Decreased lymphatic HIF-2α accentuates lymphatic remodeling in lymphedema

Pathologic lymphatic remodeling in lymphedema evolves during periods of tissue inflammation and hypoxia through poorly defined processes. In human and mouse lymphedema, there is a significant increase of hypoxia inducible factor 1 α (HIF-1α), but a reduction of HIF-2α protein expression in lymphatic endothelial cells (LECs). We questioned whether dysregulated expression of these transcription factors contributes to disease pathogenesis and found that LEC-specific deletion of Hif2α exacerbated lymphedema pathology. Even without lymphatic vascular injury, the loss of LEC-specific Hif2α caused anatomic pathology and a functional decline in fetal and adult mice. These findings suggest that HIF-2α is an important mediator of lymphatic health. HIF-2α promoted protective phosphorylated TIE2 (p-TIE2) signaling in LECs, a process also replicated by upregulating TIE2 signaling through adenovirus-mediated angiopoietin-1 (Angpt1) gene therapy. Our study suggests that HIF-2α normally promotes healthy lymphatic homeostasis and raises the exciting possibility that restoring HIF-2α pathways in lymphedema could mitigate long-term pathology and disability.

An effective diagnostic strategy for accurate detection of RhD variants including Asian DEL type in apparently RhD-negative blood donors in Korea

BACKGROUND AND OBJECTIVES

The purpose of this study was to provide an effective RHD genotyping strategy for the East Asian blood donors.

MATERIAL AND METHODS

RhD phenotyping, weak D testing and RhCE phenotyping were performed on 110 samples from members of the RhD-negative club, private organization composed of RhD-negative blood donors, in the GwangJu-Chonnam region of Korea. The RHD promoter, intron 4, and exons 7 and 10 were analysed by real-time PCR. Two nucleotide changes (c.1227 G>A, and c.1222 T>C) in exon 9 were analysed by sequencing.

RESULTS

Of 110 RhD-negative club members, 79 (71·8%) showed complete deletion of the RHD gene, 10 (9·1%) showed results consistent with RHD-CE-D hybrid, and 21 (19·1%) showed amplification of RHD promoter, intron 4, and exons 7 and 10. Of the latter group, 16 (14·5%) were in the DEL blood group including c.1227 G>A (N = 14) and c.1222 T>C (N = 2), 2 (1·8%) were weak D, 1(0·9%) was partial D, and 2 (1·8%) were undetermined. The RhD-negative phenotype samples consisted of 58 C-E-c+e+, 19 C-E+c+e+, 3 C-E+c+e-, 21 C+E-c+e-, 6 C+E-c+e+ and 3 C+E-c-e + . Notably, all 58 samples with the C-E-c+e+ phenotype were revealed to have complete deletion of the RHD gene. The C-E-c+e+ phenotype showed 100% positive predictive value for detecting D-negative cases.

CONCLUSIONS

RHD genotyping is not required in half of D-negative cases. We suggest here an effective RHD genotyping strategy for accurate detection of RhD variants in apparently RhD-negative blood donors in East Asia.

Clinical audit: recent practice in caring for patients with acute severe colitis compared with published guidelines--is there a problem?

BACKGROUND

Acute severe colitis (ASC) is a serious condition with possible outcomes of emergency colectomy and mortality. Validated guidelines exist to help avoid these.

AIMS

To examine local adherence to guidelines and identify (a) opportunities to improve care and (b) possible barriers to adherence.

METHODS

Retrospective, hospital-wide audit of all patients with ASC during a 2-year period (2009-2010) at a major metropolitan hospital. Cases were identified by an electronic search of all discharges with International Classification of Diseases-10 codes for colitis, colectomy, ulcerative colitis or Crohn disease.

RESULTS

Twenty-six patients had 30 ASC admissions (14 female). Most admissions were under gastroenterology (25), 4 (13%) were under general medicine and 1 was under general surgery. Only 8 patients' (26%) management (all under gastroenterology) included all major details: blood investigations, Clostridium difficile test, abdominal X-ray, colonic examination and venous thromboembolism prophylaxis. Only one patient had formal severity scoring on admission, and seven patients (24%) had descriptive severity recorded. On day 3, nine patients (30%) had some recorded severity assessment; however, no formal criteria were used. Four had colectomy, three during first admission and one on re-admission. Of these patients, three received cyclosporine prior to colectomy. The mean duration of admission was 10 days (standard deviation 10.54, range 1-61).

CONCLUSION

Opportunities to optimise care exist including formal severity assessments on days 1 and 3, better deep vein thrombosis/pulmonary embolism prophylaxis and prompt colonic examination. Admission under teams other than gastroenterology appeared to be a barrier to better care. Despite the low rate of ideal management, the colectomy rate was acceptably low at 20%.

A novel HLA-A*31 allele, A*31:57, identified by sequence-based typing

The novel allele A*31:57 allele showed a single nucleotide difference with A*31:01:02 at nt 235 G>C in exon 2.

A novel HLA-DRB1*12 allele, DRB1*12:16:02, identified by sequence-based typing

The novel allele DRB1*12:16:02 allele showed two single nucleotide differences with HLA-DRB1*12:16:01 at nucleotides 303 G>C and 321 C>T in exon 2.