Simple and reliable conditions for routine, long-term culturing of fetal human pancreatic tissue fragments

Hasnyálmirigy-sebészet

Közleményünk célja bemutatni az új sebészi technikát és módszereket, amelyeket 1986 óta alkalmazunk az inficiálódott necrotizáló pancreatitis, a krónikus pancratitis gyógyításakor, illetve a szigetsejt-transzplantáció alkalmával.

Az inficiálódott necrotizáló pancreatitis (INP) az akut pancreatitis legsúlyosabb formája, amely az esetek többségében felelős a pancreatitishez kapcsolódó morbiditásért és magas halálozásért. 1986 óta 224 beteget gyógyítottunk INP miatt. A sebészi terápia magában foglalta a kiterjesztett necrosectomiát, a többszörös drenázst, amely biztosította a folyamatos öblítést. A sebészi beavatkozást követően supportiv kezelést alkalmaztunk. A globális kórházi mortalitás 7,7% volt. Tapasztalataink szerint, az INP komplex terápiája, amely magában foglalja az adequat sebészi beavatkozást, a folyamatos, hosszan tartó, többszörös öblítést és a supportiv kezelést, biztosíthatja a sikeres gyógyítást.

A krónikus pancreatitisben szenvedő betegek egyharmadában az inflammatoricus folyamat a pancreasfej gyulladásos tumorát idézi elő, amely a vezetékrendszerek obstructioját, alkalmasint a duodenum kompresszióját idézi elő, fájdalmat és fogyást okozva. Minthogy egy benignus elváltozással állunk szemben, egy biztonságos szervmegtartó pancreasfej-resectiót (OPPHR) dolgoztunk ki, amely magában foglalja a pancreasfejben kialakult gyulladásos tumor széles resectióját, anélkül, hogy a pancreast a v. portae felett izolálnánk, illetve átvágnánk. Napjainkig 196 esetben végeztünk szervmegtartó pancreasfej-resectiót mortalitás nélkül. A műtét után a betegek életminősége 89%-ban javult. A 10 éves klinikai megfigyelés és a prospektiv randomizált összehasonlító vizsgálat egyértelműen alátámasztotta, hogy az OPPHR-műtét egy biztonságos és hatásos beavatkozás, amely hosszú távon javítja a betegek életminőségét.

A distalis pancreas resectio leggyakoribb szövődménye a pancreas fistula, amelynek kivédésére számos műtéti megoldást alkalmaznak, változó sikerrel. Az irodalmi adatok alapján a fistula kialakulása 6–30% -ra tehető distalis resectio után. Műtéti gyakorlatunkban 1994-ben alkalmaztuk először a pancreas resectios felszínének zárására a Premium PolysorbR (abszorbeálodó laktomer) kapocssort. Napjainkig e módszert 187 distalis resectiós műtétnél alkalmaztuk. A postoperativ időszakban két esetben jelentkezett pancreas fistula, amelyek konzervatív kezelésre szanálódtak. Így a postoperativ fistula incidenciája 0,9% volt.

A hasnyálmirigy-szigetsejt beültetésének egyik potenciális és egyben ígéretes forrása az embrionális hasnyálmirigy. Az embrionális pancreas endokrin szövet tartama csaknem 90%. Az izolált szigetek megfelelő feltételek mellett hosszabb ideig mesterséges körülmények között tenyészthetők, és ez alatt jelentős mértékű sejtosztódás, illetve differenciálódás jön létre. Előnynek tekinthető, hogy a tenyésztett szövetkultúra mélyfagyasztásos tárolása is megoldott, mely ún. szövetbank kialakítását teszi lehetővé. Az első embrionális szigetsejt klinikai transzplantációnk 1982-ben történt. Az ezt követő 25 esetben, köztük egy kombinált vese- és szigetsejt-beültetés, bár inzulinmentességet nem sikerül elérni, de az inzulinszükséglet szignifikáns csökkenése mellett, a cukoranyagcsere normalizálódott, és az 5–10 évig működő szigetsejtapparátus hatására a még nem visszafordíthatatlan másodlagos diabeteszes szövődmények (retinopathia, nephropathia, neuropathia) progressziója megállt, sőt az esetek egy részében javulást is eredményezett.

Fetal Islet Cell Transplants: Promises and Limits of the Experience in the Eastern Countries

The fetal pancreas is a potential source of islet ceils for transplantation. Despite marked advances in experimental islet grafting over the past two decades, successful clinical fetal transplantation seems to be very rare. The possible reasons for the failure of this transplantation are discussed. The review summarizes the development of a method for the isolation of fetal tissue, and the factor influencing the growth and differentiation of isolated fetal islets prior to and after transplantation. Finally, a brief overview is given of the status of clinical human pancreatic transplantation and a possible key to successful grafting.

In vitro reconstitution of pancreatic islets

The lack of transplantable pancreatic islets is a serious problem that affects the treatment of patients with type 1 diabetes mellitus. Beta cells can be induced from various sources of stem or progenitor cells, including induced pluripotent stem cells in the near future; however, the reconstitution of islets from β cells in culture dishes is challenging. The generation of highly functional islets may require three-dimensional spherical cultures that resemble intact islets. This review discusses recent advances in the reconstitution of islets. Several factors affect the reconstitution of pseudoislets with higher functions, such as architectural similarity, cell-to-cell contact, and the production method. The actual transplantation of naked or encapsulated pseudoislets and islet-like cell clusters from various stem cell sources is also discussed. Advancing our understanding of the methods used to reconstitute pseudoislets should expand the range of potential strategies available for developing de novo islets for therapeutic applications.

Gadolinium chloride-induced macrophage blockade prevents rejection of human insulinoma cell xenograft in rats

The effect of gadolinium chloride (GdCl3)-induced Kupffer cell blockade on the survival of discordant insulinoma cell xenografts was investigated. Insulinoma cells isolated by means of collagenase from human insulinoma and subsequently cultured were transplanted through the portal vein into the liver of streptozotocin-induced diabetic, male, CFY inbred rats. In the control, streptozotocin-treated rats, the decrease in blood glucose level was only transitory, in contrast with the GdCl3-pretreated diabetic rats, which remained normoglycemic during the 2-week observation period. Histologically, in the liver and lung of rats pretreated with GdCl3, large areas of extensively proliferating insulinoma cells were seen, whereas no insulinoma cells were seen in either the liver or the lung of diabetic control rats, not treated with GdCl3. These studies suggest that the Kupffer cells play significant roles in the recognition of xenoantigens and the induction of xenograft rejection.

Successful simultaneous transplantation of kidney and fetal pancreatic islet masses

This paper reports our experience with the successful simultaneous transplantation of kidney and fetal pancreatic islets in 46-year-old diabetic man. No detectable C-peptide level was noted and the end-stage nephropathy required hemodialysis. The cadaver kidney and two masses of 8-week-cultured fetal islets were grafted simultaneously. After revascularization of the kidney, the islet masses were placed under the kidney capsule. Following transplantation, islet function was demonstrated by a higher C-peptide level, which subsequently persisted. Twenty-four months after grafting, islet function was provoked by glucagon and glucose, which led to elevations in the C-peptide and insulin levels. The insulin requirement fell from 58 to 24 U/day during the post-transplant period of 24 months. The mean value of HbA1C (5.6% +/- 0.3%) indicated a constantly normal carbohydrate metabolism. Improvements in retinopathy were also noted. Three periods of kidney rejection were diagnosed, but these proved reversible with high-dose steroid treatment. The serum and urine beta-2-microglobulin levels correlated well with rejection and recovery. More than 2 years after grafting, kidney functions is in the normal range. On sonography, the transplanted islet masses were repeatedly clearly visible, and 24 months following transplantation the volume was twice the original one. The results indicate that simultaneous kidney and fetal pancreatic islet grafting is advantageous in end-stage nephropathy secondary to type I diabetes mellitus.

Regulation of major histocompatibility complex (MHC) products in fresh and cultured human fetal pancreata aged 9-16 gestational weeks by gamma-interferon

Immunological data on the human fetal pancreas (HFP) are mainly confined to its constitutive expression of the MHC antigens. However, cytokines, such as gamma-interferon (g-IFN), released by lymphocytes during immune reactions, can induce or upregulate the expression of MHC products in allografts and alter their immunological behaviour. We investigated the effects of g-IFN on fresh and cultured HFPs aged 9-16 gestational weeks (gw). Following g-IFN stimulation of fresh HFPs, there was class I hyperexpression by the ductal cells, and some of the ductal, endothelial and islet cells also became class II+. Conventional tissue culture (5% CO2 in air at 37 degrees C) reduced the number of interstitial class II+ cells within the HFP after 1 week but was associated with de novo class I expression by some of the ductal cells. Remarkably, the changes in major histocompatibility complex (MHC) antigen expression by the ductal cells occurred earlier and were markedly enhanced when the HFPs were cultured beforehand. The number of interstitial class II+ cells in fresh and cultured HFPs was not influenced by g-IFN. The significance of these observations with regard to clinical HFP transplantation is discussed.

Characteristics of bovine parathyroid cell organoids in culture

Adult bovine parathyroid glands were enzymatically dispersed and groups of 2 to 5 million cells were reassociated into multicellular aggregates (organoids) by rotation in roller tubes in serum-free medium. Fifty to seventy percent of the seeded cells were incorporated into each organoid at 3 d of culture, and in a typical experiment where DNA content was assayed before and after culture 49 +/- 3% of the original seeded DNA was present after 19 d of culture. No significant differences in DNA content were observed between experimental groups at any time of culture. The morphology of the cells in organoids was similar to that of cells in fresh tissue as determined by light and electron microscopy. The organoids secreted intact parathyroid hormone (PTH) and COOH-terminal hormone fragments which were similar to those released from monolayer cell cultures. Organoids maintained the ability to modulate PTH secretion in response to extracellular calcium for over 2 wk in culture. Each organoid was cultured separately and secreted PTH such that the mean standard deviation of secretion within groups on a per organoid basis was 16.3% of the mean. Using a perifusion system to study acute regulation over a 2-wk period of culture, PTH secretion was suppressed 58 +/- 4% by 2.5 mM compared to that at 0.25 mM calcium. To examine PTH secretion over a range of calcium concentrations, the perifusion system was used to apply 4-h linear gradients of decreasing calcium to fresh tissue slices and to organoids. The results indicated that the calcium (ionized) concentration at 50% secretory suppression (set-point) were 1.30 +/- 0.11 and 1.20 +/- 0.9 mM for the organoids and slices, respectively. Acute secretory control by calcium decreased after 14 d and was not detectable at 22 d of culture. The results demonstrated that the organoids maintained their differentiated function and tissuelike morphology for extended periods in vitro and therefore represent a suitable model system for studies on the long-term modulation of PTH secretion by vitamin D metabolites, ions, and other agents.