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Multimodal sentinel lymph node imaging using nanoscale-tailored particles; The importance of particle size

Kjellman, Pontus LU (2015)
Abstract (Swedish)
Popular Abstract in Swedish

Beräkningar från Cancerfonden visar på att ungefär var tredje person i Sverige kommer att få en cancerdiagnos under sin livstid. Cancerceller är celler som har utvecklat speciella förmågor som gör att de har börjat dela sig ohämmat. Denna ohämmade celldelning leder till bildandet av en tumör och när tumören har nått ett visst stadie i sin utveckling så börjar den sprida sig. För många typer av cancer så sker denna spridning framförallt genom lymfsystemet.

Lymfsystemet är uppbyggt av ett nätverk av kärl som löper genom hela kroppen. Dess funktion är att dränera överskottsvätska från de olika vävnaderna i kroppen och återföra denna till blodomloppet. På vägen genom lymfsystemet kommer... (More)
Popular Abstract in Swedish

Beräkningar från Cancerfonden visar på att ungefär var tredje person i Sverige kommer att få en cancerdiagnos under sin livstid. Cancerceller är celler som har utvecklat speciella förmågor som gör att de har börjat dela sig ohämmat. Denna ohämmade celldelning leder till bildandet av en tumör och när tumören har nått ett visst stadie i sin utveckling så börjar den sprida sig. För många typer av cancer så sker denna spridning framförallt genom lymfsystemet.

Lymfsystemet är uppbyggt av ett nätverk av kärl som löper genom hela kroppen. Dess funktion är att dränera överskottsvätska från de olika vävnaderna i kroppen och återföra denna till blodomloppet. På vägen genom lymfsystemet kommer lymfan att föra med sig celler och partiklar (både främmande och kroppsegna) till lymfnoder där mängder av immunceller väntar på signaler som aktiverar deras försvarsuppgift i kroppen. När tumörceller, så kallade metastaserande celler, lossar från modertumören är det lymfnoderna där de först kommer att fastna.

Två av de vanligaste cancerformerna i Sverige är bröstcancer och hudcancer. Båda dessa former sprider sig genom lymfsystemet. Eftersom lymfa från ett visst område alltid kommer att dränera till samma lymfnod är det i denna nod som man först kan förvänta sig att påträffa metastaser. Sentinel lymph node- eller portvaktskörteldiagnos är en metod som används för att leta upp den dränerande lymfnoden och analysera denna för förekomst av tumörceller. Som metoden ser ut idag används en radioaktiv nanopartikel och en blå färg som injiceras runt modertumören för att hitta rätt lymfnod. Denna metod behöver dock förbättras eftersom varken den radioaktiva partikeln eller den blå färgen stannar när de når den första lymfnoden. Den blå färgen kan även ge allvarliga allergiska reaktioner i vissa patienter.

Studierna i denna avhandling är menade att undersöka om det går att utveckla en ny sorts spårmolekyl, baserad på nanopartiklar, för att på ett effektivare sätt kunna identifiera den första lymfnoden. Tanken med dessa nanopartiklar är även att de ska kunna detekteras i flera olika medicinska bildgivningssystem, en så kallad multimodal nanopartikel. Försök har utförts på friska råttor och möss med implanterade tumörer och mycket vikt har lagts på att hitta en optimal storlek på partiklarna som får dem att stanna när de når den första lymfnoden.

Resultaten från studierna visar att även väldigt små skillnader i partikelstorlek har inflytande på hur mycket av en injicerad dos nanopartiklar som hamnar i lymfnoderna. Det visade sig till exempel att 15 nm partiklar tas upp både snabbare och i större utsträckning än 27 nm eller 58 nm partiklar i friska råttor. Efter injektion i möss med implanterade tumörer tog framförallt 29 nm nanopartiklar upp medan 58 nm partiklar knappt kunde detekteras i lymfnoderna. Men i djur där tumörerna hade fått växa sig större togs båda storlekarna av nanopartiklar upp i lymfnoderna i lika stor utsträckning. Denna skillnad relaterades till att denna snabbt växande tumörtyp belastar lymfsystemet så hårt att dynamiken för partikelupptag påverkas.

Genom att modifiera ytan på nanopartiklarna kunde deras potential som multimodalt spårämne för sentinel lymph node diagnostik påvisas. Dock behövs det ytterligare studier för att undersöka hur upptaget av nanopartiklarna i sjuka djur fungerar och vilken storlek av partiklar som är den optimala för diagnostik. Kanske är det så att en blandning av olika noga utvalda storlekar är den bästa lösningen. (Less)
Abstract
As a cancer grows it will, at a certain stage of disease progression, start spreading in the body. For several types of cancer this spreading will first occur through the lymphatic system and the first place where metastatic cell will be encountered is the first lymph node that drains the area where the tumor is located. This lymph node is defined as the sentinel lymph node (SLN). By analyzing the SLN for the presence of tumor cells the metastatic status of the primary tumor can be determined. Today the process of sentinel lymph node biopsy is lengthy and requires numerous steps to be taken in succession. A major reason for this is the contrast agents that are used for the procedure. Exchanging these contrast agents for a more suitable... (More)
As a cancer grows it will, at a certain stage of disease progression, start spreading in the body. For several types of cancer this spreading will first occur through the lymphatic system and the first place where metastatic cell will be encountered is the first lymph node that drains the area where the tumor is located. This lymph node is defined as the sentinel lymph node (SLN). By analyzing the SLN for the presence of tumor cells the metastatic status of the primary tumor can be determined. Today the process of sentinel lymph node biopsy is lengthy and requires numerous steps to be taken in succession. A major reason for this is the contrast agents that are used for the procedure. Exchanging these contrast agents for a more suitable compound could streamline the procedure allowing for a higher throughput of patients as well as eliminating the negative effects associated with the current contrast agents.

In this thesis the possibility of developing a novel multimodal contrast agent for sentinel lymph node biopsies, based on ultra-small superparamagnetic iron oxide nanoparticles (USPIOs), is explored. The USPIOs used here are non-toxic in the applicable amounts and are coated with a polyethylene glycol based substance. The coating material gives the particles the ability for conjugation of functional surface groups through rather simple chemistry. The configuration of the coating also acts as a natural chelate, allowing for the attachment of metallic ion based radioisotopes.

Emphasis has been put on investigating the multimodal traits of differently sized USPIOs as well as their retention in SLN of healthy animals and a disease model.

In healthy rats it was concluded that 15 nm USPIOs accumulate faster and at a higher amount in the popliteal lymph node, than 27 or 58 nm USPIOs, after subcutaneous injection in the hind paw. It was also documented that the USPIOs were readily detectable with magnetic resonance imaging (MRI) and with fluorescence microscopy. The multimodal nature of the nanoparticles was further evaluated by detecting injected 31 nm and 67 nm USPIOs in healthy rats with magnetomotive ultrasound. The results showed that the smaller of the two sizes of particles were present in the SLN at higher amount than the larger USPIOs. It also demonstrated that the magnetomotive ultrasound technique has potential as an intraoperative tool for locating nanoparticle-laden lymph nodes.

The lymphatic retention of two different sizes of USPIOs, 29 nm and 58 nm, were tested in a subcutaneous EL-4 tumor model in mice. The particles were injected peritumorally and the results were detected with MRI in vivo and fluorescence imaging ex vivo. As the rapidly growing EL-4 tumors increased in size the dynamics of lymphatic uptake of USPIOs was altered. In animals injected with 58 nm nanoparticles on day-5 of tumor growth, only 1 of 5 had detectable amount of particles in the SLN when imaged with MRI the next day. The corresponding findings for the 29 nm USPIOs were 4 of 5 SLN with detectable amounts of nanoparticles. When the particles were injected in animals with 6 days old tumors USPIOs could be detected in all SLN the following day, regardless of particle size.

The distribution of the two different sizes of USPIOs was further evaluated by labeling the particles with radionuclides. The two particle sizes were labeled with either Indium-111 (26 nm) or Lutetium-177 (64 nm). The labeled USPIOs were mixed and injected peritumorally in EL-4 tumor bearing mice. The results were analyzed with SPECT/CT and autoradiography and demonstrated the possibility to detect and separate the two sizes of nanoparticles in vivo with SPECT and ex vivo with autoradiography.

In summary, the results presented in this thesis show that the nanoparticles produced have the potential for truly multimodal imaging. A size dependency for lymphatic uptake of USPIOs could be demonstrated, both in healthy and diseased animals. A size dependent lymphatic uptake of USPIOs could also be related to size of the tumors. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Garbrielsson, Susanne, Karolinska institutet
organization
publishing date
type
Thesis
publication status
published
subject
keywords
multimodal contrast agent, USPIO, sentinel lymph node, in vivo, EL-4 tumor
pages
102 pages
publisher
Department of Medical Radiation Physics, Clinical Sciences, Lund, Lund University
defense location
Föreläsningssalen, Nya strålbehandlingshuset, Klinikgatan 5, Lund
defense date
2015-10-26 09:00
ISBN
978-91-7623-496-9 (print)
978-91-7623-497-6 (pdf)
language
English
LU publication?
yes
id
b95d095e-be02-497d-bd1b-0e8c1ac6dfd8 (old id 8033369)
date added to LUP
2015-09-30 16:06:57
date last changed
2016-09-19 08:45:09
@misc{b95d095e-be02-497d-bd1b-0e8c1ac6dfd8,
  abstract     = {As a cancer grows it will, at a certain stage of disease progression, start spreading in the body. For several types of cancer this spreading will first occur through the lymphatic system and the first place where metastatic cell will be encountered is the first lymph node that drains the area where the tumor is located. This lymph node is defined as the sentinel lymph node (SLN). By analyzing the SLN for the presence of tumor cells the metastatic status of the primary tumor can be determined. Today the process of sentinel lymph node biopsy is lengthy and requires numerous steps to be taken in succession. A major reason for this is the contrast agents that are used for the procedure. Exchanging these contrast agents for a more suitable compound could streamline the procedure allowing for a higher throughput of patients as well as eliminating the negative effects associated with the current contrast agents.<br/><br>
In this thesis the possibility of developing a novel multimodal contrast agent for sentinel lymph node biopsies, based on ultra-small superparamagnetic iron oxide nanoparticles (USPIOs), is explored. The USPIOs used here are non-toxic in the applicable amounts and are coated with a polyethylene glycol based substance. The coating material gives the particles the ability for conjugation of functional surface groups through rather simple chemistry. The configuration of the coating also acts as a natural chelate, allowing for the attachment of metallic ion based radioisotopes.<br/><br>
Emphasis has been put on investigating the multimodal traits of differently sized USPIOs as well as their retention in SLN of healthy animals and a disease model.<br/><br>
In healthy rats it was concluded that 15 nm USPIOs accumulate faster and at a higher amount in the popliteal lymph node, than 27 or 58 nm USPIOs, after subcutaneous injection in the hind paw. It was also documented that the USPIOs were readily detectable with magnetic resonance imaging (MRI) and with fluorescence microscopy. The multimodal nature of the nanoparticles was further evaluated by detecting injected 31 nm and 67 nm USPIOs in healthy rats with magnetomotive ultrasound. The results showed that the smaller of the two sizes of particles were present in the SLN at higher amount than the larger USPIOs. It also demonstrated that the magnetomotive ultrasound technique has potential as an intraoperative tool for locating nanoparticle-laden lymph nodes.<br/><br>
The lymphatic retention of two different sizes of USPIOs, 29 nm and 58 nm, were tested in a subcutaneous EL-4 tumor model in mice. The particles were injected peritumorally and the results were detected with MRI in vivo and fluorescence imaging ex vivo. As the rapidly growing EL-4 tumors increased in size the dynamics of lymphatic uptake of USPIOs was altered. In animals injected with 58 nm nanoparticles on day-5 of tumor growth, only 1 of 5 had detectable amount of particles in the SLN when imaged with MRI the next day. The corresponding findings for the 29 nm USPIOs were 4 of 5 SLN with detectable amounts of nanoparticles. When the particles were injected in animals with 6 days old tumors USPIOs could be detected in all SLN the following day, regardless of particle size.<br/><br>
The distribution of the two different sizes of USPIOs was further evaluated by labeling the particles with radionuclides. The two particle sizes were labeled with either Indium-111 (26 nm) or Lutetium-177 (64 nm). The labeled USPIOs were mixed and injected peritumorally in EL-4 tumor bearing mice. The results were analyzed with SPECT/CT and autoradiography and demonstrated the possibility to detect and separate the two sizes of nanoparticles in vivo with SPECT and ex vivo with autoradiography.<br/><br>
In summary, the results presented in this thesis show that the nanoparticles produced have the potential for truly multimodal imaging. A size dependency for lymphatic uptake of USPIOs could be demonstrated, both in healthy and diseased animals. A size dependent lymphatic uptake of USPIOs could also be related to size of the tumors.},
  author       = {Kjellman, Pontus},
  isbn         = {978-91-7623-496-9 (print)},
  keyword      = {multimodal contrast agent,USPIO,sentinel lymph node,in vivo,EL-4 tumor},
  language     = {eng},
  pages        = {102},
  publisher    = {ARRAY(0x8d24f00)},
  title        = {Multimodal sentinel lymph node imaging using nanoscale-tailored particles; The importance of particle size},
  year         = {2015},
}