Increased number of retinal vessels in acromegaly

OBJECTIVE

Excess of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as in acromegaly, is associated with increased risk of diabetes, but whether retinal vessels are altered is unknown. The aim of this study was to evaluate retinal vessel morphology in patients with acromegaly at diagnosis and after treatment and to describe the prevalence of diabetic retinopathy in patients with long-standing acromegaly and diabetes.

DESIGN

Two independent observational studies, one being prospective and the other retrospective and cross-sectional.

METHODS

Retinal vessel morphology of 26 patients with acromegaly was examined at diagnosis and 1 year after treatment and compared to 13 healthy controls. Cross-sectional evaluation of 39 patients with long-standing acromegaly and diabetes was performed. Fundus photographs were digitally analyzed for vessel morphology.

RESULTS

Patients with acromegaly had a median (interquartile range) of 34.3 (30.0-39.0) vessel branching points compared to 27.0 (24.0-29.0) for healthy controls (P < 0.001). Tortuosity of arterioles and venules remained unchanged. Vessel morphology did not change significantly after treatment. Patients with acromegaly and diabetes for a median of 14 years also had a high number of branching points (34.2 (32.5-35.6)), but the prevalence of diabetic retinopathy was not higher than expected in diabetic patients without acromegaly.

CONCLUSIONS

Patients with acromegaly have an increased number of vascular branching points in the retina without an alteration of macroscopic vessel morphology. This is consistent with an angiogenic effect of GH/IGF-1 in humans. The prevalence of diabetic retinopathy was not increased in patients with acromegaly and diabetes.

Muscle strength in patients with acromegaly at diagnosis and during long-term follow-up

OBJECTIVE

Patients with acromegaly have decreased body fat (BF) and increased extracellular water (ECW) and muscle mass. Although there is a lack of systematic studies on muscle function, it is believed that patients with acromegaly may suffer from proximal muscle weakness despite their increased muscle mass. We studied body composition and muscle function in untreated acromegaly and after biochemical remission.

DESIGN

Prospective observational study.

METHODS

Patients with acromegaly underwent measurements of muscle strength (dynamometers) and body composition (four-compartment model) at diagnosis (n = 48), 1 year after surgery (n = 29) and after long-term follow-up (median 11 years) (n = 24). Results were compared to healthy subjects.

RESULTS

Untreated patients had increased body cell mass (113 ± 9% of predicted) and ECW (110 ± 20%) and decreased BF (67 ± 7.6%). At one-year follow-up, serum concentration of IGF-I was reduced and body composition had normalized. At baseline, isometric muscle strength in knee flexors and extensors was normal and concentric strength was modestly increased whereas grip strength and endurance was reduced. After one year, muscle strength was normal in both patients with still active disease and patients in remission. At long-term follow-up, all patients were in remission. Most muscle function tests remained normal, but isometric flexion and the fatigue index were increased to 153 ± 42% and 139 ± 28% of predicted values, respectively.

CONCLUSIONS

Patients with untreated acromegaly had increased body cell mass and normal or modestly increased proximal muscle strength, whereas their grip strength was reduced. After biochemical improvement and remission, body composition was normalized, hand grip strength was increased, whereas proximal muscle fatigue increased.

Case report: vitamin D-dependent rickets type 1 caused by a novel CYP27B1 mutation

Vitamin D‐dependent rickets type 1 VDDR‐1 is a recessive inherited disorder with impaired activation of vitamin D, caused by mutations in CYP27B1. We present long‐time follow‐up of a case with a novel mutation including high‐resolution peripheral quantitative computed tomography of the bone. Adequate treatment resulted in a normalized phenotype.

Inhibition of reactive astrocytosis in established experimental autoimmune encephalomyelitis favors infiltration by myeloid cells over T cells and enhances severity of disease

Reactive astrocytosis, involving activation, hypertrophy, and proliferation of astrocytes, is a characteristic response to inflammation or injury of the central nervous system. We have investigated whether inhibition of reactive astrocytosis influences established experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. We made use of transgenic mice, which express herpes simplex virus-derived thymidine kinase under control of a glial fibrillary acidic protein promotor (GFAP HSV-TK mice). Treatment of these mice with ganciclovir leads to inhibition of reactive astrocytosis. When GFAP HSV-TK mice were treated for seven days following onset of EAE with ganciclovir, disease severity increased. Although aquaporin-4 staining on astrocyte endfeet at the glia limitans remained equally detectable, GFAP immunoreactivity and mRNA expression in CNS were reduced by this treatment. Ganciclovir-treated GFAP HSV-TK mice with EAE had a 78% increase in the total number of infiltrating myeloid cells (mainly macrophages), whereas we did not find an increase in infiltrating T cells, using quantitative flow cytometry. Per cell expression of mRNA for the macrophage-associated molecules TNFα, MMP-12 and TIMP-1 was elevated in spinal cord of GFAP HSV-TK mice treated with ganciclovir. Relative expression of CD3ε was downregulated, and expression levels of IFNγ, IL-4, IL-10, IL-17, and Foxp3 were not significantly changed. mRNA expression of CCL2 was upregulated, and CXL10 was downregulated. Thus, inhibition of reactive astrocytosis after initiation of EAE leads to increased macrophage, but not T cell, infiltration, and enhanced severity of EAE. This emphasizes the role of astrocytes in controlling leukocyte infiltration in neuroinflammation.