assessment by CAN severity.
Limitations
- Cross-sectional design limits causal inference and prognostic assessment.
- Access to CCM may be limited in some settings; need for standardization and operator training.
Future Directions: Prospective longitudinal studies to assess CCM’s predictive value for CAN progression and outcomes, and implementation studies to integrate CCM into routine diabetes care.
OBJECTIVE: Advanced cardiac autonomic neuropathy (CAN) is associated with increased mortality in people with diabetes. Early identification and reduction of risk factors can limit the progression of CAN. However, the diagnosis of early CAN relies on cardiac autonomic reflex testing (CART's) which is not widely available. We have compared the diagnostic utility of corneal confocal microscopy (CCM) to CART's in diagnosing CAN. RESEARCH DESIGN AND METHODS: Two-hundred and thirty eight individuals with type 1 and type 2 diabetes and thirty seven healthy controls were assessed using CARTs and CCM. RESULTS: There was a progressive and significant reduction in DB-HRV, E:I ratio, 30:15 ratio, corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fibre length (CNFL) with increasing severity of CAN. The receiver operating characteristic (ROC) area under the curve (AUC) and sensitivity/specificity of CCM were comparable to those of CARTs for identifying early and definite CAN. CONCLUSION: CCM is a rapid, non-invasive ophthalmic test which could be used to detect early and established CAN.