PATHOLOGICALLY-CONFIRMED ISOLATED HYPOTHALAMO-PITUITARY SARCOIDOSIS REFRACTORY TO PULSE-DOSE GLUCOCORTICOIDS AND SUCCESSFULLY TREATED WITH METHOTREXATE

Isolated sarcoidosis of the hypothalamic-pituitary system is a very rare form of neurosarcoidosis. A high index of suspicion is required for diagnosis and the choice of therapy embodies another challenge due to lack of standardized protocols. Glucocorticoids are the mainstay of initial treatment, whereas the second and third-line therapy include immunomodulators and cytotoxic drugs, in addition to monoclonal antibodies. This report presents an unusual case of panhypopituitarism in a 32-year-old previously healthy male patient due to isolated hypothalamo-pituitary sarcoidosis confirmed histologically, refractory to pulse-dose glucocorticoids and then successfully treated by methotrexate. Based on our report, in patients requiring additional therapy usage of the methotrexate as the second line agent should be considered, however the time frame and the dosing schedule of methotrexate are still unknown and deserve further investigation.

Satiety signalling histaminergic system and brain-gut peptides in regulation of food intake in rats with portocaval anastomosis

Brain histamine plays a regulatory role in feeding behaviour, acting as an inhibitory modulator. Portocaval anastomosis (PCA) is associated with cerebral aminergic systems alterations, including high histamine accumulation and release from neurons. Despite that, the rats with PCA eat significantly more, their body mass being lower than sham-operated animals. To disclose underlying regulatory mechanisms, food intake was measured before and after treatment with antagonists of histamine H(1) and H(2), orexin type 1 (OX(1)) and cannabinoid type 1 (CB(1)) receptors in adult male Lewis rats 6 months following the end-to-side PCA or sham operation. Hypothalamic concentrations of orexin A and histamine as well as serum concentrations of leptin, insulin and cholecystokinin (CCK) were analysed. PCA rats with body mass lower by 30%, have consumed more feed and water 150% and 200%, respectively. The modifying effects of pyrilamine, ranitidine, SB 334867 and rimonabant were less pronounced in PCA compared with sham-operated rats. Hypothalamic orexin A and histamine concentrations were higher in PCA rats than in the control group with intact portocaval system. In PCA rats, serum concentrations of CCK were higher, leptin concentrations lower, while there were no differences between the groups in insulin levels. In conclusion, the adaptive mechanisms efficiently render PCA rats less sensitive to peripheral and central anorexigenic signals. Orexin A appears to be involved in the counteracting mechanisms preventing further body mass loss in PCA rats.

DNA released from rejecting organs is an indicator of the degree of graft cellular damage

Warm and cold ischemia as well as rejection of the transplanted organ or tissue cause destructive changes in the graft parenchyma. Fragments of disintegrated cellular organelles are phagocytized and digested by recipient scavenger cells in lymph nodes, spleen, and liver. Some fragments engulfed by dendritic cells are processed including donor DNA present in the ingested cellular debris. The question arises as to whether the DNA from the disintegrated cells may be used as a measure of graft damage. In this study we provide evidence that both syngeneic and allogeneic organ transplantation followed by "seeding" of donor DNA from graft cells is internalized in recipient macrophages and dendritic cells in lymphoid organs. The kinetics of accumulation of donor DNA in recipient tissues reflected the degree of ischemic and immune graft damage. Immunosuppression with cyclosporine or tacrolimus did not significantly attenuate the DNA release. Measurements of the concentration of donor DNA gives insight into the kinetics of allograft rejection. Real-time polymerase chain reaction for donor DNA in recipient serum and blood leukocytes that have engulfed donor cell debris may be useful for clinical diagnostic application.

Recipient immature dendritic cells do not prolong allograft survival

Experimental studies on allogeneic transplantation have shown that recipient dendritic cells (DC) play a role in peripheral tolerance as well as in rejection of allografts. It is not known whether DCs exert their tolerogenic function in the graft or in recipient lymphoid tissue. To answer this question we created a chimeric heart model deprived of its own DCs and repopulated with recipient DCs. The rationale for this model was to observe whether recipient mature and immature DCs located in the graft attenuate recruitment and stimulation of recipient lymphocytes, subsequently prolonging graft survival. Vascularized bone marrow transplants from the prospective recipient to the lethally irradiated heart donor, which function for a period of 14 days, were used to replace donor DCs with prospective recipient either mature or immature DCs. Replacement of the donor heart with either of these cells did not prolong graft survival. The intragraft microchimerism did not mitigate the allogeneic rejection reaction.

Activation of splenic dendritic cells by bacterial and allogeneic antigens

Allograft ischemia and cellular degradation accompanying rejection favor graft colonization by translocated microorganisms. Bacterial colonization adds to the graft destruction. The dendritic cells (DC) of allograft recipients engage in allogeneic and antibacterial reactions; they process and present to lymphocytes 2 types of antigens. This may lead to overstimulation of DCs that may nonspecifically intensify the rejection process. We investigated the effects of allogeneic and bacterial antigens on splenic DCs phenotypes. In vitro stimulation of a spleen DC-enriched population by E. coli, LPS, and CpG DNA brought about an increase in expression of OX6(+) (MHC class II) from 47.4% in the control cells to 65% in the E. coli-stimulated group (P < .05) and 85% in the LPS and CpGDNA groups (P < .05). Interestingly, a significant drop in the frequency of OX62(+) DC was observed after incubation with LPS. Allogeneic heart transplants brought about an increase of OX6(+) in DCs to 100% and a decrease of ED1(+) monocyte frequency. Simultaneously, an increase in expression of W3/13(+) T cells in DC-enriched splenic cells was observed. There was no significant change in the frequency of OX62(+) expression. Both types of antigens evoked splenic DC response; however, there were differences in the frequency of phenotype expression. Allogeneic but not bacterial antigens increased W3/13 antigen expression; the frequency of OX62(+) in cells decreased after LPS but not after bacterial stimulation.

Transplantation of organs is transplantations of donor DNA: fate of DNA disseminated in recipient

Microchimerism after allogeneic organ transplantation has been widely documented using DNA identification techniques. However, the question as to whether the detected donor DNA is present in the surviving donor passenger cells, recipient macrophages phagocytizing rejected donor cells, or dendritic cells (DC) internalizing donor apoptotic bodies or cell fragments has not been answered. We provide evidence that allogeneic organ transplantation is followed not only by cellular microchimerism caused by release of graft passenger cells but also dissemination of donor DNA from the ischemic rejecting graft cells and its internalization in recipient DC. The high levels of donor DNA at the time of heart rejection were inversely proportional to the concentration of donor passenger cells detected with use of flow cytometry. Depending on the type of graft, the kinetics of DNA distribution in recipient tissues were different. Immunosuppressive drugs attenuated the rejection reaction and release of DNA from grafts. Allogeneic but not syngeneic donor DNA fragments were found in recipient splenic DC-enriched population. Interestingly, that donor DNA fragments could be detected in recipient tissue at high levels on day 30. This challenges the notion that fragments of DNA are immediately cleaved by cell plasmatic enzymes. The biologic significance of our findings is not clear. We speculate that donor DNA fragments in recipient DC may play a, so far unknown, role in the immunization/tolerance process to allogeneic antigens.

Repopulation of donor heart by recipient bone marrow–derived dendritic cells prior to transplantation causes acute rejection by both the allogeneic and syngeneic recipient

Experimental studies on allogeneic transplantation have shown that recipient dendritic cells (DC) play a role in peripheral tolerance as well as in rejection of allografts. It is not known whether DC exert their tolerogenic function in recipient lymphoid tissue, and whether they process shed alloantigen in the graft itself. To answer this question we created a chimeric heart model deprived of its own DC and repopulated by recipient DC. The rationale for this model was to observe whether recipient DC located in the graft attenuate recruitment and stimulation of recipient lymphocytes, subsequently prolonging graft survival. Vascularized bone marrow transplants (VBMTx) from the prospective recipient to the lethally irradiated heart donor, which function for a period of 14 days, were used to replace donor DC with prospective recipient DC. Hearts from chimeric LEW rats (with BN DC) were transplanted to untreated BN rats. Also, hearts from chimeric LEW rats (with BN DC) were returned to untreated LEW rats. Replacement of the donor heart with recipient DC did not prolong graft survival. Rather, it initiated a rejection reaction that was already present in the donor. Recipient DC retained their immunogenic properties also when the graft was returned back to a donor strain animal.

DNA from rejecting donor organs can be detected in recipient lymphoid and non-lymphoid tissues

Rejecting tissue and organ grafts shed cellular debris from damaged cells. Cellular debris contains fragments of nuclei with their genetic material. The question arises what is the fate of donor DNA in recipient fluids and tissues. Is it enzymatically disintegrated and becomes a waste product or it is utilized by recipient cells. We have shown, using sex-mismatched transplants and the Sry-gene fragment PCR detection method, that at the time of rejection recipient tissue contain donor DNA. The concentration of donor DNA did not parallel the concentration of live donor passenger cells. There were differences in donor DNA concentration depending on whether heart, skin or BMC were transplanted. Moreover, there was more donor DNA in recipient tissues than in control syngeneic transplants. Interestingly, a relatively high donor DNA concentration was detected in syngeneic recipients reflecting the extent of non-immune pre-transplantation ischemic damage of the graft.

Similar response of dendritic cells to bacterial and allogeneic antigens

The dendritic cells (DC) of an allograft recipients become engaged not only in an allogeneic but also antibacterial reaction. They react to the alloantigens and microorganisms which colonize the rejecting grafts. This leads to overstimulation of DCs what may non-specifically intensity the rejection process. We investigated the effects of allogeneic and bacterial antigens on splenic DCs phenotypes. In vitro stimulation of spleen DC-enriched population by E. coli, LPS and CpG DNA brought about an increase in expression of OX6 (MHC class II) from 47.4% in the control population to 65% in the E. coli stimulated group (p < 0.05) and to 85% in the LPS and CpGDNA groups (p < 0.05). Interestingly, a significant drop in the frequency of OX62+ antigen was observed after incubation with LPS. Allogeneic heart transplants brought about an increase of OX6+ (MHC class II) DCs to 100% and a decrease of EDI+ cells. Simultaneously, an increase in expression of W3/13 on DC-enriched splenic cells was observed. There was no significant change in the frequency of OX62+ expression in conclusion, both bacterial and alloantigens strongly activate splenic DCs what may add to the intensity of the rejection process.

Protection of heart and rejection of lymphocyte allografts from the same donor in recipients of donor-specific transfusions

Organ allografts survive in hosts treated with immunosuppressive drugs. The question arises as to whether cells isolated from organ or tissue of an allogeneic donor and transplanted to a genetically disparate recipient can also benefit from the immunosuppressive regimen. We reported previously that the DST (donor specific transfusion) recipients accept heart allografts but reject hyperacutely i.v. infused lymphocytes from the same as DST donor. The present study was devoted to elucidation of the mechanism of these divergent processes. Syngeneic BN hearts and mesenteric lymph node lymphocytes were transplanted to LEW rats pretreated one week previously with donor specific blood transfusions. The allogeneic BN lymphocytes transplanted i.v. to LEW rats receiving one BN DST were rejected hyperacutely within 6 hrs, whereas BN heart grafts transplanted to the BN DST-treated LEW recipients survived 14 +/- 2 days. Adoptive transfer of LEW anti-BN DST sera to naive LEW rats caused destruction of the transplanted BN lymphocytes. The LEW BN DST recipients possessed IgG and IgM class alloantibodies binding to BN lymphocytes and heart endothelial cells. mAbs against MHC class I (OX18) and class II (OX6) antigens neither blocked binding of antibodies of DST-recipient sera to BN lymphocytes nor protected the preincubated BN lymphocytes against destruction after transplantation. Western blot analysis revealed that alloantibodies from DST-recipient sera bound strongly to BN lymphocyte membrane proteins of 60 kd m.w. but not to 45 kd and 30 kd MHC class I and II proteins. Taken together, DST has no protective effect on intravenously transplanted cells. In contrast, it accelerates the rejection. Alloantibodies present in DST-recipient sera "shield" antigens on the surface of organ allograft endothelial cells, thereby protecting them from recognition and cytotoxic effect. Simultaneously, these alloantibodies "opsonize" the intravenously transplanted lymphocytes and facilitate their halting in lymphoid organs and subsequent lysis. Antibodies other than those directed against MHC seem to mediate both these processes. The results of these studies provide also evidence that the effector mechanism of rejection may be different depending on location of the graft, in the lymphoid as in case of transplanted lymphocytes or in non-lymphoid tissues as heart grafts.

Cyclosporin A decreases lymphocyte migration to the heart allograft through suppression of their L-selectin expression

Cyclosporin A (CsA) changes the distribution of the circulating pool of lymphocytes and decreases their traffic to organ allograft. The mechanism of this process is complex and includes, among others, inhibition of induction of nuclear factor of activated T cells and suppression of GM CSF and E-selectin expression. We studied the expression adhesion molecules CD11a, CD18, CD44, CD54 and CD62L on the thoracic duct lymphocytes of rats treated with CsA. The 7-day administration of CsA evidently decreased the expression of CD62L but did not affect the other adhesion molecules. Lower concentration of CD62L molecules on the surface of circulating lymphocytes may influence their migration to allograft and distribution in host lymphoid tissues.

[Evaluation of binocular vision in persons employed at high work posts]

The study covered 250 workers, aged 20-63 years, employed at workposts over 3 meters high. We analysed visual acuity, refraction, anterior segment, eye ground, visual field, colour vision and binocular vision. The study revealed that 20% of persons examined lack the stereoscopic vision ability. In conclusion it is suggested to use combined methods in order to evaluate binocular vision and certify ability to work at high workposts.

[Optic symptoms in Arnold-Chiari syndrome]

An unusual case of 47-years-old female with progressive deterioration of visual acuity, which occurred during the Arnold-Chiari syndrome, is presented. Normally, most clinical manifestations are related to cerebellum lesion and cranial nerves paresis. The described case resulted in optic nerve atrophy.

Liver sinusoidal passenger lymphocytes reveal suppressive properties and prolong allograft survival

Liver sinusoidal washout cells are low responders to mitogens, and suppressive in autologous PBM, and portal blood mononuclear cells, PHA supplemented, and autologous mixed lymphocyte cultures. They are less immunogenic after IV administration into allogeneic recipients than PBM, which could be measured in an in vivo allogeneic lymphocyte elimination test. The level of immunization is strain dependent. In the BN to LEW combination, they are more immunogenic than in the LEW to DA pairs. This parallels heart allograft survival times, which were longer in LEW to DA than BN to LEW combinations.

Liver sinusoidal washout cells transferred to allogeneic recipients reveal tolerogenic properties

Liver sinusoidal washout cells, containing a large fraction of LGL cytotoxic to tumor cell lines in vitro, are less responsive to mitogens and suppress the responsiveness of autologous and third-party PBM to mitogens and autologous mixed lymphocyte culture, compared with autologous portal vein or PBM. They are less immunogenic after IV administration into allogeneic recipients, which can be observed in an in vivo allogeneic lymphocyte cytotoxicity test. Immunization of allogeneic recipients with liver sinusoidal washout cells slightly prolongs heart allograft survival time.

Tunnel capillaries in hypertrophied myocardium of rats with aorto-caval fistula

Male inbred rats (Wag) with aorto-caval fistula were used as a model of volume-overloaded heart hypertrophy. Hearts were taken after 1, 2, and 6 months postoperatively for immunohistochemical, histological and ultrastructural investigations. Immunohistochemical staining with some anti-extracellular matrix antibodies and ultrastructural findings allowed us to recognize intracardiocytic tunnels which were intracellular invaginations of plasmalemma surrounded by basement membrane. Inside the tunnels endothelial cells forming well-developed capillaries were entrapped. Tunnel capillary formation is discussed as an adaptive response to increased cardiac work due to volume overload.