Consideration of sex as a biological variable in diabetes research across twenty years

BACKGROUND

Sex differences exist in the risk of developing type 1 and type 2 diabetes, and in the risk of developing diabetes-associated complications. Sex differences in glucose homeostasis, islet and β cell biology, and peripheral insulin sensitivity have also been reported. Yet, we lack detailed information on the mechanisms underlying these differences, preventing the development of sex-informed therapeutic strategies for persons living with diabetes. To chart a path toward greater inclusion of biological sex as a variable in diabetes research, we first need a detailed assessment of common practices in the field.

METHODS

We developed a scoring system to evaluate the inclusion of biological sex in manuscripts published in Diabetes, a journal published by the American Diabetes Association. We chose Diabetes as this journal focuses solely on diabetes and diabetes-related research, and includes manuscripts that use both clinical and biomedical approaches. We scored papers published across 3 years within a 20-year period (1999, 2009, 2019), a timeframe that spans the introduction of funding agency and journal policies designed to improve the consideration of biological sex as a variable.

RESULTS

Our analysis showed fewer than 15% of papers used sex-based analysis in even one figure across all study years, a trend that was reproduced across journal-defined categories of diabetes research (e.g., islet studies, signal transduction). Single-sex studies accounted for approximately 40% of all manuscripts, of which > 87% used male subjects only. While we observed a modest increase in the overall inclusion of sex as a biological variable during our study period, our data highlight significant opportunities for improvement in diabetes research practices. We also present data supporting a positive role for journal policies in promoting better consideration of biological sex in diabetes research.

CONCLUSIONS

Our analysis provides significant insight into common practices in diabetes research related to the consideration of biological sex as a variable. Based on our analysis we recommend ways that diabetes researchers can improve inclusion of biological sex as a variable. In the long term, improved practices will reveal sex-specific mechanisms underlying diabetes risk and complications, generating knowledge to enable the development of sex-informed prevention and treatment strategies.

Platelets and osteoblasts: secretome connections

Megakaryocyte hyperplasia associated with myeloproliferative neoplasms commonly leads to abnormal bone tissue deposition in the bone marrow, known as osteosclerosis. In this study, we aimed to synthesize the known proteomics literature describing factors released by megakaryocytes and platelets and to examine if any of the secreted factors have a known ability to stimulate the bone-forming cells, osteoblasts. Using a systematic search of Medline, we identified 77 articles reporting on factors secreted by platelets and megakaryocytes. After a full-text screening and analysis of the studies, we selected seven papers that reported proteomics data for factors secreted by platelets from healthy individuals. From 60 proteins reported in at least two studies, we focused on 23 that contained a putative signal peptide, which we searched for a potential osteoblast-stimulatory function. From nine proteins with a positive effect on osteoblast formation and function, two extracellular matrix (ECM) proteins, secreted protein acidic and rich in cysteine (SPARC) and tissue inhibitor of metalloproteinase-1 (TIMP1), and three cellular proteins with known extracellular function, the 70-kDa heat shock protein (HSP70), thymosin-β4 (TB4), and super dismutase (SOD), were identified as hypothetical candidate molecules to be examined as potential mediators in mouse models of osteomyelofibrosis. Thus, careful analysis of prior literature can be beneficial in assisting the planning of future experimental studies.

Detailed deletion mapping on the short arm of chromosome-3 in nasopharyngeal carcinomas

Allelic loss on the short arm of chromosome 3 is one of the most consistent molecular genetic alterations observed in primary nasopharyngeal carcinoma (NPC). Detailed mapping of the region of common deletion on chromosome 3p will help to locate the site of candidate tumor suppressor gene(s) involved in the pathogenesis of NPC. We have examined allelic deletion in 27 primary undifferentiated NPC at 11 chromosomal loci (spanning from 3p13-3p25) using microsatellite polymorphic markers. Allelic loss was observed in 18 of 27 primary tumors (67%) when comparing tumor DNA with normal constitutional DNA of the same patient. Among these 18 cases, 10 showed allelic loss in all informative loci of chromosome 3p and 8 showed partial or interstitial deletion, The highest frequency of allelic loss was found in three loci, D3S1038 (52%), D3S1228 (50%) and D3S659 (50%). In 5 of the 8 cases with partial deletion of chromosome 3p, a common deletion region within 3p13 to 3p14.3, flanked by two loci, D3S1079 (3p13) proximally and D3S1228 (3p14.1-14.3) distally, was identified. These results suggest strongly the presence of tumor suppressor gene(s) within the 3p13 to 3p14.3 region, the deletion of which represent a critical event in the development of NPC. In the remaining 3 cases with partial chromosomal deletion, the pattern of allelic loss suggests the presence of two other regions of deletion distal to the commonly deleted region (3p13-14.3) identified. The presence of multiple deleted regions on chromosome 3p in NPC suggests that more than one tumor suppressor gene on 3p may be involved in the development of NPC.

Loss of heterozygosity on chromosome 14 in primary nasopharyngeal carcinoma

Multiple genetic alterations are believed to be involved in the pathogenesis of nasopharyngeal carcinomas (NPC). Loss of heterozygosity (LOH) of chromosomes 3p, 9p and 11q were previously reported in NPC. In order to further define the genetic alterations in NPC, 42 pairs of normal and tumor DNA of NPC were examined for LOH on chromosomes 5p, 5q, 6q, 14q, 15q, 16p, 16q, 17q using 16 polymorphic microsatellite markers. Frequent LOH (33%; 7 out of 21 cases) was observed in chromosome 14q at locus D14s81 (14q31). In order to define the common region of deletion, nine polymorphic microsatellite markers on 14q were examined for LOH in NPC. A common region of deletion was defined in NPC at chromosome 14q24.3-q32.1 flanked by two microsatellite markers D14s76 and D14s45. The common region of deletion (14q24.3-32.1) identified in NPC overlapped with the deleted regions of 14q reported in several human cancers. In 2 cases of NPC, the pattern of LOH revealed the presence of another commonly deleted region defined by loci D14s63 and D14s69 (mapped to 14q11.1-24.1) and located proximal to locus D14s76(14q24.3). This study suggests that multiple tumor suppressor genes present on chromosome 14q are involved in the pathogenesis of NPC.

An improved in vivo method for atrioventricular node ablation via thoracotomy

The atrioventricular (AV) node is permanently damaged in approximately 3% of congenital heart surgery operations, requiring implantation of a permanent pacemaker. Improvements in pacemaker design and in alternative treatment modalities require an effective in vivo model of complete heart block (CHB) before testing can be performed in humans. Such a model should enable accurate, reliable, and detectable induction of the surgical pathology. Through our laboratory's efforts in developing a tissue engineering therapy for CHB, we describe here an improved in vivo model for inducing chronic AV block. The method employs a right thoracotomy in the adult rabbit, from which the right atrial appendage may be retracted to expose an access channel for the AV node. A novel injection device was designed, which both physically restricts needle depth and provides electrical information via electrocardiogram interface. This combination of features provides real-time guidance to the researcher for confirming contact with the AV node, and documents its ablation upon formalin injection. While all animals tested could be induced to acute AV block, those with ECG guidance were more likely to maintain chronic heart block >12 h. Our model enables the researcher to reproduce both CHB and the associated peripheral fibrosis that would be present in an open congenital heart surgery, and which would inevitably impact the design and utility of a tissue engineered AV node replacement.

Transport and photodetection in self-assembled semiconductor quantum dots

A great step forward in science and technology was made when it was discovered that lattice mismatch can be used to grow highly ordered, artificial atom-like structures called self-assembled quantum dots. Several groups have in the meantime successfully demonstrated useful infrared photodetection devices which are based on this technology. The new physics is fascinating, and there is no doubt that many new applications will be found when we have developed a better understanding of the underlying physical processes, and in particular when we have learned how to integrate the exciting new developments made in nanoscopic addressing and molecular self-assembly methods with semiconducting dots. In this paper we examine the scientific and technical questions encountered in current state of the art infrared detector technology and suggest ways of overcoming these difficulties. Promoting simple physical pictures, we focus in particular on the problem of high temperature detector operation and discuss the origin of dark current, noise, and photoresponse.

Pulmonary vein stenosis mimicking chronic lung disease

The presence of recurrent respiratory symptoms and right heart enlargement in an ex-premature infant is suggestive of chronic lung disease. Pulmonary vein stenosis is a rare, progressive disorder that produces similar symptoms and signs. A case is reported in which pulmonary vein stenosis was revealed by Doppler echocardiography, and this application is recommended in similar cases. Pulmonary vein stenosis is an extremely rare and progressive disorder, which, if left untreated, is usually fatal. The possibility of this diagnosis may not be considered during clinical examination and may be overlooked during routine echocardiography.

CONCLUSION

This report describes a patient with pulmonary vein stenosis in whom the diagnosis was delayed as she had symptoms and signs more commonly associated with chronic lung disease.

In vitro activity of garlic oil and four diallyl sulphides against antibiotic-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae

The in vitro antibacterial activities of garlic oil and four diallyl sulphides naturally occurring in this oil were studied against Pseudomonas aeruginosa and Klebsiella pneumoniae (total 237 clinical isolates). Garlic oil at 4 x MIC could reduce original inoculum to <or=2 log(10) in both P. aeruginosa and K. pneumoniae within 8 h. The MIC values of four diallyl sulphides against these two pathogens followed the order diallyl monosulphide > diallyl disulphide > diallyl trisulphide (DAT) > diallyl tetrasulphide (DATS) (P < 0.05). Most interactions of ceftazidime, gentamicin, imipenem and meropenem with DAT or DATS, determined according to the fractional inhibitory concentration index, showed synergic or additive effects. These results suggest that garlic oil, DAT and DATS may have potential for the prevention or treatment of nosocomial, antibiotic-resistant bacterial infections.

cAMP-mediated inhibition of the epithelial brush border Na+/H+ exchanger, NHE3, requires an associated regulatory protein

NHE3 is the Na+/H+ exchanger located on the intestinal and renal brush border membrane, where it functions in transepithelial Na+ absorption. The brush border Na+ absorptive process is acutely inhibited by activation of cAMP-dependent protein kinase, but the molecular mechanism of this inhibitory effect is poorly understood. We have identified two regulatory proteins, E3KARP and NHERF, that interact with NHE3 to enable cAMP to inhibit NHE3. The two regulatory proteins are structurally related, sharing approximately 50% identity in amino acid sequences. It has been previously shown that when NHE3 is transfected into PS120 fibroblasts or Caco-2 cells, cAMP failed to inhibit NHE3 activity. Northern blot analysis showed that both PS120 and Caco-2 cells lacked the expression of both E3KARP and NHERF. In contrast, other cell lines in which cAMP inhibits NHE3, including OK, CHO, and LLC-PK1 cells, expressed NHERF-related regulatory proteins. To determine their functions in cAMP-dependent inhibition of NHE3, E3KARP and NHERF were transfected into PS120/NHE3 fibroblasts. Transfection in PS120/NHE3 fibroblasts with either NHERF or E3KARP reconstituted cAMP-induced inhibition of NHE3, resulting in 25-30% inhibition in these cells.

Nuclear matrix of human nasopharyngeal carcinoma cells in culture

Nuclear matrix is a scaffold-like structure of the nucleus after sequential treatments with detergents, DNase, and high salt buffers. Its involvement in various cellular activities has been emphasised in various studies. In this study, nuclear matrix of two human nasopharyngeal carcinoma cell Lines were compared and analysed in terms of their morphological appearance and electrophoretic patterns of proteins. The stability of nuclear matrices against enzymatic digestion was found to be similar in these two cell lines. However, cell line specific nuclear matrix proteins were detected in each cell line. The significance of these proteins in cellular function and oncogenesis will be investigated in due course.