Significance of Serum Lactate Dehydrogenase and its Isoenzymes During Post-Burn Follow-Up

Significance of Serum Lactate Dehydrogenase and its Isoenzymes During Post-Burn Follow-Up The present study aims to evaluate the role of lactate dehydrogenase (LDH) isoenzymes in thermal burns. A total of 18 patients of both genders with 20 to 50% total burn surface area (TBSA), admitted to the Burn Ward of JN Medical College and Hospital was assessed. These patients were subjected to general and systemic examinations. The sera collected at day 1, 2, 5 and 10 during follow-up of burn patients were used for LDH quantitation. PAGE profiles showed significant differences in the levels of LDH isoenzymes in all the burn subjects (P=0.05). Software analysis of gel-scans showed the presence of five isoenzyme bands of which LDH-1 and -2 are the least contributors. During follow-up, it was observed that the ranking of LDH isoenzymes approaches control values at day 2 in 20% TBSA patients, while in the remaining cases it occurs at day 5. 3D-densitograms indicated high activity of LDH in 50% of TBSA patients even at day 10; however, the relative ranking of these isoenzymes was similar to control values (LDH-4>- 5>-3>-1>-2). We were of the opinion that the high activity of LDH enzyme is due to the enzyme-immunoglobulin-G (LDH-IgG) complex, but surprisingly we did not observe this complex in 50% of burn patients at any of the durations. Therefore, it is suggested that LDH isoenzymes play a role in the pathophysiology of the disease and can be an asset to ascertain the invisible tissue damage. Moreover, the high activity of LDH in 50% of burns is due to some unknown mechanism and not due to the binding of LDH with IgG. Značaj Laktat Dehidrogenaze u Serumu i Njenih Izoenzima u Praćenju Opekotina Cilj studije je da se odredi uloga izoenzima laktat dehidrogenaze (LDH) u termičkim opekotinama. Analizirano je ukupno 18 pacijenata oba pola sa ukupnom površinom opekotina 20 - 50% koji su primljeni na Odeljenje za opekotine Medicinskog koledža i bolnice Džavaharlal Nehru. Pacijenti su podvrgnuti opštim i sistemskim ispitivanjima. Za kvantifikaciju LDH korišćeni su serumi uzeti posle 1, 2, 5 i 10 dana praćenja stanja paci jenata sa opekotinama. Profili PAGE pokazali su značajne razlike u nivoima izoenzima LDH kod svih pacijenata sa opekotinama (P=0,05). Softverskom analizom gel-skenova otkriveno je prisustvo pet nizova izoenzima, od kojih su LDH-1 i -2 dali najmanji doprinos. Tokom praćenja stanja uočeno je da se rangiranje izoenzima LDH približava kontrolnim vrednostima 2. dana kod pacijenata sa ukupnom površinom opekotina od 20%, dok se u preostalim slučajevima isto događa 5. dana. Trodimenzionalni densitogrami MERAč GUSTINE pokazali su visoku aktivnost LDH kod 50% pacijenata sa opekotinama čak i 10. dana, međutim, relativno rangiranje tih izoenzima bilo je slično kontrolnim vrednostima (LDH-4>-5>-3>-1>-2). Mišljenja smo da se visoka aktivnost enzima LDH javlja usled kompleksa enzim-imunoglobulin-G (LDH-IgG), ali začudo nismo uočili taj kompleks kod 50% pacijenata sa opekotinama u bilo kom trenutku. Stoga, verujemo da izoenzimi LDH učestvuju u patofiziologiji bolesti i mogu biti korisni za utvrđivanje nevidljivih oštećenja tkiva. štaviše, visoka aktivnost LDH kod 50% pacijenata sa opekotinama javlja se usled nekog drugog mehanizma a ne usled vezivanja LDH za IgG.