Salvage radiation therapy in prostate cancer: relationship between rectal dose and long-term, self-reported rectal bleeding

Purpose

To quantify the relationship between the rectal dose distribution and the prevalence of self-reported rectal bleeding among men treated with salvage radiotherapy (ST) delivered by three-dimensional conformal radiotherapy (3DCRT) for prostate cancer. To use this relationship to estimate the risk of rectal bleeding for a contemporary cohort of patients treated with volumetric modulated arc therapy (VMAT) ST.

Methods and patients

Rectal bleeding of any grade was reported by 56 (22%) of 255 men in a PROM-survey at a median follow-up of 6.7 years after 3DCRT ST. Treatment plan data were extracted and dose–response relationships for the rectal volumes receiving at least 35 Gy (V_35Gy) or 63 Gy (V_63Gy) were calculated with logistic regression. These relationships were used to estimate the risk of rectal bleeding for a cohort of 253 patients treated with VMAT ST.

Results

In the dose–response analysis of patients in the 3DCRT ST cohort, both rectal V_35Gy and V_63Gy were statistically significant parameters in univariable analysis (p = 0.005 and 0.003, respectively). For the dose–response models using either rectal V_35Gy or V_63Gy, the average calculated risk of rectal bleeding was 14% among men treated with VMAT ST compared to a reported prevalence of 22% for men treated with 3DCRT ST.

Conclusions

We identified dose–response relationships between the rectal dose distribution and the risk of self-reported rectal bleeding of any grade in a long-term perspective for men treated with 3DCRT ST. Furthermore, VMAT ST may have the potential to decrease the prevalence of late rectal bleeding.

BMI change during puberty and the risk of heart failure

AIM

Hospitalization for heart failure amongst younger men has increased. The reason for this is unknown but it coincides with the obesity epidemic. The aim of this study was to evaluate the association between childhood BMI (Body Mass Index) and BMI change during puberty for risk of adult heart failure in men.

METHODS

Using the BMI Epidemiology Study (BEST), a population-based study in Gothenburg, Sweden, we collected information on childhood BMI at age 8 years and BMI change during puberty (BMI at age 20 - BMI at 8) for men born 1945-1961, followed until December 2013 (n = 37 670). BMI was collected from paediatric growth charts and mandatory military conscription tests. Information on heart failure was retrieved from high-quality national registers (342 first hospitalizations for heart failure).

RESULTS

BMI change during puberty was independently of childhood BMI associated with risk of heart failure in a nonlinear J-shaped manner. Subjects in the upper quartile of BMI change during puberty (Q4) had more than twofold increased risk of heart failure compared with subjects in Q1 [HR (Hazard Ratio) = 2.29, 95% CI (Confidence Interval) 1.68-3.12]. Childhood BMI was not independently associated with risk of heart failure. Boys developing overweight during puberty (HR 3.14; 95% CI 2.25-4.38) but not boys with childhood overweight that normalized during puberty (HR 1.12, 95% CI 0.63-2.00) had increased risk of heart failure compared with boys without childhood or young adult overweight.

CONCLUSION

BMI change during puberty is a novel risk factor for adult heart failure in men.

High plasma osteocalcin is associated with low blood haemoglobin in elderly men: the MrOS Sweden Study

BACKGROUND

It has been suggested that osteoblasts are involved in the regulation of haematopoietic stem cells. Whether osteocalcin, which is derived from osteoblasts and is metabolically active, influences blood haemoglobin (Hb) levels is not known.

OBJECTIVE

To determine whether plasma osteocalcin is a determinant of Hb in elderly men.

METHODS

A total of 993 men (mean age 75.3 ± 3.2 years) participated in the population-based MrOS (osteoporotic fractures in men) study. Plasma osteocalcin concentration was evaluated in relation to Hb and adjustments were made for potential confounders (i.e. age, body mass index, erythropoietin, total oestradiol, fasting insulin, adiponectin, ferritin and cystatin C).

RESULTS

Hb correlated (age adjusted) negatively with osteocalcin in the total study group (r = -0.12, P < 0.001) as well as in the subgroup of nondiabetic men (r = -0.16, P < 0.001). In nondiabetic men with higher osteocalcin levels, it was more likely that Hb would be in the lowest quartile (odds ratio per SD decrease in osteocalcin 1.32, 95% confidence interval 1.13-1.53). Quartiles of Hb were negatively associated (age adjusted) with osteocalcin (P < 0.001). Anaemic men (47/812) (Hb <130 g L(-1) ) had significantly higher mean osteocalcin levels than nonanaemic men (33.9 vs. 27.1 μg L(-1) , P < 0.001). In multiple stepwise linear regression analyses (adjusted for age, body mass index, total oestradiol, adiponectin, erythropoietin, fasting insulin, cystatin C, leptin, ferritin and holotranscobalamin), osteocalcin was an independent predictor of Hb concentration in nondiabetic men (P < 0.05).

CONCLUSIONS

These data add further support to the evidence indicating that the bone-specific protein osteocalcin has several endocrine functions targeting the pancreas, testes, adipocytes, brain. An additional novel finding is that osteocalcin may also have a paracrine function as a regulator of haematopoiesis.

Expression and localization of Indian hedgehog (Ihh) and parathyroid hormone related protein (PTHrP) in the human growth plate during pubertal development

Indian Hedgehog (Ihh) has been reported to control the rate of cartilage differentiation during skeletal morphogenesis in rodents through a negative feedback loop involving parathyroid hormone related protein (PTHrP). The role of Ihh and PTHrP in the regulation of human epiphyseal chondrocytes is unknown. The aim of the current study was to examine the expression and localization of Ihh and PTHrP in the human growth plate at various pubertal stages. Growth plate biopsies were obtained from patients subjected to epiphyseal surgery and the expression of Ihh and PTHrP was detected by immunohistochemistry. We show that Ihh and PTHrP are expressed mainly in early hypertrophic chondrocytes in the human growth plate. The levels of expression of Ihh and PTHrP are higher in early stages of puberty than later. Our results suggest that Ihh and PTHrP are present in the human growth plate and that Ihh and PTHrP may be involved in the regulation of pubertal growth in humans.

Ablation of TRalpha2 and a concomitant overexpression of alpha1 yields a mixed hypo- and hyperthyroid phenotype in mice

Thyroid hormone governs a diverse repertoire of physiological functions through receptors encoded in the receptor genes alpha and beta, which each generate variant proteins. In mammals, the alpha gene generates, in addition to the normal receptor TRalpha1, a non-hormone-binding variant TRalpha2 whose exact function is unclear. Here, we present the phenotype associated with the targeted ablation of TRalpha2 expression. Selective ablation of TRalpha2 resulted in an inevitable, concomitant overexpression of TRalpha1. Both TRalpha2 +/- and -/- mice show a complex phenotype with low levels of free T3 and free T4, and have inappropriately normal levels of TSH. The thyroid glands exhibit mild morphological signs of dysfunction and respond poorly to TSH, suggesting that the genetic changes affect the ability of the gland to release thyroid hormones. However, the phenotype of the mutant mice also has features of hyperthyroidism, including decreased body weight, elevated heart rate, and a raised body temperature. Furthermore, TRalpha2-/- and TRalpha2+/- mice are obese and exhibit skeletal alterations, associated with a late-onset growth retardation. The results thus suggest that the overexpression of TRalpha1 and the concomitant decrease in TRalpha2 expression lead to a mixed hyper- and hypothyroid phenotype, dependent on the tissue studied. The phenotypes suggest that the balance of TRalpha1:TRalpha2 expressed from the TRalpha gene provides an additional level of tuning the control of growth and homeostasis in mammalian species.

Increased resistin expression in the adipose tissue of male prolactin transgenic mice and in male mice with elevated androgen levels

The aim of this study was to investigate the regulation of resistin, a recently identified adipocyte-secreted peptide, in the adipose tissue of prolactin (PRL)-transgenic (tg) mice using ribonuclease protection assay. The level of resistin mRNA increased 3.5-fold in the adipose tissue of untreated male PRL-tg mice compared to controls. However, there was no difference in resistin expression in the adipose tissue of female PRL-tg mice compared to control mice. PRL-tg male mice have elevated serum testosterone levels and we therefore analyzed the effects of testosterone alone on resistin mRNA expression. Furthermore, the effects of elevated androgen levels on PRL receptor (PRLR) mRNA expression in the adipose tissue were investigated. Resistin mRNA increased 2.6-fold in the adipose tissue of control male mice with elevated serum androgen levels. In addition, PRLR mRNA expression was increased in the adipose tissue of male mice with elevated testosterone. These results suggest testosterone to be a regulator of resistin and PRLR mRNA expression in the adipose tissue of male mice.

GH substitution reverses the growth phenotype but not the defective ossification in thyroid hormone receptor alpha 1-/-beta-/- mice

Thyroid hormone receptor alpha 1, beta 1 and beta 2-deficient mice (TR alpha 1-/-beta-/- mice) demonstrate growth retardation and defective ossification in the epiphyses associated with an inhibition of the GH/IGF-I axis. There are differences between TR alpha 1-/-beta-/- mice (receptor deficient) and the hypothyroid animal model (ligand deficient). Such differences include possible repressive actions exerted by unliganded receptors in the ligand-deficient (hypothyroid) model but not in the receptor-deficient model. In the present study we have investigated whether or not GH substitution rescues the skeletal phenotype of TR alpha 1-/-beta-/- mice. TR alpha 1-/-beta-/- and wild-type (WT) mice were treated with GH from day 18 until 10 weeks of age. GH substitution of mutant mice resulted in a significant and sustained stimulatory effect on the body weight that was not seen in WT mice. GH-treated mutant mice but not GH-treated WT mice demonstrated increased length and periosteal circumference of the femur. However, GH substitution did not reverse the defective ossification seen in TR alpha 1-/-beta-/- mice. TR alpha 1-/-beta-/- mice displayed increased width of the proximal tibial growth plate, which was caused by increased width of the proliferative but not the hypertrophic layer. GH substitution did not restore the disturbed morphology of the growth plate in TR alpha 1-/-beta-/- mice. In summary, GH substitution reverses the growth phenotype but not the defective ossification in TR alpha 1-/-beta-/- mice. Our data suggest that TRs are of importance both for the regulation of the GH/IGF-I axis and for direct effects on cartilage.

Investigation of the role of prolactin in the development and function of the lacrimal and harderian glands using genetically modified mice

PURPOSE

To determine whether prolactin receptor is essential for normal development and function of the lacrimal gland and whether hyperprolactinemia can alter lacrimal development.

METHODS

Lacrimal gland morphology and function were examined in two genetic mouse models of prolactin action: a prolactin receptor knockout model that is devoid of prolactin action and a transgenic model of hyperprolactinemia.

RESULTS

Image analysis of lacrimal and Harderian gland sections was used to quantify glandular morphology. In females, lacrimal acinar area decreased by 30% and acinar cell density increased by 25% over control subjects in prolactin transgenic animals, but prolactin receptor knockout mice showed no changes. In males, transgenic animals showed no changes, but prolactin receptor knockout mice showed a 5% reduction in acinar area and an 11% increase in acinar cell density, which was lost after castration. The morphology of the Harderian glands underwent parallel changes but to a lesser degree. A complete loss of porphyrin accretions was seen in the Harderian glands of male and female knockout animals. No differences in tear protein levels were seen in knockout animals by two-dimensional gels. Enzyme-linked immunosorbent assay (ELISA) and Western blot analysis showed that the level of secretory component and IgA in knockout mouse tears remained unchanged. There was no change in the predisposition of the 129 mouse strain to conjunctivitis in the knockout animals.

CONCLUSIONS

Prolactin plays a small role in establishing the sexual dimorphism of male lacrimal glands. In females, hyperprolactinemia causes a hyperfemale morphology, suggesting a role in dry eye syndromes. Prolactin is required for porphyrin secretion by the Harderian gland but plays no essential role in the secretory immune function of the lacrimal gland.

Fusion of the NH2-terminal domain of the basic helix-loop-helix protein TCF12 to TEC in extraskeletal myxoid chondrosarcoma with translocation t(9;15)(q22;q21)

Extraskeletal myxoid chondrosarcomas (EMCs) are characterized by recurrent t(9;22) or t(9;17) translocations resulting in fusions of the NH2-terminal transactivation domains of EWS or TAF2N to the entire TEC protein. We report here an EMC with a novel translocation t(9; 15)(q22;q21) and a third type of TEC-containing fusion gene. The chimeric transcript encodes a protein in which the first 108 amino acids of the NH2-terminus of the basic helix-loop-helix (bHLH) protein TCF12 is linked to the entire TEC protein. The translocation separates the NH2-terminal domain of TCF12 from the bHLH domain as well as from a potential leucine zipper domain located immediately downstream of the breakpoint. These results demonstrate that the NH2-terminal transactivation domains of EWS or TAF2N are not unique in their ability to convert the TEC protein into an oncogenically active fusion protein, and that they may be replaced by a domain from a bHLH protein that presumably endows the fusion protein with similar functions.

Mice devoid of all known thyroid hormone receptors are viable but exhibit disorders of the pituitary-thyroid axis, growth, and bone maturation

Thyroid hormone (T3) has widespread functions in development and homeostasis, although the receptor pathways by which this diversity arises are unclear. Deletion of the T3 receptors TRalpha1 or TRbeta individually reveals only a small proportion of the phenotypes that arise in hypothyroidism, implying that additional pathways must exist. Here, we demonstrate that mice lacking both TRalpha1 and TRbeta (TRalpha1(-/-)beta-/-) display a novel array of phenotypes not found in single receptor-deficient mice, including an extremely hyperactive pituitary-thyroid axis, poor female fertility and retarded growth and bone maturation. These results establish that major T3 actions are mediated by common pathways in which TRalpha1 and TRbeta cooperate with or substitute for each other. Thus, varying the balance of use of TRalpha1 and TRbeta individually or in combination facilitates control of an extended spectrum of T3 actions. There was no evidence for any previously unidentified T3 receptors in TRalpha1(-/-)beta-/- mouse tissues. Compared to the debilitating symptoms of severe hypothyroidism, the milder overall phenotype of TRalpha1(-/-)beta-/- mice, lacking all known T3 receptors, indicates divergent consequences for hormone versus receptor deficiency. These distinctions suggest that T3-independent actions of T3 receptors, demonstrated previously in vitro, may be a significant function in vivo.

Transgenic mice overexpressing the prolactin gene develop dramatic enlargement of the prostate gland

An altered endocrine status of elderly men has been hypothesized to be important for development of prostate hyperplasia. The present study addresses the question whether increased PRL expression is of importance for development of prostate hyperplasia in mice. Three lines of PRL transgenic mice were generated having serum levels of PRL of approximately 15 ng/ml, 100 ng/ml, and 250 ng/ml, respectively. These mice developed dramatic enlargement of the prostate gland, approximately 20 times the normal prostate weight and they had a 4- to 5-fold increased DNA content. Histologically, the prostate glands in the transgenic mice were distended from secretion, and the amount of interstitial tissue was increased. The levels oftestosterone and IGF-I were increased in the PRL transgenic animals. In mice overexpressing the bovine GH gene, displaying elevated IGF-I levels, the prostate gland was slightly larger compared with normal mice, indicating that the effect of PRL was not primarily mediated through elevated plasma IGF-I levels. The present study suggests that PRL is an important factor in the development of prostate hyperplasia acting directly on the prostate gland or via increased plasma levels of testosterone.