Study on the expression of testin in the testes of dogs.

Introduction: Testin is a protein involved in cell mobility, adhesion and colony formation. In rats, testin presence has been reported in the testes, and its possible role in spermatogenesis has been suggested. Studies in humans also suggest a possible role of testin as a cancer suppressor protein. In the dog, which represents both an important pet species and a good animal model for studying biological and pathological testicular processes, the presence of testin has never been reported. Material and Methods: In the present study, the expression of testin in foetal, prepubertal, adult and aged canine testes was investigated. Testes from 5 adult and 3 aged dogs, from 2 one-month-old puppies and from 2 foetuses miscarried at the end of pregnancy were immunohistochemically examined with a commercial antibody against testin. Results: Testin was intensely expressed in Sertoli cells in every testis examined. Spermatids were also positive for testin in mature dogs and in the testicular areas of the aged ones which were not atrophic. Weak expression of testin was also detected in all testes examined. Conclusion: The present study, the first demonstrating the presence of testin in canine testes, provides the basis for further dog-human comparative research and for studies on the role of this protein in canine physiology, reproduction and testicular pathologies.

Hemosiderin Accumulation in Liver Decreases Iron Availability in Tachycardia-Induced Porcine Congestive Heart Failure Model.

Despite advances in the management of iron deficiency in heart failure (HF), the mechanisms underlying the effects of treatment remain to be established. Iron distribution and metabolism in HF pathogenesis need to be clarified. We used a porcine tachycardia-induced cardiomyopathy model to find out how HF development influences hepatic and myocardial iron storing, focusing on ferritin, the main iron storage protein. We found that cumulative liver congestion (due to the decrease of heart function) overwhelms its capacity to recycle iron from erythrocytes. As a consequence, iron is trapped in the liver as poorly mobilized hemosiderin. What is more, the ferritin-bound Fe3+ (reflecting bioavailable iron stores), and assembled ferritin (reflecting ability to store iron) are decreased in HF progression in the liver. We demonstrate that while HF pigs show iron deficiency indices, erythropoiesis is enhanced. Renin-angiotensin-aldosterone system activation and hepatic hepcidin suppression might indicate stress erythropoiesisinduced in HF. Furthermore, assembled ferritin increases but ferritin-bound Fe3+ is reduced in myocardium, indicating that a failing heart increases the iron storage reserve but iron deficiency leads to a drop in myocardial iron stores. Together, HF in pigs leads to down-regulated iron bioavailability and reduced hepatic iron storage making iron unavailable for systemic/cardiac needs.

Catabolic/Anabolic Imbalance Is Accompanied by Changes of Left Ventricular Steroid Nuclear Receptor Expression in Tachycardia-Induced Systolic Heart Failure in Male Pigs.

BACKGROUND: Steroid hormones play an important role in heart failure (HF) pathogenesis, and clinical data have revealed disordered steroidogenesis in male patients with HF. However, there is still a lack of studies on steroid hormones and their receptors during HF progression. Therefore, a porcine model of tachycardia-induced cardiomyopathy corresponding to HF was used to assess steroid hormone concentrations in serum and their nuclear receptor levels in heart tissue during the consecutive stages of HF. METHODS AND RESULTS: Male pigs underwent right ventricular pacing and developed a clinical picture of mild, moderate, or severe HF. Serum concentrations of dehydroepiandrosterone, testosterone, dihydrotestosterone, estradiol, aldosterone, and cortisol were assessed by enzyme-linked immunosorbent assay. Androgen receptor, estrogen receptor alpha, mineralocorticoid receptor, and glucocorticoid receptor messenger RNA levels in the left ventricle were determined by qPCR.The androgen level decreased in moderate and severe HF animals, while the corticosteroid level increased. The estradiol concentration remained stable. The quantitative real-time polymerase chain reaction revealed the downregulation of androgen receptor in consecutive stages of HF and increased expression of mineralocorticoid receptor messenger RNA under these conditions. CONCLUSIONS: In the HF pig model, deteriorated catabolic/anabolic balance, manifested by upregulation of aldosterone and cortisol and downregulation of androgen signaling on the ligand level, was augmented by changes in steroid hormone receptor expression in the heart tissue.

Expression and complex formation of MMP9, MMP2, NGAL, and TIMP1 in porcine myocardium but not in skeletal muscles in male pigs with tachycardia-induced systolic heart failure.

Matrix metalloproteinases (MMPs) are involved in the remodeling of extracellular matrix in various tissues. Their functioning could be related to the formation of complexes, containing MMP9, MMP2, tissue inhibitor of metalloproteinases type 1 (TIMP1), and neutrophil gelatinase-associated lipocalin (NGAL). Such complexes have not been investigated in either myocardial or skeletal muscles. We examined 20 male pigs with heart failure (HF), and 5 sham-operated animals. There were no differences in the mRNA expression of MMP9, MMP2, TIMP1, and NGAL between diseased and healthy animals, in either left ventricle (LV) myocardium or skeletal muscles. In LV from both diseased and healthy animals, in nonreducing and nondenaturing conditions, we demonstrated the presence of high molecular weight (HMW) complexes (130, 170, and 220 kDa) containing MMP9, TIMP1, and NGAL (also MMP2 in 220 kDa complex) without proteolytic activity, and a proteolytically active 115 kDa MMP9 form together with 72 and 68 kDa bands (proMMP2 and MMP2). Proteolytically active bands were also spontaneously released from HMW complexes. In skeletal muscles from both diseased and healthy animals, in nonreducing and nondenaturing conditions, we found no HMW complexes, and proteolytic activity was associated with the presence of 72 and 68 kDa bands (proMMP2 and MMP2).